Parturition and Hypocalcemia Blunts Calcium Signals in Immune Cells of Dairy Cattle

Mechanisms by which feeding synthetic zeolite A and dietary cation-anion difference diets affect feed intake, energy metabolism, and milk performance: Part II

The objectives of this study were to assess the effects of feeding 2 different diets, a diet with low dietary cation-anion difference (DCAD) or a diet with synthetic zeolite A, to multiparous Holstein cows during the close-up period on dry matter intake (DMI) and energy metabolism, as well as to evaluate colostrum and milk production. A total of 121 multiparous Holstein cows, blocked by lactation number and expected parturition date were enrolled at 254 d of gestation and randomly assigned to 1 of 3 dietary treatments: control (CON; +190 mEq/kg; n = 40), negative DCAD (-DCAD, -65 mEq/kg; n = 41; Ultra Chlor; Vita Plus, Lake Mills, WI), or a diet containing sodium aluminum silicate zeolite (XZ; +278 mEq/kg, fed at 3.3% dry matter, targeting 500 g/d; n = 40; X-Zelit, Protekta Inc., Lucknow, ON, Canada/Vilofoss, Graasten, Denmark). Prepartum DMI was measured daily using Insentec roughage intake control (RIC) gates (RIC System, Holofarm Group, the Netherlands). All cows received the same postpartum diet. Blood and urine samples were collected daily beginning 14 d before parturition (d -14) until parturition (d 0), and on 1, 2, 3, 6, 9, 12, 15, 18, 21, 35, and 49 d postpartum. Colostrum collected within 6 h of parturition, weighed, and based on samples' Brix value, IgG concentrations, and nutrient composition were analyzed. Prepartum, cows fed the XZ diet had decreased DMI (11.70 ± 0.26, 13.88 ± 0.26, and 13.45 ± 0.25 kg/d for XZ, CON, and -DCAD, respectively) and lower rumination (487 ± 8.1, 531 ± 8.3, and 527 ± 8.5 min for XZ, CON, and -DCAD, respectively) compared with CON and -DCAD. However, rumination was not different postpartum due to treatment. No prepartum or postpartum differences were observed for glucose or BHB concentrations in blood between dietary treatments. Colostrum collected from cows fed XZ had the highest IgG concentrations (91.10 ± 2.63, 78.00 ± 2.63, and 78.90 ± 2.63 mg/mL for XZ, CON, and -DCAD, respectively), but yield did not differ between dietary treatments. Additionally, cows in their third lactation or greater fed XZ had the highest milk production (51.0 ± 1.1 kg) during the first 49 d in milk. This study demonstrates that despite a decrease in DMI and rumination in cows fed XZ prepartum, blood BHB concentrations were not altered. Additionally, cows fed XZ had higher colostral IgG concentrations and cows in their third lactation or greater fed XZ produced the most milk. These data suggest that feeding XZ prepartum may improve colostrum quality and milk yield in mature cows, and does not affect energy metabolism.

Predictive models for metritis cure using farm-collected data, metabolic and inflammation biomarkers, and hemogram variables measured at diagnosis

Our objective was to evaluate the accuracy of predictive models for metritis spontaneous cure (SC) and cure among ceftiofur-treated cows using farm-collected data only, and with the addition of hemogram variables and circulating concentration of metabolites, minerals, and biomarkers (BM) of inflammation measured at time of diagnosis. Data related to parity, calving-related issues, BCS, rectal temperature, and DIM at metritis diagnosis were collected from a randomized clinical trial that included 422 metritic cows from 4 herds in Texas, California, and Florida. Metritis was defined as the presence of red-brownish, watery, and fetid vaginal discharge, and cure was defined as the absence of metritis 14 d after initial diagnosis. Cows were randomly allocated to receive systemic ceftiofur therapy (2 subcutaneous doses of 6.6 mg/kg of ceftiofur crystalline-free acid on the day of diagnosis and 3 d later; CEF) or to remain untreated (control). At enrollment (day of metritis diagnosis), blood samples were collected and submitted to complete blood count (CBC) and processed for the measurement of 13 minerals and BM of metabolism and inflammation. Univariable analysis to evaluate the association of farm-collected data and blood-assessed variables with metritis cure were performed, and variables with P ≤ 0.20 were offered to multivariable logistic regression models and retained if P ≤ 0.15. The areas under the curve for models predicting SC using farm data only and farm + BM were 0.70 and 0.76, respectively. Complete blood count variables were not retained in the models for SC. For models predicting cure among CEF cows, the area under the curve was 0.75, 0.77, 0.80, and 0.80 for models using farm data only, farm + CBC, farm + BM, and farm + CBC + BM, respectively. Predictive models of metritis cure had fair accuracy, with SC models being less accurate than models predictive of cure among CEF cows. Additionally, adding BM variables marginally improved the accuracy of models using farm collected data, and CBC data did not improve the accuracy of predictive models.

Association of Bovine Respiratory Disease during the Pre-Weaning Period with Blood Cell Counts and Circulating Concentration of Metabolites, Minerals, and Acute Phase Proteins in Dairy Calves Transported to a Calf Raising Facility

Our objective was to investigate the association of bovine respiratory disease (BRD) occurring within the first 56 days of life with blood cell counts and the circulating concentration of metabolites, minerals, and acute phase proteins throughout the pre-weaning period in dairy calves transported to a heifer raising facility within their first week of life. Data from 305 calves transported from dairies in Minnesota to a calf raising facility in New Mexico within their first four days of life were used in this retrospective cohort study. Blood samples were collected at 7, 17, 34, and 56 days of life for the analysis of blood cell counts, biochemistry, and the concentration of acute phase proteins. Blood urea nitrogen, albumin, GLDH, CK, P, Na, K, Cl, Zn, Hp, SAA, and monocyte counts were associated with BRD status throughout or at least at one of the time points evaluated in this study. In conclusion, several hematological variables were associated with BRD status in dairy calves that underwent transportation stress in early life.

Peripartal changes of metabolic and hormonal parameters in Romanian spotted cows and their relation with retained fetal membranes

This clinical study investigates various metabolic and physiological parameters in dairy cows during puerperium. Retained fetal membranes (RFM) is a significant postpartum complication that can affect the overall health, fertility and productivity of dairy cattle. The research focuses on changes in total proteins, albumin, glucose, triglycerides, total cholesterol, aspartate aminotransferase (AST) and alanine aminotransferase (ALT), cortisol, insulin, and insulin-like growth factor 1 (IGF-1) levels among cows experiencing normal post-partum period (NP) and those with RFM. A significant increase in protein levels was noted during the post-partum period in the RFM group, indicating physiological impacts of RFM at this stage. Albumin levels showed significant differences, highlighting a significant biological effect of RFM in the post-partum period. Glucose levels varied significantly in the weeks leading to parturition, suggesting altered metabolic states in cows that suffered RFM. Triglyceride and cholesterol levels were significantly higher during the antepartum period in the group that experienced reproductive failure, indicating substantial alterations in lipid metabolism which could herald the apparition of RFM. AST and ALT levels provided insights into cellular stress and liver function, with significant increases noted around parturition which could be attributed to the substantial physiological strain of parturition itself. Cortisol levels were higher in RFM cows 2 weeks before parturition, which could indicate an increasing stress response or a physiological preparation for the upcoming labor, and may be more pronounced in cows predisposed to RFM. Insulin levels decreased significantly before and at parturition in RFM cows, indicating a strong energy deficit. IGF-1 levels decreased significantly in RFM cows after parturition. Significant changes in metabolic parameters, such as glucose, triglycerides, and cholesterol levels, delineate the pronounced metabolic challenges faced by cows with RFM. The study elucidates that while some variations are noted as parturition approaches, the most substantial impacts attributable to RFM on metabolic and physiological parameters occur after parturition. These changes may have implications for the health, recovery, and productivity of cows postpartum, suggesting the need for targeted management strategies to mitigate the effects of RFM.

Periparturient Mineral Metabolism: Implications to Health and Productivity

Mineral metabolism, in particular Ca, and to a lesser extent phosphorus (P) and magnesium (Mg), is altered with the onset of lactation because of extensive irreversible loss to synthesize colostrum and milk. The transient reduction in the concentration of Ca in blood, particularly when it lasts days, increases the risk of mineral-related disorders such as hypocalcemia and, to a lesser extent, hypophosphatemia. Although the incidence of clinical hypocalcemia can be reduced by prepartum dietary interventions, subclinical hypocalcemia remains prevalent, affecting up to 60% of the dairy cows in the first 3 d postpartum. More importantly, strong associations exist between hypocalcemia and increased susceptibility to other peripartum diseases and impaired reproductive performance. Mechanistic experiments have demonstrated the role of Ca on innate immune response in dairy cows, which presumably predisposes them to other diseases. Hypocalcemia is not related to inadequate Ca intake as prepartum diets marginal to deficient in Ca reduce the risk of the disease. Therefore, the understanding of how Ca homeostasis is regulated, in particular how calciotropic hormones such as parathyroid hormone and 1,25-dihydroxyvitamin D3, affect blood Ca concentrations, gastrointestinal Ca absorption, bone remodeling, and renal excretion of Ca become critical to develop novel strategies to prevent mineral imbalances either by nutritional or pharmacological interventions. A common method to reduce the risk of hypocalcemia is the manipulation of the prepartum dietary cation-anion difference. Feeding acidogenic diets not only improves Ca homeostasis and reduces hypocalcemia, but also reduces the risk of uterine diseases and improves productive performance. Feeding diets that induce a negative Ca balance in the last weeks of gestation also reduce the risk of clinical hypocalcemia, and recent work shows that the incorporation of mineral sequestering agents, presumably by reducing the absorption of P and Ca prepartum, increases blood Ca at calving, although benefits to production and health remain to be shown. Alternative strategies to minimize subclinical hypocalcemia with the use of vitamin D metabolites either fed prepartum or as a pharmacological agent administered immediately after calving have shown promising results in reducing hypocalcemia and altering immune cell function, which might prove efficacious to prevent diseases in early lactation. This review summarizes the current understanding of Ca homeostasis around parturition, the limited knowledge of the exact mechanisms for gastrointestinal Ca absorption in bovine, the implications of hypocalcemia on the health of dairy cows, and discusses the methods to minimize the risk of hypocalcemia and their impacts on productive performance and health in dairy cows.

