The effect of heat stress on performance, fertility, and adipokines involved in regulating systemic immune response during lipolysis of early lactating dairy cows

The aim of this study was to assess the potential effect of heat stress on dairy cow productivity, fertility, and biochemical blood indices during the early lactation stage in a temperate climate. Additionally, the study aimed to determine the role of leptin and adiponectin in regulating the immune response accompanying lipolysis after calving in dairy cows. The study included 100 clinically healthy Polish Holstein-Friesian dairy cows selected based on parity and 305 d of milk yield from 5 commercial farms with similar herd management and housing systems. Prospective cohort data were recorded from calving day until 150 d in milk, and microclimate loggers installed inside the barns were used to record temperature and relative humidity data to calculate daily temperature-humidity index (THI) on the calving day, through +7, +14, and +21 d during early lactation. Additionally, monthly productive performance parameters such as milk yield, chemical composition, fatty acids composition, and fertility indices were analyzed. Results showed that the THI from calving day through +7, +14, and +21 d during early lactation was negatively associated with fertility parameters such as delayed first estrus postpartum and an elongated calving interval, respectively, by 29, 27, 25, and 16 d. Furthermore, an increase in THI value during early lactation was associated with an elongated artificially inseminated service period, days open, and intercalving period. Increasing THI from calving day (0 d) through +7, +14, and up to +21 d during early lactation was also linked to decreased milk yield by 3.20, 4.10, 5.60, and 5.60 kg, respectively. The study also found that heat stress during early lactation was associated with a lower body condition score in dairy cows and higher concentrations of leptin, nonesterified fatty acids, and β-hydroxybutyrate, accompanied by a drastic reduction in adipose tissue-secreted adiponectin levels after calving. Additionally, heat stress-induced lipolysis in adipose tissue caused an inflammatory response that increased biochemical blood indices associated with immune responses such as cytokines, acute phase proteins, and heat shock protein. These findings suggest that exposing dairy cows to heat stress during early lactation can negatively affect their productive performance, fertility, and biochemical blood indices in subsequent lactations. Thus, farm management changes should be implemented during early lactation to mitigate the negative consequences of heat stress occurrence.

The Most Important Metabolic Diseases in Dairy Cattle during the Transition Period

This review paper provides an in-depth analysis of three critical metabolic diseases affecting dairy cattle such as subacute ruminal acidosis (SARA), ketosis, and hypocalcemia. SARA represents a disorder of ruminal fermentation that is characterized by extended periods of depressed ruminal pH below 5.5-5.6. In the long term, dairy herds experiencing SARA usually exhibit secondary signs of the disease, such as episodes of laminitis, weight loss and poor body condition despite adequate energy intake, and unexplained abscesses usually 3-6 months after an episode of SARA. Depressed milk-fat content is commonly used as a diagnostic tool for SARA. A normal milk-fat test in Holstein dairy cows is >4%, so a milk-fat test of <3% can indicate SARA. However, bulk tank testing of milk fat is inappropriate to diagnose SARA at the herd level, so when >4 cows out of 12 and <60 days in milk are suspected to have SARA it can be considered that the herd has a problem. The rapid or abrupt introduction of fresh cows to high-concentrate diets is the most common cause of SARA. Changes in ruminal bacterial populations when exposed to higher concentrate rations require at least about 3 weeks, and it is recommended that concentrate levels increase by no more than 400 g/day during this period to avoid SARA. Ketosis, a prevalent metabolic disorder in dairy cattle, is scrutinized with a focus on its etiological factors and the physiological changes leading to elevated ketone bodies. In total mix ration-fed herds, an increased risk of mastitis and reduced fertility are usually the first clinical signs of ketosis. All dairy cows in early lactation are at risk of ketosis, with most cases occurring in the first 2-4 weeks of lactation. Cows with a body condition score ≥3.75 on a 5-point scale at calving are at a greater risk of ketosis than those with lower body condition scores. The determination of serum or whole blood acetone, acetoacetate, beta-hydroxybutyrate (BHB) concentration, non-esterified fatty acids (NEFA), and liver biopsies is considered the best way to detect and monitor subclinical ketosis, while urine or milk cowside tests can also be used in on-farm monitoring programs. Concentrations >1.0 mmol/L or 1.4 mmol/L blood or serum BHB are considered diagnostic of subclinical ketosis. The standard threshold used for blood is 1.2 mmol/L, which corresponds to thresholds of 100 mcmol/L for milk and 15 mg/dL for urine. Oral administration of propylene glycol (250-400 g, every 24 h for 3-5 days) is the standard and most efficacious treatment, as well as additional therapy with bolus glucose treatment. Hypocalcemia is a disease of adult dairy cows in which acute hypocalcemia causes acute to peracute, afebrile, flaccid paralysis that occurs most commonly at or soon after parturition. Dairy cows are at considerable risk for hypocalcemia at the onset of lactation, when daily calcium excretion suddenly increases from about 10 g to 30 g per day. Cows with hypocalcemia have a more profound decrease in blood calcium concentration-typically below 5.5 mg/dL. The prevention of parturient paresis has been historically approached by feeding cows low-calcium diets during the dry period. Negative calcium balance triggers calcium mobilization before calving and better equips the cow to respond to the massive calcium needs at the onset of lactation. Calcium intake must be limited to <20 g per day for calcium restriction to be effective. The most practical and proven method for monitoring hypocalcemia is by feeding cows an acidogenic diet for ~3 weeks before calving. Throughout the review, emphasis is placed on the importance of early diagnosis and proactive management strategies to mitigate the impact of these metabolic diseases on dairy cattle health and productivity. The comprehensive nature of this paper aims to serve as a valuable resource for veterinarians, researchers, and dairy farmers seeking a deeper understanding of these prevalent metabolic disorders in dairy cattle.

Association between genomic daughter pregnancy rate and expected milk production on the resumption of estrus behavior in Holstein cattle

The objective of this observational study was to evaluate estrous expression at the first estrus occurring between 7 to 30 d in milk (DIM), as detected by an automated activity monitor (AAM), and its association with genomic daughter pregnancy rate (GDPR) and genomic expected milk production (GEM) in lactating dairy cows. A total of 4,119 lactations from 2,602 Holstein cows were included. Cows were enrolled as first lactation (n = 1,168), second lactation (n = 1,525) and third and greater lactation (n = 1,426). Hair samples were collected from the tail switch, and cows were genotyped using an SNP platform (Clarifide, Zoetis, São Paulo, SP, Brazil). Postpartum cows were examined daily by the farm personnel from calving until 10 DIM. Calving was classified as assisted (forced calf extraction) and unassisted (normal calving). Retained fetal membranes (RFM), hyperketonemia (KET), and left displaced abomasum (LDA) were also recorded. Mean GDPR (± SD) was -0.29 ± 1.4, and the intensity and duration of the first estrus event was 15.9 ± 13.1 x-factor (intensity unit measurement) and 11.1 ± 3.8 h, respectively. Cows that had greater GDPR had greater intensity and longer duration of estrus at the alert, independent of parity. Overall resumption of estrous expression, between 7 to 30 DIM, was 41.2% (1,695/4,119), where 58.8% (2,424/4,119) did not have an estrus event, 31.0% (1,274/4,119) of cows had one event of estrus, and 10.2% (421/4,119) of cows had 2 or more events of estrus early postpartum. Mean DIM (± SD) at first estrus event, detected by the AAM, was 19.4 ± 4.4 d. Days in milk at first event for cows with one event was 20.7 ± 1.6 d and 15.9 ± 3.1 d for cows with 2 or more events of estrus. First lactation cows were more likely to have an estrus event early postpartum when compared with second and third and greater lactation cows (45.2 ± 1.4% [530/1168] vs. 41.6 ± 1.3% [636/1525] vs. 37.2 ± 1.3% [529/1426], respectively). There was an interaction of parity and GDPR on the proportion of cows demonstrating an early postpartum estrus. There was no difference in the proportion of cows with an early postpartum estrus between those with assisted or unassisted calving, RFM, or LDA. However, cows that had KET were less likely to have an alert early postpartum when compared with cows that did not have KET. Mean genomic expected milk production (± SD) was 256.8 ± 600.1 kg. There was no interaction between GEM and parity on estrous expression (i.e., intensity and duration). There was no interaction between GEM and GDPR on the proportion of estrus early postpartum.

Application of behavior data to predictive exploratory models of metritis self-cure and treatment failure in dairy cows

The objective was to evaluate the performance of exploratory models containing routinely available on-farm data, behavior data, and the combination of both to predict metritis self-cure (SC) and treatment failure (TF). Holstein cows (n = 1,061) were fitted with a collar-mounted automated- health monitoring device (AHMD) from -21 ± 3 to 60 ± 3 d relative to calving to monitor rumination and activity. Cows were examined for diagnosis of metritis at 4 ± 1, 7 ± 1, and 9 ± 1 DIM. Cows diagnosed with metritis (n = 132), characterized by watery, fetid, reddish/brownish vaginal discharge (VD) were randomly allocated to one of 2 treatments: Control (CON; n = 62) - no treatment at the time of metritis diagnosis (d 0); Ceftiofur (CEF; n = 70) - subcutaneous injection of 6.6 mg/kg of ceftiofur crystalline-free acid on d 0 and 3 relative to diagnosis. Cure was determined 12 d after diagnosis and was considered when VD became mucoid and not fetid. Cows in CON were used to determine SC and cows in CEF were used to determine TF. Univariable analyses were performed using farm-collected data (parity, calving season, calving-related disorders, body condition score, rectal temperature, and days in milk at metritis diagnosis) and behavior data (i.e., daily averages of rumination, activity generated by AHMD, and derived variables) to assess their association with metritis SC or TF. Variables with a P ≤ 0.20 were included in the multivariable logistic regression exploratory models. To predict SC, the area under the curve (AUC) for the exploratory model containing only data routinely available on-farm was 0.75. The final exploratory model to predict SC combining routinely available on-farm data and behavior data increased the AUC to 0.87, sensitivity (Se) 87% and specificity (Sp) 71%. To predict TF, the AUC for the exploratory model containing only data routinely available on-farm was 0.90. The final exploratory model combining routinely available on-farm data and behavior data increased the AUC to 0.93, Se of 93% and Sp of 82%. Cross-validation analysis revealed that generalizability of the exploratory models was poor, which indicates that the findings are applicable to the conditions of the present exploratory study. In summary, the addition of behavior data contributed to increasing the prediction of SC and TF. Developing and validating accurate prediction models for SC could lead to a reduction in antimicrobial use, whereas accurate prediction of cows that would have TF may allow for better management decisions.

