Effects of pattern of concentrate allocation in the dry period and early lactation on feed intake and lactational performance in dairy cows

Abstract

With the objective to study the effects of concentrate allocation strategy in the dry period and early lactation on feed intake and lactation performance, 96 dairy cows were used in a 2×3 factorial design experiment. The dry cow feeding strategy was with [volatile fatty acid (VFA)-load] or without (control) a daily VFA-load generated by feeding concentrates and forage at different times of day. The three feeding strategies compared in early lactation were separate feeding of silage ad libitum and restricted concentrate with a daily increase in concentrate allowance of 0.3 kg (C-0.3) or 0.5 kg (C-0.5) up to a total of 10.2 kg/day or a complete diet. The postpartum diets were designed to contain 50% of concentrates on a DM basis. The VFA-load during the dry period did not improve postpartum feed intake and body weight changes, whilst minor reductions in milk yield and milk composition were observed during the first few weeks of lactation. The lack of positive effects suggests that the strategy had little effect on the rumen epithelium surface area and absorption capacity. Group C-0.5 ate less silage DM during weeks 2 to 4 than group C-0.3. The substitution rate between concentrate and silage was 0.94 during lactation weeks 2 to 4, with a higher concentrate to roughage ratio in group C-0.5. Daily milk yield did not differ between C-0.5 and C-0.3 but group C-0.5 had a depressed milk fat percentage during lactation weeks 4 and 5. Group C-0.5 had the most marked changes in body weight, probably due to differences in gut fill. Cows fed a complete diet had a significantly higher feed intake compared to cows fed concentrate and forages separately, particularly during the first 3 weeks of lactation. Feeding the complete diet improved energy corrected milk yield by 11% as a result of higher milk yield during the first 4 weeks and a higher milk fat percentage from week 6 of lactation.