Increased Milk Production of Heat-Stressed Cows on Protected Met

The objective was to determine long-lasting effects of a rumen-protected methionine (RPM) product (SmartamineMTM) on milk production properties of early lactation cows under extended very high ambient temperatures. Twenty four fresh Holstein cows including 12 second lactation and 12 higher lactation cows were randomly assigned to either control or RPM-supplemented total mixed rations (TMR) and fed continuously for 5 months. The RPM group had consistently greater 5-month-long average DM intake (21.9 vs. 19.1 kg/d), milk yield (42.4 vs. 37.4 kg/d), milk fat content (33 vs. 27.5 g/kg), fat yield (1.40 vs. 1.04 kg/d), milk protein content (29.6 vs. 27.5 g/kg) and protein yield (1.25 vs. 1.02 kg/d). Mature cows tended to produce more milk (42.2 vs. 37.6 kg/d) and milk fat (1.30 vs. 1.13 kg/d) than second lactation cows. Findings prove beneficial effects of long longlasting RPM provision on DMI and milk production of Holstein cows under concurrent metabolic pressures of early lactation and high ambient temperatures.

کلیدواژه ها:

Dairy cow ، Heat stress ، Milk production ، Smartamine