Effects of supplemental glycerol feeding on physiological responses and lactation performance of dairy cows during the hot season
2016
Wada, T. (Fukui Prefectural Okuetsu General Office of Agriculture and Forestry (Japan)) | Nihongi, T. | Nishimura, Y.
The objective of this study was to evaluate the effect of supplemental glycerol feeding which has lower heat production in the rumen, for improving dairy milk performance by the mitigation of summer heat stress. Experiment 1: Six Holstein cows in mid-late lactation were used (free stall barn, Total Mixed Ration feeding) in a 3 x 3 Latin square design, each periods consisted of 3 wk for treatment adjustment followed by 1 wk for data collection. Treatments were 0g of glycerol/day (control, CO), 300g of glycerol/day (GL), and 200g of oligosaccharide containing feedstuff (OL). As a result, no differences were observed in dry matter intake, milk yield and rumen fluid characteristics. Body surface temperature and respiration rates were tending to be lower (not significant) for GL and OL cows in comparison with CO cows. Experiment 2: We conducted on-farm research. 10 Holstein cows (tie-stall barn, component feeding: this system is said to be subject to heat stress) were assigned to two treatments: no glycerol (control) and 300g of glycerol/day (test). Results of Experiment 2 indicate that: 1. In severe summer heat conditions where the temperature humidity index exceeds all day 72, the group fed glycerol had a significantly lower body temperature (p<0.05) and respiration rates (p<0.05) compared to the untreated control group. 2. Milk composition, blood metabolites, heat stress index were similar in both groups. 3. Milk yield during the summer heat period (June to September) was increased by 7% in the test group.
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