Review: Effects of feeding sugars on productivity of lactating dairy cows

International Symposium on Ruminant Physiology: Current perspective on rumen microbial ecology to improve fiber digestibility

Although cellulose has received the most attention, further research is needed for a complete comprehension of other fiber components in forage and nonforage fiber sources corresponding with the array of enzymes needed for depolymerization and resulting fermentation of sugars. The carbohydrate-active enzymes (CAZymes) have been described in detail herein, although new information will no doubt accumulate in the future. Known CAZymes are attributed to taxa that are easily detected via 16S rRNA gene profiling techniques, but such approaches have limitations. We describe how closely related species or strains expand into different niches depending on diet and the dynamic availability of remaining fibrous substrates. Moreover, expression of CAZymes and other enzymes such as in fermentation pathways can shift among strains and even within strains over time of incubation. We describe unique fibrolytic components of bacteria, protozoa, and fungi while emphasizing the development of consortia that efficiently increase neutral detergent fiber degradability (NDFD). For example, more powerful genome-centric functional omics approaches combined with expanded bioinformatics and network analyses are needed to expand our current understanding of ruminal function and the bottlenecks that lead to among-study variation in NDFD. Specific examples highlighted include our lack of fundamental understanding why starch limits NDFD, whereas moderate inclusion of rumen-degraded protein, certain supplemental fatty acids (especially palmitic), and supplemental sugars sometimes stimulates NDFD. Current and future research must uncover deeper complexity in the rumen microbiome through a combination of approaches described herein to be followed by validation using novel cultivation studies and, ultimately, NDFD measured in vivo for integration with ruminant productivity traits.

Utilization of Purple Napier Grass Silage on Milk Quality and Blood Antioxidant Activity in Lactating Dairy Goats

In this study, our subjects were 18 female crossbred Saanen lactating goats; the goats weighed approximately 43.25 ± 2.35 kg and had been producing milk for 14 ± 2 days. They were assigned to three equally sized experimental groups based on the cycle of the lactation period. In accordance with the randomized complete block design (RCBD), six animals were randomly assigned to the treatments in each block. There were three treatments: (1) control = Napier Pakchong-1 grass silage (NPS); (2) = sweet grass silage (SGS); and (3) = purple Napier silage (PNS). Our findings show that the goats fed with purple Napier grass silage had a higher DM intake (1805.97 g/day) than those that underwent a different treatment (1312.76 and 1443.43 g/day). The goats fed with purple Napier grass silage had higher protein digestibility (79.85) than those fed with Napier Pakchong-1 and sweet grass silage. There were significant differences in the ruminal ammonia nitrogen and blood urea nitrogen. Nevertheless, purple Napier grass silage significantly increased butyric acid 2 and 4 h after feeding and increased the number of microorganisms. In the dairy goats fed purple Napier grass silage, we observed a reduction in protozoa and methanogen populations. The levels of antioxidants shown by the plasma indices differed in the goats fed with purple Napier grass silage and showed enhanced milk composition, higher levels of total antioxidants, superoxide dismutase and glutathione peroxidase in the plasma, reduced protozoa methanogen, and a decreased level of malondialdehyde in the plasma. This study highlights that purple Napier grass silage has the potential to be a beneficial source of roughage for lactating dairy goats.

Soybean molasses can be used as a substitute for corn in grazing beef cattle supplements during the rainy season

Soybean molasses (SBMO) is a byproduct derived from the production of soy protein concentrate, obtained through solubilization in water and alcohol. The utilization of SBMO as an animal feed ingredient shows promising potential, primarily due to its low cost and as a potential energy concentrate. This study aimed to assess the intake, digestibility, ruminal parameters (pH and ruminal ammonia - NH3), nitrogen retention (NR) and microbial protein synthesis in grazing beef cattle supplemented with SBMO as a substitute for corn during the rainy season. Five Nellore (10-month-old) bulls with an average initial weight of 246 ± 11.2 kg were utilized in a 5 × 5 Latin square design. The animals were housed in five paddocks, each consisting of 0.34 ha of Marandu grass (Urochloa brizantha). Five isonitrogenous protein-energy supplements (300 g crude protein [CP]/kg supplement) were formulated, with SBMO replacing corn at varying levels (0, 0.25, 0.50, 0.75, or 1.00 g-1 g). The supplements were provided daily at a quantity of 2.0 kg-1 animal. The inclusion of SBMO at any level of corn substitution did not significantly affect the intake of pasture dry matter or total dry matter (P > 0.10). Likewise, the intake of CP and, consequently, the ruminal concentration of NH3 did not differ among the SBMO levels. Increasing the inclusion of SBMO did not have a significant impact on NR (P > 0.10), indicating that animals receiving supplements containing 100% SBMO as a substitute for corn may perform similarly to animals receiving supplements with 100% corn (0% SBMO). Soybean molasses represents a viable alternative energy source for grazing beef cattle during the rainy season and can entirely replace corn without adversely affecting animal nutritional performance.

Effects of altering diet carbohydrate profile and physical form on zoo-housed giraffe Giraffa camelopardalis reticulata

Unlike wild giraffe that primarily consume low starch browse, the preference of zoo-housed giraffe for consuming supplemental feeds over forage could increase the risk of digestive disorders such as ruminal acidosis. Our objective was to evaluate the effects of modifying a supplemental feed's non-fibre carbohydrate profile and physical form on nutritional, behavioural, and blood measures of giraffe in a zoological setting. Six non-lactating, adult, female reticulated giraffes were used in a two-pen modified reversal study using two dietary treatments in seven 21-day periods with data collected on days 15-21. Dietary treatments were a control feed comprised of commercially available products used at the time as the giraffe feed (GF) and an unpelleted experimental feed (EF). On a dry matter basis, GF and EF, respectively, contained 17.0% and 17.4% crude protein, 14.2% and 1.5% starch, 14.9% and 21.3% ethanol-soluble carbohydrates, 22.9% and 26.0% acid detergent fibre (ADF) and 9.50% and 14.9% ND-soluble fibre (NDSF), with modulus of fineness values of 3.62 and 4.82. Supplemental feeds, alfalfa hay, salt, and water were available for ad libitum consumption. Significance was declared at p ≤ 0.05. Intakes of hay, supplemental feeds, and total feed did not differ by diet (p > 0.28), though intakes of starch (0.93 and 0.12 kg; p = 0.05) and ADF (1.83 and 2.23 kg; p = 0.04) differed between GF and EF respectively. Giraffe behaviour values (min/48 h) were greater with EF for total eating (p = 0.04); diets were not detected as different for engagement in oral stereotypes (GF = 433, EF = 318 min/48 h; p = 0.22). Blood glucose was higher on GF than EF (99.0 and 82.3 mg/dL; p = 0.03). The lower EF blood glucose value is more similar to ranges reported for domesticated ruminants. No differences were detected for changes in body weight or body condition score in the 21-day periods (p > 0.32). Modification of supplemental feed carbohydrate profile and physical form can influence behaviour and blood glucose values of zoo-housed giraffe.

Whole Genome Scan Uncovers Candidate Genes Related to Milk Production Traits in Barka Cattle

In this study, our primary aim was to explore the genomic landscape of Barka cattle, a breed recognized for high milk production in a semi-arid environment, by focusing on genes with known roles in milk production traits. We employed genome-wide analysis and three selective sweep detection methods (ZFST, θπ ratio, and ZHp) to identify candidate genes associated with milk production and composition traits. Notably, ACAA1, P4HTM, and SLC4A4 were consistently identified by all methods. Functional annotation highlighted their roles in crucial biological processes such as fatty acid metabolism, mammary gland development, and milk protein synthesis. These findings contribute to understanding the genetic basis of milk production in Barka cattle, presenting opportunities for enhancing dairy cattle production in tropical climates. Further validation through genome-wide association studies and transcriptomic analyses is essential to fully exploit these candidate genes for selective breeding and genetic improvement in tropical dairy cattle.

Effects of complete substitution of dietary grain and protein sources with by-products on the production performance of mid-lactation dairy cows fed diets based on barley silage under heat-stress conditions

This study evaluated the effects of replacing cereal grains and soybean meal with by-products (BY) on production performance, nutrient digestibility, ruminal fermentation, nutrient recovery, and eating and chewing behavior of moderate-producing dairy cows under heat-stress conditions. Twelve multiparous Holstein cows (116.7 ± 12.01 d in milk; 42.7 ± 5.06 kg/d milk yield; 665 ± 77 kg body weight; mean ± SD) were used in a replicated 3 × 3 Latin square with 28-d periods (21 d for diet adaptation and 7 d for sampling and data collection). Cows were fed a total mixed ration containing a 39.2:60.8 ratio of forage to concentrate throughout the experiment. All diets were formulated to be isoenergetic and isonitrogenous, with different concentrates. Diets were (1) control diet based on cereal grains (CON: ground corn and ground barley, plus soybean meal); (2) sugar-rich BY diet (S-BY-CM: beet pulp, citrus pulp, and liquid molasses, plus canola meal); and (3) cereal grain BY diet (CG-BY: rice bran, corn germ meal, wheat bran, barley sprout, and broken corn). Our results showed that replacing grains with BY increased neutral detergent fiber intake and digestibility but decreased starch intake, human-edible energy, and human-edible protein. Milk yield and dry matter intake (DMI) decreased more in cows fed the CG-BY diet compared with the other 2 treatments. In contrast, no significant differences were observed between the CON and S-BY-CM diets in terms of milk yield and DMI. The S-BY-CM diet increased energy-corrected milk production compared with the CG-BY diet (36.2 vs. 34.3 kg/d), but CG-BY enhanced feed conversion efficiency compared with the other 2 treatments. Although the S-BY-CM diet prolonged the eating and sorting of small particles, neither of the dietary treatments affected chewing activity or ruminal pH 4 h after feeding. Furthermore, both diets containing BY contributed to an increase in milk fat content in comparison to the CON group. Additionally, the CG-BY and S-BY-CM diets demonstrated better performance than the CON diet in terms of human-edible feed conversion efficiency for protein and energy. The results indicated that S-BY-CM can completely replace barley and corn grain in the diet of mid-lactating dairy cows exposed to heat-stress conditions without any negative effect on production and ruminal pH. However, the inclusion of CG-BY did impair DMI, milk yield, and digestibility of nutrients and is not recommended during heat-stress conditions.