Transition Cow Nutrition and Management Strategies of Dairy Herds in the Northeastern United States: Associations of Nutritional Strategies with Analytes, Health, Milk Yield, and Reproduction

The objective was to identify relationships between transition cow nutritional strategies and the prevalence of elevated analytes (nonesterified fatty acids (NEFA), β-hydroxybutyrate (BHB), and haptoglobin (Hp)), disorder incidence (DI), milk yield, and reproductive performance. Multiparous and primiparous cows from 72 farms in the northeastern US were enrolled in a herd-level cohort study. Farms were dichotomized within parity into a nutritional strategy within each period; far-off: controlled energy (CE; <16.5% starch and ≥40% forage neutral detergent fiber (FNDF)) or not CE (NCE; ≥16.5% starch or <40% FNDF or both), close-up: high FNDF (HF; ≥40% FNDF) or low FNDF (LF; <40% FNDF), and fresh: low starch (LS; <25.5% starch) or high starch (HS; ≥25.5% starch). No evidence existed that transition cow nutritional strategies were associated with milk yield outcomes (p ≥ 0.20). In general, our results support feeding multiparous cows HF close-up and HS fresh to minimize excessive BHB and DI; however, multiparous cows fed LF close-up had a higher pregnancy rate, and lower prepartum NEFA and Hp. Similarly, our results support feeding primiparous cows CE far-off, HF close-up, and HS fresh to maximize reproductive performance, and minimize BHB and DI; however, herds fed HF close-up or HS fresh had higher Hp.

Epidemiology of bovine colostrum production in New York Holstein herds: Prepartum nutrition and metabolic indicators

Colostrum yield and quality are influenced by prepartum nutrition and the metabolic status of the cow; however, data considering these associations on multiple dairy farms are limited. Our objective was to identify cow-level prepartum metabolic indicators, as well as farm-level nutritional strategies associated with colostrum yield and the indicator of colostrum quality, Brix %. A convenience sample of 19 New York Holstein dairies (median: 1,325 cows; range: 620 to 4,600 cows) were enrolled in this observational study. Records for individual colostrum yield and Brix % were collected by farm personnel between October 2019 and February 2021. Farms were visited 4 times, approximately 3 mo apart, to obtain feed samples of the prepartum diets, collect blood samples from 24 pre- and postpartum cows, respectively, and determine prepartum body condition score. Feed samples were submitted for analysis of chemical composition, and particle size was determined on-farm using a particle separator. Prepartum serum samples (n = 762) were analyzed for glucose and nonesterified fatty acid concentrations. Whole blood from postpartum cows was analyzed for herd prevalence of hyperketonemia (proportion of samples with β-hydroxybutyrate ≥1.2 mmol/L). A cohort of primiparous (PP; n = 1,337) and multiparous (MPS; n = 3,059) cows calving ± 14 d of each farm visit were included in the statistical analysis. Animals calving in this period were assigned results for the close-up diet composition and herd prevalence of hyperketonemia collected from the respective farm visit. Greatest colostrum yield from PP and MPS cows was associated with moderate starch [18.6-22.5% of dry matter (DM)] and a moderate herd prevalence of hyperketonemia (10.1-15.0%). Greatest colostrum yield from MPS cows was associated with moderate crude protein (13.6-15.5% of DM) and a less severe negative dietary cation-anion difference (DCAD; >-8 mEq/100 g), whereas greatest colostrum yield from PP cows was associated with low crude protein (≤13.5% of DM). In addition, a moderate proportion of the diet with particle length ≥19 mm (15.3-19.1%) was associated with lowest colostrum yield from PP and MPS cows. Highest colostrum Brix % was associated with prepartum dietary factors of low neutral detergent fiber (≤39.0% of DM) and high proportion of the diet with particle length ≥19 mm (>19.1%). In addition, low starch (≤18.5% of DM) and low and moderate DCAD level (≥-15.9 mEq/100 g) were associated with greatest Brix % from PP cows, whereas moderate DCAD (-15.9 to -8.0 mEq/100 g) was associated with greatest Brix % from MPS cows. Prepartum serum nonesterified fatty acid concentration ≥290 µEq/L was associated with increased colostrum yield, but prepartum serum glucose concentration and body condition score were not associated with colostrum yield or Brix %. These data provide nutritional and metabolic variables to consider when troubleshooting colostrum production on farms.

Animal board invited review: The contribution of adipose stores to milk fat: implications on optimal nutritional strategies to increase milk fat synthesis in dairy cows

A wide range of nutritional and non-nutritional factors influence milk fat synthesis and explain the large variation observed in dairy herds. The capacity of the animal to synthesize milk fat will largely depend on the availability of substrates for lipid synthesis, some of which originate directly from the diet, ruminal fermentation or from adipose tissue stores. The mobilization of non-esterified fatty acids from adipose tissues is important to support the energy demands of milk synthesis and will therefore have an impact on the composition of milk lipids, especially during the early lactation period. Such mobilization is tightly controlled by insulin and catecholamines, and in turn, can be affected indirectly by factors that influence these signals, namely diet composition, lactation stage, genetics, endotoxemia, and inflammation. Environmental factors, such as heat stress, also impact adipose tissue mobilization and milk fat synthesis, mainly through endotoxemia and an immune response-related increase in concentrations of plasma insulin. Indeed, as proposed in the present review, the central role of insulin in the control of lipolysis is key to improving our understanding of how nutritional and non-nutritional factors impact milk fat synthesis. This is particularly the case during early lactation, as well as in situations where mammary lipid synthesis is more dependent on adipose-derived fatty acids.

Transition cow nutrition and management strategies of dairy herds in the northeastern United States: Part III-Associations of management and dietary factors with analytes, health, milk yield, and reproduction

The objective was to evaluate relationships between putative periparturient management and dietary factors at the pen and herd levels with metabolic- and inflammation-related analytes, health disorders, milk yield, and reproductive performance. Multiparous and primiparous cows from 72 farms in the northeastern United States were enrolled in a prospective cohort study. Farms were visited 3 times during the prepartum and postpartum periods: during the far-off dry, close-up dry, and fresh periods. Pen measurements were taken at each visit for the pens where cows sampled were housed, and particle size was determined for the total mixed ration for the pen. A survey was used to acquire data on herd-level management variables. Blood samples were collected from the same 11 to 24 cows per farm during the close-up and fresh period visits. Whole blood was analyzed for postpartum β-hydroxybutyrate (BHB) concentrations, and plasma was analyzed for prepartum and postpartum nonesterified fatty acids (NEFA) and postpartum haptoglobin (Hp) concentrations. Health event, milk yield, and reproductive records were acquired through the records management software program used on the farm. For the pen-level analysis, primiparous and multiparous cows were analyzed separately. For the pen- and herd-level analysis, a simple linear regression was conducted on all possible explanatory variables. Variables were included in the full multivariable general linear model if P < 0.20, and a manual backward stepwise elimination process ensued until all variables had P < 0.10. Our results indicate that pen- and herd-level management factors are associated with blood biomarkers, health, milk yield, and reproductive performance. For the prepartum period, our results support increasing the proportion of particles on the 19-mm sieve of the Penn State Particle Separator, optimizing bunk space, and not overfeeding metabolizable energy (ME), to decrease the prevalence of elevated postpartum NEFA, BHB, and Hp concentrations, decrease disorder incidence, maximize milk yield, and improve pregnancy risk to first service. For the fresh period, our results generally support optimizing bunk space, avoiding commingling, increasing feeding frequency, avoiding high physically effective undigested neutral detergent fiber (NDF) after 240 h of in vitro fermentation and high total fermentable carbohydrate diets while optimizing the inclusion of forage NDF, and ensuring adequate diet ME and metabolizable protein to reduce the prevalence of elevated postpartum NEFA, BHB, and Hp concentrations, minimize disorder incidence, maximize milk yield, and improve pregnancy risk to first service. At the herd level, our results generally support not vaccinating in the calving pen, minimizing the number of prepartum and postpartum pen moves, and avoiding long stays in the calving pen after parturition to reduce the prevalence of elevated biomarker concentrations, decrease disorder incidence, increase milk yield, and improve reproductive performance.

Effects of dietary energy density and feeding strategy during the dry period on feed intake, energy balance, milk production, and blood metabolites of Holstein cows

Our study aimed to assess the effects of dietary energy density and strategy of delivery during the dry period on production and metabolic responses of Holstein cows free of displacement of abomasum, retained placenta, metritis, or hypocalcemia. Twenty-seven multiparous cows dried-off 50 d before calving were assigned randomly to 1 of 3 dietary treatments: a controlled energy, high-fiber diet [CE; 1.39 Mcal net energy for lactation (NE_L)/kg of dry matter (DM)] formulated to supply 100% of the NE_L requirement at ad libitum intake; or a higher energy diet (1.58 Mcal/kg) fed either at ad libitum (HE) or restricted (RE) intake to supply ∼150 or 80% of the NE_L requirements, respectively. After calving, all cows were fed the same lactation diet. Cows were individually fed and remained in the study until 28 d postpartum. Data were analyzed using 2 contrasts: CE versus HE (effect of diet composition in cows fed for ad libitum DM intake) and HE versus RE (effect of ad libitum or restricted intake of the same diet). Prepartum intakes of DM and NE_L as well as energy balance (EB), were greater for HE than CE and greater for HE than RE. Body weight (BW) gain was higher in HE than in RE, but CE and HE did not differ. Change in body condition score did not differ between CE and HE or HE and RE. Postpartum intakes of DM and NE_L, EB, BW, body condition score, calf birth BW, milk yield, and milk components did not differ between CE and HE or HE and RE. Concentrations of glucose, insulin, nonesterified fatty acids, β-hydroxybutyrate, Ca, and Mg pre- and postpartum did not differ among diets. Although sample size was low, dry period plane of energy intake affected prepartum DM intake, EB, and BW gain but did not affect postpartum intakes of DM and NE_L, yields of milk and milk components, or blood metabolites in healthy cows.

Effects of dietary branched-chain amino acid supplementation on serum and milk metabolome profiles in dairy cows during early lactation

The 3 branched-chain AA (BCAA), Val, Leu, and Ile, are essential AA used by tissues as substrates for protein synthesis and energy generation. In addition, BCAA are also involved in modulating cell signaling pathways, such as nutrient sensing and insulin signaling. In our previous study, dietary BCAA supplementation was shown to improve protein synthesis and glucose homeostasis in transition cows. However, a more detailed understanding of the changes in metabolic pathways associated with an increased BCAA availability is desired to fine-tune nutritional supplementation strategies. Multiparous Holstein cows (n = 20) were enrolled 28 d before expected calving and assigned to either the BCAA treatment (n = 10) or the control group (n = 10). Cows assigned to BCAA were fed 550 g/d of rumen-protected BCAA mixed with 200 g/d of dry molasses from calving until 35 DIM, whereas the cows assigned to the control were fed only 200 g/d of dry molasses. Serum samples were collected on d 10 before expected calving, as well as on d 4 and d 21 postpartum. Milk samples were collected on d 14 postpartum. From a larger cohort, we selected 20 BCAA-supplemented cows with the greatest plasma urea nitrogen concentration, as an indicator for greater BCAA availability, for the metabolomics analysis herein. Serum and milk samples were subjected to a liquid chromatography-mass spectrometry-based assay, detecting and measuring the abundance of 241 serum and 211 milk metabolic features, respectively. Multivariable statistical analyses revealed that BCAA supplementation altered the metabolome profiles of both serum and milk samples. Increased abundance of serum phosphocholine and glutathione and of milk Val, Ile, and Leu, and decreased abundance of milk acyl-carnitines were associated with BCAA supplementation. Altered phosphocholine and glutathione abundances point to altered hepatic choline metabolism and antioxidant balance, respectively. Altered milk acyl-carnitine abundances suggest changes in mammary fatty acid metabolism. Dietary BCAA supplementation was associated with a range of alterations in serum and milk metabolome profiles, adding to our understanding of the role of BCAA availability in modulating dairy cow protein, lipid, and energy metabolism on a whole-body level and how it affects milk composition.

