1608
Modification of the Feeding Behavior of Dairy Cows through Live Yeast Supplementation
The objective of this study was to determine if the feeding behavior of lactating dairy cows can be modified through live yeast supplementation. Twelve lactating Holstein dairy cows (2 primiparous and 10 multiparous) were individually exposed to each of 2 treatment diets (over 35-d periods) in a replicated crossover design. Treatment diets were: 1) control TMR, and 2) control TMR plus 1x1010 cfu/head/d live yeast (Saccharomyces cerevisiae CNCM I-1077; Levucell SC20; Lallemand Animal Nutrition, Montreal, QC, Canada). Milk production, feeding, and rumination behavior were electronically monitored for each animal for the last 7 d of each treatment period. Milk samples were collected for the last 6 d of each period for milk component analysis. Data were analyzed in a general linear mixed model. DMI (28.3 kg/d), eating time (229.3 min/d) and rate (0.14 kg DM/min) were similar between treatments. With yeast supplementation, meal criteria were shorter (20.0 vs 25.8 min; SE=2.3; P=0.04), translating into cows tending to have more meals (9.0 vs 7.8 meals/d; SE=0.6; P=0.07), which tended to be smaller in size (3.4 vs 3.8 kg/meal; SE=0.2; P=0.09). Meal length (33.9 min) was similar between treatments. Yeast supplemented cows also tended to ruminate longer (570.3 vs 544.9 min/d; SE=13.2; P=0.08). Milk yield (45.8 kg/d) and efficiency of production (1.64 kg milk/kg DMI) were similar between treatments. There was a tendency for higher milk fat % (3.71 vs 3.55 %; SE=0.08; P=0.09) and yield (1.70 vs 1.63 kg/d; SE=0.04; P=0.1) when cows were supplemented yeast. No differences in milk fatty acid composition were seen, with the exception of a tendency for a greater concentration of 18:2, cis-9, cis-12 fatty acid (2.71 vs 2.48 % of total FA; SE=0.13; P=0.08) when cows were yeast supplemented. Yeast supplemented cows had lower mean ruminal temperature (38.4 vs 38.5 °C; SE=0.01; P=0.02), spent less time with rumen temperature above 39.0°C (353.1 vs 366.9 min/d; SE=5.5; P=0.001), and tended to spend less time with rumen temperature above 38.0°C (693.9 vs 780.0 min/d; SE=29.1; P=0.06). The results suggest that live yeast supplementation had a beneficial impact on rumen fermentation as evidenced by improvements in meal patterns and rumination, milk fat production, and rumen temperature.
Keywords: live yeast, rumination, meal pattern