Interaction of blood calcium with milk yield, energy metabolites, subclinical mastitis, and reproductive performance in crossbred dairy cows

Limited literature is available on the consequences of postpartum low blood calcium (Ca) concentration in crossbred cows. The research aimed to investigate the correlation between postpartum serum Ca levels and various parameters, including milk yield, serum energy metabolites, milk somatic cell count, and reproductive factors in crossbred cows. Following parturition, a total of 45 potential high-yielding F2 (HF × Sahiwal; Genotype: 75:25) dairy cows were enrolled . These cows were categorized based on plasma calcium concentrations into three groups: a low calcium group (Ca-L) with a calcium concentration of <5 mg/dL, a medium calcium group (Ca-M) with a calcium concentration ranging from 5 to 8.5 mg/dL, and a high calcium group (Ca-H) with a calcium concentration exceeding 8.5 mg/dL. The study parameters were measured over an 8-week period. The results indicated that overall milk yield and blood glucose were significantly higher in the Ca-H group compared to Ca-M and Ca-L (p < .01). Blood cholesterol was significantly higher in Ca-M (p < .01), while blood triglyceride was significantly lower in both Ca-M and Ca-H. Overall, blood cortisol did not show a significant change between these groups (p < .01); however, progesterone levels were higher (p < .01) in Ca-M and Ca-H cows. Furthermore, somatic cell count (SCC) significantly (p < .01) decreased in cows with Ca-H compared to Ca-L. Additionally, postpartum oestrous interval and interestrus interval decreased significantly (p < .01) in Ca-M and Ca-H compared to Ca-L. These findings suggest that cows with blood calcium levels exceeding 8.5 mg/dL exhibited significantly higher milk yield, blood metabolite levels, a lower likelihood of subclinical mastitis, and earlier reproductive activity after calving.

Propaedeutic and Therapeutic Practices Used for Retained Fetal Membranes by Rural European Veterinary Practitioners

The present study aimed to monitor the practices of European veterinarians for the diagnosis and treatment of retained fetal membranes in cattle. A questionnaire was established and distributed to veterinarians from five European countries. A total of 700 veterinarians participated in the survey. A vaginal examination, general examination and uterine palpation are carried out by 71%, 38% and 23% of veterinarians, respectively. Moreover, half of the veterinarians attempt to remove the placenta manually, 70% of them administer a combined local and general treatment if the cow has a fever (more than 39.5 °C), and 50% of them only administer IU treatment if no fever is observed. Tetracyclins, cefapirin and penicillins are the most used intrauterine (IU) antibiotics, whereas penicillin is the most used parenteral one. All other European veterinarians were less likely to use cefapirin and more likely to use oxytocin, Ca perfusion and NSAID than French and Walloon veterinarians. In conclusion, our study confirms the necessity of improving and rationalizing the diagnostic and therapeutic approach of the RFM, mainly to reduce the important problem of antibiotic resistance.

Effects of timing of oral calcium administration on milk production in high-producing early-lactation Holstein cows

Supplementation of oral Ca via blanket administration of an oral Ca bolus at 0 and 24 h after calving has shown limited success in increasing production and minimizing adverse health events. Recent evidence that reductions in blood Ca at 4 d in milk (DIM) are more closely associated with negative outcomes than hypocalcemia at 0 to 24 h postpartum might explain this lack of Ca bolus efficacy. Therefore, our primary objective was to explore the effect of delayed oral Ca bolus supplementation on milk production, with secondary objectives of exploring the effects on disease incidence and postpartum blood Ca dynamics. We conducted a randomized controlled trial on multiparous Holstein cows (n = 998) from 4 herds in New York. At calving, cows were randomly assigned to 1 of 3 treatment groups: (1) control, no supplemental Ca at or around parturition (CON; n = 343); (2) conventional bolus, an oral Ca bolus containing 43 g of Ca at calving and 24 h later (BOL-C; n = 330); or (3) delayed bolus, an oral Ca bolus containing 43 g of Ca at 48 and 72 h after calving (BOL-D; n = 325). We created generalized linear mixed models to analyze differences in milk yield for the first 10 wk of lactation and serum total Ca (tCa) at 1 and 4 DIM between treatment groups; multivariable Poisson regression models were used to analyze adverse event outcomes (metritis, displaced abomasum, herd removal, or a combination of one or more of the 3) in the first 30 DIM. Milk yield increased by week and was not affected by treatment. However, a treatment by parity group interaction for milk yield showed that BOL-D cows in the third parity produced more milk than third-parity BOL-C or CON cows (BOL-D = 52.0 kg/d, 95% confidence interval [50.6, 53.4] kg/d, BOL-C = 47.9 [46.3, 49.5] kg/d, CON = 49.8 [48.2, 51.2] kg/d). The incidence of adverse health events was similar between treatments (BOL-D = 3.7%, BOL-C = 3.7%, CON = 3.6%). Serum tCa was lower at 1 than 4 DIM, and we detected no difference in tCa between treatment groups. Our findings suggest that delaying oral Ca bolus supplementation has limited influence on blood Ca concentrations but may be beneficial to cohorts of cows as a targeted prophylactic supplement to support milk production.

Identification of genetic variants and individual genes associated with postpartum hypocalcemia in Holstein cows

Periparturient hypocalcemia is a complex metabolic disorder that occurs at the onset of lactation because of a sudden irreversible loss of Ca incorporated into colostrum and milk. Some cows are unable to quickly adapt to this demand and succumb to clinical hypocalcemia, commonly known as milk fever, whereas a larger proportion of cows develop subclinical hypocalcemia. The main goal of this study was to identify causative mutations and candidate genes affecting postpartum blood calcium concentration in Holstein cows. Data consisted of blood calcium concentration measured in 2513 Holstein cows on the first three days after parturition. All cows had genotypic information for 79 k SNP markers. Two consecutive rounds of imputation were performed: first, the 2513 Holstein cows were imputed from 79 k to 312 k SNP markers. This imputation was performed using a reference set of 17,131 proven Holstein bulls with 312 k SNP markers. Then, the 2513 Holstein cows were imputed from 312 k markers to whole-genome sequence data. This second round of imputation used 179 Holstein animals from the 1000 Bulls Genome Project as a reference set. Three alternative phenotypes were evaluated: (1) total calcium concentration in the first 24 h postpartum, (2) total calcium concentration in the first 72 h postpartum calculated as the area under the curve; and (3) the recovery of total calcium concentration calculated as the difference in total calcium concentration between 72 and 24 h. The identification of genetic variants associated with these traits was performed using a two-step mixed model-based approach implemented in the R package MixABEL. The most significant variants were located within or near genes involved in calcium homeostasis and vitamin D transport (GC), calcium and potassium channels (JPH3 and KCNK13), energy and lipid metabolism (CA5A, PRORP, and SREBP1), and immune response (IL12RB2 and CXCL8), among other functions. This work provides the foundation for the development of novel breeding and management tools for reducing the incidence of periparturient hypocalcemia in dairy cattle.

Store-operated Ca2+ entry-sensitive glycolysis regulates neutrophil adhesion and phagocytosis in dairy cows with subclinical hypocalcemia

Hypocalcemia in dairy cows is associated with a decrease of neutrophil adhesion and phagocytosis, an effect driven partly by changes in the expression of store-operated Ca2+ entry (SOCE)-related molecules. It is well established in nonruminants that neutrophils obtain the energy required for immune function through glycolysis. Whether glycolysis plays a role in the acquisition of energy by neutrophils during hypocalcemia in dairy cows is unknown. To address this relationship, we performed a cohort study and then a clinical trial. Neutrophils were isolated at 2 d postcalving from lactating Holstein dairy cows (average 2.83 ± 0.42 lactations, n = 6) diagnosed as clinically healthy (CON) or with plasma concentrations of Ca2+ <2.0 mmol/L as a criterion for diagnosing subclinical hypocalcemia (HYP, average 2.83 ± 0.42 lactations, n = 6). In the first experiment, neutrophils were isolated from blood of CON and HYP cows and used to analyze aspects of adhesion and phagocytosis function through quantitative reverse-transcription PCR along with confocal laser scanning microscopy, mRNA expression of the glycolysis-related gene hexokinase 2 (HKII), and components of the SOCE moiety ORAI calcium release-activated calcium modulator 1 (ORAI1, ORAI2, ORAI3, stromal interaction molecule 1 [STIM1], and STIM2). Results showed that adhesion and phagocytosis function were reduced in HYP cows. The mRNA expression of adhesion-related syndecan-4 (SDC4), integrin β9 (ITGA9), and integrin β3 (ITGB3) and phagocytosis-related molecules complement component 1 R subcomponent (C1R), CD36, tubulinß1 (TUBB1) were significantly decreased in the HYP group. In the second experiment, to address how glycolysis affects neutrophil adhesion and phagocytosis, neutrophils isolated from CON and HYP cows were treated with 2 μM HKII inhibitor benserazide-d3 or 1 μM fructose-bisphosphatase 1 (FBP1) inhibitor MB05032 for 1 h. Results revealed that the HKII inhibitor benserazide-d3 reduced phagocytosis and the mRNA abundance of ITGA9, and CD36 in the HYP group. The FBP1 inhibitor MB05032 increased adhesion and phagocytosis and increased mRNA abundance of HKII, ITGA9, and CD36 in the HYP group. Finally, to investigate the mechanism whereby SOCE-sensitive glycolysis affects neutrophil adhesion and phagocytosis, isolated neutrophils were treated with 1 μM SOCE activator thapsigargin or 50 μM inhibitor 2-APB for 1 h. Results showed that thapsigargin increased mRNA abundance of HKII, ITGA9, and CD36, and increased adhesion and phagocytosis in the HYP group. In contrast, 2-APB decreased mRNA abundance of HKII and both adhesion and phagocytosis of neutrophils in the CON group. Overall, the data indicated that SOCE-sensitive intracellular Ca2+ levels affect glycolysis and help regulate adhesion and phagocytosis of neutrophils during hypocalcemia in dairy cows.