Activated autophagy-lysosomal pathway in dairy cows with hyperketonemia is associated with lipolysis of adipose tissues

Activated autophagy-lysosomal pathway (ALP) can degrade virtually all kinds of cellular components, including intracellular lipid droplets, especially during catabolic conditions. Sustained lipolysis and increased plasma fatty acids concentrations are characteristic of dairy cows with hyperketonemia. However, the status of ALP in adipose tissue during this physiological condition is not well known. The present study aimed to ascertain whether lipolysis is associated with activation of ALP in adipose tissues of dairy cows with hyperketonemia and in calf adipocytes. In vivo, blood and subcutaneous adipose tissue (SAT) biopsies were collected from nonhyperketonemic (nonHYK) cows [blood β-hydroxybutyrate (BHB) concentration <1.2 mM, n = 10] and hyperketonemic (HYK) cows (blood BHB concentration 1.2-3.0 mM, n = 10) with similar days in milk (range: 3-9) and parity (range: 2-4). In vitro, calf adipocytes isolated from 5 healthy Holstein calves (1 d old, female, 30-40 kg) were differentiated and used for (1) treatment with lipolysis inducer isoproterenol (ISO, 10 µM, 3 h) or mammalian target of rapamycin inhibitor Torin1 (250 nM, 3 h), and (2) pretreatment with or without the ALP inhibitor leupeptin (10 μg/mL, 4 h) followed by ISO (10 µM, 3 h) treatment. Compared with nonHYK cows, serum concentration of free fatty acids was greater and serum glucose concentration, DMI, and milk yield were lower in HYK cows. In SAT of HYK cows, ratio of phosphorylated hormone-sensitive lipase to hormone-sensitive lipase, and protein abundance of adipose triacylglycerol lipase were greater, but protein abundance of perilipin 1 (PLIN1) and cell death-inducing DNA fragmentation factor-α-like effector c (CIDEC) was lower. In addition, mRNA abundance of autophagy-related 5 (ATG5), autophagy-related 7 (ATG7), and microtubule-associated protein 1 light chain 3 beta (MAP1LC3B), protein abundance of lysosome-associated membrane protein 1, and cathepsin D, and activity of β-N-acetylglucosaminidase were greater, whereas protein abundance of sequestosome-1 (p62) was lower in SAT of HYK cows. In calf adipocytes, treatment with ISO or Torin1 decreased protein abundance of PLIN1, and CIDEC, and triacylglycerol content in calf adipocytes, but increased glycerol content in the supernatant of calf adipocytes. Moreover, the mRNA abundance of ATG5, ATG7, and MAP1LC3B was upregulated, the protein abundance of lysosome-associated membrane protein 1, cathepsin D, and activity of β-N-acetylglucosaminidase were increased, whereas the protein abundance of p62 was decreased in calf adipocytes treated with ISO or Torin1 compared with control group. Compared with treatment with ISO alone, the protein abundance of p62, PLIN1, and CIDEC, and triacylglycerol content in calf adipocytes were higher, but the glycerol content in the supernatant of calf adipocytes was lower in ISO and leupeptin co-treated group. Overall, these data indicated that activated ALP is associated with increased lipolysis in adipose tissues of dairy cows with hyperketonemia and in calf adipocytes.

Effects of prepartum metabolizable protein supply and management strategy on lactational performance and blood biomarkers in dairy cows during early lactation

Our objective was to investigate the effects of prepartum metabolizable protein (MP) supply and management strategy on milk production and blood biomarkers in early lactation dairy cows. Ninety-six multigravida Holstein cows were used in a randomized complete block design study, blocked by calving date, and then assigned randomly to 1 of 3 treatments within block. Cows on the first treatment were fed a far-off lower MP diet [MP = 83 g/kg of dry matter (DM)] between -55 and -22 d before expected calving and then a close-up lower MP diet (MP = 83 g/kg of DM) until parturition (LPLP). Cows on the second treatment were fed the far-off lower MP diet between -55 to -22 d before expected parturition and then a prepartum higher MP diet (MP = 107 g/kg of DM) until calving (LPHP). Cows on the third treatment had a shortened 43-d dry period and were fed the prepartum higher MP diet from dry-off to parturition (SDHP). After calving, cows received the same fresh diet from d 0 to 14 and the same high diet from d 15 to 84. Data were analyzed separately for wk -6 to -1 and wk 1 to 12, relative to parturition. Dry matter intake from wk -6 to -1 was not different between LPHP and LPLP and increased for SDHP compared with LPLP. In contrast, dry matter intake for wk 1 to 12 postpartum did not change for LPHP versus LPLP or for SDHP versus LPLP. Compared with LPLP cows, LPHP cows had lower energy-corrected milk yield and tended to have decreased milk fat yield during wk 1 to 12 of lactation. Conversely, yields of energy-corrected milk and milk fat and protein were similar for SDHP compared with LPLP. Plasma urea N during wk -3 to -1 increased for LPHP versus LPLP and for SDHP versus LPLP; however, no differences in plasma urea N were observed postpartum. Elevated prepartum MP supply did not modify circulating total fatty acids, β-hydroxybutyrate, total protein, albumin, or aspartate aminotransferase during the prepartum and postpartum periods. Increased MP supply prepartum combined with a shorter dry period (SDHP vs. LPLP) tended to increase whole-blood β-hydroxybutyrate postpartum; however, other blood metabolites were not affected. Taken together, under the conditions of this study, elevated MP supply in close-up diets reduced milk production without affecting blood metabolites in multiparous dairy cows during early lactation. A combination of a shorter dry period and increased prepartum MP supply (i.e., SDHP vs. LPLP) improved prepartum dry matter intake without modifying energy-corrected milk yield and blood biomarkers in early lactation cows.

Effects of Concentrate Levels in Prepartum Diet on Milk Performance, Energy Balance and Rumen Fermentation of Transition Montbéliarde-Holstein Crossbred Cows

This study was conducted to investigate the effect of three rates of prepartum dietary concentrate feeding on the milk performance, energy balance, and rumen fermentation of Montbéliarde−Holstein crossbred cows. Eighteen transition Montbéliarde−Holstein crossbred cows with similar days of gestation (258 ± 12 day) and body weights (622 ± 44 kg) were selected and randomly divided into three groups. In the prepartum period, the addition of concentrates accounted for 0.3% (low concentrate, LC), 0.6% (medium concentrate, MC), and 0.9% (high concentrate, HC) of the cow’s body weight. The forage was corn stover, which was fed to the cows ad libitum with free access to water. Postpartum, all of the cows were fed a common lactation total mixed ration. The experimental period lasted from 21 days prepartum to 28 days postpartum. The energy balance (EB), net energy intake (NEI), and dry matter intake (DMI) of the HC group were greater than those of the other groups (p < 0.05). Likewise, the non-esterified fatty acids (NEFA), β-hydroxybutyric acid (BHBA), and total bilirubin (TBIL) in the blood of the LC group had significantly higher concentrations than they did in the other groups (p < 0.05). Moreover, the increase in the level of dietary concentrate had no significant effect on the rumen fermentation parameters (p > 0.05), and the total intestinal digestibility of dry matter (DM), crude protein (CP), and ether extract (EE) in the HC group was significantly higher (p < 0.05) than it was in the other groups during the prepartum period. In conclusion, the administration of the MC diet in the prepartum period had no negative effect on the performance and rumen fermentation of postpartum dairy cows and can satisfy the energy needs of prepartum dairy cows. Therefore, under our experimental conditions, the 0.6% prenatal concentrate feeding amount was the most appropriate for Montbéliarde−Holstein crossbred cows.

Untargeted Metabolomics Reveals Metabolic Stress Alleviation by Prepartum Exercise in Transition Dairy Cows

Prepartum exercise (PA) has been proposed as a strategy for the peripartum management of dairy cows; however, the mechanism by which PA affects metabolism has not been elucidated. Here, we investigated the metabolic changes in transition dairy cows with PA. Holstein transition multiparous dairy cows were assigned to an exercise (n = 12) or a control (n = 12) group; the cows in the exercise group walked for a targeted 45 min at 3.25 km/h, two times a day. Plasma non-esterified fatty acid (NEFA), β-hydroxybutyric acid (BHBA), glucose, and triglyceride levels were measured, and metabolic profiles were analyzed using untargeted mass spectrometry. Compared with those in the control group, the concentrations of NEFA at −7 d, glucose at 0 d, and BHBA at +7 d relative to calving were considerably decreased in the exercise group. Untargeted metabolomics analysis revealed differences in the levels of key metabolites, including kynurenine, tryptophan, homovanillic acid, dopamine, cis-9-palmitoleic acid, and palmitic acid, between the exercise and control group cows. This study suggests that PA may decrease homovanillic acid and cis-9-palmitoleic acid levels and increase tryptophan levels to alleviate the metabolic stress in dairy cows during calving, thereby improving postpartum health.

Oversupplying metabolizable protein during late gestation to beef cattle does not influence ante- or postpartum glucose-insulin kinetics but does affect prepartum insulin resistance indices and colostrum insulin content

The objective of this study was to evaluate whether oversupplying metabolizable protein (MP) during late gestation influences glucose and insulin concentrations, and insulin resistance (IR) in late gestation and early lactation. Crossbred Hereford, first-lactation heifers were individually fed diets to supply 133% (HMP, n = 11) or 100% (CON, n = 10) of their predicted MP requirements for 55 ± 4 d (mean ± SD) prior to calving. All heifers received a common lactation ration formulated to meet postpartum requirements (103% MP and 126% ME). After feed was withheld for 12 h, cattle underwent an intravenous glucose tolerance test (IVGTT) on d -6.7 ± 0.9 and 14.3 ± 0.4 by infusing a 50% dextrose solution (1.36 g glucose/kg BW 0.75) through a jugular catheter with plasma collected at -10, 0 (immediately after infusion), 5, 10, 15, 20, 25, 30, 45, 60, 75, 90, and 120 min, respective to the infusion. Glucose and insulin concentrations were assessed. Insulin resistance indices (homeostasis model of insulin resistance [HOMA-IR], quantitative insulin sensitivity check index [QUICKI], revised quantitative insulin sensitivity check index [RQUICK], and RQUICKI incorporating serum beta-hydroxybutyrate concentrations [RQUICKIBHB]) were calculated from measurements of serum non-esterified fatty acids and beta-hydroxybutyrate and plasma glucose and insulin concentrations on d -34 ± 4, -15 ± 4, 7 ± 1, 28 ± 3, 70 ± 3, and 112 ± 3. Colostrum samples were collected within an hour of calving (prior to suckling) and analyzed for insulin concentration. Data were analyzed as a randomized block design using the PROC GLIMMIX of SAS, accounting for repeated measurements when necessary. Baseline (-10 min) plasma glucose and insulin concentrations were elevated (P ≤ 0.038) for HMP heifers during the antepartum IVGTT, but not (P ≥ 0.25) during the postpartum IVGTT. Plasma glucose and insulin concentrations throughout the antepartum or postpartum IVGTT did not differ (P ≥ 0.18) by prepartum treatment, nor did other glucose and insulin IVGTT parameters (i.e., max concentration and time to reach max concentration, nadir values, clearance rates and half-lives, area-under-the-curve, and insulin sensitivity index; P ≥ 0.20). Antepartum IVGTT IR indices indicated that HMP heifers were more (P ≤ 0.011) IR than their counterparts. Similarly, the prepartum HOMA-IR was greater (P = 0.033) for HMP heifers, suggesting increased IR. Postpartum IR indices did not (P ≥ 0.25) indicate that prepartum MP consumption impacted postpartum IR. Colostrum insulin concentration was increased (P = 0.004) by nearly 2-fold for HMP relative to CON heifers. These data demonstrate that prepartum MP overfeeding alters baseline glucose-insulin concentrations in late-pregnant beef heifers and increases colostrum insulin content without having carry-over effects on postpartum glucose-insulin concentrations and IR.

