Dietary replacement of soybean meal with heat-treated soybean meal or high-protein corn distillers grains on nutrient digestibility and milk composition in mid-lactation cows.

Lactation diets dependent on rumen undegradable protein (RUP) sources derived from soybean meal (SBM) products are generally high in Lys and poor in Met. We conducted an experiment to evaluate the effects of increasing dietary RUP and altering digestible AA supply by inclusion of heat-treated soybean meal (HTSBM) or high-protein corn dried distillers grains with soluble (DDGS) on performance in mid-lactation dairy cows. Twenty-four Holstein cows (200 ± 40 d in milk and 30.0 ± 3.92 kg/d of milk yield) blocked according to parity, milk yield, and days in milk were used in a 3 × 3 Latin square design experiment with 21-d periods. Treatments were (1) control (CON), a diet with 6.0% RUP containing 15.9% SBM as the main protein source; (2) HTSBM, a diet with 6.7% RUP containing 4.4% HTSBM partially replacing SBM; and (3) high-protein DDGS (FP; FlexyPro, SJC Bioenergia), a diet with 6.9% RUP containing 5.34% FP partially replacing SBM and ground corn. Diets had similar crude protein (16.9%) and net energy of lactation. Data were submitted to ANOVA using the mixed procedure of SAS software (SAS Institute Inc.). Treatment differences were evaluated using orthogonal contrasts: (1) increasing RUP (SBM vs. HTSBM + FP) and (2) altering digestible AA supply (HTSBM vs. FP). Cows fed HTSBM and FP had greater intake (values in parentheses represent treatment means of CON, HTSBM, and FP, respectively) of neutral detergent fiber (7.14, 7.35, and 7.69 kg/d), crude protein (4.27, 4.37, and 4.51 kg/d), and ether extract (0.942, 0.968, and 1.04 kg/d) compared with cows fed CON. Feeding FP resulted in greater intake of neutral detergent fiber and ether extract compared with HTSBM. Cows fed HTSBM and FP had lower sorting index for feed particles <4 mm than cows fed CON (1.029, 1.008, and 1.022). Feeding FP resulted in greater intake of feed particles <4 mm compared with HTSBM. Treatments containing HTSBM or FP tended to decrease organic matter digestibility (72.4, 71.2, and 71.1%), but no other effects were detected in digestibility of neutral detergent fiber, crude protein, or ether extract. No evidence for differences among treatments was detected in excretion of purine derivatives in milk and urine. Milk yield was greater in cows fed HTSBM or FP than in cows fed CON (28.0, 28.9, and 28.8 kg/d, respectively). Cows fed HTSBM or FP tended to have greater energy-corrected milk and protein yield compared with those fed CON. Milk protein concentration was greater in DDGS cows than those in the HTSBM group (3.45 and 3.40%, respectively). No differences were detected in milk fat yield and concentration, milk urea nitrogen, feed efficiency, or serum concentrations of urea and glucose. Overall, increasing dietary RUP by feeding HTSBM or FP improved intake of nutrients and milk yield without affecting feed efficiency. Altering digestible AA supply while maintaining similar dietary RUP had negligible effects on performance of cows.

Feeding encapsulated pepper to dairy cows during the hot season improves performance without affecting core and skin temperature.

