Effects of grass pasture and concentrate-based feeding systems for spring-calving dairy cows in early spring on performance during lactation

The effect of offering a total mixed ration of silage and concentrate (proportionately 0(.)44 silage) system [indoor feeding system (IF)] was compared with grazing at a high daily herbage allowance with a low level of concentrate supplementation [early grazing system (EG)] in early spring on the performance of spring-calving dairy cows in Ireland. Sixty-four spring-calving Holstein-Friesian dairy cows (mean calving date, 2 February) were allocated to one of two systems between 16 February and 4 April 2004. An equal number of primiparous and multiparous cows were assigned to each system. The dairy cows on the IF system were housed for a 7-week period and offered a diet of 10(.)9 kg DM cow(-1) d(-1) (s.d. 2(.)3) of concentrate, the remainder of the diet was 8(.)6 kg DM cow(-1) d(-1) (s.d. 1(.)9) of grass silage. The dairy cows on the EG system were offered a mean daily herbage allowance of 15(.)1 kg DM cow(-1) d(-1) (s.d. 3-7) and were supplemented with 3(.)0 kg DM cow(-1) d(-1) (s.d. 1(.)0) of concentrate. There was no difference in milk yield between the two systems but the cows in the EG system had a higher milk protein concentration (2(.)9 g kg(-1)) and a higher milk protein yield than in the IF system. Milk fat concentration was higher for cows in the IF than EG system (3(.)0 g kg(-1)). There was no difference in total daily dry-matter intake between the systems, measured in week 6 of the study. Mean live weight of the cows in the IF system was greater than in the EG system. The results of the study suggest that a slightly greater performance can be achieved by a system offering a high daily herbage allowance to spring-calving dairy cows in early lactation compared with a system offering a total mixed ration containing a high proportion of concentrate with grass silage.