Effects of Concentrate Feeding Strategy on Milk Production and Composition in Dairy Cows

The current study aimed to compare 3 strategies of distribution of concentre in 84 Holstein breed dairy cows divided into 3 equal groups (average initial liveweight: 553 kg, average stage of lactation: 122 days, row of lactation: 8 cows at the first and 20 at the second lactation in each group) on intake and milk yield and composition. They received a basal diet composed of oat hay, corn or grass silage and green ryegrass. The concentrate was distributed either in Total Mixed Ration (TMR) or Partially Mixed Ration (PMR) or Separate Ration (SR). Intake (3 times during the experiment) and individual dairy production (twice a month) were measured among a 13-weeks experimental period. Also, milk composition (protein and fat) were analysed in milk samples taken in every control. The trial lasted 13 weeks, preceded by 3 weeks of adaptation. Results indicated that Dry Matter (DM) intake of concentrate was significantly, but slightly (p<0.05) higher in SR than in PMR and in TMR (11.5, 11.3 and 11 kg). The same trend was almost observed in total diet DM intake. Animals from the group PMR produced significantly (p<0.05) more milk (31.4 kg day-1) than the tow other groups which were similar (averaged: 26.5 kg day-1). Milk from SR group was slightly higher (p<0.05) in protein than PMR and TMR, which were similar (31.3, 30.2 and 29.9 g kg-1, respectively). No significant differences were observed in fat (mean average: 32 g kg-1). It was mainly concluded that with the current low-quality based diet, the mixed strategy (PMR) seamed to result in the highest milk production with no considerable effects on milk fat and protein content.