The Many Hosts of Mycobacteria 9 (MHM9): A conference report

The Many Hosts of Mycobacteria (MHM) meeting series brings together basic scientists, clinicians and veterinarians to promote robust discussion and dissemination of recent advances in our knowledge of numerous mycobacterial diseases, including human and bovine tuberculosis (TB), nontuberculous mycobacteria (NTM) infection, Hansen's disease (leprosy), Buruli ulcer and Johne's disease. The 9th MHM conference (MHM9) was held in July 2022 at The Ohio State University (OSU) and centered around the theme of "Confounders of Mycobacterial Disease." Confounders can and often do drive the transmission of mycobacterial diseases, as well as impact surveillance and treatment outcomes. Various confounders were presented and discussed at MHM9 including those that originate from the host (comorbidities and coinfections) as well as those arising from the environment (e.g., zoonotic exposures), economic inequality (e.g. healthcare disparities), stigma (a confounder of leprosy and TB for millennia), and historical neglect (a confounder in Native American Nations). This conference report summarizes select talks given at MHM9 highlighting recent research advances, as well as talks regarding the historic and ongoing impact of TB and other infectious diseases on Native American Nations, including those in Southwestern Alaska where the regional TB incidence rate is among the highest in the Western hemisphere.

Behavioral patterns as indicators of resilience after parturition in dairy cows

During the transition phase, dairy cows are susceptible to develop postpartum diseases. Cows that stay healthy or recover rapidly can be considered to be more resilient in comparison to those that develop postpartum diseases. An indication of loss of resilience will allow for early intervention with preventive and supportive measures before the onset of disease. We investigated which quantitative behavioral characteristics during the dry period could be used as indicators of reduced resilience after calving, using noninvasive Smart Tag neck and Smart Tag leg sensors in dairy cows (Nedap N.V.). We followed 180 cows during 2 wk before until 6 wk after parturition at 4 farms in the Netherlands. Serving as proxy for loss of resilience, as defined by the duration and severity of disease, a clinical assessment was performed twice weekly and blood samples were taken in the first and fifth week after parturition. For each cow, clinical and serum value deviations were aggregated into a total deficit score (TDS total). We also calculated TDS values relating to inflammation, locomotion, or metabolic problems, which were further divided into macro-mineral and liver-related deviations. Smart Tag neck and leg sensors provided continuous behavioral activity signals of which we calculated the average, variance, and autocorrelation during the dry period. Diurnal patterns in the behavioral activity signals were derived by fast Fourier transformation and the calculation of the nonperiodicity. To select significant predictors of resilience, we first performed a univariate analysis with TDS as dependent variable and the behavioral characteristics that were measured during the dry period, as potential predictors with cow as experimental unit. We included parity group as fixed effect and farm as random effect. Next, we performed multivariable analysis with only significant predictors, followed by a variable selection procedure to obtain a final linear mixed model with an optimal subset of predictors with parity group as fixed effect and farm as random effect. The TDS total was best predicted by average inactive time, nonperiodicity ruminating, nonperiodicity of bouts standing up and fast Fourier transformation stand still. Average inactive time was negatively correlated with average eating time, and these 2 predictors could be exchanged with only little difference in model performance. Our best performing model predicted TDS total at a cutoff level of 60 points, with a sensitivity of 79.5% and a specificity of 73.2% with a positive predicted value of 0.69 and a negative predicted value of 0.83. The models to predict the other TDS categories showed a lower predictive performance as compared with the TDS total model, which could be related to the limited sample size and therefore, low occurrence of problems within a specific TDS category. Furthermore, more resilient dairy cows are characterized by high averages of eating time with high regularity in rumination and low averages of inactive time. They reveal high regularity in standing time and transitions from lying to standing, in the dry period. These behaviors can be used as indicators of resilience and allow for preventive intervention during the dry period in vulnerable dairy cattle. However, further examination is still required to find clues for adequate intervention strategies.

Comparison of prepartum blood parameters in dairy cows with postpartum ketosis and new risk prediction candidates

Introduction

Ketosis is a predominant metabolic problem and a risk factor for several postpartum diseases. This retrospective study aimed to evaluate the complete blood count (CBC), plasma biochemistry, and osteocalcin and identify significant prepartum and early postpartum values expressed in ketotic cows.

Methods

In 135 Holstein Friesian cows, 210 parturitions of 114 primiparous and 96 multiparous cows were examined. According to the plasma concentrations of β-hydroxybutyrate (BHB; ≥ 1.4 mmol/L) or non-esterified fatty acids (NEFA; ≥ 0.7 mmol/L) in the postpartum period, cows were divided into healthy cows (CON) and ketotic cows (KET). Analyses of CBC and biochemistry profiles were performed from -6 to 4 weeks of parturition every 2 weeks (prepartum; BW-5, BW-3, and BW-1, postpartum; BW1 and BW3), and osteocalcin ELISA tests were performed using blood samples from -2 to 2 weeks of parturition (BW-1 and BW1).

Results

In primiparous KET (n = 114) before parturition, lower lymphocyte (Lym) in BW-5 and BW-3, lower red blood cell (RBC) in BW-5, higher mean corpuscular volume (MCV) in BW-1, and higher NEFA in BW-3 were significant compared with CON. Primiparous KET showed lower carboxylated osteocalcin (cOC) levels and a significant decrease after parturition. In multiparous KET (n = 96) before parturition, lower neutrophil (Neu) in BW-5, higher hemoglobin (HGB) in BW-5, higher MCV in BW-5 and BW-1, higher MCH in BW-5, lower total cholesterol (TC) in BW-5, higher triglyceride (TG) in BW-3, higher NEFA in BW-1, higher glucose (Glu) in BW-3, lower γ-glutamyl transferase (GGT) in BW-5, lower inorganic phosphate (iP) in BW-3, and higher body condition score (BCS) in BW-5 and BW-3 were significant compared with CON. Multiparous KET showed decreased cOC and uncarboxylated osteocalcin (ucOC) after parturition, which was lower than that in the CON group.

Discussion

The blood parameters expressing different values between CON and KET in prepartum or early postpartum periods are presumed to show individual nutrition and health states, liver function, and overweight status. These parameters could be valuable indicators that can be used to prevent the occurrence of ketosis and improve management practices by recognizing these differences in ketotic cows before calving.

Metabolic Factors at the Crossroads of Periparturient Immunity and Inflammation

Periparturient cows have the highest risk for disease and culling in the adult dairy herd. This risk is compounded by the multiple physiological changes of metabolism and immune function occurring around calving that alter the cow's inflammatory response. In this article, the authors summarize the current knowledge on immunometabolism in the periparturient cow, discussing major changes in immune and metabolic function around parturition that will facilitate the assessment of periparturient cow management programs.

Relationship between blood calcium level and post-milking teat canal closure in dairy cows

The teat canal-one of the primary defense mechanisms of the udder-ensures the milk flow during milking in bovines and prevents pathogens from entering the udder by forming a barrier through the elastic muscle and keratin layers tightly closing the surrounding area. The current study investigated the effects of blood calcium status on teat closure in cows after milking. The study covered 200 healthy teats, of which 100 were from normocalcemic (NC) cows and 100 were from subclinical hypocalcemic (SCH) cows. Teat canal length (TCL) and width (TCW) were measured with ultrasonography at 0-min pre-milking and 15- and 30-min post-milking. Cylindrically shaped teat canal volume (TCV) was calculated by deriving from TCL and TCW. Time-dependent changes in teat canal closure and their relationships with blood calcium levels were analyzed. The results showed that the calcium level did not affect TCL, TCW, and TCV (P > 0.05) during the 15-min post-milking period. However, TCL (P < 0.001), TCW (P < 0.05), and TCV (P < 0.001) were lower in NC cows than in SCH cows at 30-min post-milking. At 15-min post-milking, no correlation existed between the teat canal closure (ΔTCL, ΔTCW, and ΔTCV) and the blood calcium level, while significant correlations were available between the teat canal closure and the blood calcium level {ΔTCL (r: - 0.288, P < 0.001), ΔTCW (r: - 0.260, P < 0.001), ΔTCV (r: - 0.150, P < 0.05)} at 30-min post-milking. The current study concluded that the blood calcium status significantly impacts the teat canal closure in bovines, and calcium status should be meticulously monitored with the mastitis control program to apply necessary strategic steps.

The association of subclinical hypocalcemia at 4 days in milk with reproductive outcomes in multiparous Holstein cows

Delayed or persistent episodes of subclinical hypocalcemia (SCH) have been associated with reduced milk production and feed intake and they put cows at risk for additional disease development. However, little is known about the effect of delayed or persistent SCH on reproductive outcomes. The objectives of our study were to describe the association between SCH status at 4 d in milk (DIM) with the odds of pregnancy to first service and time to pregnancy through 150 DIM. Data were collected from multiparous Holstein cows (n = 697) from 4 farms in New York State that did not receive supplemental Ca during the first 5 DIM. Cows were classified into 1 of 2 SCH groups based on blood total Ca (tCa) at 4 DIM: normocalcemic (NC; n = 515) if tCa >2.2 mmol/L at 4 DIM or SCH (n = 182) if tCa ≤2.2 mmol/L at 4 DIM. We created a multivariable logistic regression model to assess the association between SCH group and pregnancy to first service and a time-to-event analysis to evaluate the effect of SCH group on the hazard of pregnancy by 150 DIM. Cows that were SCH at 4 DIM had lower odds of pregnancy to first service [odds ratio = 0.75, 95% confidence interval (CI) = 0.61 to 0.93, incidence = 18.1%] compared with their NC counterparts (incidence = 27.4%). Similarly, SCH cows tended to have a lower hazard of pregnancy by 150 DIM (hazard ratio = 0.82, 95% CI = 0.67 to 1.01, incidence = 65.4%) than NC cows (incidence = 70.7%). Our results indicate that delayed or prolonged reductions in blood Ca in the early postpartum period, resulting in SCH at 4 DIM, were associated with reduced reproductive outcomes in multiparous cows. Our findings, in conjunction with previous reports of the negative associations of delayed or persistent SCH on health and production, suggest that reductions in blood Ca beyond the first day of lactation might be indicative of maladaptation to lactation, and the ramifications can persist beyond the immediate postpartum period.