Symposium review: The role of adipose tissue in transition dairy cows: Current knowledge and future opportunities

Adipose tissue (AT) is a central reservoir of energy stored in the form of lipids. In addition, AT has been recognized as an immunologically and endocrinologically active tissue of dairy cattle. The recent literature on AT biology of transition dairy cows has often focused on the possible negative effects that originate from excessive body fat. However, the highly efficient energy-storage capability of this tissue is also vital to the adaptability of dairy cattle to the change in nutrient availability, and to support lactation and reproduction. An excessive degree of mobilization of this tissue, however, is associated with high circulating fatty acid concentrations, and this may have direct and indirect negative effects on reproductive health, productivity, and disease risk. Furthermore, rapid lipolysis may be associated with postpartum inflammation. Research on the role of AT is complicated by the greater difficulty of accessing and measuring visceral AT compared with subcutaneous AT. The objective of this review is to provide a transition cow-centric summary of AT biology with a focus on reviewing methods of measuring AT mass as well as to describe the importance for production, health, and reproductive success.

Dietary supplementation with rumen-protected capsicum during the transition period improves the metabolic status of dairy cows

In ruminants, it has been observed that capsicum oleoresin can alter insulin responses and that high-intensity artificial sweetener can increase glucose absorption from the small intestine. Because glucose metabolism and insulin responses are critical during early lactation, these supplements might have an effect on the metabolic status of dairy cows during the transition period. The objective of this experiment was to evaluate the effects of rumen-protected capsicum oleoresin fed alone or in combination with artificial sweetener during the transition period on lactational performance and susceptibility to subclinical ketosis in dairy cows. Fifteen primiparous and 30 multiparous Holstein cows (a total of 39 cows finished the study) were arranged in a randomized complete block design during d -21 to 60 relative to parturition. Cows within block were randomly assigned to one of the following treatments: no supplement (CON), supplementation with 100 mg of rumen-protected capsicum/cow per day (RPCap), or RPCap plus 2 g of high-intensity artificial sweetener/cow per day (RPCapS). For both the RPCap and RPCapS treatments, only rumen-protected capsicum was fed during the dry period. From d 8 to 11 of lactation, intake was limited to 70% of predicted dry matter intake to induce subclinical ketosis. Production variables were recorded daily, samples for milk composition were collected on wk 2, 4, 6, and 8, and blood samples were collected on wk -2, 1, 2, and 4 of the experiment for analysis of metabolic hormones and blood cell counts. Supplementation with rumen-protected capsicum increased serum insulin and decreased β-hydroxybutyrate concentrations precalving, indicating a decrease in lipolysis. During the lactation period, RPCap was associated with a trend for increased milk production and feed efficiency following the ketosis challenge. Supplementation with RPCapS appeared to negate the response to rumen-protected capsicum. All cows developed subclinical ketosis during the challenge, and this was not affected by treatment. We conclude that treatments did not decrease susceptibility to subclinical ketosis; however, dietary supplementation with rumen-protected capsicum was effective at improving energy status precalving and tended to increased milk production and feed efficiency. The mechanism underlying these responses is unclear.

Effects of prepartum dietary protein level and feed intake on postpartum lactation performance and feeding behavior of multiparous Holstein dairy cows

An experiment was conducted to determine the effects of low and high metabolizable protein (MP) diets when fed for ad libitum and controlled intake during the prepartum period on postpartum lactation performance and feeding behavior of dairy cows. Thirty-six multiparous Holstein cows were blocked by parity, expected calving date, and previous lactation milk yield at -21 d relative to expected calving and were randomly assigned to 1 of 4 close-up period dietary treatments providing low MP (LMP) or high MP (HMP) diets with controlled intake (CNI) or ad libitum intake (ALI). The concentrations of MP were 65 and 90 g/kg dry matter for LMP and HMP diets, respectively, whereas intake was controlled to supply 100 and 160% of the NRC (2001) energy requirements for CNI and ALI groups, respectively. The concentration of net energy for lactation (NE_L) in the treatment diets was 1.50 Mcal/kg. All cows were fed a similar lactation diet after calving (1.50 Mcal/kg of NE_L and 83.3 g/kg of MP). The HMP diet increased dry matter intake during the first 3 wk and tended to increase dry matter intake over the 9 wk of lactation. Meal size and eating rate increased in the ALI cows during the prepartum period. Meal frequency increased with the HMP diet during the postpartum period. Milk yield increased by 15.2% with the HMP diet over the 9 wk of lactation. The HMP diet increased energy-corrected milk (ECM) yield in CNI versus ALI cows, whereas the LMP diet increased ECM yield in ALI versus CNI cows over the 9 wk of lactation. The increase in ECM yield of LMP-ALI versus LMP-CNI cows was supported by greater body condition loss and serum β-hydroxybutyrate over the 9 wk of lactation. Taken together, these data indicate that prepartum controlled intake of a high protein diet can provide the benefits of both strategies.

Hepatic effects of rumen-protected branched-chain amino acids with or without propylene glycol supplementation in dairy cows during early lactation

Essential amino acids (EAA) are critical for multiple physiological processes. Branched-chain amino acid (BCAA) supplementation provides energy substrates, promotes protein synthesis, and stimulates insulin secretion in rodents and humans. Most dairy cows face a protein and energy deficit during the first weeks postpartum and utilize body reserves to counteract this shortage. The objective was to evaluate the effect of rumen-protected BCAA (RP-BCAA; 375 g of 27% l-leucine, 85 g of 48% l-isoleucine, and 91 g of 67% l-valine) with or without oral propylene glycol (PG) administration on markers of liver health status, concentrations of nonesterified fatty acids (NEFA) and β-hydroxybutyrate (BHB) in plasma, and liver triglycerides (TG) during the early postpartum period in dairy cows. Multiparous Holstein cows were enrolled in blocks of 3 and randomly assigned to either the control group or 1 of the 2 treatments from calving until 35 d postpartum. The control group (n = 16) received 200 g of dry molasses per cow/d; the RP-BCAA group (n = 14) received RP-BCAA mixed with 200 g of dry molasses per cow/d; the RP-BCAA plus PG (RP-BCAAPG) group (n = 16) received RP-BCAA mixed with 200 g of dry molasses per cow/d, plus 300 mL of PG, once daily from calving until 7 d in milk (DIM). The RP-BCAA and RP-BCAAGP groups, on average (± standard deviation), were predicted to receive a greater supply of metabolizable protein in the form of l-Leu 27.4 ± 3.5 g/d, l-Ile 15.2 ± 1.8 g/d, and l-Val 24.2 ± 2.4 g/d compared with the control cows. Liver biopsies were collected at d 9 ± 4 prepartum and at 5 ± 1 and 21 ± 1 DIM. Blood was sampled 3 times per week from calving until 21 DIM. Milk yield, dry matter intake, NEFA, BHB, EAA blood concentration, serum chemistry, insulin, glucagon, and liver TG and protein abundance of total and phosphorylated branched-chain ketoacid dehydrogenase E1α (p-BCKDH-E1α) were analyzed using repeated measures ANOVA. Cows in the RP-BCAA and RP-BCAAPG groups had lower liver TG and lower activities of aspartate aminotransferase and glutamate dehydrogenase during the first 21 DIM, compared with control. All cows, regardless of treatment, showed an upregulation of p-BCKDH-E1α at d 5 postpartum, compared with levels at 21 d postpartum. Insulin, Met, and Glu blood concentration were greater in RP-BCAA and RP-BCAAPG compared with control during the first 35 DIM. Therefore, the use of RP-BCAA in combination with PG might be a feasible option to reduce hepatic lipidosis in dairy cows during early lactation.

Invited Review: Ketosis Diagnosis and Monitoring in High-Producing Dairy Cows

This work reviews the current impact and manifestation of ketosis (hyperketonemia) in dairy cattle, emphasizing the practical use of laboratory methods, field tests, and milk data to monitoring this disease. Ketosis is a major issue in high-producing cows, easily reaching a prevalence of 20% during early postpartum when the negative energy balance is well established. Its economic losses, mainly related to decreasing milk yield, fertility, and treatment costs, have been estimated up to €250 per case of ketosis/year, which can double if associated diseases are considered. A deep relationship between subclinical or clinical ketosis and negative energy balance and related production diseases can be observed mainly in the first two months postpartum. Fourier transform infrared spectrometry methods gradually take place in laboratory routine to evaluates body ketones (e.g., beta-hydroxybutyrate) and probably will accurately substitute cowside blood and milk tests at a farm in avenir. Fat to protein ratio and urea in milk are largely evaluated each month in dairy farms indicating animals at risk of hyperketonemia. At preventive levels, other than periodical evaluation of body condition score and controlling modifiable or identifying non-modifiable risk factors, the ruminatory activity assessment during the peripartum seems to be a valuable tool at farms. We conclude that a technological advance progressively takes place to mitigate the effects of these metabolic diseases, which challenge the high-yielding cows.