Peppers (Capsicum spp.) contain capsaicin, an organic compound with a group of alkaloids that has shown thermoregulation properties in humans and mice, and may influence glucose and lipid metabolism in ruminants. An experiment was conducted to evaluate different doses of a feed additive containing encapsulated pepper on milk yield and composition, dry matter intake, feed sorting index, total-tract apparent digestibility of nutrients, purine derivatives excretion, and serum concentrations of urea-N and glucose, N excretion, respiration rate, rectal temperature, and skin temperature in different regions (forehead, face, and rumen). Thirty-six Holstein cows (150 ± 102.1 d in milk and 29.3 ± 5.81 kg/d milk yield) were used in a 9-wk randomized complete block (n = 12) design experiment. Following a 2-wk covariate period, cows were blocked according to parity, days in milk, and milk yield and were randomly assigned to the following treatments: 0 (CAP0), 0.75 (CAP75), or 1.5 (CAP150) g/d of a feed additive containing encapsulated pepper (1 g/kg, Capcin; NutriQuest) added to the concentrate along with minerals. Treatment differences were evaluated through orthogonal contrasts (CAP0 vs. CAP75 + CAP150 or CAP75 vs. CAP150). The average temperature-humidity index during the experiment was 72.0 ± 2.07. Dry matter intake was greater in cows fed a feed additive containing encapsulated pepper (CAP) treatments (CAP75 and CAP150) compared with CAP0. Cows fed CAP150 tended to have greater dry matter intake than those in CAP75 group. Feeding CAP decreased sorting for feed particles with size between 8 and 4 mm. An interaction effect between treatment and week was observed for crude protein digestibility whereas cows fed CAP150 had the greatest digestibility on the third week of experiment. Orthogonal contrasts did not detect differences in serum concentrations of glucose and urea-N, or purine derivatives excretion. Nitrogen excretion (as % of N intake) in milk, urine, and feces was not altered by treatments. Feeding CAP increased yields of 3.5% fat-corrected milk, fat, protein, and lactose. A tendency toward greater milk protein content was observed for cows fed CAP150 than CAP75. No differences were detected on respiration rate, rectal temperature, and skin temperature of cows. A feed additive containing encapsulated pepper fed at 0.75 or 1.5 g/d can improve yield of fat-corrected milk and milk solids by increasing feed intake without affecting nutrient digestibility and body temperature of lactating cows during the hot season.

Increasing doses of carbohydrases: Effects on rumen fermentation, nutrient digestibility, and performance of mid-lactation cows.

The objective of this study was to evaluate the effects of exogenous enzymes on nutrient intake and digestibility, rumen fermentation, and productivity of mid-lactating cows. Experiment 1 was designed to test increasing doses [0, 0.5, 1.0, or 1.5 g/kg of dry matter (DM)] of a combination of 2 enzyme products with xylanase and ß-glucanase activities (Ronozyme Wx and Ronozyme VP, respectively; DSM Nutritional Products) on rumen fermentation and total apparent digestibility. Enzyme combinations had a ratio of endo-1,3(4)-ß-glucanase to endo-1,4-ß-xylanase of 8:2 (wt/wt). For experiment 1, 8 rumen cannulated lactating cows were used into a double 4 × 4 Latin square design experiment with 14 d of diet adaptation and 7 d of sampling. Despite no differences in feed intake, carbohydrases linearly increased neutral detergent fiber digestibility. Treatments marginally affected rumen fermentation, where a linear trend for lower rumen pH and a linear trend for greater isobutyrate concentration were observed with increasing enzyme dose. A trend for lower rumen NH3-N concentration was observed for cows receiving carbohydrases in comparison with control group. When comparing all enzyme treatments against control group, cows fed enzymes tended to produce more 3.5% fat-corrected milk (FCM), produced more milk fat, and had greater blood glucose concentration. Experiment 2 evaluated 3 doses (0, 0.5, or 0.75 g/kg of DM) of the same combination of enzyme products on performance of cows (n = 36) in a complete randomized block (n = 12) design. Cows received treatments for 9 wk. No interaction effects between treatments and time were observed for all variables assessed in this study. In agreement with experiment 1, no differences were detected for feed intake, but cows fed the enzyme products tended to produce more 3.5% FCM and milk fat compared with control. In addition, cows fed enzymes exhibited greater efficiency of FCM production (FCM ÷ DM intake) compared with control. No differences were detected for intake and productivity when comparing the 2 doses of carbohydrases. In summary, the enzyme products tested in this study may improve feed efficiency due to greater milk fat concentration.