Implications of supplementing mid-lactation multiparous Holstein cows fed high by-product low-forage diets with rumen-protected methionine and lysine in a commercial dairy

Supplementation of rumen-protected amino acids may improve dairy cow performance but few studies have evaluated the implications of supplementing low-forage diets. Our objective was to evaluate the effects of supplementing rumen-protected methionine (Met) and lysine (Lys) on milk production and composition as well as on mammary gland health of mid-lactating Holstein cows from a commercial dairy farm feeding a high by-product low-forage diet. A total of 314 multiparous cows were randomly assigned to control (CON; 107 g of dry distillers' grains) or rumen-protected Met and Lys (RPML; 107 g dry distillers' grains + 107 g of RPML). All study cows were grouped in a single dry-lot pen and fed the same total mixed ration diet twice a day for a total of 7 weeks. Treatments were top-dressed on the total mix ration immediately after morning delivery with 107 g of dry distillers' grains for 1 week (adaptation period) and then with CON and RPML treatments for 6 weeks. Blood samples were taken from a subset of 22 cows per treatment to determine plasma AA (d 0 and 14) and plasma urea nitrogen and minerals (d 0, 14, and 42). Milk yield and clinical mastitis cases were recorded daily, and milk components were determined bi-weekly. Body condition score change was evaluated from d 0 to 42 of the study. Milk yield and components were analyzed by multiple linear regression. Treatment effects were evaluated at the cow level considering parity and milk yield and composition taken at baseline as a covariate in the models. Clinical mastitis risk was assessed by Poisson regression. Plasma Met increased (26.9 vs 36.0 µmol/L), Lys tended to increase (102.5 vs 121.1 µmol/L), and Ca increased (2.39 vs 2.46 mmol/L) with RPML supplementation. Cows supplemented with RPML had higher milk yield (45.4 vs 46.0 kg/d) and a lower risk of clinical mastitis (risk ratio = 0.39; 95% CI = 0.17-0.90) compared to CON cows. Milk components yield and concentrations, somatic cell count, body condition score change, plasma urea nitrogen, and plasma minerals other than Ca were not affected by RPML supplementation. Results suggest that RPML supplementation increases milk yield and decreases the risk of clinical mastitis in mid-lactation cows fed a high by-product low-forage diet. Further studies are needed to clarify the biological mechanisms for mammary gland responses to RPML supplementation.

The Influence of Energy Balance, Lipolysis and Ketogenesis on Metabolic Adaptation in Cows Milked Twice and Three Times Daily

Increasing milk production requires increasing milking frequency (MF) from two times daily (2X) to three (3X) or more. High milk production leads to negative energy balance (NEB) and homeorhesis, characterized by lipolysis, ketogenesis, and endocrinological changes. The relationship among energy balance (EB), lipolysis, and ketogenesis with endocrine and metabolic parameters in blood of cows milked 2X and 3X daily was studied. Holstein Friesian cows milked 2X (n = 45) and 3X (n = 45) were analyzed, with approximately 50% of cows in each group in positive EB (PEB) and 50% in NEB. After determining EB, blood samples were collected from all cows and blood serum was analyzed for non-esterified fatty acids (NEFA), beta-hydroxybutyrate (BHB), glucose (GLU), cholesterol (CHOL), triglycerides (TGC), total bilirubin (TBIL), aspartate aminotransferase (AST), gamma-glutamyl transferase (GGT), calcium (Ca), inorganic phosphate (P), total protein (TPROT), albumin (ALB), urea, insulin (INS), T3, T4, and cortisol (CORT), and the RQUICKIBHB index of insulin resistance was calculated. Cows milked 3X in NEB represent a special cluster that partially overlaps with cows milked 2X in NEB and has no contact points with cows in PEB. Cows milked 3X had higher levels of NEFA, BHB, AST, GGT, TBIL, and CORT and lower levels of GLU, Ca, INS, and T4. Cows milked 3X in NEB had higher levels of NEFA, BHB, AST, GGT, TBIL, and CORT and lower levels of GLU, CHOL, TGC, TPROT, P, INS, RQUICKIBHB, and T3 compared with cows milked 2X in NEB and cows in PEB. In cows milked 3X, lipolysis and ketogenesis were much more prominent, and EB levels were lower, implying a pronounced shift in homeorhesis. Metabolic and endocrinology parameters were determined mainly by the values of EB, NEFA, and BHB in cows milked 3X in NEB compared with other categories of cows. The results confirm the peculiarity of metabolic adaptation in cows with increased MF, characterized not only by differences in the concentration of metabolites but also in their interactions.

Transcriptomics of circulating neutrophils in dairy cows with subclinical hypocalcemia

Hypocalcemia is closely associated with inflammatory diseases in dairy cows. Recent research has underscored the key role of calcium in the adaptations of the innate immune system during this period. The main objective in the present study was to compare the transcriptome profiles and analyze differences in the expression of neutrophil (PMNL) immune function-related genes and calcium binding-related genes in hypocalcemic cows. At 2 days postpartum, a concentration &gt;2.10 mmol Ca2+/L was used to classify cows as controls (CON), and a concentration &lt;2.00 mmol Ca2+/L used to classify cows as low-calcium (LCAL) (n = 8 in each group). A routine medical examination was conducted by the attending veterinarian to ensure there were no other complications and that the blood β-hydroxybutyrate was &lt;1.2 mmol/L. Blood was collected from the tail vein (20 mL) to isolate PMNL, and 5 cows in each group were used for RNA sequencing and statistical analysis of gene expression differences. Transcriptome RNA-seq sequencing analysis was via omicsstudio using the R package edgeR. GO and KEGG enrichment analysis were used for bioinformatics. The remaining 3 cows in each group were used for validation of RNA sequencing data via quantitative PCR, which confirmed the observed responses. Compared with CON, 158 genes in LCAL were significantly up-regulated and 296 genes were down-regulated. The downregulation of Interleukin-12 (CXCL12), Tubulin beta chain (TUBB1), L1 cell adhesion molecule (L1CAM), and Myeloperoxidase (MPO) indicated a decrease in immune function of PMNL in LCAL cows. The decreased expression of calcium-binding pathway-related genes in PMNL of LCAL cows indicated a decrease in immune function of PMNL likely related to calcium ions. For example, cartilage acid protein 1 (CRTAC1) and calcium/calmodulin-dependent kinase 4 (CAMK4) were significantly reduced in LCAL cows. The upregulation of Cyclin dependent kinase inhibitor 1A (CDKN1A), Perforin 1 (PRF1), and Homeodomain interacting protein kinase 3 (HIPK3) indicated that LCAL led to greater cell apoptosis and senescence. Overall, the analyses indicated that the reduction in PMNL immune function during hypocalcemia is associated with downregulation of intracellular Ca2+ related genes and upregulation of genes controlling apoptosis and senescence. Together, these alterations contribute to an immunosuppressive state during the transition period.

Metabolic profiling in periparturient dairy cows and its relation with metabolic diseases

Objective

Periparturient period is associated with multiple changes including serum concentration of macro minerals and drop in feed intake. Therefore, it is essential to know the actual concentrations of major macro minerals, glucose and ketone bodies in blood during the periparturient period. The objectives of the study were to study the dynamics of calcium, magnesium, phosphorus, and glucose in serum and ketone bodies in the urine of periparturient cows and to estimate the incidence of subclinical metabolic diseases.

Results

Results showed that all the urine samples were negative for ketone bodies. Incidence of subclinical form of hypocalcaemia, hypomagnesaemia, hypophosphatemia, and hypoglycemia in periparturient cows was 31.03%, 48.28%, 17.24% and 55.17%, respectively. Older cows with high BCS and milk yield were mostly affected with a subclinical form of hypocalcaemia and hypoglycemia. No significant differences were observed in serum level of macro minerals and glucose at different time points of periparturient period of cows fed with a balanced ration, and between two groups of cows those were given IV injection of calcium and magnesium on the day of parturition and those were not given. Age, parity, and milk yield had no significant effect on the concentration of calcium, magnesium, phosphorus, and glucose.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13104-022-06130-z.

Nutrigenomic Interventions to Address Metabolic Stress and Related Disorders in Transition Cows

For dairy cattle, the period involving a shift from late pregnancy to early lactation termed transition or periparturient is an excruciating phase. Health-related disorders are likely to happen in this time frame. Timely postpartum and metabolic adjustments to this new physical state demands correct management strategies to fulfill the cow's needs for a successful transition to this phase. Among the management strategies, one of the most researched methods for managing transition-related stress is nutritional supplementation. Dietary components directly or indirectly affect the expression of various genes that are believed to be involved in various stress-related responses during this phase. Nutrigenomics, an interdisciplinary approach that combines nutritional science with omics technologies, opens new avenues for studying the genome's complicated interactions with food. This revolutionary technique emphasizes the importance of food-gene interactions on various physiological and metabolic mechanisms. In animal sciences, nutrigenomics aims to promote the welfare of livestock animals and enhance their commercially important qualities through nutritional interventions. To this end, an increasing volume of research shows that nutritional supplementation can be effectively used to manage the metabolic stress dairy cows undergo during the transition period. These nutritional supplements, including polyunsaturated fatty acids, vitamins, dietary amino acids, and phytochemicals, have been shown to modulate energy homeostasis through different pathways, leading to addressing metabolic issues in transition cows.

Maladaptation to the transition period and consequences on fertility of dairy cows

After parturition, dairy cows undergo a plethora of metabolic, inflammatory, and immunologic changes to adapt to the onset of lactation. These changes are mainly due to the homeorhetic shift to support milk production when nutrient demand exceeds dietary intake, resulting in a state of negative energy balance. Negative energy balance in postpartum dairy cows is characterized by upregulated adipose tissue modelling, insulin resistance, and systemic inflammation. However, half of the postpartum cows fail to adapt to these changes and develop one or more types of clinical and subclinical disease within 5 weeks after calving, and this is escorted by impaired reproductive performance in the same lactation. Maladaptation to the transition period exerts molecular and structural changes in the follicular and reproductive tract fluids, the microenvironment in which oocyte maturation, fertilization, and embryo development occur. Although the negative effects of transition diseases on fertility are well-known, the involved pathways are only partially understood. This review reconstructs the mechanism of maladaptation to lactation in the transition period, explores their key (patho)physiological effects on reproductive organs, and briefly describes potential carryover effects on fertility in the same lactation.

Serum Calcium Levels and in-Hospital Infection Risk in Patients with Acute Ischemic Stroke

Purpose

Stroke-associated infection (SAI) is one of the most common post-stroke complications, which may lead to a relatively poor prognosis. This study aims to explore the potential relationship between serum calcium levels and SAI.

Patients and Methods

This is a cross-sectional study involving 395 participants. SAI is a term that covers stroke-associated pneumonia (SAP), urinary tract infection (UTI), as well as other infections diagnosed during the first week after a stroke. Serum calcium levels were measured within 24 hrs of admission. To determine the association of serum calcium levels with the SAI, logistic regression models were calculated. An adjusted spline regression model was used to further confirm the relationship between the two.

