Effects of Saccharomyces cerevisiae boulardii (CNCM I-1079) on feed intake, blood parameters, and production during early lactation.

The periparturient period is a metabolically demanding time for dairy animals because of increased nutrient requirements for milk yield. The objective of this study was to investigate the effect of feeding Saccharomyces cerevisiae boulardii (CNCM I-1079), a commercial active dry yeast (ADY), in dairy cows on productive and metabolic measures during the periparturient period. Primiparous (n = 33) and multiparous (n = 35) cows were fed a close-up total mixed ration (TMR) before calving and a lactation TMR postpartum. Three weeks before expected calving time, animals were blocked by parity and body weight and then randomly assigned to either control group (control; n = 34) or treatment (ADY; n = 34). All animals were housed in a tie-stall barn with individual feed bunks; the ADY animals received supplementary Saccharomyces cerevisiae boulardii (CNCM I-1079), top dressed daily at a predicted dosage of 1.0 × 1010 cfu (12.5 g) per head. Blood samples were collected weekly along with milk yield and milk composition data; feed intake data were collected daily. Serum samples were analyzed for glucose, nonesterified fatty acid, ß-hydroxybutyrate, haptoglobin (Hp), and the cytokines tumor necrosis factor-α, IL-6, and IL-18. Colostrum samples collected within the first 6 to 10 h were analyzed for somatic cell score and IgG, IgA, and IgM concentrations. Data were analyzed using PROC GLIMMIX in SAS with time as a repeated measure; model included time, parity, treatment, and their interactions. The ADY groups had greater milk yield (39.0 ± 2.4 vs. 36.7 ± 2.3 kg/d) and tended to produce more energy-corrected milk with better feed efficiency. There was no difference in plasma glucose, serum nonesterified fatty acid, serum ß-hydroxybutyrate, Hp, IL-6, or IL-18 due to ADY treatment. The tumor necrosis factor-α increased in ADY-supplemented animals (1.17 ± 0.69 vs. 4.96 ± 7.7 ng/mL), though week, parity, and their interactions had no effect. Serum amyloid A tended to increase in ADY-supplemented animals when compared to control animals and was additionally affected by week and parity; there were no significant interactions. No difference in colostrum IgG, IgA, and IgM was observed between treatments. Supplementing transition cow TMR with ADY (CNCM I-1079) improved milk production and tended to improve efficiency in early lactation; markers of inflammation were also influenced by ADY treatment, though the immunological effect was inconsistent.

Production performance and nitrogen metabolism in dairy cows fed supplemental blends of rumen undegradable protein and rumen-protected amino acids in low- compared with high-protein diets containing corn distillers grains.

Feeding corn dried distillers grains with solubles (DDGS) in low crude protein (CP) diets could limit N waste in lactating cows. However, it also could possibly reduce metabolizable AA supply, especially Lys, and compromise milk production. Therefore, the objective of this study was to evaluate the effects of feeding supplemental blends of rumen undegradable protein (RUP) and rumen-protected (RP) AA in a low compared with high CP diet containing corn DDGS on milk production and selected measures of N utilization. Six multiparous Holstein cows (619.3 ± 49.8 kg of body weight; 26.8 ± 6.2 d in milk) were subjected to a split-plot, 3 × 3 Latin square design (21-d periods) with dietary CP content [low (14.6%; LP) or high (16.6%; HP)] as the whole-plot factor, and blend of RUP and RP-AA [control (CON), no supplement; blend A (0.11 kg/cow per d); or blend B (0.45 kg/cow per d)] as the sub-plot factor. All diets contained 10% corn DDGS; blends of RUP and RP-AA were top-dressed during morning feeding. There was no dietary CP content × supplemental blend interaction for all measured variables. Nutrient (dry matter, organic matter, neutral detergent fiber, acid detergent fiber, and CP), milk and milk component yields, and feed and apparent N efficiency did not differ for cows fed the low- compared with the high-protein diet. However, apparent total-tract CP digestibility, blood and milk urea-N concentrations, and urinary excretion (g/d) of N and urea-N were lower for cows fed the low-protein compared with the high-protein diet. There was no supplemental blend effect on nutrient intake and apparent total-tract digestibility, and milk and milk component yields. Except for a tendency for total urinary purine derivative excretion and microbial N flow to be lower for cows fed blend B compared with CON but not blend A, there was no supplemental blend effect on measures of N utilization. Both dietary CP content and supplemental blend of RUP and RP-AA had a marginal effect on the plasma free AA profile. In summary, reducing dietary CP content in diets containing corn DDGS had no effect on lactation performance, possibly accounting for the lack of a positive response following the provision of supplemental blends of RUP and RP-AA. However, reducing dietary CP content resulted in a decrease in blood and milk urea-N concentrations, and urinary excretion of N and urea-N, suggestive of an improvement in the efficiency of N use.

Effects of hydrolyzed cottonseed protein supplementation on performance, blood metabolites, gastrointestinal development, and intestinal microbial colonization in neonatal calves.

