Short communication: Production performance and nutrient digestibility of lactating dairy cows fed diets with and without addition of a live-yeast supplement

Abstract

The objective of this study was to evaluate the use of a live-yeast product when feeding relatively high-forage diets to high-producing cows in mid lactation. Eight primiparous [607 ± 43 kg of body weight (BW) and 130 ± 16 d in milk (DIM) at the beginning of the experiment] and 16 multiparous (706 ± 63 kg of BW and 137 ± 22 DIM at the beginning of the experiment) Holstein cows were blocked by parity and DIM, and randomly assigned to 1 of 2 diets (control vs. yeast) for a 12wk period according to a randomized complete block design. The formulated diets contained 50.4% corn silage, 10.4% alfalfa hay, and 39.2% concentrate. The yeast diet was formulated to provide approximately 5.4 × 10 11 cfu/d of Saccharomyces cerevisiae (BeneSacc; Global Nutritech Biotechnology LLC, Richmond, VA). Total-tract nutrient digestibility was estimated using 240-h undigested neutral detergent fiber (NDF) as an internal marker. Supplementing live yeast to lactating dairy cows did not affect dry matter intake (25.0 kg/d), milk yield (38.6 kg/d), milk fat concentration (4.78%), milk fat yield (1.83 kg/d), milk protein concentration (3.09%), milk protein yield (1.18 kg/d), milk lactose concentration (4.79%), milk lactose yield (1.84 kg/d), BW gain (−0.05 kg/d), or body condition score gain (0.16 units). The digestibility of dry matter was greater for the control treatment than for the yeast treatment (69.3 and 67.1%, respectively), but the digestibilities of crude protein (61.5%), NDF (40.5%), and starch (98.6%) were not affected by treatment. In conclusion, supplementation of live yeast did not affect production performance or nutrient digestibility of high-producing cows in mid lactation. The reasons for the lack of effect are not clear, but an evaluation of interactions between yeast and rumen buffer supplementation is warranted.

Influence of yeast on rumen fermentation, growth performance and quality of products in ruminants: A review

“…(2020) added yeast to the diets of ewes and reported an increased milk yield, improved milk fat, increased milk protein, and solids rather than fats. Contrary to the above studies, some authors reported no effect of yeast treatment on milk yield and milk fat in lactating Holstein cows ( Ambriz-Vilchis et al., 2017 ; Al- Mallah, 2018 ; Ferreira, 2019 ). Similarly, the milk yield, milk fat, and milk protein of buffalo cows were not affected by yeast supplementation ( Ramírez et al., 2007 ).…”

“…(2007) Holstein Friesian cows Mid-lactation Concentrate 2.5 g yeast/cow per day Increased milk yield; no effects on milk composition Maamouri et al. (2014) Holstein cows 20 ± 2 wk of lactation Forage and concentrate 10 g yeast/cow per day Increased milk yield; increased yield of milk fat Rezaeian (2003) Holstein cows 130 ± 16 DIM Forage and concentrate 5.4 × 10 11 CFU yeast per day No effects on milk fat yield, milk yield, milk protein concentration; no effects on milk protein yield, milk lactose concentration, and milk lactose yield Ferreira (2019) Holstein cows 21 d prepartum to 60 d postpartum Forage and concentrate 4 g yeast/cow per day Increased milk total solid; increased concentrations of milk fat; increased milk yield Nasiri et al. (2019) Holstein cows 95 ± 12 DIM Forage and concentrate 35 g yeast/cow per day No effects on milk yield, fat corrected milk, milk fat; no effects on milk protein and lactose Al- Mallah (2018) Holstein cows 176 ± 18 DIM Forage and concentrate 15 g inactivated dry yeast/cow per day Increased milk yield; increased milk fat; increased lactose concentration Dias et al.…”