Results

Among the total patients, SAI occurred in 107 (27.1%) patients. Serum calcium was associated with SAI and was independent of the SAI risk factors for age, admission NIHSS score, and intravascular therapy [adjusted OR 0.040 (95% CI = 0.005-0.291), p = 0.002]. Remarkably, this trend applies predominantly to serum calcium levels less than 2.25mmol/L (p= 0.005 for linearity).

Conclusion

Serum calcium levels are associated with the risk of SAI, when serum calcium is below normal (2.25mmol/L), the risk of SAI increases as serum calcium levels decrease.

Effects of Parity and Stage of Lactation on Trend and Variability of Metabolic Markers in Dairy Cows

Simple Summary

The rise in milk yield per cow, herd size, and the percentage of primiparous cows in dairy herds increasingly requires optimized health management in order to ensure the health of the cows. The transition period (three weeks before to three weeks after calving) has a key role in health problems, because dairy cows undergo tremendous metabolic changes. Metabolic monitoring provides an in-depth insight into how the cows cope with these challenges. A remarkable variability in the metabolic parameters reflects the adaptation of dairy cows during the transition from pregnancy to lactation. In addition, primiparous cows undergo physical adaptations because of growth, first gestation, the maturation of the mammary glands, the onset of lactation, and fighting for social dominance. Previous studies have rarely considered these specific demands due to the influences of parity and the lactation stage. Thus, the objective of our study was to describe the variation in metabolic parameters due to parity and the stage of lactation based on a huge number of primiparous and multiparous cows, observed at all stages of lactation, in a retrospective analysis of laboratory data. The remarkable impact of both parity and lactation was elucidated for most parameters. This should be taken into account for a correct interpretation of the laboratory diagnostics in the framework of metabolic monitoring.

Abstract

Metabolic monitoring is a tool that is helpful with the increasing requirements regarding feeding and health management in dairy herds. This study aimed at describing the trend and variability of different biochemical parameters in blood and urine in relation to the stages of lactation and parity, in a retrospective analysis of laboratory data from clinically healthy German Holstein cows. The results were derived from metabolic monitoring in Thuringia (Germany), during 2009–2019. A total of 361,584 measured values, of 13 different metabolic variables, were assigned to parity (primiparous and multiparous) and stage of lactation (10 classes from −30 to 300 days in milk). The Kruskal–Wallis test was applied for the evaluation of differences regarding parity or the stage of lactation. Non-esterified fatty acids, beta hydroxybutyrate, and the activity of aspartate aminotransferase in serum were clearly affected by parity and lactation. Serum concentrations of cholesterol, bilirubin, and phosphorus, as well as the serum activity of glutamate dehydrogenase, were affected by the stage of lactation, while parity impacted urea concentration. The serum activity of creatine kinase, serum concentrations of calcium, and urine concentrations of net acid base excretion, potassium, and sodium were not affected by parity or lactation. In conclusion, specific reference limits, with respect to parity and the stage of lactation, are necessary.

Reduced Milk Production, Economic Losses, and Risk Factors Associated to Subclinical Hypocalcemia in Holstein Friesian × Zebu Crossbreed Cows in North-West Ethiopia

Hypocalcemia is a metabolic disorder that occurs when calcium leaves the blood to support milk production or for the growth of the fetus faster than calcium can be put back into the blood. Subclinical hypocalcemia (SCH) refers to clinically normal cows but with concentrations of calcium lower than measured in normal cows. A study was conducted to estimate economic losses and to identify risk factors associated with SCH in Holstein Friesian × Zebu crossbreed Cows in North-West Ethiopia. A total of 221 lactating dairy cows obtained from 81 dairy farms were selected and serum samples were collected and analyzed to estimate the level of calcium in the serum using an automated electrolyte analyzer (Roch, UVL Japan, 2014). Forty-seven cows obtained from 12 farms were grouped into two: cows with SCH and cows without SCH and milk yield was measured for eight consecutive days to estimate milk production loss associated with SCH. Prevalence was estimated and univariable and multivariable logistic regression analyses were used to identify determinants of SCH. The prevalence of SCH was 20.3% (51/221, 90% CI = 18.6%−28.1%). Grazing on pasture, membership to dairy cooperative, feeding above the cows' requirement (based on farmers' opinion), and previous experience of metritis reduced the odds of SCH (P < 0.05). The average economic losses associated with reduced milk production due to SCH were 11.25 Ethiopian Birr (ETB) (1 ETB = 0.023 US Dollar) and 3,026.25 ETB (69.6 US Dollar) per cow per lactation, respectively. The main findings of the study have shown that SCH was a problem in crossbreed dairy cows in Northwestern Ethiopia and identified few risk factors that could be targeted to mitigate the problem. Actually, in this study, the economic cost of SCH was significant and needs attention in the dairy extension and dairy health training programs.

A Randomized Clinical Trial Evaluating the Effect of an Oral Calcium Bolus Supplementation Strategy in Postpartum Jersey Cows on Mastitis, Culling, Milk Production, and Reproductive Performance

Simple Summary

The time around parturition is a challenging period in the lactation cycle of high-yielding dairy cows as it is characterized by several endocrine, metabolic, and physiological changes. Among those challenges, calcium demands are rapidly increased to support colostrogenesis and lactogenesis during a time of reduced dry matter intake; invariably, some cows may suffer from clinical and subclinical hypocalcemia. Oral calcium supplementation is a common preventative strategy adopted in the postpartum of high-yielding dairy cows to minimize the negative impact of suboptimal blood calcium concentration during this period. Despite a great number of studies evaluating the effects of oral calcium supplementation in postpartum Holstein cows, very limited information is available for the Jersey breed. This study aimed to evaluate the effect of an oral Ca supplementation strategy in the first 24 h after parturition on health and production outcomes in multiparous Jersey cows. Overall, treatment did not improve milk production or reproductive performance compared to control cows. Additionally, treatment had no effect on early lactation culling. A tendency for a minor impact on the odds of mastitis was evident though it depended on the parity of the cows.

Abstract

The objectives of this study were to evaluate the effects of a postpartum oral calcium supplementation strategy in multiparous Jersey cows on (1) the odds of clinical mastitis in the first 60 days in milk (DIM); (2) the odds of culling up to 60 DIM; (3) the risk of pregnancy in the first 150 DIM; (4) milk production in the first 15 weeks of lactation. A randomized clinical trial was performed in a dairy herd located in west Texas, United States. A total of 809 cows were used in the final analyses. Overall, postpartum oral calcium supplementation did not influence milk production, reproductive performance, or culling. Among second parity cows, oral calcium supplementation tended to decrease the odds of clinical mastitis in the first 60 DIM compared to controls; however, no differences were observed for cows in parities three and greater. To date, data evaluating the effect of postpartum oral calcium supplementation in multiparous Jersey cows are limited. In our study, oral calcium supplementation tended to reduce clinical mastitis in second parity cows. No positive benefits based on the reduction of culling, and improvement of milk production and reproductive performance were evident for the herd included in this study.

Pharmacokinetics of 1,25-dihydroxyvitamin D3 glycosides from Solanum glaucophyllum extract given in a rumen bolus on blood mineral profiles in dry pregnant dairy cows

Providing tablets of 1,25-dihydroxyvitamin D3 (1,25(OH)2D3), the biologically active metabolite of vitamin D3, in a rumen bolus may be used as prevention for periparturient hypocalcemia in dairy cows. This study investigated the pharmacokinetics of 1,25(OH)2D3 glycosides extracted from Solanum glaucophyllum (SGE) on blood serum 1,25(OH)2D3, Ca, P and Mg response in dry pregnant dairy cows. Boluses contained tablets of SGE which differed in their release properties (rapid release, slow release and combination) and galenics (200 μg uncoated, 300 μg and 500 μg uncoated or coated, 2 × 500 μg uncoated). Nineteen blood samples were collected from 29 cows between 96 h before and 336 h after bolus administration. Blood serum 1,25(OH)2D3, Ca and P increased between 12 h and 120 h, 12 h and 264 h and 24 h and 264 h, respectively. Highest values were reached at 30 h, 72 h and 120 h for 1,25(OH)2D3, Ca and P, respectively. Baseline values were then reached at 216 h for 1,25(OH)2D3 and 336 h for Ca and P. Concentration of Mg decreased between 24 h and 216 h, before reaching values comparable to baseline at 264 h. Highest Ca values were obtained with the combined rapid and slow release properties (500 μg) and there was no effect from coating on pharmacokinetics. In conclusion, the antepartum oral SGE bolus administration may be suitable for the prevention of periparturient hypocalcemia.

Randomized clinical trial to evaluate the effects of a prepartum cholecalciferol injection on postpartum serum calcium dynamics and health and performance in early-lactation multiparous dairy cows

The objectives of the present study were (1) to evaluate the effect of prepartum cholecalciferol treatment on serum Ca concentration during the first 10 d after calving and (2) to evaluate the effect of treatment on subsequent health and performance. Multiparous Holstein cows (n = 377) from one dairy farm were fed a negative dietary cation-anion difference diet (-31 mEq/kg of DM) for the last 21 d of gestation. On d 275, the animals were randomly assigned to a control or a treatment group. Cows in the control group were left untreated, and cows in the treatment group received an injection of 12 × 10⁶ IU of cholecalciferol intramuscularly on the day of enrollment. If treated cows did not deliver the calf within 6 d, they were reinjected with 10 × 10⁶ IU of cholecalciferol. Blood samples were drawn on 1, 2, 3, 5, 7, and 10 days in milk (DIM) and analyzed for serum Ca, P, and Mg concentrations. In a subsample of cows (50 control cows, 35 cows treated once with cholecalciferol, and 15 cows treated twice) serum haptoglobin, nonesterified fatty acids, β-hydroxybutyrate, and 25-hydroxycholecalciferol concentrations were analyzed on 1, 5, and 10 DIM. Binary data [retained placenta (RP), metritis] were analyzed using logistic regression models. Repeated measures ANOVA with first-order autoregressive covariance was performed to evaluate the treatment effect on milk yield over the first 10 test days after parturition, 25-hydroxycholecalciferol, serum Ca, P, Mg, β-hydroxybutyrate, nonesterified fatty acids, and haptoglobin concentrations. Cox proportional hazards were used to model the time to event outcomes (time to pregnancy within 200 d, culling until 300 DIM). After enrollment of 31.4% of cows and a preliminary analysis, adverse reactions became apparent, and the study was stopped. Cows treated with cholecalciferol had a greater risk of incurring RP and metritis. The adjusted mean incidences were 2.0%, 7.7%, and 4.0% for RP, and 21.6%, 39.3%, and 33.3% for metritis for control cows, cows treated once, and cows treated twice with cholecalciferol, respectively. Compared with control cows, cows injected once with 12 × 10⁶ IU of cholecalciferol produced less energy-corrected milk on the first (-3.76 kg) and second (-2.75 kg) test days, respectively. Cows injected twice with cholecalciferol (12 × 10⁶ IU of cholecalciferol and 10 × 10⁶ IU 1 wk later) had a reduced milk yield only at first test day (-3.80 kg). Treatment with cholecalciferol led to a significant increase in 25-hydroxycholecalciferol on d 1, 5, and 10 after calving. Serum Ca and P concentrations were significantly increased in cows treated with cholecalciferol, but serum Mg concentrations were significantly reduced. Haptoglobin concentrations were significantly increased on 5 DIM in cows injected once with 12 × 10⁶ IU of cholecalciferol. Although we observed no effect of treatment on culling until 300 DIM, time to pregnancy was delayed by 34 d in cows injected once with 12 × 10⁶ IU of cholecalciferol. In the present study, injection with 12 × 10⁶ IU of cholecalciferol had detrimental effects on health and milk production despite the beneficial effects on Ca homeostasis.