Mixed ensiling plus nitrate destroy fiber structure of rape straw, increase degradation, and reduce methanogenesis through in vitro ruminal fermentation

BACKGROUND

Better utilization of rape straw can provide alternative strategies for sustainable ruminant and food production. The research reported here investigated changes in the carbohydrate composition of rape straw as a result of mixed ensiling with whole-crop corn or inoculated with nitrate, and the consequent effects on ruminal fermentation through in vitro batch culture. The three treatments included: rape straw and corn silage (RSTC), and ensiling treatment of rape straw with whole-crop corn (RSIC) or with calcium nitrate inoculation (RSICN).

RESULTS

Ensiling treatment of rape straw and whole-crop corn or plus nitrate enriched lactic acid bacteria and lactate. The treatments broke the fiber surface connections of rape straw, leading to higher neutral detergent soluble (NDS) content and lower fiber content. Ensiling treatments led to greater (P < 0.05) dry matter degradation (DMD), molar proportions of propionate and butyrate, relative abundance of the phylum Bacteroidetes and genus Prevotella, and lower (P < 0.05) methane production in terms of g kg-1 DMD, molar proportions of acetate, and lower acetate to propionate ratio than the RSTC treatment. The RSICN treatment led to the lowest (P < 0.05) hydrogen concentration and methane production among the three treatments.

CONCLUSION

Ensiling treatments of rape straw and whole-crop corn destroy the micro-structure of rape straw, promote substrate degradation by enriching the phylum Bacteroidetes and the genus Prevotella, and decrease methane production by favoring propionate and butyrate production. Nitrate inoculation in the ensiling treatment of rape straw and whole-crop corn further decreases methane production without influencing substrate degradation by providing an additional hydrogen sink. © 2023 Society of Chemical Industry.

In vitro rumen fermentation characteristics of bakery by-products containing high starch and sugar

The objectives of this study were to evaluate the nutritional characteristics of bakery by-products (castella, pancake, baumkuchen) and their effect on rumen fermentation in vitro as compared with steam-flaked corn and barley as human-edible grains. The fermentation pattern of sugar and starch as pure components was also investigated. Additionally, rumen pH was evaluated using a low-capacity buffer. Bakery by-products contained high sugar (212-590 g/kg DM) and starch (262-545 g/kg DM). Castella exhibited the highest sugar content, whereas pancake and baumkuchen were rich in starch and ether extract within bakery by-products, respectively. The gas production rate at the early phase of incubation was higher in bakery by-products than in grains, and the highest in castella among all feeds. Bakery by-products produced higher total organic acids and propionate than grains. Bakery by-products also exhibited a lower rumen pH than grains during twenty-four hours of incubation with a low-capacity buffer. As pure components, sucrose showed a higher gas production rate and lower pH than starch. Overall, compared with grains, bakery by-products have the potential not only to supply more energy to ruminants but also decrease rumen pH because sugar and starch in bakery by-products ferment rapidly and produce higher organic acids in the rumen.

Partial replacement of corn with chocolate byproducts or protected fat in diets of early lactating Holstein cows: feed utilization and lactational performance

This study determined the effects of the partial replacement of corn with chocolate byproducts or protected fat on the performance of cows. Forty multiparous Holstein cows were assigned to four treatments in a completely randomized design for 90 d. The control diet was a complete diet containing 41.2% concentrate feed mixture, 41.2% corn silage, and 17.6% berseem hay. In the other experimental diets, each kg of crushed corn grain in the control diet (DM basis) was replaced with 600 g chocolate byproducts (CH), 400 g protected fat (PF), or 500 g of a mixture of chocolate byproducts and protected fat (1:1 DM basis) (CHPF). Both amounts of PF and CH had the same energy concentration as 1 kg of corn. The experimental treatments did not affect total intake; however, they increased (p < 0.001) daily production of milk, milk fat content, and feed efficiency. Moreover, treatments increased (p < 0.05) blood total protein, albumin, glucose, cholesterol, and triglyceride. The CH, PF, and CHPF treatments increased (p < 0.01) nutrient digestibility. It is concluded that replacing 1 kg of corn in the diet of lactating Holstein cows with PF at 400 g, followed by CHPF at 500 g, and CH at 600 g enhanced milk production and feed efficiency.

Effects of increasing levels of lasalocid supplementation on growth performance, serum biochemistry, ruminal fermentation profile, in vitro nutrient digestibility, and gas production of growing goats

Introduction

Lasalocid is a feed additive widely used in ruminant nutrition and plays a crucial role in improving livestock productivity, digestibility, immunity, and overall wellbeing. The current study was conducted to investigate the effect of different levels of lasalocid (LAS) supplementation on growth performance, serum biochemistry, ruminal fermentation profile, in vitro nutrient digestibility, and gas production of growing goats.

Methods

A total of 60 growing Aardi male goats with an average body weight of ~17.12 kg (3-month-old) were used for an 84-day trial. Animals were randomly divided into four treatment groups with 5 replicates of 3 goats each. All four groups were provided with a basal diet supplemented with lasalocid (LAS) at 0 (without supplementation; LAS0), 10 (LAS10), 20 (LAS20), or 30 (LAS30) ppm LAS/kg dry matter (DM). Feed intake was measured weekly, and goats were weighed every 2 weeks for an evaluation of the performance parameters. Blood samples were collected for the measurement of biochemical variables. In vitro nutrient digestibility and gas production were evaluated.

Results and discussion

The supplementation of LAS at level 30 ppm/kg DM increased (P < 0.05) the body weight gain and average daily gain without linear or quadratic effect. The serum concentrations of high-density lipoprotein were significantly (P < 0.05) higher in the LAS20 group than in other groups with linear and quadratic effects, while low-density lipoprotein concentration was significantly lower in the LAS20 group than in LAS0 and LAS30 with a linear effect. Different levels of lasalocid supplementation had no effect on the ruminal fermentation profile, in vitro gas production, and nutrient digestibility. In conclusion, the addition of LAS (20-30 ppm/kg DM) to the goat's diet can improve the growth performance and lipoprotein profile.

Chocolate byproducts and protected fats enriched with chromium to replace corn in diets of early lactation Holstein cows: feed utilization, blood profile, and lactational performance

The present experiment aimed to evaluate the partial replacement of corn with chocolate byproducts or protected fats in the diet of lactating cows on feed utilization, blood profile and lactation performance. Fifty multiparous Holstein cows (560±22 kg BW, 3±1 parity, 7±1 days in milk, and previous milk production of 34±3 kg/d), were randomly assigned to 5 treatments in a completely randomized design for 90 days. The control diet contained a concentrate feed mixture containing (per kg DM 412 g concentrate feed mixture, 412 g corn silage, and 176 g berseem hay). The control diet contained 17.6% crushed corn (DM basis). In another treatment, the control diet was supplemented with 1 g chromium daily (Chromium diet). In the other diets, each kg of crushed corn grain was replaced with 600 g chocolate byproducts (CH diet), 400 g protected fats (PF diet), or 500 g of chocolate byproducts and protected fats mixture (1:1 DM basis) (CHPF diet), DM basis, and each of the diets was also supplemented with 1 g chromium daily. Both amounts of protected fats and chocolate byproducts had the same energy concentration as 1 kg of corn. Without affecting feed intake, the replacement increased (P<0.01) milk production, milk fat concentration, and feed efficiency. The replacement (P<0.05) increased the concentrations of serum total proteins, albumin, glucose, cholesterol, triglyceride, and chromium in comparison with the control diet. Higher (P<0.001) nutrient digestibility was observed with CH, PF, and CHPF treatments. It is concluded that chromium supplementation did not affect feed utilization or cows performance; however, partial replacement of corn with chromium supplemented protected fat, chocolate byproducts or their mixture improved milk production and feed efficiency.

Symposium review: Effects of carbohydrate digestion on feed intake and fuel supply

Carbohydrates are the primary energy source for lactating dairy cows, and dairy diets are usually formulated for certain concentrations of forage neutral detergent fiber (NDF) and starch due to their direct effects on dry matter intake and milk production. Forage NDF exerts greater filling effects in the rumen than other dietary components and can limit maximum voluntary feed intake of lactating dairy cows. Since an analytical method for NDF was developed more than a half century ago, it has been used widely to characterize forages and diets for dairy cows. However, because NDF is a chemical measurement varying in its digestibility, in vitro digestibility measurements were developed as a biological approach to assess forage quality. Research efforts over the last several decades led to the development of forage cultivars or hybrids with enhanced in vitro NDF digestibility, such as brown midrib, and management practices considering differences in NDF digestibility of forages. In addition, in vitro NDF digestibility and undigested NDF are commonly measured in commercial labs, and estimated rates of digestion are used in dynamic models in an effort to improve the accuracy and precision of diet formulation. Starch digestion in the rumen also varies among starch sources, being affected by grain type, extent of processing, and conservation method. The site and rate of starch digestion affect dry matter intake and nutrient partitioning in dairy cows by modifying temporal supply of fuel. In addition, dietary starch content and its fermentability can affect digestion rates of starch itself and NDF in the rumen. Previous research has increased our understanding of dietary carbohydrates, but its application for diet formulations requires integrated approaches accounting for factors affecting the filling effects of forage NDF, starch digestion, and temporal fuel supply.

The enrichment of chocolate byproducts and protected fats with zinc to partially replace corn in diets of early lactation Holstein cows

The present experiment aimed to evaluate the effect of partial replacement of corn with chocolate byproducts, protected fats, or their mixture supplemented with zinc in the diet of lactating cows on feed utilization and lactation performance for 90 days. Fifty multiparous Holstein cows (565±25 kg BW, 3±1 parity, 7±1 days in milk, a previous milk production of 35±2.9 kg/d), were randomly assigned to 5 treatments in a completely randomized design. The control diet contained (per kg DM): 412 g concentrate feed mixture, 412 g corn silage, and 176 g berseem hay. The control diet was supplemented with 1 g of zinc daily (Zinc diet). In the other diets, each kg of crushed corn grain was replaced with (DM basis) 600 g chocolate byproducts (CH diet), 400 g protected fats (PF diet), or 500 g of chocolate byproducts and protected fats mixture (1:1 DM basis) (CHPF diet). Both amounts of protected fats and chocolate byproducts had the same energy concentration as 1 kg of corn. The total mixed ration was prepared and distributed using a horizontal mixer system after mixing for 20 min. Chemical analysis showed that the replacement minimally affected the composition of the total mixed rations. Additionally, treatments did not affect feed intake. Compared to the control treatment, the zinc treatment did not affect milk production, milk composition, or feed efficiency. Increased (P<0.05) daily production of milk and component yields, and feed efficiency as well as fat concentration were observed by the CH, PF and CHPF treatments. Without affecting other measured blood parameters or hematocrit, treatments increased (P<0.05) the concentrations of total proteins, albumin, glucose, cholesterol, triglyceride, and zinc in the blood of cows. Additionally, the CH, PF and CHPF treatments increased (P<0.01) the digestibility of nutrients compared to the control treatment. It is concluded that the addition of zinc to the control did not affect cow performance; however, its addition to chocolate byproducts, protected fats, or their mixture to partially replace corn improved the performance of cows.

