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Eating Behavior Patterns of Multigrain and Barley Fed Lactating Dairy Cows
The objective of this research was to establish postprandial patterns of eating in lactating dairy cows on diets based on either solely barley grain or a choice of multiple grains. Eight multiparous (642 ± 57 kg body weight; 72 ± 58 days in milk; mean ± SD) lactating Holstein cows were studied in a cross-over design experiment with two 21-d periods. Cows were housed and managed in free individual boxes and fed alfalfa hay-corn silage based total mixed rations with either barley as the only grain (BR) or a mixture of barley, corn, wheat and sorghum (MG). Proportion of cereals in the multigrain treatment was equal, each equal to 25%. Grains were included as 30% of total dietary dry matter. Diets were prepared as total mixed rations and offered for 5-10% daily orts. Cows were fed at 0530, 1330 and 2130 h. Feed intake and eating rate were monitored continuously for the entire experiment and collected for data analysis during the third week of both periods. Feed intake patterns were expressed every 3-h post-feeding as a percentage of total daily intake. Statistical data analysis was conducted with Mixed Models Procedures of SAS program. Feeding MG vs. BR increased eating rate shortly post-feeding (P<0.05), such that MG and BR cows, respectively, consumed 80% and 73% of their daily TMR intake within the first 3-h post-feeding, summing all feeding occasions. Based on individual data, some cows in the MG group consumed up to 90% of their total daily intake within only 3-h post-feeding. These suggest a stronger crave for fresh feed in MG compared to BR cows, which could indicate improved feed palatability when multigrain rather than solely barley grain was fed. Total daily feed intake was greater for MG vs. BR (21.2 vs. 19.9 kg/d, P<0.05). These results suggest that type/mixture of starch is a determinant of circadian eating patterns and influences voluntary feed intake regulation in lactating dairy cows. Since eating behavior patterns determine circadian patterns of rumen metabolism and peripheral substrate availability, findings on the superiority of MG over BR in stimulating the cow crave for fresh feed, provide metabolic and health implications.
Keywords: Eating behavior, Multigrain, Dairy cow