Effects of postpartum milking strategy on plasma mineral concentrations and colostrum, transition milk, and milk yield and composition in multiparous dairy cows

The effects of postpartum milking strategy on plasma mineral concentrations, blood β-hydroxybutyrate (BHB) concentration, and colostrum, transition milk, and first monthly test milk yield and composition were evaluated in 90 multiparous Jersey and Jersey × Holstein crossbreed cows from a commercial farm. Before first postpartum milking, cows were randomly assigned to the following milking strategies, implemented during the first 2 d postpartum: twice-a-day milking (M2, standard industry practice, milking every 12 h; n = 22), once-a-day milking (M1, milking every 24 h; n = 24), restricted milking (MR, 3-L milking every 12 h; n = 21), and delayed milking (MD, no milking for the first 24 h, and milking every 12 h afterward; n = 23). Blood samples for total plasma Ca, P, and Mg determination were collected from enrollment every 4 h up to 48 h, and at 3 d in milk. Blood BHB concentration was determined at 3 and 11 d in milk. Colostrum and transition milk yields were recorded, and samples were collected at each study milking for IgG and somatic cell count (SCC) determinations. Information for first monthly test milk yield and composition was obtained from the Dairy Herd Improvement Association. Statistical analyses were conducted using generalized multiple linear and Poisson regressions with Dunnett adjustment and M2 as reference group for mean comparisons. Overall, plasma Ca concentration within 48 h after enrollment was higher for MD (2.17 mmol/L), tended to be higher for MR (2.15 mmol/L), and was similar for M1 (2.09 mmol/L) compared with M2 cows (2.06 mmol/L). No statistically significant differences compared with M2 cows were observed for plasma P and Mg concentrations. Colostrum and transition milk and total Ca harvested within 48 h after enrollment were lower for M1, MR, and MD compared with M2 cows. The MD strategy prevented harvesting colostrum with >50 g of IgG/L. No statistically significant effects were detected on plasma mineral concentrations at 3 DIM, blood BHB concentration, colostrum and transition milk SCC within 48 h after enrollment, or milk yield, energy-corrected milk yield, and SCC at first monthly test. Our results suggest that postpartum plasma Ca concentration may be influenced by postpartum milking strategy, without interfering with future milk yield and udder health. Further studies should evaluate whether the proposed milking strategies in early postpartum affect production, reproduction, or health.

Prepartum level of dietary cation-anion difference fed to nulliparous cows: Acid-base balance, mineral metabolism, and health responses

Objectives were to determine the effects of 3 different levels of dietary cation-anion difference (DCAD) fed during the last 22 d of gestation to pregnant nulliparous cows on pre- and postpartum acid-base balance, mineral metabolism, and health responses. In all, 132 pregnant nulliparous Holstein cows were enrolled at 250 (248-253) d of gestation, blocked by genomic merit of energy-corrected milk yield, and assigned randomly to diets varying in DCAD: +200 (P200, n = 43), -50 (N50, n = 45), or -150 (N150, n = 44) mEq/kg of dry matter. Dietary treatments were fed until calving, after which cows received the same lactation diet for the first 100 d postpartum. Urine and blood were sampled throughout the prepartum period and in the first weeks postpartum, and urine was assessed for pH, whereas blood was analyzed for gases, measures of acid-base balance, minerals, and metabolites. Calcium (Ca) and magnesium (Mg) retention and phosphorus (P) digestibility were evaluated in the last week of gestation and first week of lactation. Incidence of diseases was evaluated for the first 100 d postpartum. Data are presented in sequence as P200, N50, N150 (LSM ± SEM). Reducing the DCAD reduced urine (8.17 vs. 6.50 vs. 5.51 ± 0.11) and blood pH (7.442 vs. 7.431 vs. 7.410 ± 0.004) and induced a state of compensated metabolic acidosis with a reduction in blood HCO₃^- (28.4 vs. 26.7 vs. 24.9 ± 0.3 mM) and partial pressure of CO₂ (41.8 vs. 40.1 vs. 39.1 ± 0.4 mmHg) prepartum. Reducing the DCAD linearly increased blood ionized Ca (iCa; 1.224 vs. 1.243 vs. 1.259 ± 0.008 mM) and serum total Ca (tCa; 2.50 vs. 2.53 vs. 2.56 ± 0.02 mM) prepartum, blood iCa on the day of calving, and serum Mg in the first days postpartum. Reducing the DCAD linearly increased the apparent absorption of Ca (12.9 vs. 19.0 vs. 20.9 ± 1.4 g/d) and Mg (7.0 vs. 9.9 vs. 10.4 ± 1.4 g/d) prepartum, but apparent retention of both Ca (13.9 g/d) and Mg (3.4 g/d) did not differ with treatment. Treatment did not affect digestibility of P pre- or postpartum or retention of Ca or Mg postpartum. Treatment did not affect the incidence or prevalence of subclinical hypocalcemia, hepatic composition, or the prevalence of fatty liver. Reducing the DCAD had a quadratic effect on incidence of fever (46.5 vs. 17.6 vs. 33.9 ± 7.0%), uterine diseases (36.3 vs. 25.6 vs. 46.0 ± 7.3%), and morbidity (41.4 vs. 28.1 vs. 55.6 ± 7.3%). Feeding a diet with -50 mEq/kg of dry matter promoted moderate changes in acid-base balance, altered mineral metabolism, and benefited health of nulliparous cows; however, further reducing the DCAD to -150 mEq/kg negated the benefits to health.

Association of low serum calcium concentration after calving with productive and reproductive performance in multiparous Jersey cows

Consequences of postpartum low blood calcium (Ca) concentration are still under study and literature describing this condition in Jersey cows is scarce. A prospective cohort study was conducted to evaluate the association of low serum Ca concentration shortly after calving with milk and energy-corrected milk yields, somatic cell count linear score, and pregnancy to first service and within 150 d in milk in multiparous Jersey cows from 2 commercial herds. Blood samples for serum Ca determination were collected on average at 3 h 10 min postpartum from 352 multiparous Jersey cows. Productive data up to the 10th monthly test were obtained from the Dairy Herd Improvement Association and reproductive data were obtained from herd records. Multiple linear, log-binomial, and Cox's proportional hazards regressions were used to evaluate the association of low serum Ca concentration with productive and reproductive outcomes. Serum Ca concentration ≤2.18 mmol/L was associated with 1.43 and 1.85 kg/d more milk and energy-corrected milk. However, lower serum Ca concentrations were associated with a 0.28-unit-higher somatic cell count linear score per monthly test (Ca ≤2.00 mmol/L), and decreased pregnancy risk at first service (risk ratio = 0.64; Ca ≤1.94 mmol/L) and hazard of pregnancy within 150 d in milk (hazard ratio = 0.40; Ca ≤1.90 mmol/L). The present study is based on a convenience sample of multiparous Jersey cows from 2 commercial herds; further research including more herds and additional blood Ca determinations is needed to describe postpartum blood Ca dynamics and its association with productive and reproductive outcomes for the Jersey breed.

Effect of peripartal administration of mycobacterium cell wall fraction on health and fertility of Holstein cows under organic-certified management

The main objective of this study was to evaluate the effect of peripartal administration of a commercially available nonspecific immune stimulant (mycobacterium cell wall fraction; MCWF [Amplimune, NovaVive Inc., Napanee, ON, Canada]) on the incidence of disease during early lactation and subsequent fertility of dairy cows. A second objective was to characterize the dynamics of circulating white blood cells (WBC) and metabolic markers following treatment administration. Cows in an United States Department of Agriculture (USDA) organic-certified dairy herd were blocked by parity and, based on sequential calving dates, randomly assigned to receive two injections (5 mL s.c.) of either a placebo (saline solution) as a control (CON; n = 71) or MCWF (n = 65) at enrollment (7 d before expected calving) and within 24 h after calving. Blood samples were collected from a subsample of the study population (MCWF = 16; CON = 18) for WBC count at enrollment, at day 2 post enrollment, and at days 1, 3, 7, and 14 after calving. Serum fatty acids, beta-hydroxybutyrate, and Ca concentrations were determined at days 1 and 7 postpartum (MCWF = 21; CON = 21). Main outcome variables included incidence risk of peripartal and early lactation health disorders and pregnancy at first artificial insemination (AI), at 100, and at 150 days in milk (DIM). In addition, the average daily milk yield up to 90 DIM and death and live culling before 305 DIM were compared. Treatment effects were assessed using multivariable logistic regression, time-to-event analyses, and repeated measures analysis of variance (ANOVA). A treatment effect on the incidence risk of some of the health disorders in the study was established. Incidence risk of metritis and clinical mastitis <28 DIM was smaller in MCWF than in CON cows (36.9% vs. 50.7% and 6.3% vs. 19.7%, respectively). On the contrary, the incidence risk of respiratory disease <28 DIM was smaller in CON (0%) than in MCWF (7.7%). Reproductive performance of multiparous cows was affected by MCWF administration: pregnancy at first AI and pregnancy at 100 and 150 DIM were greater in MCWF than in CON (35.6% vs. 19.2%; 51.1% vs. 25.0%; and 64.4% vs. 40.4%, respectively). Overall, median intervals from calving to pregnancy were 90 vs. 121 d in MCWF and CON cows, respectively. No treatment effects on the dynamics of circulating WBC or in postpartum metabolic status were established. No differences for milk yield or for the proportion of cows that survived up to 305 DIM were determined, although cows in MCWF left the herd earlier than cows in CON. In conclusion, incidence risks of metritis and mastitis in early lactation were smaller in cows receiving MCWF, whereas the incidence risk of respiratory disease was smaller in CON. Fertility significantly improved in MCWF compared with CON cows. As this study was performed in an organic-certified dairy, specific health and reproductive management practices may affect the external validity of the current findings.