The Impact of Biotechnologically Produced Lactobionic Acid in the Diet of Lactating Dairy Cows on Their Performance and Quality Traits of Milk

Dairy processing is one of the most polluting sectors of the food industry as it causes water pollution. Given considerable whey quantities obtained via traditional cheese and curd production methods, manufacturers worldwide are encountering challenges for its rational use. However, with the advancement in biotechnology, the sustainability of whey management can be fostered by applying microbial cultures for the bioconversion of whey components such as lactose to functional molecules. The present work was undertaken to demonstrate the potential utilization of whey for producing a fraction rich in lactobionic acid (Lba), which was further used in the dietary treatment of lactating dairy cows. The analysis utilizing high-performance liquid chromatography with refractive index (HPLC-RID) detection confirmed the abundance of Lba in biotechnologically processed whey, corresponding to 11.3 g L-1. The basic diet of two dairy cow groups involving nine animals, Holstein Black and White or Red breeds in each, was supplemented either with 1.0 kg sugar beet molasses (Group A) or 5.0 kg of the liquid fraction containing 56.5 g Lba (Group B). Overall, the use of Lba in the diet of dairy cows during the lactation period equal to molasses affected cows' performances and quality traits, especially fat composition. The observed values of urea content revealed that animals of Group B and, to a lesser extent, Group A received a sufficient amount of proteins, as the amount of urea in the milk decreased by 21.7% and 35.1%, respectively. After six months of the feeding trial, a significantly higher concentration of essential amino acids (AAs), i.e., isoleucine and valine, was observed in Group B. The percentage increase corresponded to 5.8% and 3.3%, respectively. A similar trend of increase was found for branched-chain AAs, indicating an increase of 2.4% compared with the initial value. Overall, the content of fatty acids (FAs) in milk samples was affected by feeding. Without reference to the decrease in individual FAs, the higher values of monounsaturated FAs (MUFAs) were achieved via the supplementation of lactating cows' diets with molasses. In contrast, the dietary inclusion of Lba in the diet promoted an increase in saturated FA (SFA) and polyunsaturated FA (PUFA) content in the milk after six months of the feeding trial.

Impact of Molasses on Ruminal Volatile Fatty Acid Production and Microbiota Composition In Vitro

The aim of this study was to assess if molasses could modify VFA production and the rumen microbial community in vitro. Three beet (treatment Beet) and three cane (treatment Cane) molasses preparations were randomly selected from a variety of samples collected worldwide and incubated in vitro with rumen fluid along with a control sample (treatment CTR, in which no molasses was used). Flasks for VFA analysis were sampled at 0, 1, 2, 3, 4, 6, 8, and 24 h of each incubation. For microbiota analysis, samples from each fermentation flask after 12 and 24 h were subjected to microbial DNA extraction and V3-V4 16S rRNA gene sequencing on an Illumina MiSeq platform. Total net VFA production was higher in the beet and cane preparations than in the control (CTR) group at 24 h (33 mmol/L, 34 mmol/L, and 24.8 mmol/L, respectively), and the composition of VFAs was affected by the inclusion of molasses: acetic acid increased in the CTR group (73.5 mol%), while propionic acid increased in the beet and cane molasses (19.6 mol% and 18.6 mol%, respectively), and butyric acid increased, especially in the cane group (23.2 mol%). Molasses even influenced the composition of the rumen microbiota, and particularly the relative abundance of the most dominant family in the rumen, Prevotellaceae, which decreased compared to CTR (37.13%, 28.88%, and 49.6%, respectively). In contrast, Streptococcaceae (19.62% and 28.10% in molasses compared to 6.23% in CTR), Veillonellaceae (6.48% and 8.67% in molasses compared to 4.54% in CTR), and Fibrobacteraceae (0.90% and 0.88% in molasses compared to 0.62% in CTR) increased in the beet and cane groups compared to the CTR group. Another important finding is the lower proportion of Methanobacteriaceae following the addition of molasses compared to CTR (0.26%, 0.28%, and 0.43%, respectively). This study showed the impact of molasses in influencing VFA production and composition as a result of a modified rumen microbial composition.

Effects of the addition of non-fibre carbohydrates with different rumen degradation rates in dairy cow high-forage diets using the Rumen Simulation Technique

Nutrient synchronisation of protein and carbohydrates is a promising practice to improve ruminal nutrient utilisation. However, dietary sources supplying these nutrients can vary in ruminal nutrient availability due to differing degradation rates, therefore potentially affecting utilisation of nitrogen (N). The effects of the addition of non-fibre carbohydrates (NFCs) with different rumen degradation rates in high-forage diets on ruminal fermentation, efficiency and microbial flow were investigated in vitro using the Rumen Simulation Technique (RUSITEC). Four diets were tested: control with 100% ryegrass silage (GRS) and substitution of 20% on a DM basis of ryegrass silage with corn grain (CORN), processed corn (OZ) or sucrose (SUC). The four diets were assigned to 16 vessels in two sets of RUSITEC apparatuses in a randomised block design over a 17 d experimental trial; 10 d consisted of adaptation and 7 d for sample collection. Rumen fluid was collected from four rumen-cannulated dry Holstein-Friesian dairy cows and was treated without mixing. Then, rumen fluid from each cow was used to inoculate four vessels, and diet treatments were randomly allocated to each one. This was repeated for all cows resulting in 16 vessels. The inclusion of SUC in ryegrass silage diets improved DM and organic matter digestibility. The only diet to significantly lower ammonia-N concentration compared with GRS was SUC. The outflows of non-ammonia-N, microbial-N, and efficiency of microbial protein synthesis were not affected by diet type. However, the efficiency of nitrogen utilisation was improved by SUC compared with GRS. This indicates that the inclusion of an energy source with a high rumen degradation rate in high-forage diets improves rumen fermentation, digestibility, and N utilisation. Specifically, this effect was observed for the more readily available energy source, SUC, compared with the more slowly degradable NFC sources, CORN and OZ.

Effect of a molasses-based liquid supplement on gastrointestinal tract barrier function, inflammation, and performance of newly received feedlot cattle before and after a transport stress

The objective of this study was to determine the effect of a dry versus a molasses-based liquid supplement on ruminal butyrate concentration, gastrointestinal tract (GIT) barrier function, inflammatory status, and performance of newly received feedlot cattle. In experiment 1, 60 mixed breed steers (234 ± 2.1 kg) were weaned, held overnight at a sale barn, then transported 14 h to Purdue University. After arrival, steers were weighed, blocked by body weight, and allotted within block to treatments (six pens per treatment and five steers per pen). Diets consisted of 45% roughage and 55% concentrate (dry matter basis). Treatments differed in the supplement source as follows: DRY: 10% dry supplement or LIQUID: 10% liquid molasses-based supplement. Feed intake, average daily gain (ADG), and gain:feed were determined for the three 21-d periods and overall. In experiment 2, 16 crossbred heifers (246 ± 7.5 kg) were used (8 heifers per treatment). Diets were the same as in experiment 1 and were fed for 60 d. On d 56 ruminal fluid samples were collected at 0, 3, 6, and 9 h after feeding. To mimic a stress event, heifers were transported for 4 h on d 61, rested overnight, and transported 12 h on d 62. Blood was collected from heifers immediately prior to transport and immediately upon their return. Gut barrier function using a Cr-EDTA marker was determined after transportation. Data were analyzed using the GLIMMIX procedure of SAS. Steers fed the liquid supplement had greater (P ≤ 0.03) ADG through d 42 and overall compared to steers fed the dry supplement. Feed intake did not differ (P = 0.25) between treatments from d 0 to d 21. However, steers fed the liquid supplement showed greater (P < 0.001) dry matter intake after d 21 and overall compared to those fed the dry supplement. Steers fed the liquid supplement tended (P < 0.09) to have reduced serum haptoglobin and lipopolysaccharide-binding protein (LBP) compared to those fed the dry supplement. Heifers fed the liquid supplement had greater (P = 0.02) Cr in urine and tended (P = 0.07) to have lower serum LBP after transport compared to those fed the dry supplement. Heifers fed the liquid supplement had 72% lower serum haptoglobin before, but only a 19% lower serum haptoglobin after transport compared to animals fed the dry supplement (treatment × time; P = 0.07). Therefore, the liquid supplement altered GIT barrier function, and improved inflammatory status, resulting in increased growth of receiving cattle.

Granulated Cane Sugar as a Partial Replacement for Steam-Flaked Corn in Diets for Feedlot Cattle: Ruminal Fermentation and Microbial Protein Synthesis

The aim of this study was to evaluate the influence of supplemental granulated cane sugar (GCS) levels (0, 13.3, 26.6, and 39.9% on a dry matter basis) in a steam-flaked corn-based finishing diet on measures of ruminal fermentation and the site and extent of nutrient digestion. Four Holstein steers (251 ± 3.6 kg live weight) with “T” type cannulas in the rumen and proximal duodenum were used in a 4 × 4 Latin square experiment to evaluate the treatments. The experiment lasted 84 d. Replacing steam-flaked corn (SFC) with GCS linearly decreased the flow of ammonia-N (NH3-N) to the small intestine, increasing the flow of microbial nitrogen (MN; quadratic effect, p = 0.02), ruminal N efficiency (linear effect, p = 0.03) and MN efficiency (quadratic effect, p = 0.04). The ruminal digestion of starch and neutral detergent fiber (NDF) decreased (linear effect, p ≤ 0.02) as the level of GCS increased. The postruminal digestion of organic matter (OM), neutral detergent fiber (NDF), and starch were not affected by the GCS inclusion. However, postruminal N digestion decreased (linear effect, p = 0.02) as the level of GCS increased. There were no treatment effects on total tract OM digestion. However, total tract NDF and N digestion decreased (linear effect, p ≤ 0.02) as the level of GCS increased. The ruminal pH decreased (linear effect, p < 0.01) as the GCS increased in the diet. The ruminal acetate molar proportion decreased (linear effect, p = 0.02) and the ruminal valerate molar proportion tended to increase (linear effect, p = 0.08) as the level of GCS increased. It is concluded that replacing as much as 13% of SFC with GCS in a finishing diet will enhance the efficiency of N utilization (g non-ammonia-N entering the small intestine/g N intake) without detrimental effects on total tract OM digestion. The inclusion of GCS decreased the ruminal proportion of acetate linearly without an effect on the acetate-to-propionate ratio or estimated methane production. Some of the effects on N utilization at a high level of GCS inclusion (27 and 40%) can be magnified by the differences in the CP content between diets. A higher level of GCS supplementation in the diet decreased the ruminal pH below 5.5, increasing the risk of ruminal acidosis.