The objective of this study was to investigate the effects of an enzymatically hydrolyzed cottonseed protein (HCSP) as a peptide source on performance, blood metabolites, gastrointestinal development, and intestinal microbes. Forty-eight newborn Holstein calves were randomly assigned to 1 of the 4 dietary treatments including 0, 2, 4, and 6% of HCSP (dry matter basis). All calves received the same amount of pasteurized whole milk, weaned on d 56 of the experiment, and the study was concluded on d 70. Data were analyzed using PROC MIXED in SAS (SAS Institute Inc., Cary, NC) as a randomized complete block design with linear and quadratic contrasts. Results showed that increased amount of HCSP linearly decreased the starter intake during the postweaning (d 57 to 70) and overall period (d 1 to 70). In addition, when dietary HCSP increased during the overall period, average daily gain tended to linearly decrease. All skeletal growth variables also linearly decreased as dietary HCSP increased at the end of the study, except for body length, which did not differ among the treatments. Serum cortisol concentration was higher in calves supplemented with 6% of HCSP at weaning and at the end of the study. This indicates that these calves may have experienced a stressful condition compared with calves in other treatments. Total antioxidant capacity was quadratically affected by HCSP supplementation; calves fed 2 and 4% of HCSP diets had the highest total antioxidant capacity, whereas calves fed 0 and 6% HCSP diets had lower total antioxidant capacity at weaning and at end of the study. Calves supplemented with 6% HCSP had lower empty reticulo-rumen and omasum weights and rumen wall thickness compared with calves in other treatments at the end of the study. In conclusion, supplementation of HCSP at the rate of 2% of starter diet enhanced antioxidant status without any detrimental effects on the performance and metabolic status of calves, whereas greater inclusion rates impaired starter intake and growth of calves, and exposed them to a stressful status.

Effects of dietary betaine on milk yield and milk composition of mid-lactation Holstein dairy cows.

Betaine, naturally found in plants and an oxidative product of choline, is converted to acetate in the rumen, which may be used for milk fat synthesis. The objective of this study was to determine the effect of supplemental dietary betaine on milk yield and milk composition. Eighteen Holstein dairy cows (126±5 d in milk; mean ± SD) were randomly assigned to a sequence of treatments of rumen-unprotected betaine at 0, 25, 50, and 100 g/d added to a standard lactation ration in a 4×4 Latin square design. Animals were fed individually with feed intake and milk yield recorded daily. Body condition score and body weight were recorded on the last day of each period that lasted 16 d, with milk sampled on the last 2 d of each period. Milk composition was determined by a Dairy Herd Improvement Association laboratory and milk fatty acids were determined by gas chromatography. Data collected over the last 2 to 3 d were analyzed using the MIXED procedure in SAS (SAS Institute Inc., Cary, NC). Milk yield (mean ± SEM) was increased by betaine when fed at 100g/d (22.4, 22.5, 22.8, 24.1±1.19 kg/d for 0, 25, 50, and 100g of betaine/d, respectively). No effect of dietary betaine was detected on dry matter intake, feed efficiency, body weight, or body condition score. Percentages of milk fat, lactose, solids-not-fat, and somatic cell count were not altered; however, protein concentration was decreased by betaine supplementation as compared with the control (3.35, 3.28, 3.27, and 3.28±0.07% for 0, 25, 50, and 100 g of betaine/d, respectively). Daily yields of milk protein, fat, lactose, energy-corrected milk, and 3.5% fat-corrected milk did not differ with betaine supplementation. Overall, inclusion of dietary betaine at 100 g/d increased milk yield, whereas all levels of betaine supplementation decreased milk protein percent and slightly altered milk fatty acid profile. Further studies are needed to determine the ruminal fermentation characteristics and the optimum rate of supplemental betaine for dairy cows.

Effects of trans fatty acids on markers of inflammation in bovine mammary epithelial cells.

Trans fatty acids (tFA) contribute to inflammation. The objective was to investigate the effects of tFA on mRNA expression of proinflammatory markers in cultured bovine mammary epithelial cells (MAC-T cell line). Bovine mammary epithelial cells were grown in Dulbecco's Modified Eagle Medium containing 10% fetal bovine serum. Cells were then subcultured in a medium lacking fetal bovine serum, to which incremental concentrations (up to 90 µM) of elaidic acid (trans-9 C18:1) or linoleidic acid (trans-9, trans-12 C18:2) were added. Bovine serum albumin (fatty acid-free) solutions were added and cells were collected at specific time points over 48 h. Then, RNA was extracted and converted to complementary DNA for quantitative real-time PCR analysis of proinflammatory gene expression. Presence of elaidic acid caused increases in mRNA expression of interleukin (IL)-1ß (3.4-fold; dose-independently over a 6-h period) and intercellular adhesion molecule (ICAM)-1 (up to 1.4-fold) relative to that for cells treated with no tFA, whereas expression of IL-6 and IL-8 was reduced 0.75- and 0.85-fold, respectively. Presence of linoleidic acid reduced mRNA expression of IL-6 and IL-8 relative to that for control (0.95- and 0.87-fold, respectively). Trans mono- and dienoic fatty acids upregulated mRNA expression of IL-1ß and ICAM-1, whereas expression of IL-6 and IL-8 was downregulated in MAC-T cells. Because these genes are ultimately involved in inflammation, elaidic or linoleidic acid, either directly fed or formed in the rumen during biohydrogenation, may alter the risk for mastitis in vivo.