Effect of protein level and methionine supplementation on dairy cows during the transition period

Cows experience a significant negative protein balance during the first 30 d of lactation. Given the functional effects of AA on health, especially in challenging periods such as calving, higher levels of protein and specific AA in the diet may act to improve health and feed intake. The response of dairy cows to 3 protein supplementation strategies during the transition period and through the first 45 d in milk was evaluated. The final data set had 39 Holstein cows blocked based on parity (primiparous vs. multiparous) and expected calving and randomly assigned within each block to one of 3 dietary treatments: low protein (LP), high protein (HP), or high protein plus rumen-protected methionine (HPM). Treatments were offered from d -18 ± 5 to 45 d relative to parturition. Pre- and postpartum diets were formulated for high metabolizable protein (MP) supply from soybean meal, and HP and HPM provided higher MP balance than LP. Preplanned contrasts were LP versus HP+HPM and HP versus HPM. Significance was declared at P ≤ 0.05 and trends at 0.05 <P ≤ 0.10. Cows fed HP and HPM had greater fry matter intake (DMI) prepartum than LP (+2 kg/d), and there was a trend for greater DMI with HPM than with HP (+1.6 kg/d). Body weight and condition score before and after calving did not differ among treatments. High protein (HP and HPM) tended to increase milk yield during the first 45 d of lactation (+1.75 kg/d), increased milk lactose content and urea-N in milk and plasma, tended to increase blood BHB 14 d postpartum, and tended to reduce milk/DMI compared with LP. Blood concentrations of calcium at calving and of glucose, and nonesterified fatty acids pre- and postpartum did not differ. High protein induced lower concentration of plasma IL-1 at calving and lowered blood lymphocytes 21 d postpartum, suggestive of a reduced inflammatory status compared with LP. The concentrations of IL-10, tumor necrosis factor alpha, and other hemogram variables did not differ among treatments. Addition of rumen-protected methionine to the HP diet did not alter milk yield but increased fat and total solids concentrations. The rumen-protected methionine had no effect on blood metabolites and immunity markers, with the exception of increased pre-partum insulin concentrations. The data indicate that dairy cows around calving respond positively to an increase in the supply of MP and to rumen-protected methionine supplementation of the HP diet by increasing intake and improving immune status.

Monitoring and Improving the Metabolic Health of Dairy Cows during the Transition Period

Simple Summary

The transition from late gestation to early lactation is a challenging period for dairy cows. A successful transition period depends on metabolic adaptation to the new physiological state in early lactation and proper management in order to support the cow’s requirements. This review paper will discuss various aspects of routine and consistent approaches to collect and analyze herd records, to detect unintended disruptions in performance. In addition, we discuss how to incorporate methods to assess health, production, nutrition, and welfare information to monitor cows during the transition period. Lastly, we discuss management strategies that can be implemented to improve the metabolic health and performance of transition dairy cows.

Abstract

The peripartum period of a dairy cow is characterized by several physiological and behavioral changes in response to a rapid increase in nutrient demands, to support the final stages of fetal growth and the production of colostrum and milk. Traditionally, the transition period is defined as the period 3 weeks before and 3 weeks after parturition. However, several researchers have argued that the transition period begins at the time of dry-off (~60–50 days prior to calving) and extends beyond the first month post-calving in high producing dairy cows. Independent of the definition used, adequate adaptation to the physiological demands of this period is paramount for a successful lactation. Nonetheless, not all cows are successful in transitioning from late gestation to early lactation, leading to approximately one third of dairy cows having at least one clinical disease (metabolic and/or infectious) and more than half of the cows having at least one subclinical case of disease within the first 90 days of lactation. Thus, monitoring dairy cows during this period is essential to detect early disease signs, diagnose clinical and subclinical diseases, and initiate targeted health management to avoid health and production impairment. In this review, we discuss different strategies to monitor dairy cows to detected unintended disruptions in performance and management strategies that can be implemented to improve the metabolic health and performance of dairy cows during the transition period.

Addition of straw to the early-lactation diet: Effects on feed intake, milk yield, and subclinical ketosis in Holstein cows

This study evaluated feed intake, milk yield, and subclinical ketosis in dairy cows in early lactation fed 2 different diets postpartum. Cows are typically offered a high-energy ration immediately after calving. We compared a conventional high-energy total mixed ration (TMR) with a transition ration that contained chopped straw. We predicted that adding chopped straw would increase dry matter intake, milk production, and indicators of energy metabolism during the first 3 wk of lactation compared to cows fed a conventional high-energy TMR. We also predicted that carryover effects would be likely for at least 2 wk after treatment ended. A total of 68 mixed-age Holstein cows were enrolled in the study 3 wk before their expected calving. All cows were managed on a single high-forage diet during the dry period. At calving, cows were allocated to 1 of the 2 diets: half to the conventional high-energy TMR (CTMR; n = 34; net energy for lactation = 1.61 Mcal/kg; neutral detergent fiber = 31.7%), and the other half to a high-forage TMR containing chopped wheat straw, equivalent to 4.27% dry matter (STMR; n = 34; net energy for lactation = 1.59 Mcal/kg; neutral detergent fiber = 33.7%) for 3 wk after calving. Cows on STMR were then shifted to CTMR for the next 2 wk to study short-term residual effects on the performance of cows. Treatments were balanced for parity, body condition score, and body weight. Feed intake was measured daily from 2 wk before to 5 wk after calving using automatic feed bins. Blood was sampled twice weekly from 2 wk before to 5 wk after calving, and β-hydroxybutyrate and glucose were measured in serum samples. Subclinical ketosis was identified using a threshold of β-hydroxybutyrate ≥1.0 mmol/L in wk 1 after calving and ≥1.2 mmol/L in wk 2 to 5 after calving. Cows were milked twice daily, and weekly samples (composite samples of morning and afternoon milkings) were analyzed to determine total solids, fat, protein, lactose, and somatic cell count. Data were analyzed in 2 separate periods: the treatment phase (wk +1, +2, and +3) and the post-treatment phase (wk +4 and +5). The addition of straw to the TMR negatively affected the dry matter intake of STMR cows during wk 2 and 3 of lactation. Daily milk yield during the first 5 wk of lactation was lower in STMR cows than in CTMR cows. Concentrations of β-hydroxybutyrate were higher in CTMR cows than in STMR cows during wk 1, but this effect was reversed during wk 2 and 3 of lactation. By 21 d in milk, STMR cows had a greater risk of developing subclinical ketosis than CTMR cows. Adding chopped wheat straw to the TMR during the first 21 d after calving lowered dry matter intake and provided no metabolic or production benefits to lactating dairy cattle.

Effects of feeding a moderate- or high-energy close-up diet to cows on response of newborn calves to milk replacer feeding and intravenous injection of glucagon-like peptide 1

In this study, we investigated the effects of feeding a moderate- or high-energy close-up diet to close-up cows on response of newborn calves to intravenously (i.v.) injected glucagon-like peptide 1 (GLP-1). Newborn Holstein heifer calves (n = 37) from cows fed with a moderate-energy [M, 1.54 Mcal/kg of dry matter (DM) NEl; 14% starch; n = 17] or high-energy (H, 1.63 Mcal/kg of DM NEl; 26% starch; n = 20) diet in the last 28 d prepartum were assigned to one of two treatment groups, which were i.v. injected with saline (MC and HC, n = 9 and 10, respectively) or GLP-1 solution at 1.0 μg/kg BW (MG and HG, n = 8 and 10, respectively) immediately after milk replacer (MR; 26% CP, 16% fat) feeding. Blood samples were obtained through a jugular vein catheter at -10, 0, 10, 20, 30, 40, 50, 60, 90, and 120 min relative to MR feeding at 2, 10, and 20 d after birth, and plasma glucose, insulin, and GLP-1 concentrations were measured. Plasma GLP-1 concentration tended to increase starting from 30 min after MR feeding in the MC relative to the HC group at 10 (0.77 ng/mL vs 0.69 ng/mL for MC and HC, respectively; P = 0.10) and 20 d after birth (0.47 ng/mL vs 0.35 ng/mL for MC and HC, respectively; P = 0.07). Plasma glucose and insulin concentrations after MR feeding did not differ between MC and HC groups at 2 and 20 d after birth but were higher (P < 0.05) in MC (158 mg/dL and 3.64 ng/mL for glucose and insulin, respectively) than in HC (143 mg/dL and 2.46 ng/mL for glucose and insulin, respectively) calves at 10 d after birth. The elevation in plasma glucose concentration after MR feeding was suppressed by direct glucose-lowering action of i.v. injected GLP-1 at 2, 10, and 20 d after birth in M and H calves; this direct glucose-lowering action by GLP-1 was greater (P < 0.05) for H than for M calves at 20 d after birth. These results indicate that feeding a high-energy close-up diet to cows affects glucose status in their female offspring via suppression of postprandial plasma concentrations of GLP-1 and insulin as well as the alteration in the glucose-lowering action of GLP-1 after feeding depending on the day after birth.

Effects of prepartum diets varying in dietary energy density and monensin on early-lactation performance in dairy cows

Our objectives were to evaluate the effects of prepartum monensin supplementation and dry-period nutritional strategy on the postpartum productive performance of cows fed monensin during lactation. A total of 102 Holstein cows were enrolled in the experiment (32 primiparous and 70 multiparous). The study was a completely randomized design, with randomization restricted to balance for parity, body condition score, and expected calving date. A 2 × 2 factorial arrangement of prepartum treatments was used; the variables of interest were prepartum feeding strategy [controlled-energy diet throughout the dry period (CE) vs. controlled-energy diet from dry-off to 22 d before expected parturition, followed by a moderate-energy close-up diet from d 21 before expected parturition through parturition (CU)] and prepartum monensin supplementation [0 g/t (control, CON) or 24.2 g/t (MON); Rumensin; Elanco Animal Health, Greenfield, IN]. Lactation diets before and after the dry period contained monensin at 15.4 g/t. During the close-up period, cows fed CU had greater DM and NE_L intakes than cows fed CE. Calf BW at birth tended to be greater for cows fed CU than for those fed CE but was not affected by MON supplementation. Diet did not affect calving difficulty score, but cows supplemented with MON had an increased calving difficulty score. We found a tendency for a MON × parity interaction for colostral IgG concentration, such that multiparous MON cows tended to have lower IgG concentration than CON cows, but colostral IgG concentration for primiparous MON and CON cows did not differ. Postpartum milk yield did not differ between diets but tended to be greater for cows supplemented with MON. Milk fat and lactose content were greater for cows fed CU than for those fed CE, and lactose content and yield were increased for cows supplemented with MON. Solids-corrected and fat-corrected milk yields were increased by MON supplementation, but were not affected by diet. Overall means for postpartum DMI did not differ by diet or MON supplementation. The CU diet decreased the concentration of nonesterified fatty acids during the close-up period but increased it postpartum. Neither diet nor monensin affected β-hydroxybutyrate or liver composition. Overall, postpartum productive performance differed little between prepartum dietary strategies, but cows fed MON had greater energy-corrected milk production. In herds fed monensin during lactation, monensin should also be fed during the dry period.