Does the timing of pasture allocation affect rumen and plasma metabolites and ghrelin, insulin and cortisol profile in dairy ewes?

A study was undertaken to assess the impact of the timing of grazing on rumen and plasma metabolites and some metabolic hormones in lactating dairy sheep allocated to an Italian ryegrass (Lolium multiflorum Lam) pasture in spring for 4 h/d. Twenty-four mid lactation Sarda ewes stratified for milk yield, body weight, and body condition score, were divided into four homogeneous groups randomly allocated to the treatments (2 replicate groups per treatment). Treatments were morning (AM, from 08:00 to 12:00) and afternoon pasture allocation (PM, from 15:30 to 19:30). Samples of rumen liquor (day 39) and blood plasma (days 17 and 34 of the experimental period) were collected before and after the grazing sessions. Moreover, on days 11 and 35, grazing time was assessed by direct observation and herbage intake measured by the double weighing procedure. Grazing time was longer in PM than AM ewes (P < 0.001) but herbage intake was undifferentiated between groups. The intake of water-soluble carbohydrates at pasture was higher in PM than AM ewes (P < 0.05). The post-grazing propionic and butyric acid concentration, as measured on day 39, were higher in PM than AM ewes (P < 0.05). The basal level of glucose on day 34 and insulin (on both sampling days) were higher in PM than AM (P < 0.05). The opposite trend was detected for non-esterified fatty acids (P < 0.05, day 34) and urea (both days). Pasture allocation in the afternoon rather than in the morning decreased plasma concentration of ghrelin (P < 0.001) and cortisol (P < 0.001), with a smoothed trend on day 34 in the latter variable. To conclude, postponing the pasture allocation to afternoon increased the intake of WSC, favoring a glucogenic pattern of rumen fermentation and a rise of glucose and insulin levels in blood, although these effects were not consistent across the whole experimental period. Moreover, the afternoon grazing decreased the level of cortisol and ghrelin, suggesting a higher satiation-relaxing effect.

Supplementation of Molasses-Based Liquid Feed for Cattle Fed on Limpograss Hay

Two experiments were performed to evaluate the effects of (1) different levels of liquid supplementation (LS) based on molasses enriched with 32% (as fed; 45% on DM basis) crude protein (CP) on intake of Hemarthria altissima hay (LH), digestibility, and rumen fermentation, and (2) different levels of LS based on molasses enriched with 32% CP in the in vitro gas production in LH diets. In Exp. 1, twelve heifers and 12 adult male castrated and cannulated cattle were used. Treatments were allocated in a randomized block design, in four treatments: (CTL) access ad libitum to the LH; (SUP2) ad libitum access to LH and supplementation with 0.9 kg d−1; (SUP4) ad libitum access to LH and supplementation with 1.8 kg d−1 and; (SUP6) ad libitum access to LH with 2.7 kg d−1. In Exp. 2, treatments were carried out in a randomized block design with four different proportions of LH diet: (CTL) 100 LH, (SUP2) 85 LH and 15 LS, (SUP4) 70 LH and 30 LS, (SUP6) 55 LH and 45% LS. In Exp. 1, liquid molasses-based supplementation did not affect LH intake (p > 0.05). Molasses intake improved as the supply increased, not reducing the intake of LH. In Exp. 2, the addition of LS to the LH caused a change in the VFA profile, with an increase in propionate production in vitro.

In Vitro Fermentation of Browsable Native Shrubs in New Zealand

Information on the nutritive value and in vitro fermentation characteristics of native shrubs in New Zealand is scant. This is despite their potential as alternatives to exotic trees and shrubs for supplementary fodder, and their mitigation of greenhouse gases and soil erosion on hill-country sheep and beef farms. The objectives of this study were to measure the in vitro fermentation gas production, predict the parameters of the in vitro fermentation kinetics, and estimate the in vitro fermentation of volatile fatty acids (VFA), microbial biomass (MBM), and greenhouse gases of four native shrubs (Coprosma robusta, Griselinia littoralis, Hoheria populnea, and Pittosporum crassifolium) and an exotic fodder tree species, Salix schwerinii. The total in vitro gas production was higher (p < 0.05) for the natives than for the S. schwerinii. A prediction using the single-pool model resulted in biologically incorrect negative in vitro total gas production from the immediately soluble fraction of the native shrubs. However, the dual pool model better predicted the in vitro total gas production and was in alignment with the measured in vitro fermentation end products. The in vitro VFA and greenhouse gas production from the fermentation of leaf and stem material was higher (p < 0.05), and the MBM lower (p < 0.05), for the native shrubs compared to the S. schwerinii. The lower in vitro total gas production, VFA, and greenhouse gases production and higher MBM of the S. schwerinii may be explained by the presence of condensed tannins (CT), although this was not measured and requires further study. In conclusion, the results from this study suggest that when consumed by ruminant livestock, browsable native shrubs can provide adequate energy and microbial protein, and that greenhouse-gas production from these species is within the ranges reported for typical New Zealand pastures.

The Replacement of Ground Corn with Sugar Beet in the Diet of Pasture-Fed Lactating Dairy Cows and Its Effect on Productive Performance and Rumen Metabolism

(1) Background: Sugars have a potential to provide great amounts of fermentable energy in the rumen. Feeding fresh sugar beet (SB) to dairy cattle to replace a portion of the grain in the ration has not received sufficient attention. This study determined dry matter intake (DMI), feeding behavior, rumen fermentation and milk production responses when replacing corn grain with increasing levels of SB in pasture-fed lactating dairy cow diets. (2) Methods: A total of 12 early-lactation cows were used in a replicated (n = 4) 3 × 3 Latin square design. The control diet consisted of 21 kg dry matter (DM) composed of 6.3 kg DM green chopped perennial ryegrass, 7 kg DM grass silage, 2 kg DM of concentrate, 1 kg DM soybean meal and 4.5 kg DM of ground corn. The other treatments replaced 50% or 100% of the ground corn with SB roots. (3) Results: The replacement of ground corn with sugar beet reduced DMI and milk yield (p < 0.05), but it increased milk fat concentration (p = 0.045), reduced feeding costs and increased margin over feed costs (p < 0.01). Urinary nitrogen was linearly reduced with SB supplementation (p = 0.026). (4) Conclusions: Using SB roots as energetic supplement can be a suitable alternative to ground corn in pasture-fed lactating dairy cows.

Optimizing Anthocyanin-Rich Black Cane (Saccharum sinensis Robx.) Silage for Ruminants Using Molasses and Iron Sulphate: A Sustainable Alternative

Anthocyanin-rich black cane (aBC) is a grass rich in lignin and carbohydrates, with an abundance of anthocyanins. Silages of aBC produced with molasses (MS) and/or ferrous sulphate (FS) mixtures may have beneficial effects on silage quality and animal performance in ruminants. However, the addition of MS and FS to ensiled grass is relatively unexplored. Therefore, this study systematically evaluated the effect of their administration at different doses to select an effective treatment to modulate the ensiling characteristics of aBC. In the first trial, fresh or pre-ensiled materials (PBC) were compared with ensiled PBC treated with: 0% MS 0% FS, 4% MS, 8% MS, 0.015% FS, 0.030% FS, 4% MS + 0.015% FS, 4% MS + 0.030% FS, 8% MS + 0.015% FS, and 8% MS + 0.030% FS on a fresh matter basis. The quality of ensiling characteristics was determined in laboratory-scale silos after 42 d of preservation. Based on these results, the second trial was further conducted in rumen cultures to ensure that the selected treatment would not impair rumen fermentation. For this, ruminal biogases, rumen fermentation profiles, and microbial communities were evaluated. Ensiled PBC with the incremental addition of MS and FS resulted in the observations for anthocyanin contents and the ensiling characteristics of the aBC silages. The combination of MS (4%) and FS (0.030%) incorporated into silages had the highest silage production effect among the experimental treatments. This combination demonstrated the sustainable mitigation of the ruminal biogases of methane and carbon dioxide without impairment of total gas production. Concurrently, this combination improved total volatile fatty acid concentrations, modulated cellulolytic bacteria, and suppressed methanogenic bacteria in rumen fluids. The results presented here indicated that addition of a mixture of 4% MS and 0.030% FS to aBC resulted in an optimal balance of ensiling characteristics and is suitable for use in ruminants.

Increased intake of mono- and disaccharides by Reeves's muntjac (Muntiacus reevesi). Effect on gastrointestinal tract structure and function and blood parameters

The aim of this study was to determine the effect of an increased mono- and disaccharide (MD) intake on selected functions and structure of the gastrointestinal tract (GIT), and selected blood parameters in Reeves's muntjac (Muntiacus reevesi), a small browsing ruminant. Eighteen male muntjacs were fed diets consisting of lucerne (ad libitum), a high fibre pellet (100 g/day) and wheat bran (30 g/day) without (MD0) or with addition of 10 or 20 g of glucose, fructose and sucrose mixture/day (MD10 and MD20, respectively) for 14 days. MD dosages were set to increase intake of these saccharides by 25% and 50% relative to MD0, which resulted in a range of water-soluble carbohydrate content in the consumed dry matter from 7% to 12%. Compared to MD0 animals, MD20 animals had a lower dry matter intake, a higher MD concentrations in the reticulorumen (RR), abomasal and small intestinal digesta, higher ruminal butyrate concentration, higher SGLT1 expression in the epithelium of proximal jejunum, higher plasma glucose, lower RR tissue weight but greater caecal tissue weight (p ≤ 0.05), and had or tended to have shorter papillae and lower mucosa surface area in the Atrium ruminis (by 44%; p = 0.02 and p = 0.10, respectively); MD10 animals tended to have higher MD concentrations in the abomasal and small intestinal digesta (p ≤ 0.10), and a higher amylolytic activity (p = 0.02) as well as a tendency to lower xylanolytic activity in the RR digesta (p = 0.06). MD supplementation did not affect ruminal pH. In conclusion, low to moderate increase of MD intake increased MD concentrations in the RR, abomasal and intestinal digesta, and SGLT1 expression in intestinal epithelium, suggesting incomplete fermentation of those saccharides in the RR. MD supplementation dose-dependently affects structure of GIT in Reeves's muntjac.

