Effect of whole cottonseed, gossypol, and ruminally protected lysine supplementation on milk yield and composition.

To determine whether the gossypol content of the diet affected availability of dietary Lys, 4 cows with ruminal and duodenal cannulas and 16 intact cows in early lactation were assigned to diets containing either glanded cottonseed, glanded cottonseed plus 15 g/d of ruminally protected Lys, glandless cottonseed, or glandless cottonseed plus 15 g/d of ruminally protected Lys. The experimental design was a 4 x 4 Latin square design with 3-wk experimental periods. Gossypol concentrations in plasma were lower when cows were fed glandless cottonseed. Lysine supplementation increased the flow and percentage of Lys in duodenal digesta and increased the concentration of Lys in plasma. Neither type of cottonseed nor Lys supplementation affected dry matter intake. Yields of milk and fat-corrected milk from cannulated cows were not affected by diet, but yields from intact cows were increased by Lys supplementation. For both cannulated and intact cows, Lys supplementation increased the percentage of milk protein, and milk protein yield was increased by Lys in intact cows. Dietary gossypol did not affect the response to Lys, indicating that dietary gossypol had little or no effect on the availability of Lys for dairy cows.

Baker's yeast effluent as a liquid feed for dairy cows and heifers.

Liquid effluent from baker's yeast production was fed to dairy cows to determine whether effluent is an acceptable feed and whether it affects milk yield or composition. Effluent averaged 5.4% DM and 6.1% N (DM basis). In experiment 1, 20 Holstein cows were offered effluent free choice or no effluent for 8 wk. Milk yield, composition, and group feed intake were measured. In Experiment 2, 20 cows were fed effluent blended into the TMR (11.3 L/d per cow) or no effluent for 4 wk. In Experiment 3, six groups of 6 heifers were offered free choice or no effluent. Free choice intake of effluent peaked at 15 L/d per cow at wk 3 but declined to 5.3 L/d per cow by wk 6. Milk and 3.5% FCM yields were not affected by effluent regardless of feeding system. Milk protein and fat percentages were higher for cows offered effluent free choice. Milk protein percentage and yield were lower with effluent in the TMR. Intake of effluent by heifers was 1.05 L/d, and effluent did not affect DMI or weight gain. Acceptability of yeast effluent fed free choice is poor, but when yeast is blended into the TMR, cows consume effluent without adverse effects on milk yield or DMI.

Effect of whole cottonseeds and calcium salts of long-chain fatty acids on performance of lactating dairy cows.

Holstein cows were assigned to diets containing no supplemental fat, supplemental fat from whole cottonseed, or supplemental fat from whole cottonseed plus Ca salts of fatty acids (Megalac). The TMR contained 46% forage and 54% concentrate or mixtures of concentrate and whole cottonseed on a DM basis and were fed from wk 3 through 44 of lactation. The mean fat content of the three diets was 3.0, 4.7, and 6.4% of DM for control, whole cottonseed, and whole cottonseed plus Ca salts of fatty acids, respectively. Supplemental fat increased NEL intake, percentage of milk fat, milk fat production, and rate of recovery of BW and body condition. Supplemental fat decreased milk protein production in early lactation, but not in late lactation. Addition of supplemental fat had no significant effect on ruminal concentration of VFA, NH3 N, or in situ digestibility of fiber. The proportion of unsaturated fatty acids in milk fat was increased with supplemental whole cottonseed or whole cottonseed plus Ca salts of fatty acids. During the first 3 mo of lactation, the proportion increased of fatty acids C14 or less, C16, and C18:2. Proportion of fatty acids C16:1 and C18:1 correspondingly decreased. The change in composition of milk fatty acids during early lactation is consistent with the use of body fat for milk synthesis.

Effect of buffer addition to high grain total mixed rations on rumen pH, feed intake, milk production, and milk composition.

Lactating Holstein cows (n = 56) were fed high grain TMR in three feeding experiments to determine the effects of two rumen buffers on feed intake, milk production, and milk composition. The basal diet in Experiment 1 was 40% grass silage, 12% whole cottonseed, and 48% concentrate with treatments of 1) control (no added buffer), 2) 1.5% of dietary DM as Alkaten, and 3) 1.5% of dietary DM as Rumen 8. In Experiment 2, diets consisted of 12% corn and sunflower silage, 20% whole cottonseed, and 68% concentrate with treatments as in Experiment 1. The diets in Experiment 3 were identical to those in Experiment 2, except that buffers were increased to 2.2% of dietary DM. The DMI was greater for cows fed buffered diets than control diets in Experiments 2 and 3. Milk production was unaffected by treatment. Milk fat percentage was unaffected by diet in Experiment 1 and averaged 3.8%. Milk fat depression was alleviated for cows fed buffered diets in Experiments 2 and 3. No differences in rumen fluid pH or molar percentage of VFA were significant among treatments.

Effect of inoculation rate of selected strains of lactic acid bacteria on fermentation and in vitro digestibility of grass-legume forage.

Grass-legume forage was used to evaluate the effect of inoculation rate of selected strains of lactic acid bacteria on fermentation and in vitro digestibility during 57 d of ensiling. Chopped forage (DM = 28%) was ensiled in 4 to 6-kg quantities and treated as: 1) control, 10(3) epiphytic lactic acid bacteria; 2) 10(5) added lactic acid bacteria; and 3) 10(6) added lactic bacteria/g of wet forage. Samples were obtained for analyses on d 0, 1, 2, 3, 6, 10, 14, 29, and 57 of fermentation. Treated silages were observed to have: 1) greater quantities of lactic acid bacteria, 2) a greater proportion of homofermentative lactic acid bacteria, and 3) lactic acid bacteria with greater biological activity. Addition of each amount of lactic acid bacteria: 1) increased the rate of utilization of water-soluble carbohydrate and decline in pH, 2) limited the formation of NH3 N, and 3) increased the in vitro digestibility of DM and ADF. No differences were observed in the lactic acid content of the silages after 57 d of fermentation.