The Association between Selected Dietary Minerals and Mastitis in Dairy Cows-A Review

The aim of this paper is to describe the association between selected dietary minerals and mastitis in dairy cows. Minerals are a group of nutrients with a proven effect on production and reproductive performance. They also strongly affect immune system function. In particular their deficiencies may result in immunosuppression, which is a predisposing factor for udder inflammation occurrence. The role of selected dietary minerals (including calcium, phosphorus, magnesium, selenium, copper and zinc) has been reviewed. Generally, minerals form structural parts of the body; as cofactors of various enzymes they are involved in nerve signaling, muscle contraction and proper keratosis. Their deficiencies lead to reduced activity of immune cells or malfunction of teat innate defense mechanisms, which in turn promote the development of mastitis. Special attention was also paid to minerals applied as nanoparticles, which in the future may turn out to be an effective tool against animal diseases, including mastitis. To conclude, minerals are an important group of nutrients, which should be taken into account on dairy farms when aiming to achieve high udder health status.

Relationships among Macro-Minerals, Other Selected Serum Markers of Bone Profile and Milk Components of Dairy Cows During Late Lactation

Testing blood and milk parameters as well as analysing the relationships among these markers is very useful for monitoring the internal homeostasis and health in high-yielding dairy cows during various production periods. The aim of the study was to assess the correlations (relationships) among macro-minerals, such as calcium (Ca), inorganic phosphorus (P), magnesium (Mg), other selected bone profile markers, such as total protein (TP), albumin, activity of alkaline phosphatase (ALP) measured in serum and selected milk components such as number of somatic cells (SCC), colony-forming units (CFU), milk fat (MF), milk protein (MP), milk lactose (ML), solids, solids non-fat (SNF) and milk production in late-lactation cows. Both blood and milk samples were collected from 11 clinically healthy milking cows during the late-lactation period. The cows were examined once a day for 3 consecutive days resulting in 33 sets of blood and milk samples for laboratory and statistical analysis. Significant correlations were observed between: Mg and MP, Mg and SNF, ALP and SCC, TP and SCC, TP and MP, TP and SNF, albumin and MP, albumin and SNF, P and Mg, Mg and albumin, and between TP and albumin. When monitoring macro-mineral homeostasis and mammary gland health, especially in intensively fed high-yielding dairy cows correlations between these markers should be considered. The revealed correlations can allow for deeper comparative laboratory diagnostics of homeostasis and can be especially useful for laboratory monitoring of the potential risk of subclinical macro-mineral deficiency in high-yielding dairy cows.

Invited review: The influence of immune activation on transition cow health and performance-A critical evaluation of traditional dogmas

The progression from gestation into lactation represents the transition period, and it is accompanied by marked physiological, metabolic, and inflammatory adjustments. The entire lactation and a cow's opportunity to have an additional lactation are heavily dependent on how successfully she adapts during the periparturient period. Additionally, a disproportionate amount of health care and culling occurs early following parturition. Thus, lactation maladaptation has been a heavily researched area of dairy science for more than 50 yr. It was traditionally thought that excessive adipose tissue mobilization in large part dictated transition period success. Further, the magnitude of hypocalcemia has also been assumed to partly control whether a cow effectively navigates the first few months of lactation. The canon became that adipose tissue released nonesterified fatty acids (NEFA) and the resulting hepatic-derived ketones coupled with hypocalcemia lead to immune suppression, which is responsible for transition disorders (e.g., mastitis, metritis, retained placenta, poor fertility). In other words, the dogma evolved that these metabolites and hypocalcemia were causal to transition cow problems and that large efforts should be enlisted to prevent increased NEFA, hyperketonemia, and subclinical hypocalcemia. However, despite intensive academic and industry focus, the periparturient period remains a large hurdle to animal welfare, farm profitability, and dairy sustainability. Thus, it stands to reason that there are alternative explanations to periparturient failures. Recently, it has become firmly established that immune activation and the ipso facto inflammatory response are a normal component of transition cow biology. The origin of immune activation likely stems from the mammary gland, tissue trauma during parturition, and the gastrointestinal tract. If inflammation becomes pathological, it reduces feed intake and causes hypocalcemia. Our tenet is that immune system utilization of glucose and its induction of hypophagia are responsible for the extensive increase in NEFA and ketones, and this explains why they (and the severity of hypocalcemia) are correlated with poor health, production, and reproduction outcomes. In this review, we argue that changes in circulating NEFA, ketones, and calcium are simply reflective of either (1) normal homeorhetic adjustments that healthy, high-producing cows use to prioritize milk synthesis or (2) the consequence of immune activation and its sequelae.

Effect of oral calcium administration on metabolic status and uterine health of dairy cows with reduced postpartum rumination and eating time

Background

Hypocalcemia has detrimental effects on health and performance of dairy cows. As hypocalcemic cows show reduced feed intake, we hypothesized that cows with reduced combined rumination and eating time (CRET) may benefit from Ca supplementation. The objective was to evaluate the effect of postpartum oral Ca administration on metabolic status (Calcium [Ca], fatty acids [FA], and β-Hydroxybutyrate [BHB] serum concentrations) and incidence of puerperal metritis (PM) in dairy cows with reduced postpartum CRET. Cows in an organic-certified dairy, diagnosed with reduced CRET (< 489 min/d; n = 88) during the first day postpartum were assigned into 1 of 2 treatments: i) Calcium administration (CA; n = 45) that received 1 Ca oral capsule (Bovikalc bolus, Boehringer Ingelheim, St. Joseph, MO) containing CaCl2 and CaSO4 (43 g of Ca) once per day, for 3 consecutive days, starting at d 1 postpartum; and ii) Control (CON; n = 43) that did not receive oral Ca. A convenience group consisting of cows with CRET ≥489 min/d was used for comparison and did not receive oral Ca (NOR; n = 96).

Results

At day 1 postpartum cows with reduced CRET had lower Ca serum concentrations (CA = 2.08 mmol/L; CON = 2.06 mmol/L) compared with NOR cows (2.17 mmol/L). Calcium concentrations at d 3, 5, and 12 postpartum were not different among the three groups. Serum FA concentrations at d 1, 3 and 5 postpartum were higher in both CA and CON cows compared with NOR. At d 12, only CA cows had higher FA concentrations than NOR cows. Serum BHB concentrations at d 3 were highest in CA, with no difference between CON and NOR. At d 5, BHB concentrations were higher in CA, followed by CON, and NOR. No effect was observed for Ca administration on incidence of PM and reproductive performance. CON cows had lower survival at 30 DIM (86.5%) than NOR cows (97.9%).

Conclusions

The use of remote sensor technology identified cows with reduced rumination and eating time that had lower postpartum serum concentrations of calcium and altered metabolic status. However, oral calcium administration to cows with reduced CRET did not affect incidence of metabolic disorders nor reproductive health and subsequent pregnancy. Although survival at 30 days postpartum was lower for non-Ca supplemented cows, the identification of effective interventions in cows with reduced CRET requires further consideration.

Clinical disease incidence during early lactation, risk factors and association with fertility and culling in grazing dairy cows in Uruguay

This paper aims to describe clinical disease incidence in early lactation and explore its association with fertility and culling in 13 commercial grazing dairy herds in Uruguay. Seven farms with less than 250 dairy cows considered small herds (SH) with a herd size average ± (SD) of 144 ± (56) cows and six farms with more than 500 cows considered large herds (LH) with a herd size average ± (SD) of 830 ± (239) cows were selected. Herd managers recorded health events during the first 90 days in milk in 5375 Holstein dairy cows [24.5% (n=1316) of them were primiparous cows, (PP)] during one year. Overall, 36.5% (n=1959) of the cows had at least one clinical health event between 1-90 days in milk. The cumulative incidences were 2.2% for twin birth and 4.9% for stillbirth. Cumulative incidence was 4.4% for retained placenta-metritis (RP-metritis), 27.6% for clinical mastitis and 5.0% for lameness. Our data showed that parity and herd size were risk factors for postpartum disease in grazing dairy herds. In PP cows, stillbirth incidence was higher than in multiparous (MP) cows (PP=6.9 ± 3.4, SD vs. MP=4.3 ± 2.6, SD), while in MP cows twin births (MP=2.7 ± 1.7, SD vs. PP=0.7 ± 2.7, SD), RP-metritis (MP=4.6 ± 3.9, SD vs. PP=3.8 ± 3.7, SD) and mastitis incidence (MP=30.9 ± 11.4, SD vs. PP=17.2 ± 13.9, SD) was higher. Clinical mastitis (LH=29.4 ± 9.6, SD vs. SH=19.1 ± 11.3, SD) and lameness incidence (LH=5.6 ± 1.9, SD vs. SH=2.3 ± 2.1, SD) was higher in large herds than in small herds. RP-metritis was increased by stillbirth (OR=4.4, 95 % CI=2.9-6.5) and twin birth (OR=2.8, 95 % CI=1.5-5.1). Diseases had a negative impact on time to first service and pregnancy rate and increased culling hazard rate. Disease incidence in early lactation was high and showed a wide variation among herds (10.4%-48.7%), which highlights the relevance of a herd health program prioritizing the early lactation disease control.