Silage Fermentation Quality, Anthocyanin Stability, and in vitro Rumen Fermentation Characteristic of Ferrous Sulfate Heptahydrate-Treated Black Cane (Saccharum sinensis R.)

Pretreatment of lignocellulose agricultural biomass with iron prior to ensiling is required to accelerate biomass breakdown during fermentation, which could result in functional microorganisms and chemicals that reduce nutrition loss, harmful substances, and improve animal performance. The objective of this study was to investigate the effects of increasing dilutions of ferrous sulfate heptahydrate (FS) pretreatment at fresh matter concentrations of 0, 0.015, and 0.030% on the fermentation quality of black cane (BC) silage, anthocyanin stability, ruminal biogas, rumen fermentation profile, and microbial community. Pre-ensiled and silage materials were evaluated. High moisture, fiber, anthocyanin, and lignification of biomass, as well as undesirable ensiling microorganisms, were found in BC' pre-ensiled form. Increasing dilutions of FS incorporated into silages were observed to linearly decrease dry matter, anthocyanin, and nutritive value losses. The lignin values decreased linearly as the percentage of FS increased up to 0.030%. Given that the ruminants were fed pre-ensiled materials, BC silage treated with 0.030% FS dilution had comparable results to pre-ensiled BC in terms of increasing in vitro volatile fatty acid concentrations, maintaining total gas production, and reducing methane production, when compared to other FS-treated silages. In addition, BC silage treated with a 0.030% FS dilution inhibited methanogenic bacteria and regulated cellulolytic bacteria in rumen fluid. Overall, the anthocyanin content of BC remained constant throughout the rumen fermentation process after increasing dilutions of FS, indicating that BC is a viable ruminant feedstock and that pretreatment of BC with dilute FS-assisted ensiling at 0.030% could be used to generate ruminant diets.

Dry malt extract from barley partially replacing ground corn in diets of dairy cows: Nutrient digestibility, ruminal fermentation, and milk composition

Dry malt extract (DME) has been used in animal nutrition as an alternative source of rapidly fermentable carbohydrate. An experiment was conducted to evaluate the partial replacement of ground corn with DME in diets of dairy cows on apparent digestibility, ruminal fermentation, predicted rumen microbial protein supply, N excretion, serum urea-N concentration, and milk yield and composition. Twenty-eight Holstein cows (35.3 ± 5.88 kg/d milk yield and 148 ± 78 d in milk), 4 of which were rumen cannulated, were blocked according to the presence of rumen cannulas, parity, milk yield, and days in milk and enrolled into a crossover design experiment. Experimental periods lasted 21 d, of which the first 14 d were allowed for treatment adaptation and 7 d were used for data collection and sampling. Treatment sequences were composed of control (CON) or DME from barley (Liotécnica Tecnologia em Alimentos) replacing ground corn at 7.62% diet dry matter (∼2 kg/d). Data were analyzed using the MIXED procedure of SAS (SAS Institute Inc.) modeling the fixed effects of treatment, period, and their interaction, in addition to the random effect of animal. Ruminal fermentation data were analyzed as repeated measures including time and its interaction with treatment in the previous model as fixed effects. Treatments did not affect nutrient intake or feed sorting. Dry malt extract increased apparent digestibility of CP. Feeding DME decreased ruminal pH and molar percentage of butyrate and increased molar percentage of acetate. No treatment effects were detected for predicted rumen microbial protein supply or N excretion. Cows fed DME had lower serum urea-N concentration than CON cows. Dry malt extract increased yields of actual milk, 3.5% fat-corrected milk, fat, and protein, and improved feed efficiency (fat-corrected milk ÷ dry matter intake). Cows fed DME had lower milk urea nitrogen content in comparison with CON cows. Dry malt extract can partially replace ground corn in the diet while improving milk yield and feed efficiency.

Effects of sucrose and lactose as partial replacement to corn in lactating dairy cow diets. A review

Carbohydrates are one of the three macronutrients that provides energy in diets and are classified by their structures. Starch is a nonstructural carbohydrate and polysaccharide made of glucose monomers used for storage in plant cells. When starch makes up greater than 30% of the DM in diets there can be adverse effects on NDF digestibility due to decreases in ruminal pH. Sugars are water soluble carbohydrates that consist of monosaccharide and disaccharide units. Sugars ferment faster than starch because microorganisms in the rumen can ferment carbohydrates at different rates depending on their structure; however, this has not been shown to have negative effects on the ruminal pH. Sources of sugars such as molasses (sucrose) or whey (lactose) can be included in the diet as a partial replacement for starch in dairy cow diets. The purpose of replacing starch with sugars in a diet would be to add differing sources of carbohydrates in the diet to allow for continual fermentation of carbohydrates by the microorganisms in the rumen. It has been seen in studies and previous literature that the partial replacement of starch with sugars has the potential to maintain the ruminal environment and milk yield and composition in dairy cows without reducing NDF digestibility. The objective of this review is to evaluate the effects of partially replacing starch with sugars in dairy diets and its implication on ruminal fermentation, nutrient utilization, milk production, and feeding replacement strategy.

Brittle Culm 15 mutation alters carbohydrate composition, degradation and methanogenesis of rice straw during in vitro ruminal fermentation

Brittle Culm 15 (BC15) gene encodes a membrane-associated chitinase-like protein that participates in cellulose synthesis, and BC15 gene mutation affects cell wall composition in plant, such as cellulose or hemicellulose. The present study was designed to investigate the changes of carbohydrates composition in bc15 mutant straw, and the resulting consequence on rumen fermentation, methanogenesis, and microbial populations (qPCR) during in vitro ruminal fermentation process. Two substrates, bc15 mutant and wild-type (WT) rice straws, were selected for in vitro rumen batch culture. The first experiment was designed to investigate the kinetics of total gas and CH₄ production through 48-h in vitro ruminal fermentation, while the second experiment selected incubation time of 12 and 48 h to represent the early and late stage of in vitro ruminal incubation, respectively, and then investigated changes in biodegradation, fermentation end products, and selected representative microbial populations. The bc15 mutant straw had lower contents of cellulose, neutral detergent fiber (NDF) and acid detergent fiber (ADF), and higher contents of water-soluble carbohydrates, neutral detergent solubles (NDS) and monosaccharides. The bc15 mutant straw exhibited a distinct kinetics of 48-h total gas and CH₄ production with faster increases in early incubation when compared with WT straw. The bc15 mutant straw had higher DM degradation, NDF degradation and total volatile fatty acid concentration at 12 h of incubation, and lower NDF degradation and CH₄ production at 48 h of incubation, together with lower acetate to propionate ratio and ADF degradation and higher butyrate molar percentage and NDS degradation at both incubation times. Furthermore, the bc15 mutant straw resulted in greater 16S gene copies of F. succinogenes, with lower 18S gene copies of fungi at both incubation times. These results indicated that the BC15 gene mutation decreased fibrosis of cell wall of rice straw, enhanced degradation at the early stage of rumen fermentation, and shifts fermentation pattern from acetate to propionate and butyrate production, leading to the decreased volume and fractional rate of CH₄ production. However, BC15 gene mutation may enhance hardenability of cell wall structure of rice straw, which is more resistant for microbial colonization with decreased fiber degradation. Thus, this study modified rice straw by manipulating a cell wall biosynthesis gene and provides a potential strategy to alter degradation and CH₄ production during in vitro ruminal fermentation process.

Effects of partially replacing dietary corn with molasses, condensed whey permeate, or treated condensed whey permeate on ruminal microbial fermentation

Corn is a feedstuff commonly fed to dairy cows as a source of energy. The objective of this study was to evaluate whether partially replacing dietary corn with molasses or condensed whey permeate, in lactating dairy cow diets in a dual-flow continuous culture system, can maintain nutrient digestibility by ruminal microorganisms. Furthermore, this study evaluated whether treating condensed whey permeate before feeding could aid the fermentation of the condensed whey permeate in the rumen. Eight fermentors were used in a 4 × 4 replicated Latin square with 4 periods of 10 d each. The control diet (CON) was formulated with corn grain, and the other diets were formulated by replacing corn grain with either sugarcane molasses (MOL), condensed whey permeate (CWP), or treated condensed whey permeate (TCWP). Diets were formulated by replacing 4% of the diet dry matter (DM) in the form of starch from corn with sugars from the byproducts. Sugars were defined as water-soluble carbohydrates (WSC) in the rations. The fermentors were fed 52 g of DM twice daily of diets containing 17% crude protein, 28% neutral detergent fiber, and 45% nonfiber carbohydrates. Liquid treatments were pipetted into each fermentor. After 7 d of adaptation, samples were collected for analyses of volatile fatty acids (VFA), lactate, and ammonia, and fermentors' pH were measured at time points after the morning feeding for 3 d. Pooled samples from effluent containers were collected for similar analyses, nutrient flow, and N metabolism. Data were statistically analyzed using Proc MIXED of SAS version 9.4 (SAS Institute Inc.); fixed effects included treatment and time, and random effects included fermentor, period, and square. The interaction of treatment and time was included for the kinetics samples. The TCWP and MOL treatments maintained greater fermentor pH compared with CWP. Total VFA concentration was increased in CWP compared with MOL. The acetate:propionate ratio was increased in TCWP compared with CON, due to tendencies of increased acetate molar proportion and decreased propionate molar proportion in TCWP. Lactate concentration was increased in MOL. Digestibility of WSC was increased in the diets that replaced corn with byproducts. The partial replacement of 4% of DM from corn starch with the sugars in byproducts had minimal effects on ruminal microbial fermentation and increased pH. Treated CWP had similar effects to molasses.