The effects of prepartum energy intake and peripartum rumen-protected choline supplementation on hepatic genes involved in glucose and lipid metabolism

Nutritional interventions, either by controlling dietary energy (DE) or supplementing rumen-protected choline (RPC) or both, may mitigate negative postpartum metabolic health outcomes. A companion paper previously reported the effects of DE density and RPC supplementation on production and health outcomes. The objective of this study was to examine the effects of DE and RPC supplementation on the expression of hepatic oxidative, gluconeogenic, and lipid transport genes during the periparturient period. At 47 ± 6 d relative to calving (DRTC), 93 multiparous Holstein cows were randomly assigned in groups to dietary treatments in a 2 × 2 factorial of (1) excess energy (EXE) without RPC supplementation (1.63 Mcal of NE_L/kg of dry matter; EXE-RPC); (2) maintenance energy (MNE) without RPC supplementation (1.40 Mcal of NE_L/kg dry matter; MNE-RPC); (3) EXE with RPC supplementation (EXE+RPC); and (4) MNE with RPC supplementation (MNE+RPC). To achieve the objective of this research, liver biopsy samples were collected at -14, +7, +14, and +21 DRTC and analyzed for mRNA expression (n = 16/treatment). The interaction of DE × RPC decreased glucose-6-phosphatase and increased peroxisome proliferator-activated receptor α in MNE+RPC cows. Expression of cytosolic phosphoenolpyruvate carboxykinase was altered by the interaction of dietary treatments with reduced expression in EXE+RPC cows. A dietary treatment interaction was detected for expression of pyruvate carboxylase although means were not separated. Dietary treatment interactions did not alter expression of carnitine palmitoyltransferase 1A or microsomal triglyceride transfer protein. The 3-way interaction of DE × RPC × DRTC affected expression of carnitine palmitoyltransferase 1A, glucose-6-phosphatase, and peroxisome proliferator-activated receptor α and tended to affect cytosolic phosphoenolpyruvate carboxykinase. Despite previously reported independent effects of DE and RPC on production variables, treatments interacted to influence hepatic metabolism through altered gene expression.

Effects of starch concentration of close-up diets on rumen pH and plasma metabolite responses of dairy cows to grain challenges after calving

The objective of this study was to evaluate the effects of starch concentration of close-up diets on plasma concentrations of energy metabolites and rumen pH of dairy cows after calving. Eighteen multiparous Holstein dairy cows (mean parity = 2.78; mean body weight = 708 kg; mean body condition score = 3.08) fitted with ruminal cannulas were assigned to treatment balanced for parity, body condition score, and expected calving date. Cows were enrolled in the study at d 28 ± 3 before the expected calving date and fed either a low-starch (LS; 14.0% starch) or high-starch (HS; 26.1% starch) diet until parturition. All cows were fed a common diet after calving (25.1% starch). A grain challenge was performed on d 7 ± 2 and 21 ± 2 after calving by dosing 6.35 kg (dry matter basis) of finely ground barley and wheat grain (1:1) into the rumen via cannula. Feeding the HS diet before calving increased the duration (369 vs. 49 min/d) and area of pH below 5.8 (85.1 vs. 5.2 pH × min/d) during d -10 to -8. In addition, even though all cows were fed a common diet after calving, HS cows tended to have longer duration (177 vs. 76 min/6 h) and greater area of pH below 5.8 (67.8 vs. 20.3 pH × min/6 h) during a grain challenge on d 7. Plasma concentration of insulin tended to be greater in cows fed the HS diet (1.40 vs. 1.09 ng/mL), whereas plasma free fatty acid concentration was not different between treatments during the grain challenge on d 7. During the grain challenge on d 21, neither rumen pH nor blood metabolites were different between the HS and LS cows. These findings suggested that feeding an HS diet during the close-up period does not mitigate rumen pH depression but may exacerbate it after calving compared with feeding an LS diet.

Comparison of prepartum low-energy or high-energy diets with a 2-diet far-off and close-up strategy for multiparous and primiparous cows

Previous research demonstrated that nutrition during the far-off (early) dry period may be as important to transition success as nutrition during the close-up dry period. Our objectives were to determine if a low-energy, high-fiber diet fed throughout the dry period improved metabolic status and production of dairy cows compared with a higher-energy diet or a 2-diet system, and to compare responses of cows and heifers to those diets. Holstein cows (n = 25 with 10 primiparous per treatment) were assigned to each of 3 diets at 60 d before expected calving. Treatment LO [40.5% wheat straw; 5.6 MJ of net energy for lactation (NE_L)/kg of DM] was designed to meet but not exceed National Research Council recommendations for ad libitum intake from dry-off until calving. Treatment HI was a high-energy diet (6.7 MJ of NE_L/kg of DM) fed for ad libitum intake from dry-off until calving. For the LO+HI treatment, the LO diet was fed ad libitum from dry-off until 21 d before expected calving, followed by the HI diet until parturition. After parturition all cows were fed a lactation diet (7.0 MJ of NE_L/kg of DM) through 63 d postpartum. Dry matter intake and body weight were greater for HI cows prepartum, but not postpartum. When LO+HI cows were switched to the HI diet, their dry matter intake increased to match that of HI cows. Cows fed HI had greater gain of body condition before calving but lost more postpartum. Energy balance postpartum was higher for LO cows than for HI cows. Milk production, protein content, and protein yield did not differ among diets. Milk fat content and yield were highest for HI cows, lowest for LO, and intermediate for LO+HI cows. The HI cows had lower serum nonesterified fatty acids prepartum than either LO or LO+HI, but greater concentrations postpartum. Serum β-hydroxybutyrate did not differ prepartum, but was greater for HI than for LO or LO+HI postpartum. Serum glucose and insulin were lower for LO than HI and LO+HI prepartum; insulin was lower for LO and HI than for LO+HI postpartum. The LO cows had lower liver total lipid concentration postpartum than the HI cows and LO+HI cows. Primiparous cows generally responded to diets the same as multiparous cows. The LO+HI feeding strategy provided no benefit over the LO diet. Moreover, the high-energy diet, even when fed for only 19 d before calving in the LO+HI group, resulted in increased serum β-hydroxybutyrate and liver total lipid concentrations compared with LO.

Metabolic Stress in the Transition Period of Dairy Cows: Focusing on the Prepartum Period

All modern, high-yielding dairy cows experience a certain degree of reduced insulin sensitivity, negative energy balance, and systemic inflammation during the transition period. Maladaptation to these changes may result in excessive fat mobilization, dysregulation of inflammation, immunosuppression, and, ultimately, metabolic or infectious disease in the postpartum period. Up to half of the clinical diseases in the lifespan of high-yielding dairy cows occur within 3 weeks of calving. Thus, the vast majority of prospective studies on transition dairy cows are focused on the postpartum period. However, predisposition to clinical disease and key (patho)physiological events such as a spontaneous reduction in feed intake, insulin resistance, fat mobilization, and systemic inflammation already occur in the prepartum period. This review focuses on metabolic, adaptive events occurring from drying off until calving in high-yielding cows and discusses determinants that may trigger (mal)adaptation to these events in the late prepartum period.

Effect of Dry-Period Diet on the Performance and Metabolism of Dairy Cows in Early Lactation

Simple Summary

In dairy cows, the management of the dry period should optimize milk production and limit impact on metabolic health. In early lactation, there is little information on the effect of the dry-period diet composition on the production and composition of milk and the blood metabolites. The aim of this study was to compare the effects of different dry-period diets on the blood metabolites of dairy cows during the peripartum period and the milk yield and fatty acid profile at onset of lactation. This study showed that different dry-period diets can be used without impact on milk production and composition when these diets cover the needs of dairy cows. However, blood metabolites were more sensitive to the diet offered during the dry period. In early lactation, a dry-period diet based on corn and grass silages allowed a smooth transition with better rumen and liver function parameters.

Abstract

The objective of this work was to observe the effect of three different dry-period diets on blood metabolites (p = 9) and the production and fatty acid (FA) profile of milk (p = 19) in the peripartum period. In this study, 32 Holstein dairy cows, during their dry period, were divided in 3 different diet groups, as follows: the CONC diet (n = 11) was based on concentrate meal and straw, the CORN diet (n = 11) was based on corn silage, and the MIXED diet (n = 10) was based on corn and grass silages. According to our results, the variations of C18:2n-6, C18:3n-3, non-esterified fatty acid (NEFA), NEFA/cholesterol ratio, and albumin were significantly (p < 0.05) different, according to the dry diet. The dry-period diet also had a significant effect on the concentrations of urea and vitamin B₁₂ in the blood. In early lactation, this work showed that blood metabolites were more sensitive to changes in the dry diet than the production and FA profile of milk.

Symposium review: Nutrition strategies for improved health, production, and fertility during the transition period

Dairy cow nutritional programs are a major determinant of the profitability of dairy farms. Despite this, the sustainability of the dairy enterprise is beyond just cow nutrition. For almost 50 yr, the NC-2042 project (Management Systems to Improve the Economic and Environmental Sustainability of Dairy Enterprises) has been addressing most of these components as individual research units and in integrated ways. This review has the objective to report the body of research developed by members of the group in connection with the existing literature on dietary formulation and feeding management during the dry period, peripartal period, and early postpartum (fresh) period. Peak disease incidence (shortly after parturition) corresponds with the time of greatest negative energy balance (NEB), the peak in blood concentrations of nonesterified fatty acids, and the greatest acceleration of milk yield. Decreased fertility in the face of increasing milk production may be attributable to greater severity of postpartal NEB resulting from inadequate transition management or increased rates of disease. The depth and duration of NEB is highly related to dry matter intake. Periparturient diseases can result from adverse ruminal conditions caused by excessive grain in the precalving or fresh cow diet, perhaps aggravated by overcrowding, heat stress, or other stressors. Others have also implicated inflammatory responses in alterations of metabolism, occurrence of health problems, and impaired reproduction. Providing controlled-energy and negative dietary cation-anion difference diets prepartum may improve dairy cow performance during the transition period. A major area of concern in the fresh cow period is a sudden increase in dietary energy density leading to subacute ruminal acidosis, which can decrease dry matter intake and digestibility of nutrients. Adequate physical form of the diet, derived from either forage neutral detergent fiber content or a mixing strategy of different ingredients in a total mixed ration, must be present to stimulate ruminal activity and chewing behavior. In conclusion, formulation and delivery of appropriate diets that limit total energy intake to requirements but also provide proper intakes of all other nutrients (including the most limiting amino acids Met and Lys) before calving can help lessen the extent of NEB after calving. Effects of such diets on indicators of metabolic health are generally positive, suggesting the potential to lessen effects of periparturient disease on fertility.