Controlled trial of the effect of negative dietary cation-anion difference on postpartum health of dairy cows

The objective of this study was to assess the effects of feeding negative dietary cation-anion difference (DCAD) dry cow diets on postpartum health. Cows from 4 commercial dairy farms in Ontario, Canada, were enrolled in a pen-level controlled trial from November 2017 to April 2019. Close-up pens (1 per farm), with cows 3 wk before expected calving, were randomly assigned to a negative DCAD [TRT; -108 mEq/kg of dry matter (DM); target urine pH 6.0-6.5] or a control diet (CON; +105 mEq/kg of DM with a placebo supplement). Each pen was fed TRT or CON for 3 mo (1 period) then switched to the other treatment for the next period, with 4 periods per farm. Urine pH was measured weekly until calving, and body condition score (BCS) was measured at enrollment and at 5 wk postpartum. Data from 15 experimental units [8 TRT and 7 CON, with 1,086 (TRT: n = 681; CON: n = 405) observational units (cows)] that received the assigned diet for >1 wk were included. The incidence of milk fever (MF), retained placenta (RP), metritis, hyperketonemia (blood β-hydroxybutyrate >1.2 mmol/L, measured weekly in wk 1 and 2), clinical mastitis within 30 DIM (MAST), displaced abomasum (DA) within 30 d in milk (DIM), purulent vaginal discharge (PVD, assessed once at wk 5), and number of disease events (≥1 or ≥2) were analyzed with logistic regression models with treatment, parity, BCS, and their interactions, accounting for pen-level randomization and clustering of animals within farm with random effects, giving 10 degrees of freedom to test treatment effects. Multiparous cows fed TRT had greater blood calcium between 1 and 4 DIM than multiparous cows fed CON, and the prevalence of subclinical hypocalcemia (total Ca ≤2.14 mmol/L) was lesser when fed TRT compared with CON (d 1: 73 ± 6% vs. 93 ± 4%; d 2: 65 ± 7% vs. 90 ± 5%), with no differences between treatments detected in primiparous cows. We detected interactions of treatment and BCS at enrollment for MF in multiparous cows and of treatment and parity for ≥2 disease events. Overconditioned (BCS ≥3.75) multiparous cows had reduced incidence of MF when fed TRT (TRT: 2 ± 1%, vs. CON: 13 ± 8%). We detected no treatment effects on RP, metritis, hyperketonemia, or PVD incidence. Cows fed TRT had lesser incidence of DA (1.7 ± 0.7% vs. 3.6 ± 1.6%) and tended to have lesser incidence of MAST compared with CON (1.8% ± 0.6% vs. 4.4 ± 1.4%). No treatment effect was detected on ≥1 disease events (TRT: 38 ± 7%, vs. CON: 42 ± 8%); however, multiparous cows on TRT were less likely to have ≥2 disease events than cows on CON (14 ± 4% vs. 23 ± 6%). Under commercial herd conditions, feeding prepartum diets with negative DCAD improved several measures of postpartum health.

Graduate Student Literature Review: What do we know about the effects of clinical and subclinical hypocalcemia on health and performance of dairy cows?

This narrative literature review summarizes findings regarding the associations of clinical and subclinical hypocalcemia with postpartum health, reproduction, and milk production. To better understand the effects of hypocalcemia, we reviewed clinical and subclinical presentations of the condition and the dynamics of blood Ca concentration in the early postpartum period. We summarize and discuss the associations between hypocalcemia and performance of dairy cows. Up to 50% of dairy cows suffer from at least one disease event in the transition period. The important roles of calcium in muscle contraction and immune function make it a key component of metabolism, inflammation, and defense against infection. Although the effect of clinical hypocalcemia (milk fever) on health and performance is clear, the definition of subclinical hypocalcemia (SCH) and its consequences for health and performance are still ambiguous. Differences in study designs, sampling protocols, Ca concentration thresholds, and sample sizes that may be underpowered for health and reproduction outcomes lead to inconsistent conclusions on the effects of SCH. On current evidence, classification of SCH should be based on at least 2 measurements of blood calcium, using cutpoints supported with relevant data, which may vary depending on the outcome of interest. Arbitrary or poorly supported interpretative thresholds for blood Ca concentrations should be abandoned. Transient SCH appears to be associated with greater milk yield, whereas SCH that is present several days after calving is associated with lesser production and greater disease risk. However, when blood calcium is measured days after calving, primary effects of calcium metabolism may be confounded by feed intake, inflammation, or disease, which might either contribute to or be a consequence of hypocalcemia. Additional research is needed to refine sampling schemes to classify SCH, and to better inform the goals and means of prevention of SCH.

Peri-parturient hypocalcemia in goats: Clinical, hematobiochemical profiles and ultrasonographic measurements of postpartum uterine involution

Background and Aim:

Hypocalcemia in goats occurs around the time of parturition and is caused by decreasing level of calcium less than 10 mg/dL. This investigation characterized the hematological and biochemical profiles of peri-parturient hypocalcemia in goats and study the effects of hypocalcemia on uterine involution during the postpartum period on day 0 and then weekly postpartum (day +7, +14, +21, +28, +35, till +42).

Materials and Methods:

Forty-five polyparous native breed does age 3-5 years and weighing 40–60 kg were assigned to control and hypocalcemia groups based on their health history, clinical and biochemical findings. The control group included 10 clinically healthy pregnant does, and the hypocalcemia group included 35 late pregnant does that suffered from anorexia, weakness, muscle tremors of the hind limbs, and an inability to stand. Clinical examination and blood sampling in both groups were performed approximately 14 days before the expected time of kidding (day −14), at kidding day (day 0), on day +21, and +42 postpartum. Sonographic measurements were used to monitor uterine involution on day 0 and then weekly once the animal was postpartum (day +7, +14, +21, +28, +35, till +42) in both groups.

Results:

Results of sonographic measurement revealed that the hypocalcemia group had a greater (p<0.05) size of the uterus as assessed transrectally and retarded uterine involution when compared with the control group. Laboratory findings revealed that does in both groups showed lower red blood cells, packed cell volume%, and hemoglobin (Hb) concentrations on day −14 before kidding and day 0 when compared with postpartum measurements. A significant increase (p<0.05) in total leukocyte counts, neutrophil, serum glucose, and cortisol levels with a significant decrease (p<0.05) in lymphocytes. Significant decreases (p<,0.05) in serum calcium, phosphorous, vitamin D, and total antioxidant capacity levels with significant (p<,0.05) increases in serum malondialdehyde were recorded on day 0 and day −14 in the hypocalcemia group when compared with the control group.

Conclusion:

This investigation provides evidence that hypocalcemia in does causes both metabolic and oxidative stress during peri-parturient periods while also retarding uterine involution during postpartum periods.

Association of blood calcium concentration in the first 3 days after parturition and energy balance metabolites at day 3 in milk with disease and production outcomes in multiparous Jersey cows

Research exploring specific associations of markers of negative energy balance and Ca in postpartum Jersey cows with lactation performance is lacking. Our objectives were to evaluate the associations of total Ca concentration (tCa) measured at 1 through 3 d in milk (DIM) and free fatty acids (FFA), β-hydroxybutyrate (BHB), and glucose measured at 3 DIM with (1) the risk of multiparous Jersey cows being diagnosed with early-lactation diseases and culling, (2) milk production in the first 9 wk of lactation, and (3) the risk of pregnancy in the first 150 DIM. A cohort study was performed in 1 dairy herd in Texas. Multivariable Poisson regression models were built to evaluate the association of the analytes of interest with the risks of early-lactation diseases and culling in the first 60 DIM (i.e., binary outcomes). Linear mixed models were used to evaluate the association of the analytes of interest with milk production within the first 9 wk of lactation, and a Cox proportional hazard model was built to assess the risk of pregnancy within 150 DIM. A total of 380 cows were used in the final analyses. Total Ca measured at 1 through 3 DIM was not associated with the risk of metritis. Cows with increased FFA and BHB had an increased risk of being diagnosed with metritis and clinical mastitis, respectively. Increased concentrations of glucose and FFA and decreased tCa at 3 DIM were associated with an increased risk of culling. Reduced tCa concentrations at 1 DIM (≤1.84 mmol/L) and 2 DIM (≤2.04 mmol/L) were associated with increased milk production across the first 9 wk of lactation compared with tCa concentrations above those thresholds. Total Ca was not associated with milk production when assessed at 3 DIM, whereas increased FFA (≥0.37 mmol/L) and decreased glucose (≤2.96 mmol/L) at 3 DIM were associated with increased milk production. None of the metabolites measured were associated with the risk of pregnancy in the first 150 DIM. Our results demonstrate that tCa concentration assessed in the first 3 DIM show temporary associations with milk production and culling in multiparous Jersey cows. Although increased concentration of FFA assessed at 3 DIM was associated with greater milk yield, it was a detrimental factor for the risk of metritis. This study attempted to better elucidate the relationship of tCa, FFA, BHB, and glucose assessed in early postpartum with health and performance of Jersey cows. Based on this study, assessments performed at 3 DIM using tCa concentration ≤1.99 mmol/L for increased risk of early-lactation culling and FFA ≥0.43 mmol/L for increased risk of metritis could be used as starting points. More studies evaluating the dynamics of energy balance markers and tCa in postpartum Jersey cows using a greater number of herds are needed to better inform dairy consultants on critical levels for exacerbated postpartum negative energy balance and subclinical hypocalcemia for the Jersey breed.

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.

A new molecular risk pathway for postpartum mood disorders: clues from steroid sulfatase-deficient individuals

Postpartum mood disorders develop shortly after childbirth in a significant proportion of women. These conditions are associated with a range of symptoms including abnormally high or low mood, irritability, cognitive disorganisation, disrupted sleep, hallucinations/delusions, and occasionally suicidal or infanticidal ideation; if not treated promptly, they can substantially impact upon the mother's health, mother-infant bonding, and family dynamics. The biological precipitants of such disorders remain unclear, although large changes in maternal immune and hormonal physiology following childbirth are likely to play a role. Pharmacological therapies for postpartum mood disorders can be effective, but may be associated with side effects, concerns relating to breastfeeding, and teratogenicity risks when used prophylactically. Furthermore, most of the drugs that are used to treat postpartum mood disorders are the same ones that are used to treat mood episodes during non-postpartum periods. A better understanding of the biological factors predisposing to postpartum mood disorders would allow for rational drug development, and the identification of predictive biomarkers to ensure that 'at risk' mothers receive earlier and more effective clinical management. We describe new findings relating to the role of the enzyme steroid sulfatase in maternal postpartum behavioural processes, and discuss how these point to a novel molecular risk pathway underlying postpartum mood disorders. Specifically, we suggest that aberrant steroid hormone-dependent regulation of neuronal calcium influx via extracellular matrix proteins and membrane receptors involved in responding to the cell's microenvironment might be important. Testing of this hypothesis might identify novel therapeutic targets and predictive biomarkers.