A review on the potentials of using feeds rich in water-soluble carbohydrates to enhance rumen health and sustainability of dairy cattle production

Cows are adapted to degrade structural plant carbohydrates (SC), such as cellulose and hemicelluloses, prevailing in grasses. Yet, the need for energy-dense diets in many intensive dairy production systems has shifted the dairy cattle's diet from SC-rich to high levels of starch. Feeding of starch-rich diets increases the risk of ruminal acidosis in cows, and feeding starch in the form of grains intensifies the competition over cereal grains and arable land among different livestock species, as well as between livestock and humans. Besides cellulose and hemicelluloses, grasses are also often rich in water-soluble carbohydrates (WSC), which comprise mono-, di-, oligo- and polysaccharides (fructans). Although the ruminal fermentation profile of mono- and disaccharides resembles that of starch, the degradation of oligo- and polysaccharides is slower, and their fermentation elicits a rather protecting effect on ruminal pH. When harvested in an early phase (i.e. ear emergence), grass hay and silages can reach WSC levels up to 150-200 g kg^-1 dry matter and energy levels close to starch-rich diets, allowing a significantly reduced inclusion of concentrate supplements. By doing so, this will enhance both rumen health and the sustainability of milk production. However, because the WSC are chemically very heterogeneous, the patterns and extent of their ruminal fermentation are difficult to predict without a clear analytical characterization. This review article aims to summarize both the benefits and potentials, as well as the challenges, with respect to using WSC-rich feedstuffs in the nutrition of dairy cattle and their effects on ruminal fermentation characteristics and milk production. © 2021 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Effects of Different Combinations of Sugar and Starch Concentrations on Ruminal Fermentation and Bacterial-Community Composition in vitro

High levels of starch is known to have positive effects on both energy supply and milk yield but increases the risk of rumen acidosis. The use of sugar as a non-structural carbohydrate could circumvent this risk while maintaining the benefits, but its effects and that of the simultaneous use of both sugar and starch are not as well-understood. This study aimed to evaluate the effects of different combinations of sugar and starch concentrations on ruminal fermentation and bacterial community composition in vitro in a 4 ×4 factorial experiment. Sixteen dietary treatments were formulated with 4 levels of sugar (6, 8, 10, and 12% of dietary dry matter), and 4 levels of starch (21, 23, 25, and 27% of dietary dry matter). Samples were taken at 0.5, 1, 3, 6, 12, and 24 h after cultivation to determine the disappearance rate of dry matter, rumen fermentation parameters and bacterial community composition. Butyric acid, gas production, and Treponema abundance were significantly influenced by the sugar level. The pH, acetic acid, and propionic acid levels were significantly influenced by starch levels. However, the interactive effect of sugar and starch was only observed on the rate of dry matter disappearance. Furthermore, different combinations of starch and sugar had different effects on volatile fatty acid production rate, gas production rate, and dry matter disappearance rate. The production rate of rumen fermentation parameters in the high sugar group was higher. Additionally, increasing the sugar content in the diet did not change the main phylum composition in the rumen, but significantly increased the relative abundance of Bacteroidetes and Firmicutes phyla, while the relative abundance of Proteobacteria was reduced. At the genus level, the high glucose group showed significantly higher relative abundance of Treponema (P < 0.05) and significantly lower relative abundance of Ruminobacter, Ruminococcus, and Streptococcus (P < 0.05). In conclusion, different combinations of sugar and starch concentrations have inconsistent effects on rumen fermentation characteristics, suggesting that the starch in diets cannot be simply replaced with sugar; the combined effects of sugar and starch should be considered to improve the feed utilization rate.

Effect of dietary inclusion of winter brassica crops on milk production, feeding behavior, rumen fermentation, and plasma fatty acid profile in dairy cows

This study determined feeding behavior, dry matter (DM) intake (DMI), rumen fermentation, and milk production responses of lactating dairy cows fed with kale (Brassica oleracea) or swede (Brassica napus ssp. napobrassica). Twelve multiparous lactating dairy cows (560 ± 22 kg of body weight, 30 ± 4 kg of milk/d, and 60 ± 11 d in milk at the beginning of the experiment; mean ± standard deviation) were randomly allocated to 3 dietary treatments in a replicated 3 × 3 Latin square design. The control diet comprised 10 kg of grass silage DM/d, 4 kg of ryegrass herbage DM/d, and 8.8 kg of concentrate DM/d. Then, 25% of herbage, silage, and concentrate (DM basis) was replaced with either kale or swede. Cows offered kale had decreased total DMI compared with cows fed the control and swede diets, whereas inclusion of swede increased eating time. Milk production, composition, and energy-corrected milk:DMI ratio were not affected. Cows fed with kale had a greater rumen acetate:propionate ratio, whereas swede inclusion increased the relative percentage of butyrate. Estimated microbial N was not affected by dietary treatments, but N excretion was reduced with inclusion of kale, improving N utilization. Cows fed kale tended to have increased nonesterified fatty acids and showed presence of Heinz-Ehrlich bodies, whereas hepatic enzymes such as aspartate aminotransferase, γ-glutamyl transferase, and glutamate dehydrogenase were not affected by dietary treatments. In plasma, compared with the control, swede and kale reduced total saturated fatty acids and increased total polyunsaturated fatty acids and total n-3 fatty acids. Overall, feeding cows with winter brassicas had no negative effect on production responses. However, mechanisms to maintain milk production were different. Inclusion of swede increased the time spent eating and maintained DMI with a greater relative rumen percentage of butyrate and propionate, whereas kale reduced DMI but increased triacylglycerides mobilization, which can negatively affect reproductive performance. Thus, the inclusion of swede may be more suitable for feeding early-lactating dairy cows during winter.

Effect of Dried Distillers Grains With Solubles and Red Osier Dogwood Extract on Fermentation Pattern and Microbial Profiles of a High-Grain Diet in an Artificial Rumen System

The objective of this study was to evaluate the effect of dried distillers grains with solubles (DDGS) and red-osier dogwood (ROD) extract on in vitro fermentation characteristics, nutrient disappearance, and microbial profiles using the rumen simulation technique. The experiment was a completely randomized design with a 2 × 2 factorial arrangement of treatments and four replicates per treatment. A basal diet [10% barley silage, 87% dry-rolled barley grain, and 3% vitamin and mineral supplement, dry matter (DM) basis] and a DDGS diet (as per basal diet with 25% of wheat DDGS replacing an equal portion of barley grain) were supplemented with ROD extract at 0 and 1% (DM basis), respectively. The experimental period was 17 d, consisting 10 days of adaptation and 7 days of data and sample collection. The substitution of wheat DDGS for barley grain did not affect gas production; disappearances of DM, organic matter, and crude protein; total volatile fatty acid (VFA) production; and microbial protein production. However, replacing barley grain with wheat DDGS increased (P = 0.01) fermenter pH and molar proportion of branched-chain VFA, switched (P = 0.06) the fermentation pattern to higher acetate production due to increased (P = 0.01) disappearance of neutral detergent fiber (NDF), and decreased (P = 0.08) methane (CH4) production. In the basal barley diet, the ROD extract increased the acetate to propionate (A:P) ratio (P = 0.08) and reduced the disappearance of starch (P = 0.06) with no effect on any other variables. No effects of ROD in the DDGS diet were observed. The number of operational taxonomic unit (OTUs) and the Shannon diversity index of the microbial community had little variation among treatments. Taxonomic analysis revealed no effect of adding the ROD extract on the relative abundance of bacteria at the phylum level with either the basal diet or DDGS diet, while at the genus level, the microbial community was affected by the addition of both DDGS and the ROD extract. Prevotella and Fibrobacter were the most abundant genera in the basal diet; however, Treponema became the most abundant genus with the addition of the ROD extract. These results indicated that the substitution of wheat DDGS for barley grain may mitigate enteric CH4 emissions. The trend of reduced starch fermentability and increased NDF disappearance with the addition of ROD extract suggests a reduced risk of rumen acidosis and an improvement in the utilization of fiber for cattle-fed high-grain diet.

Behavior, health, and productivity of early-lactation dairy cows supplemented with molasses in automated milking systems

The objective of this study was to determine the effect of molasses-based liquid feed (LF) supplementation within automated milking systems (AMS) on the behavior, health, and production of early-lactation dairy cows. In 6 commercial AMS dairy herds, 390 dairy cows were randomly assigned before calving to 1 of 2 treatments, within farm, balanced by parity: (1) control group (CON) receiving a standard AMS pellet [mean = 3.9 kg/d on a dry matter (DM) basis, n = 188], or (2) same amount of standard AMS pellet (mean = 3.6 kg/d on a DM basis, n = 202) plus 1 kg/d DM of LF for multiparous cows (1.6 kg/d as fed) and 0.88 kg/d DM for primiparous cows (1.4 kg/d as fed). Across farms, cows were fed partial mixed rations similar in ingredient and nutrient composition. Cows on the LF treatment received supplementation for the first 60 d in milk (DIM). Blood samples were taken 2 times/wk for the first 3 wk postcalving to assess β-hydroxybutyrate (BHB). Samples with BHB ≥1.2 mmol/L were classified as a positive case of subclinical ketosis (SCK). Cow body condition and lameness were scored every 10 d postcalving until 60 DIM. No differences were detected between treatments for milk yield (average milk yield = 37.4 ± 1.98 kg/d) and milking frequency (average milking frequency = 3.2 ± 0.01 times/d). Similarly, no difference between treatments in daily AMS visits was detected (average AMS visits = 5.3 ± 0.3 times/d). However, CON cows experienced more AMS refusals/d than LF cows (LF = 1.6 refusals/d, CON = 2.1 refusals/d). No difference between treatments in daily rumination time was detected (average rumination time = 476 ± 10.8 min/d). Treatment was associated with the number of times cows tested positive for SCK; cows on LF had fewer repeated diagnoses of SCK, such that 15% of cows on LF had ≥3 diagnoses of SCK out of 5 tests, compared with 27% of CON cows. Cows receiving molasses tended to have lower blood BHB values at ∼15 DIM. Molasses supplementation also allowed cows to maintain a more stable body condition score, as LF cows tended to lose less body condition over the first 60 DIM compared with CON cows. Overall, the results of this study demonstrate that supplementing a molasses-based LF to AMS cows may help support the energy demands of milk production in early lactation and, thus, reduce the incidence of repeat positive SCK tests during that time period.