A randomized trial to study the effect of automatic cluster remover settings on milking performance, teat condition, and udder health

The objectives were to study the effect of 2 different automatic cluster remover settings on (1) milking characteristics, (2) milk component yields, (3) teat tissue condition, and (4) udder health. In a randomized controlled field trial, Holstein cows (n = 689) from 1 commercial dairy farm with a thrice-daily milking schedule were allocated to 2 treatment groups. Treatment consisted of a cluster remover take-off milk flow threshold of 1.2 (ACR1.2) or 0.8 kg/min (ACR0.8) for 57 d. Milking characteristics (milk yield; and milking unit-on time, MUOT) were obtained with electronic on-farm milk meters. Composite milk samples were collected and analyzed for fat, protein, lactose, and somatic cell count. Machine-milking-induced short- and long-term changes to the teat tissue condition were assessed visually. General linear mixed models demonstrated differences in MUOT, whereas no meaningful differences in milk yield were detected. Milk yield (least squares means, 95% confidence interval) was 11.3 (10.9-11.8) and 11.3 (10.8-11.8) kg in groups ACR1.2 and ACR0.8, respectively. The effect of treatment on MUOT was modified by parity. Milking unit-on time in first-, second-, and ≥third-lactation cows, respectively, was 260.7 (252.0-269.4), 257.8 (247.4-268.1), and 260.2 (252.6-267.9) s in group ACR1.2; and 273.7 (264.9-282.5), 279.1 (269.4-288.8), and 295.7 (287.9-303.6) s in group ACR0.8. We detected no meaningful differences in milk component yields or linear somatic cell score. Least squares means in groups ACR1.2 and ACR0.8, respectively, were milk fat yield, 0.42 (0.40-0.44) and 0.42 (0.40-0.44) kg; milk protein yield, 0.36 (0.35-0.37) and 0.37 (0.36-0.37) kg; milk lactose yield, 0.61 (0.60-0.63) and 0.63 (0.61-0.64) kg, and linear somatic cell score, 1.9 (1.8-2.0) and 1.9 (1.8-2.0). A generalized linear mixed model revealed an effect of treatment on machine-milking-induced short-term changes. The odds of short-term changes to the teat tissue were lower for cows in group ACR1.2 [odds ratio (95% confidence interval) = 0.78 (0.63-0.96)]. No meaningful differences were detected in machine-milking-induced long-term changes between treatment groups. Increasing cluster remover take-off milk flow threshold from 0.8 to 1.2 kg/min decreased individual milking duration and alleviated machine-milking-induced short-term changes to the teat tissue without adversely affecting milking performance or somatic cell count. Future studies are warranted to investigate the effect on milk production and udder health over a whole lactation period.

Effect of wheat- or oat-straw inclusion with wheat bran or corn grain in prepartum diets on postpartum performance of transition dairy cows

Current study evaluated the effects of feeding straw source and energy supplementation during prepartum period on postpartum production performance and changes in blood metabolites of crossbred dairy cows. Twenty-eight crossbred (Holstein × Sahiwal) cows were randomly assigned to one of the following four dietary treatments: (1) wheat straw and corn grain (WSCG), (2) wheat straw and wheat bran (WSWB), (3) oat straw and corn grain (OSCG) and (4) oat straw and wheat bran (OSWB) in a 2 × 2 factorial experiment. Iso-nitrogenous diets fed as ad libitum total mixed ration contained 25% wheat straw (WS) or oat straw (OS) and 10% corn grain (CG) or wheat bran (WB). Experimental duration was 42 days before and 56 days after calving. After calving, all animals were fed a similar lactation diet. Pre- and postpartum dry-matter intake % of BW was not affected by treatments. Prepartum energy balance (EBAL) was higher for OS than WS and higher for CG than WB animals. Postpartum EBAL was higher in the WSCG than OSCG treatment. Milk production and composition were not affected by straw source or energy concentrate. Milk yield at Weeks 1, 2 and 3 was higher in the WSWB than WSCG and OSWB treatments. Total solids and feed efficiency were higher in the WSWB than WSCG treatment. Postpartum plasma concentration of non-esterified fatty acids was higher in the WS than the OS diet; however, the measured values were within normal limits. Postpartum plasma β-hydroxybutyrate concentration was not affected by straw source or energy concentrate. Cows fed WSWB prepartum were in positive EBAL, before and after calving, closer to the recommended requirements. Moreover, cows fed WSWB had a lower incidence of health disorders and subclinical ketosis, higher milk production and better feed conversion efficiency during first 3 weeks after calving.

Characterization of metabolic and inflammatory profiles of transition dairy cows fed an energy-restricted diet

Periparturient diseases of dairy cows are caused by disproportionate energy metabolism, mineral imbalance, and perturbed immune function. The aim of the present study was to characterize metabolism, innate immune endometrial gene expression, and uterine microbial populations of transition animals receiving normal or restricted energy diets. Pregnant multiparous Holstein cows (n = 14) were randomly assigned to one of the two dietary treatments from 20 d prepartum until 35 d postpartum (DPP). One group was fed a diet providing 100% energy requirements (NE), whereas the other received an energy-restricted diet providing 80% energy requirements (RE). Feed intake, milk yield, body weight, body condition score, temperature, respiratory, and pulse rate were recorded. After calving, blood was collected weekly to analyze nonesterified fatty acids (NEFAs), β-hydroxybutyrate (BHB), and total cholesterol (TC). Endometrial cytobrushes were collected for gene expression analysis of inflammatory markers, microbial populations determination, and cytological evaluation. The restricted energy diet did not alter feed intake or milk yield but changed energy balance and metabolites levels (P < 0.05). In fact, RE animals had high NEFA and BHB levels, and low TC concentrations (P < 0.05). Moreover, RE animals had upregulated gene expression of serum amyloid A3 (SAA3) at 35 DPP (P < 0.05) and CXC chemokine receptor 2 (CXCR2) at 14 DPP (P < 0.01). Interleukin (IL) 1 and IL8 genes were downregulated 14 DPP but upregulated 35 DPP in RE animals, whereas IL6 and lipopolysaccharide-binding protein (LBP) genes were upregulated at 14 DPP (P ≤ 0.05). The most abundant phyla in RE animals (n = 3) were Bacteroidetes and Fusobacteria, whereas Proteobacteria was the least abundant at both 14 and 35 DPP. In conclusion, it can be speculated that energy balance is one of the main drivers for uterine inflammation by affecting metabolism, immune function, and uterine microbiota. However, these findings should be validated in a larger sample size.

Longitudinal Phenotypes Improve Genotype Association for Hyperketonemia in Dairy Cattle

Simple Summary

Dairy cows have differing success in supporting their physiological functions while in energy deficit right after calving. Identification of genomic regions associated with different concentrations of non–esterified fatty acids and β–hydroxybutyrate in early postpartum Holstein cows provide insight into an animal’s genetic susceptibility to these conditions. Longitudinal phenotypes may provide a different perspective than cross-sectional phenotype variation and their association with genotypes in the study of complex metabolic diseases in dairy cows. This might allow us to reinforce preventative measures that decrease the incidence of hyperketonemia and improve genetic selection criteria.

Abstract

The objective of our study was to identify genomic regions associated with varying concentrations of non-esterified fatty acid (NEFA), β-hydroxybutyrate (BHB), and the development of hyperketonemia (HYK) in longitudinally sampled Holstein dairy cows. Our study population consisted of 147 multiparous cows intensively characterized by serial NEFA and BHB concentrations. To identify individuals with contrasting combinations in longitudinal BHB and NEFA concentrations, phenotypes were established using incremental area under the curve (AUC) and categorized as follows: Group (1) high NEFA and high BHB, group (2) low NEFA and high BHB), group (3) low NEFA and low BHB, and group (4) high NEFA and low BHB. Cows were genotyped on the Illumina Bovine High-density (777 K) beadchip. Genome-wide association studies using mixed linear models with the least-related animals were performed to establish a genetic association with HYK, BHB-AUC, NEFA-AUC, and the comparisons of the 4 AUC phenotypic groups using Golden Helix software. Nine single-nucleotide polymorphisms were associated with high longitudinal concentrations of BHB and further investigated. Five candidate genes related to energy metabolism and homeostasis were identified. These results provide biological insight and help identify susceptible animals thus improving genetic selection criteria thereby decreasing the incidence of HYK.

Blood β-hydroxybutyrate concentrations and early lactation management strategies on pasture-based dairy farms in Colombia

The increasing global demand for food requires sustainable solutions to close the gap in agricultural yield between industrialized and non-industrialized countries. Our objectives in this cross-sectional study were to: 1) characterize farm populations, milk yield, and early lactation management strategies of dairy cows in three different regions of Colombia, and 2) determine the association of these management strategies with blood β-hydroxybutyrate (BHB) concentrations in the first 42 days in milk (DIM). Dairy herds (n = 56) in the Antioquia, Caldas, and Cundinamarca regions of Colombia were visited once from May through July 2018. A survey was administered to farm owners to collect demographic, management, and herd nutrition information. Blood samples from dairy cows (n = 880) between calving and 42 DIM were used to measure blood BHB concentration. Associations between management and nutritional strategies and blood BHB concentration were examined using mixed models. Prevalence of hyperketonemia was calculated as the number of samples with BHB concentration ≥1.2 mmol/L divided by the total number of samples. The estimated diet composition for early lactation dairy cows was 65.5% pasture and 31.8% commercial concentrates. The farm median milk yield, protein concentration, and fat concentration were 21.0 kg (range = 13.1-36 kg), 3.2% (range = 2.7-4.1%), and 3.5% (range = 3.0-4.1%), respectively. Milk yield least squares means (95% confidence interval; CI) differed by region: 21.7 (20.3, 23.2), 18.5 (17.0, 20.2), and 20.3 (18.5, 22.4) kg in Antioquia, Caldas, and Cundinamarca, respectively. Median blood BHB concentration was 0.5 and ranged from 0.1-4.4 mmol/L; blood BHB concentration was not different among the three regions. Pasture fertilization, increased parity, and BCS were associated with changes in blood BHB concentration. The overall prevalence of hyperketonemia was 4.5%. Geographical region affected the prevalence of hyperketonemia at 2.5%, 4.0%, and 10.2% in Antioquia, Caldas, and Cundinamarca, respectively. Mean stocking density (95% CI) was greater in Cundinamarca than Antioquia or Caldas at 3.3 (2.2, 5.0), 2.8 (2.1, 3.9) and 1.7 (1.2, 2.6) animals per ha, respectively, and was associated with hyperketonemia prevalence. Farms that abruptly stop milking cows at dry-off had 80% of the hyperketonemia events in the study. Pasture-based dairies in Colombia had lower blood BHB concentrations and estimated milk yield compared with confined production systems in temperate zones. However, geographical region, stocking density, and abrupt cessation of milking at dry-off were associated with prevalence of hyperketonemia in pasture-based dairies.

