Effects of feeding an inoculated corn silage with or without a direct-fed microbial on dry matter intake, milk production, and nutrient digestibility of high-producing lactating Holstein cows.

This study evaluated the effects of inoculating corn silage and/or feeding a direct-fed microbial (PRO) on performance and nutrient digestibility of lactating dairy cows. At harvesting, corn silage was treated either with water (culated or not [CON]) or and (INC; SiloSolve FC) at 1.5 × 10 cfu/g of corn silage.

Distinct blood and milk 18-carbon fatty acid proportions and buccal bacterial populations in dairy cows differing in reticulorumen pH response to dietary supplementation of rapidly fermentable carbohydrates.

Nine Holstein dairy cows were fed diets with increasing proportions of rapidly fermentable carbohydrates (RFCH) to investigate the effect on reticular pH, milk fat content (MFC), 18-carbon fatty acid proportions in blood plasma and milk, and bacterial community in buccal swab samples. Inter-animal variation was expected in terms of reticular pH response upon higher RFCH proportions, which would be reflected in the occurrence or not of milk fat depression (MFD). Moreover, this variation in occurrence of MFD was hypothesized to be related to differences in blood and milk fatty acid proportions and in the bacterial community in buccal samples.

Susceptibility of dairy cows to subacute ruminal acidosis is reflected in milk fatty acid proportions, with C18:1 trans-10 as primary and C15:0 and C18:1 trans-11 as secondary indicators.

The current study was carried out to assess 2 hypotheses: (1) cows differ in susceptibility to a subacute ruminal acidosis (SARA) challenge, and (2) the milk fatty acid (FA) pattern can be used to differentiate susceptible from nonsusceptible cows. For this, 2 consecutive experiments were performed. During experiment 1, the milk FA pattern was determined on 125 cows fed an increasing amount of concentrate during the first 4 wk in milk (WIM).

Effect of dietary starch or micro algae supplementation on rumen fermentation and milk fatty acid composition of dairy cows.

Two experiments with rumen-fistulated dairy cows were conducted to evaluate the effects of feeding docosahexaenoic acid (DHA; C22:6 n-3)-enriched diets or diets provoking a decreased rumen pH on milk fatty acid composition. In the first experiment, dietary treatments were tested during 21-d experimental periods in a 4 x 4 Latin square design. Diets included a control diet, a starch-rich diet, a bicarbonate-buffered starch-rich diet, and a diet supplemented with DHA-enriched micro algae [Schizochytrium sp.

Effect of glucogenic vs. lipogenic diets on energy balance, blood metabolites, and reproduction in primiparous and multiparous dairy cows in early lactation.

Increasing the availability of glucogenic nutrients relative to lipogenic nutrients has been hypothesized to decrease the production of milk fat, to improve the energy balance (EB), and to decrease the incidence and severity of metabolic and reproductive disorders in dairy cows in early lactation. Therefore, our objective was to evaluate the effects of a glucogenic, lipogenic, or mixed diet on EB, plasma metabolites and metabolic hormones, liver triacylglycerides (TAG), and reproductive variables in high-producing dairy cows in early lactation. Cows (n = 114) were randomly assigned to 1 of 3 diets and were fed either a mainly lipogenic diet, a mainly glucogenic diet, or a mixture of both diets (50:50 dry matter basis) from wk 3 before the expected calving date until 9 wk postpartum.