Milk production responses, rumen fermentation, and blood metabolites of dairy cows fed increasing concentrations of forage rape (Brassica napus ssp. Biennis)

The aim of this study was to determine animal performance, rumen fermentation, and health-related blood metabolites of dairy cows in mid lactation fed with increasing levels (30 and 45%) of forage rape (FR) in the diet. Twelve pregnant multiparous lactating Holstein-Friesian dairy cows were randomly allocated to 1 of 3 dietary treatments in a replicated 3 × 3 Latin square design. The experiment was divided into three 21-d periods. For the control diet, 13.0 kg (dry matter, DM) of grass silage, 3.0 kg DM of commercial concentrate, 2.7 kg of DM cold-pressed extracted canola meal, and 0.45 kg DM of solvent-extracted soybean meal were offered daily. For the other two treatments, 30 and 45% of the DM from silage, canola meal, and commercial concentrate were replaced in equal proportions with FR. Data were analyzed individually using linear and quadratic orthogonal polynomials. Ingestive behavior was altered by the inclusion of FR. We observed a linear increase in eating time at the expense of rumination time. Nevertheless, total DM intake was not affected by dietary treatments, averaging 19.5 ± 0.24 kg of DM/d. Milk yield increased linearly with increasing concentration of FR in the diet. Thus, feed efficiency of cows (kg of milk/kg of DM intake) increased linearly with the percentage of FR in the diet. Inclusion of FR in the diet had no effect on milk composition or milk sensory characteristics. Mean rumen pH of cows decreased linearly from the control to the 45% FR diet; however, dietary treatments had no effect on the daily amount of time that rumen pH was below 5.8 (252 ± 71.4), indicating no risk of subacute ruminal acidosis. Concentrations of total volatile fatty acids in the rumen and molar proportions of acetate and butyrate were increased with FR inclusion, whereas the proportion of propionate was linearly reduced. Excretion of uric acid and total purine derivatives tended to be greater for cows fed FR, which resulted in a trend toward a linear increase in estimated microbial N flow. However, N use efficiency was not affected by FR inclusion. Although differences for some hematological measures (increased white blood cell and neutrophils counts) and a quadratic response for glutamate dehydrogenase for cows fed FR in the diet (decreased with inclusion of 30% and increased with 45% in the diet) were observed, all values were within appropriate ranges for dairy cows. These results indicated that including FR to dairy cow diets, up to 45% of diet DM, improved milk production due to changes in volatile fatty acids and predicted microbial N flow and had no negative effects on dairy cow health or sensory characteristics of milk.

Potential of Recycling Cauliflower and Romanesco Wastes in Ruminant Feeding: In Vitro Studies

Simple Summary

The use of vegetable wastes in animal feeding is increasing worldwide, but the knowledge of the nutritional value of some of them is still limited. In this study, the nutritive value for ruminants of different fractions of cauliflower and Romanesco wastes (leaves, stems and sprouts) was assessed using in vitro techniques. In addition, we analyzed the effect of increasing the substitution rate of cauliflower for commercial concentrate in a dairy sheep diet containing 40% of alfalfa hay and 60% of concentrate. All fractions of both vegetables had high amounts of water, but their dry matter was rich in protein and sugar and it was extensively fermented in vitro by ruminal microorganisms. Stems and sprouts were more rapidly fermented than leaves, but there were only minor differences between the two assessed vegetables. In an in vitro study with diets for dairy sheep with concentrates containing increased amounts of dried cauliflower, we observed that cauliflower can be included up to 24% of the concentrate without any negative effect on rumen fermentation. The results indicate that cauliflower and Romanesco wastes could be used in ruminant feeding, but in vivo trials are needed to confirm the in vitro results.

Abstract

The nutritive values for ruminants of cauliflower (CAU) and Romanesco (ROM) wastes (leaves, stems and sprouts) were assessed by analyzing their chemical composition, in vitro ruminal fermentation, and in vitro intestinal digestibility. In addition, the in vitro ruminal fermentation of diets containing increasing amounts of CAU was studied. The dry matter (DM) content of leaves, stems and sprouts of both vegetables was lower than 10%, but they contained high crude protein (CP; 19.9 to 33.0%) and sugar (16.3 to 28.7%) levels, and low neutral detergent fiber (21.6 to 32.3%). Stems and sprouts were more rapidly and extensively fermented in the rumen than leaves, but there were only minor differences the fermentation profiles of both vegetables. The estimated metabolizable energy content ranged from 9.3 (leaves) to 10.8 (sprouts) MJ/kg DM. The CP rumen degradability (12-h in situ incubations) was greater than 80.0% for all fractions, and the in vitro intestinal digestibility of CP ranged from 85.7 to 93.2%. The inclusion of up to 24% of dried CAU in the concentrate of a mixed diet (40:60 alfalfa hay:concentrate) increased the in vitro rumen fermentation of the CAU diet, but did not affect methane (CH₄) production, indicating the lack of antimethanogenic compounds in CAU.

Contrasting effects of high-starch and high-sugar diets on ruminal function in cattle

The experiment reported in this research paper aimed to determine whether clinical and subclinical effects on cattle were similar if provided with isoenergetic and isonitrogenous challenge diets in which carbohydrate sources were predominantly starch or sugar. The study was a 3 × 3 Latin square using six adult Jersey cows with rumen cannulae, over 9 weeks. In the first 2 weeks of each 3 week experimental period cows were fed with a maintenance diet and, in the last week, each animal was assigned to one of three diets: a control diet (CON), being a continuation of the maintenance diet; a high starch (HSt) or a high sugar (HSu) diet. Reticuloruminal pH and motility were recorded throughout the study period. Blood and ruminal samples were taken on day-1 (TP-1), day-2 (TP-2) and day-7 (TP-7) of each challenge week. Four clinical variables were recorded daily: diarrhoea, inappetence, depression and ruminal tympany. The effects of treatment, hour of day and day after treatment on clinical parameters were analysed using linear mixed effects (LME) models. Although both challenge diets resulted in a decline in pH, an increase in the absolute pH residuals and an increase in the number of minutes per day under pH 5.8, systemic inflammation was only detected with the HSt diet. The challenge diets differentially modified amplitude and period of reticuloruminal contractions compared with CON diet and both were associated with an increased probability of diarrhoea. The HSu diet reduced the probability of an animal consuming its complete allocation. Because the challenge diets were derived from complex natural materials (barley and molasses respectively), it is not possible to assign all the differential effects to the difference in starch and sugar concentration: non-starch components of barley or non-sugar components of molasses might have contributed to some of the observations. In conclusion, substituting much of the starch with sugar caused no substantial reduction in the acidosis load, but inflammatory response was reduced while feed rejection was increased.

Effects of molasses-based liquid feed supplementation to a high-straw dry cow diet on feed intake, health, and performance of dairy cows across the transition period

The objective of this study was to determine the effects of adding molasses-based liquid feed to a high-straw dry cow diet on intake, behavior, health, and performance of dairy cows across the transition period. Holstein cows (n = 40) entering their second lactation or greater were enrolled at dry-off (∼45 d before expected calving) and assigned to 1 of 2 treatments: a high-straw dry cow total mixed ration (TMR) with either (1) no molasses [CON; n = 20; 10.7% crude protein (CP), 1.45 Mcal/kg of net energy for lactation (NE_L)] or (2) supplemented with 1 kg/cow daily [dry matter (DM) basis] of molasses-based liquid feed (LF; n = 20; 11.2% CP, 1.49 Mcal/kg of NE_L). At calving all cows were fed the same lactating TMR (14.9% CP, 1.68 Mcal/kg of NE_L) and followed for 28 d. During the dry period, cows fed the LF diet had greater DM intake (15.3 ± 0.24 vs. 13.4 ± 0.24 kg/d) and tended to have a shorter interval between meals (192.8 ± 8.38 vs. 216.5 ± 7.97 min) and more frequent meals (6.3 ± 0.27 vs. 5.6 ± 0.27 meals/d), while consuming their feed faster (0.09 ± 0.001 vs. 0.08 ± 0.001 kg of DM/min) compared with cows fed the CON diet. Regardless of treatment, cows sorted [100% × (actual intake/predicted intake)] against the longest ration particles (>19 mm), with cows fed the CON diet sorting more against these (81.1 ± 2.6 vs. 93.9 ± 2.6%). Cows fed the CON diet did not sort for or against short particles (<8, >4 mm; 100.2 ± 0.31%), but cows fed the LF diet tended to sort against these (99.2 ± 0.31%). Post-calving, cows fed the LF diet did not sort for long particles (98.5 ± 1.1%), but cows fed the CON diet continued to sort against these (96.3 ± 1.1%). Cows fed the LF diet had higher mean reticulorumen pH in the dry period (6.4 ± 0.05 vs. 6.2 ± 0.06 pH), in the first week after calving (CON = 5.7 ± 0.06 pH, LF = 5.8 ± 0.06 pH), and tended to have higher mean reticulorumen pH in the second week after calving (CON = 5.7 ± 0.06 pH, LF = 5.9 ± 0.06 pH). The results suggest that supplementing a molasses-based liquid feed in high-straw dry cow diets may improve intake and consistency in nutrients consumed during the dry period and in early lactation, as well as possibly promoting better rumen health across the transition period.

Feeding diets varying in forage proportion and particle length to lactating dairy cows: I. Effects on ruminal pH and fermentation, microbial protein synthesis, digestibility, and milk production

Physically effective neutral detergent fiber (peNDF) content of dairy cow diets was modified by varying the theoretical chop length of alfalfa silage and forage:concentrate (F:C) ratio, and effects on nutrient intakes, ruminal fermentation, site and extent of digestion, microbial protein synthesis, and milk production were evaluated. Estimates of dietary peNDF contents were compared with recommendations, and predictions of ruminal pH from peNDF and the recently developed physically adjusted neutral detergent fiber (paNDF) system were compared with observed pH. The experiment was designed as a triple 4 × 4 Latin square using 12 mid-lactating dairy cows with 4 intact, 4 ruminally cannulated, and 4 ruminally and duodenally cannulated cows. Site and extent of digestion and microbial protein synthesis were measured in a single 4 × 4 Latin square. Treatments were a 2 × 2 factorial arrangement; 2 forage particle lengths (FPL) of alfalfa silage (short and long) were combined with low (35:65) and high (60:40) F:C ratios [dry matter (DM) basis]. The peNDF contents were determined by multiplying the proportion (DM basis) of total mixed ration retained on 2 (8 and 19 mm; peNDF_8.0) or 3 (1.18, 8, and 19 mm; peNDF_1.18) sieves of the Penn State Particle Separator by the neutral detergent fiber content of the diet. The dietary peNDF contents ranged from 10.7 to 17.5% for peNDF_8.0 or from 23.1 to 28.2% for peNDF_1.18. Interactions between F:C ratio and FPL content were few. Increasing peNDF content of diets by increasing F:C ratio decreased DM intake, milk yield, and milk protein yield, whereas apparent total-tract DM digestibility and milk efficiency improved. Increasing F:C ratio improved ruminal pH status but decreased total volatile fatty acid concentration and microbial protein synthesis. Increasing peNDF content of diets via dietary FPL increased mean ruminal pH, but did not affect DM intake, total-tract digestibility, or milk production. The results indicate that feeding dairy cows a low F:C diet helps increase DM intake, milk production, and microbial protein synthesis, but may adversely affect feed digestibility and milk efficiency due to increased risk of subacute ruminal acidosis. Increased FPL improved ruminal pH status, but had minimal effects on feed intake, ruminal fermentation, nutrient digestibility, and milk production. The results indicate a trade-off between reducing the risk of subacute ruminal acidosis and maximizing ruminal fermentation, feed digestibility, and milk production of dairy cows. The paNDF model showed improvement in the predictability of ruminal pH over the peNDF model, but the accuracy of predictions varied depending upon the diet and ruminal fermentation variables considered in the equations.