Mammalian target of rapamycin signaling and ubiquitin-proteasome-related gene expression in skeletal muscle of dairy cows with high or normal body condition score around calving

The objective of the current study was to investigate the effects of overconditioning around calving on gene expression of key components of the mammalian target of rapamycin (mTOR) pathway and ubiquitin-proteasome system (UPS) in skeletal muscle as well as the AA profiles in both serum and muscle of periparturient cows. Fifteen weeks antepartum, 38 multiparous Holstein cows were allocated to either a high body condition group (HBCS; n = 19) or a normal body condition group (NBCS; n = 19) and were fed different diets until dry-off (d -49 relative to calving) to amplify the difference. The groups were also stratified for comparable milk yields (NBCS: 10,361 ± 302 kg; HBCS: 10,315 ± 437 kg). At dry-off, the NBCS cows (parity: 2.42 ± 1.84; body weight: 665 ± 64 kg) had a body condition score (BCS) <3.5 and backfat thickness (BFT) <1.2 cm, whereas the HBCS cows (parity: 3.37 ± 1.67; body weight: 720 ± 57 kg) had a BCS >3.75 and BFT >1.4 cm. During the dry period and the subsequent lactation, both groups were fed identical diets but maintained the BCS and BFT differences. Blood samples and skeletal muscle biopsies (semitendinosus) were repeatedly (d -49, +3, +21, and +84 relative to calving) collected for assessing the concentrations of free AA and the mRNA abundance of various components of mTOR and UPS. The differences in BCS and BFT were maintained throughout the study. The circulating concentrations of most AA with the exception of Gly, Gln, Met, and Phe increased in early lactation in both groups. The serum concentrations of Ala (d +21 and +84) and Orn (d +84) were lower in HBCS cows than in NBCS cows, but those of Gly, His, Leu, Val, Lys, Met, and Orn on d -49 and Ile on d +21 were greater in HBCS cows than in NBCS cows. The serum concentrations of 3-methylhistidine, creatinine, and 3-methylhistidine:creatinine ratio increased after calving (d +3) but did not differ between the groups. The muscle concentrations of all AA (except for Cys) remained unchanged over time and did not differ between groups. The muscle concentrations of Cys were greater on d -49 but tended to be lower on d +21 in HBCS cows than in NBCS cows. On d +21, mTOR and eukaryotic translation initiation factor 4E binding protein 1 mRNA abundance was greater in HBCS cows than in NBCS cows, whereas ribosomal protein S6 kinase 1 was not different between the groups. The mRNA abundance of ubiquitin-activating enzyme 1 (d +21), ubiquitin-conjugating enzyme 1 (d +21), atrogin-1 (d +21), and ring finger protein-1 (d +3) enzymes was greater in HBCS cows than in NBCS cows, whereas ubiquitin-conjugating enzyme 2 was not different between the groups. The increased mRNA abundance of key components of mTOR signaling and of muscle-specific ligases of HBCS cows may indicate a simultaneous activation of anabolic and catabolic processes and thus increased muscle protein turnover, likely as a part of the adaptive response to prevent excessive loss of skeletal muscle mass during early lactation.

Plasma Protein Comparison between Dairy Cows with Inactive Ovaries and Estrus

To screen differentially expressed proteins in the blood dairy cows with inactive ovaries caused by a negative energy balance and to determine the roles of the identified proteins in the development of inactive ovaries.Holstein cows at 14 to 21 days postpartum in an intensive dairy farm were examined for their energy balance (EB) status by blood β-hydroxybutyrate (BHBA) and assigned to the inactive ovary (IO) group (n = 50) and the normal oestrus control (CON) group (n = 50) at 60 to 90 days postpartum by means of the oestrus manifestation, rectal examination and B-ultrasound examination. Fourteen differentially expressed proteins from 61 proteins in the plasma of dairy cows with IOs were identified by iTRAQ/LC-MS/MS and GO, KEGG, and PATHWAY analysis. Eleven expressed proteins were upregulated, and 3 expressed proteins were downregulated. Among the 10 differentially expressed proteins verified by Western blot or ELISA, the relative expression levels of ALDOB, IGFBP2, ITIH3 and LDHB in mixed samples and single samples were consistent with the proteomic protein results. PKM2, GPX3, ALDOB, RBP4 and AHSG were significantly different between the two groups (P < 0.05); APOA4 and SPAM1 were not significantly different (P > 0.05) but were still downregulated in the ovarian resting group. This study confirmed that 14 plasma differential proteins in the inactive ovaries of postpartum dairy cows were associated with follicular development, and these findings provide a foundation for further research on the mechanism and prevention of inactive ovaries in dairy cows.

Effects of feeding a high- or moderate-starch prepartum diet to cows on newborn dairy heifer calf responses to intravenous glucose tolerance tests early in life

The objective of this study was to evaluate the effect of feeding a prepartum diet with a high or moderate starch content on growth and insulin sensitivity of female offspring early in life. Thirty-eight Holstein heifer calves were born to dams fed either a high-starch (26% starch on a DM basis, HI; n = 20) or moderate-starch (14% starch on a DM basis, MOD; n = 18) prepartum diet commencing at 28 ± 3 d before expected parturition date. Following birth, all calves were housed individually and fed three 2-L meals of colostrum within the first 24 h of life and offered 10 L/d of milk replacer (26% CP, 18% fat, mixed to 130 g/L). Body weight of calves was measured at birth and on d 2 (after colostrum feeding but before milk feeding), 10 ± 2, and 20 ± 2. A glucose tolerance test was performed at a minimum of 6 h after their last colostrum or milk meal to evaluate insulin sensitivity on d 2, 10 ± 2 and 20 ± 2. Body weight did not differ throughout between HI and MOD calves; however, calves born to primiparous dams were smaller compared with those born to multiparous dams. Glucose or insulin concentrations were not different before the glucose tolerance test. Following the glucose tolerance test, maximum glucose concentrations were not different between treatments at any time point. However, HI calves had greater insulin area under the curve, and HI calves had greater maximum insulin concentrations on d 2. Glucose or insulin clearance rates were not different nor was the calculated insulin sensitivity index between treatments. These findings suggest that feeding a HI prepartum diet may reduce some insulin sensitivity indicators of female offspring early in life.

Serum Apelin-36 alteration in late pregnancy and early lactation of dairy cows and its association with negative energy balance markers

The beneficial roles of Apelin on both energy metabolism and insulin sensitivity have been described in previous researches, but it has been little studied in dairy cows. The aim of the present study was to determine the serum Apelin-36 concentration in late pregnancy and early lactation in dairy cows and its association with negative energy balance markers. Thirty Holstein dairy cows (multiparous; n = 15 and primiparous; n = 15) with body condition score 3-3.75 at parturition were selected and blood samples were obtained for metabolic profile one month before and one month after parturition. Apelin-36, glucose, insulin, β-hydroxybutyric acid (BHBA), non-esterified fatty acid (NEFA), cholesterol, triglyceride (TG) and high density lipoproteins (HDL) were measured using commercial kits. BCS and milk production were recorded during the study. There was no effect of parity on Apelin-36, cholesterol, TG, HDL, BHB and NEFA concentrations before lactation; while insulin and glucose levels were higher in primiparous cows than multiparous cows at this period. None of the factors showed any significant difference between multiparous and primiparous cows after lactation. Serum NEFA concentration were increased after parturition, while Apelin-36, insulin and glucose concentrations were decreased after parturition in primiparous and multiparous cows. Significant correlations were observed between serum Apelin and insulin (P = .041, r = 0.672), NEFA (P = .027, r = -0.808) and glucose (P = .037, r = 0.757). In conclusion, our results showed that serum Apelin-36 concentration decreased after parturition in dairy cow. Alteration of Apelin-36 secretion after parturition may represent an endocrine adaptation in dairy cow during the lactating period.

Early lactation performance in Holstein heifers first calving at 36 months and managed for high or low weight gain during mid- and late gestation

The effect of weight gain during mid- and late gestation in dairy heifers on performance at the start of first lactation was studied. In this experiment, 47 Holstein heifers with first calving at 36 months of age were used. The plane of nutrition aimed to have a high (900 g/d, H; n = 23) and low (500, L; n = 24) average daily gain (ADG) from the 4th month of gestation until 3 weeks before the expected day of calving, achieved by ad libitum intake of high quality pasture (H) or controlled intake of a total mixed ration (L). Body weight (BW), body condition score (BCS), milking, and reproductive performances were recorded. Concentrations of plasma non-esterified fatty acids (NEFA), glucose, beta-hydroxybutyric acid (BHBA), and urea were characterised at weeks 2, 4, 6 and 8 of lactation. Milk fatty acid composition was determined at weeks 3 and 6. A total of 39 heifers successfully calved and completed first lactation. During feeding treatment the required ADG were achieved. BW and BCS were higher in H heifers at calving compared to L heifers: 707 vs. 640 kg, and 3.91 vs. 3.01 respectively. H heifers lost more weight, BCS and had lower feed intake during the beginning of first lactation (-0.8 kg DM/d/heifer over the first 4 weeks of lactation). Per day of lactation, H heifers produced significantly more milk (29.2 vs. 26.2 kg), fat (1.27 vs. 1.07 kg) and protein (0.84 vs. 0.477 kg) from 0 to 8 weeks of lactation. Concentrations of NEFA, glucose and BHBA were higher in H heifers compared to L heifers, but urea concentration was not affected. Concentration of preformed fatty acids in the milk (C16 and more) was higher. As a result, the calculated daily net energy balance during the first 8 weeks of lactation was -1.53 and -5.95 MJ for L and H heifers, respectively.

Effect of rumen-protected branched-chain amino acid supplementation on production- and energy-related metabolites during the first 35 days in milk in Holstein dairy cows

Essential AA are critical for multiple physiological processes. Branched-chain AA (BCAA) supplementation has beneficial effects on body weight, lipogenesis, and insulin resistance in several species. The BCAA are used for milk and body protein synthesis as well as being oxidized by the tricarboxylic acid cycle to produce ATP during catabolic states. The objective was to evaluate the effect of rumen-protected BCAA (375 g of 27% l-Leu, 85 g of 48% l-Ile, and 91 g of 67% l-Val) with or without propylene glycol (PG) oral administration on milk production, dry matter intake, nonesterified fatty acids, β-hydroxybutyrate, and plasma urea nitrogen during the first 35 d in milk (DIM) in dairy cattle. Multiparous Holstein cows were enrolled in blocks of three 28 d before expected calving and assigned randomly to either the control or 1 of 2 treatments. The control (n = 26) received 200 g/d of dry molasses, the BCAA treatment (n = 23) received BCAA mixed with 200 g/d of dry molasses from calving until 35 DIM, and the BCAA plus PG (BCAAPG) treatment (n = 25) received BCAA mixed with 200 g/d of dry molasses from calving until 35 DIM plus 300 mL of PG once daily from calving until 7 DIM. Postpartum, dry matter intake least squares means (LSM; 95% confidence interval) were 20.7 (19.9, 21.7), 21.3 (20.4, 22.3), and 21.9 (20.9, 22.8) kg for control, BCAA, and BCAAPG, respectively. Milk yield (1-35 DIM) LSM were 41.7 (39.4, 44.0), 42.7 (40.3, 45.0), and 43.7 (41.4, 46.0) kg for control, BCAA, and BCAAPG, respectively. Energy-corrected milk LSM were 50.3 (46.8, 53.7), 52.4 (48.9, 55.8), and 52.9 (49.5, 56.4) kg for control, BCAA, and BCAAPG, respectively. Milk urea nitrogen LSM in milk for control, BCAA, and BCAAPG were 8.60 (8.02, 9.22), 9.70 (9.01, 10.45), and 9.75 (9.08, 10.47) mg/dL. Plasma urea nitrogen concentrations LSM for control, BCAA, and BCAAPG were 8.3 (7.7, 8.9), 10.1 (9.4, 10.9), and 9.6 (9.4, 10.3) mg/dL, respectively. The numbers of plasma samples classified as hyperketonemia were 77, 44, and 57 in control, BCAA, and BCAAPG, respectively. The BCAA supplementation increased plasma urea nitrogen and milk urea nitrogen, free valine concentration in plasma, and decreased hyperketonemia events during the postpartum period.