Yeast culture supplementation prevented milk fat depression by a short-term dietary challenge with fermentable starch

Abstract

Effects of yeast culture on responses to a fermentable starch challenge were evaluated in an experiment with a crossover arrangement of treatments for yeast culture supplementation with 28-d periods and a fermentable starch challenge on the last 2 d of each 28-d period as a split plot within period. Eight ruminally cannulated, midlactation, multiparous Holstein cows (96 +/- 14 d in milk) were randomly assigned to treatment sequence. Treatments were yeast culture or control (mix of dry ground corn and soybean meal), top-dressed at 56 g per head per day throughout each period. Diets containing dry ground corn grain were fed from d 1 through 26 of each period. On the last 2 d of each period, the dry ground corn was replaced by finely ground high-moisture corn grain on an equivalent dry matter basis to abruptly increase ruminal fermentability of dietary starch. Response variables were averaged for d 25 and 26 for the dry corn treatment and for d 27 and 28 for the high-moisture corn treatment each period. The fermentable starch challenge decreased dry matter intake by 1.9 kg/d and tended to increase milk yield compared with the dry corn diet. However, effects of the fermentable starch challenge on yield of milk fat varied for the yeast culture and control diets; yield of milk fat decreased from 1.42 to 1.30 kg/d for the control treatment but increased from 1.40 to 1.47 kg/d for the yeast culture treatment. Milk fat concentration tended to decrease from 3.34 to 3.03% during the dietary challenge compared with the base diet for the control treatment but was not affected (mean = 3.32%) by the dietary challenge for the yeast culture treatment. An interaction of treatments was also detected for fat-corrected milk, which increased from 41.0 to 43.0 kg/d for the yeast culture treatment but decreased from 41.6 to 39.8 kg/d for the control diet with the fermentable starch challenge. Frequency of ruminating bouts was decreased by yeast culture compared with control (12.8 vs. 15.7 bouts/d) but not the fermentable starch challenge. No treatment interactions were observed for any measure of ruminal pH, total or individual volatile fatty acid concentration in ruminal fluid, acetate:propionate ratio, or individual fatty acid isomers in milk fat. Yeast culture supplementation may help prevent depression in milk fat during transition to a diet with highly fermentable starch, but the mechanism responsible remains to be elucidated.

Influence of Yeast Products on Rumen Microorganisms,In vitroDegradation and Fermentation of a Diet for Steers

“…However, in the current study although lower ammonia concentrations that may be associated with, increased bacteria activity by some y e a s t s cultures, no modifications of pH of the medium and increase in degradation of dry matter were found. Lack of effect of yeast products on rumen pH and degradation of dry matter is consistent with recent reports in lactating dairy cows (Longuski et al, 2009). have the capability of stimulating rumen function.…”

Diet digestibility and performance of dairy cows supplemented with live yeast

“…This dietary profile may have contributed to the responses registered to yeast supplementation. Actually, diets capable of increasing rumen environment acidity may favor the response potential to yeast supplementation (Williams et al, 1991;Longuski et al (2009).…”

“…Longuski et al (2009) reported a negative effect of yeast on the rumination activity of dairy cows, which can suggest that fiber digestibility responds positively to the yeast supplementation. However, similar phenomenon was not recorded in the present study (Table 3).…”

Microbial biodiversity of the liquid fraction of rumen content from lactating cows

“…Yeasts, in particular different strains or commercial products of Saccharomyces cerevisiae, have been tested on dairy cows with a number of positive effects such as increased dry matter intake (DMI) and milk production (Wohlt et al,1998;Dann et al, 2000); improved diet digestibility (Erasmus et al, 1992;Marden et al, 2008); stabilized rumen pH (Bach et al, 2007); and stimulated rumen bacteria growth (Newbold et al, 1995). However, there are also many studies with no or negative responses to yeast supplementation (Mwenya et al, 2005;Longuski et al, 2009;Chung et al, 2011), probably related to the strong influence of the basal diet, the variation in yeast strains and the different commercial formulations.…”