Milk production responses and rumen fermentation of dairy cows supplemented with summer brassicas

Forage brassicas, such as summer turnip (ST; Brassica rapa) and forage rape (FR; Brassica napus), are used as supplementary crops during summer. However, studies with lactating dairy cows fed these forages are limited and report inconsistent productive responses. The aim of this study was to determine dry matter intake, rumen fermentation and milk production responses of dairy cows in mid-lactation supplemented with and without summer ('ST' or 'FR') brassicas. Twelve multiparous lactating dairy cows were randomly allocated to three dietary treatments in a replicated 3 × 3 Latin square design balanced for residual effects over three 21-day periods. The control diet consisted of 16.2 kg DM of grass silage, 2.25 kg DM of commercial concentrate and 2.25 kg DM solvent-extracted soybean meal. For the other two dietary treatments, 25% of the amounts of silage and concentrates were replaced with FR or ST. The inclusion of forage brassicas had no effects on milk production (24.2 kg cow/day average) and composition (average milk fat and protein 43.2 and 33.6 g/l, respectively). Dry matter intake was 0.98 kg and 1.12 kg lower for cows supplemented with FR and ST, respectively, resulting in a greater feed conversion efficiency (1.35 kg milk/kg DM for ST and FR v. 1.27 kg milk/kg DM for the control diet). Intraruminal pH was lower for cows supplemented with ST compared to the control diet; however, it did not decrease below pH 5.8 at any time of the day. After feeding, the concentrations of total short-chain fatty acids (SCFAs) in rumen contents increased with ST supplementation compared to the control diet. Inclusion of FR in the diet increased the molar proportion of acetate (68.5 mmol/100 mmol) in total SCFA at the expense of propionate, measured 6 h after feeding of the forage. The molar proportion of butyric acid was greater with ST and FR supplementation (13.1 and 12 mmol/100 mmol, respectively) than in control cows. The estimated microbial nitrogen (N) flow was 89.1 g/day greater when supplementing FR compared to the control diet. Based on the haematological measures, the inclusion of summer brassica forages did not affect the health status of the animals. These results indicate that mid-lactation dairy cows fed brassicas are able to maintain production despite the reduced intake, probably due to improved rumen fermentation and therefore nutrient utilization.

Liquid molasses interacts with buffers to affect ruminal fermentation, milk fatty acid profile, and milk fat synthesis in dairy cows fed high-concentrate diets

We aimed to evaluate the effects of feeding sugarcane liquid molasses (LM) with or without a commercial buffer mix (BFM) on ruminal fermentation parameters, milk fatty acid (FA) profile, and milk yield and composition in dairy cows fed high-concentrate diets (35:65 forage-to-concentrate ratio). Eight multiparous Holstein cows (4 ruminally cannulated) averaging 165 ± 12 d in milk at the beginning of the study were randomly assigned to a replicated 4 × 4 Latin square design with a 2 × 2 factorial arrangement of treatments. Each period lasted 21 d with 14 d for diet adaptation and 7 d for data and sample collection. Cows were fed the following diets: (1) no LM or BFM supplementation (CTRL), (2) LM without BFM supplementation (MOL), (3) BFM without LM supplementation (BUF), and (4) LM plus BFM supplementation (COMBO). These 4 isonitrogenous and isoenergetic diets were formulated by replacing (dry matter basis) 5% ground corn with LM, whereas BFM replaced wheat bran at 0.8% of the diet. Significant LM × BFM interactions were observed for the duration of ruminal pH below 5.8, molar proportion of propionate, acetate-to-propionate ratio, milk proportions of trans-10 18:1 and total trans FA, and concentration and yield of milk fat. Feeding MOL and BUF alone were effective on reducing the time that ruminal pH remained below 5.8 compared with the CTRL treatment, and the COMBO diet decreased it further. A similar pattern was observed for the ruminal molar proportion of propionate. The milk proportions of trans-10 18:1 and total trans FA dropped significantly with BFM or LM supplementation versus cows fed CTRL, and the COMBO diet decreased these variables further. Note, however, that these changes elicited by the COMBO diet were not in the same magnitude as those caused by MOL or BUF fed alone. The ruminal molar proportion of acetate increased with the BUF diet and that of butyrate increased in cows fed MOL, but mean ruminal pH was not affected by treatments. Diets with LM resulted in increased concentrations of short- and medium-chain FA in milk fat. The yield of 3.5% fat-corrected milk increased significantly in cows fed MOL or BUF due to the improved concentration of milk fat. A trend and a significant increase for energy-corrected milk were observed with feeding MOL or BUF, respectively. Overall, inclusion of LM and BFM appears to reduce milk trans-10 18:1 FA and total trans FA by modulating ruminal pH and volatile FA profile in cows fed high-concentrate diets.

Potentials and Challenges of Former Food Products (Food Leftover) as Alternative Feed Ingredients

Simple Summary

This review focuses on the use of ex-foods, an alternative feed ingredient in farm animal diets, composed by processed and ready-to-eat food products no longer suitable for human consumption. Such foods, which are also called former food products, are usually buried in landfill sites, despite their high potential of being used as sustainable feed ingredients. In order to obtain proper balanced diets by using these alternative feed ingredients, several aspects have to be considered. In this respect, this paper aims to address the state of the art about food leftovers used in animal nutrition in general and in pig diets specifically.

Abstract

Former food products (FFPs) are foodstuffs that, even though they are nutritious and safe, have lost their value on the human consumption market for different reasons, such as production errors leading to broken or intermediate foodstuffs, surpluses caused by logistical challenges of daily delivery, or any other reason. The nutritional features of FFPs include carbohydrates, free sugars, and possibly also fats. FFPs tend to have been processed through various technological and heat treatments that impact the nutrients and the kinetics of digestion, as well as animal response and, particularly, gastro-intestinal health. This review integrates some of the most recently published works about the chemical composition, nutritional value, digestibility and glycaemic index of ex-foods. In addition, a view on the relationship between the use of FFPs and safety issues and their effects on pigs’ intestinal microbiota are also given.

Effects of replacing starch with three sugars in a concentrate and forage diet on in vitro rumen fermentation, fatty acid composition and related bacteria

Context Replacing starch with sugar could maintain dietary energy density with reduced risks of rumen acidosis and milk fat depression, but the underlying mechanism is not well understood, and the effects of sugar feeding might vary among sugars. Aims Objectives of the present study were to evaluate the effects of replacing corn starch in a diet containing 40:60 forage-to-concentrate ratio (control) with 3%, 6% and 9% of sucrose, fructose and lactose on in vitro rumen fermentation, fatty acid (FA) composition and populations of bacteria involved in the production of trans-11 and trans-10 FA. Methods A 3 × 3 + 1 (control) factorial experimental design was used, and the pH, concentrations of volatile fatty acids (VFA) and ammonia-N, profiles of FA and the relative abundance of four trans-11-producing bacteria and two trans-10 FA-producing bacteria were measured after a 6-h incubation. Key results Replacing dietary corn starch with sucrose, fructose and lactose neither altered the concentration of total VFA after 6-h fermentation, nor decreased the pH, except for substitution with 9% sucrose. Increased butyrate proportions and decreased branched-chain VFA proportions were the common effects in sugar treatments, but the proportions of acetate and propionate varied among sugars. Lactose inclusion in the diet led to a higher pH, greater acetate and butyrate concentrations, and lower propionate concentrations than did sucrose inclusion. Sugar substitution decreased the concentrations of C18:1 trans-4 and most C18:2 isomers, but did not influence the major isomers related to trans-11 and trans-10 biohydrogenation pathways. Abundance of the four measured trans-11 FA-producing bacteria was increased by sugars, with sucrose showing a greater influence than did fructose and lactose. As to trans-10 FA-producing bacteria, only Megasphaera elsdenii populations were decreased by 3% and 6% fructose inclusion compared with the control. Dose-effect varied among sugars and the parameters measured, with sucrose having the most obvious dose effect among the three sugars; however, fructose affected mainly fermentation parameters, while lactose affected mainly C18 FA profiles. Conclusions Replacing corn starch in a high-concentrate diet with up to 9% of sucrose, fructose and lactose differentially affected rumen fermentation and rumen FA metabolism, by influencing the abundance of rumen bacteria involved in rumen FA biohydrogenation. Implications Lactose may be more efficient in increasing milk fat than are sucrose and fructose, and dose effect should be considered in the utilisation of sucrose.

Nutrient concentrations and profile of non-structural carbohydrates vary among different Brassica forages

Context Brassica forages are used in times of seasonal shortage to fulfil nutritional requirements of beef cattle, dairy cows, sheep or pigs. Although brassicas have been reported with high concentrations of readily fermentable carbohydrate, details have not been fully described and there is little information about the non-structural carbohydrate (NSC) profiles of Brassica forages. Aim The study was designed to evaluate nutrient concentrations, as well as NSC levels and constituents, of the main Brassica forages and to determine differences among varieties. Methods Five varieties of each of the four main forage brassicas (summer turnip, forage rape, kale and swede) were grown in plots and harvested for chemical analysis of the nutrient concentrations and NSC profiles of leaf and bulb (turnip and swede) and leaf and stem (rape and kale) components. Key results Brassica species differed in the amounts and types of NSC; swede had the highest concentration of NSC, mainly comprising sugars (glucose and fructose), followed by kale (with similar proportions of glucose, sucrose and fructose), turnip (with similar concentrations of glucose and starch and slightly lower fructose), and forage rape (in which starch was the main NSC). Forage chemical composition and NSC profile of plant organs varied among varieties of individual Brassica forages; for example, there were significant differences among swede varieties for concentrations of starch and sugar (total and profile) in bulbs. Conclusions Brassica forages differed with respect to quantities and types of NSC; swede had higher concentrations, mainly composed of glucose and fructose, followed by kale with similar proportions of glucose, sucrose and fructose, and turnip with NSC represented by glucose, starch and slightly lower fructose; and finally, forage rape, in which starch was the main NSC. Chemical composition, as well as NSC profile of plant organs (leaves, bulbs or stems), varied among varieties of Brassica species. Implications The approach described here has implications for ration formulation and is useful when considering the nutritional and dietary requirements of the animals of interest, because the type of Brassica, the variety and the proportion of plant organs can affect animal performance.