Meta-analysis of apparent ruminal synthesis and postruminal flow of B vitamins in dairy cows.

As milk production has significantly increased over the past decade(s), existing estimates of the B-vitamin needs of the modern dairy cow are currently being reconsidered, as suboptimal B-vitamin supply may affect metabolic efficiency. At the same time, however, "true" (i.e.

Particle size and endosperm type of dry corn grain altered duodenal flow of B vitamins in lactating dairy cows.

The objective of the experiment was to determine if factors such as endosperm type (floury vs. vitreous) and particle size (fine vs. medium) of dry corn grain, known to affect starch digestibility in the rumen, modify apparent ruminal synthesis and duodenal flow of B vitamins in lactating dairy cows.

Energy and protein requirements for maintenance of dairy goats during pregnancy and their efficiencies of use.

It has been suggested that maintenance requirements are similar among animals of different physiological stages; however, important physiological changes occur in the maternal body during pregnancy. Therefore, the aim of this study was to determine the energy and protein requirements for the maintenance of pregnant dairy goats and to estimate their efficiency of energy and protein utilization for maintenance and pregnancy. We used 66 multiparous pregnant goats having 49.

Short communication: Apparent ruminal synthesis of B vitamins in lactating dairy cows fed Saccharomyces cerevisiae fermentation product.

Apparent ruminal synthesis and duodenal flow of thiamin, riboflavin, niacin, vitamin B, folates, and vitamin B were evaluated in an experiment using 15 ruminally and duodenally cannulated lactating Holstein cows fed a basal diet, according to a crossover design, supplemented or not with 56 g/d of Saccharomyces cerevisiae fermentation product. Duration of the treatment period was 28 d. The basal ration had 28% neutral detergent fber, 30% starch and 16.

Short communication: Effect of fatty acid supplements on apparent ruminal synthesis of B vitamins in lactating dairy cows.

The effect of fat supplements (FS) providing different proportions of saturated (SFA) and unsaturated (UFA) fatty acids on supply, apparent ruminal synthesis (ARS), and duodenal flow (DF) of some B vitamins (thiamine, riboflavin, niacin, vitamin B, folates, and vitamin B) were evaluated in an experiment using 8 ruminally and duodenally cannulated lactating Holstein cows. The experiment was a replicated 4 × 4 Latin square design with 21-d treatment periods. The 4 treatments were a control diet without fatty acid supplement and 3 diets with 2.