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Discipline: nutrition/feeding; Key words: concentrate allocation strategy, group feeding, individual cow feeding
In a previous RESEARCH COLUMN I discussed results of a study which investigated the method of concentrate feeding on the overall performance of the high-yielding cow. The methods were: (1) concentrate offered on a flat-rate basis via an out-of-parlour feeding system, (2) concentrate offered based on the individual cow’s milk yield in early lactation via an out-of-parlour feeding system, (3) concentrate offered as part of a partial mixed ration (target intake of 5 kg per cow per day) with additional concentrate offered based on the individual cow’s milk yield in early lactation from an out-of-parlour feeding system, and (4) concentrate offered as part of a partial mixed ration containing a fixed quantity of concentrate for each cow in the group. The results of the investigation showed that method of concentrate feeding had little effect on the overall performance of the cows in early to mid lactation, which was surprising and maybe contrary to what one would have expected. In a further study by the same research institution, the effect on cow performance of individual cow concentrate allocation was compared with group concentrate allocation. The results of Dr M.W. Little and colleagues were published in the Journal of Dairy Science, Volume 99 of 2016, page 4360 to 4373, the title being: A comparison of individual cow versus group concentrate allocation strategies on dry matter intake, milk production, tissue changes, and fertility of Holstein-Friesian cows offered a grass silage diet.
The objectives of the study were to examine the effects on cow performance of adopting two contrasting concentrate allocation strategies over the first 140 days of lactation. Performance was measured by dry matter intake, milk yield and composition, body tissue changes and fertility. Seventy-seven Holstein-Friesian dairy cows were allocated to one of two concentrate allocation strategies at calving, namely group or individual cow. Cows on the group strategy were offered a mixed ration comprising grass silage and concentrates in a 50:50 ratio on a dry matter basis. Cows on the individual cow strategy were offered a basal mixed ration comprising grass silage and concentrates (the latter included in the mix to achieve a mean intake of 6 kg per cow per day), which was formulated to meet the cow’s energy requirements for maintenance plus 24 kg of milk per cow per day. Additional concentrates were offered from an out-of-parlour feeding system, with the amount offered adjusted weekly based on each individual cow’s milk yield during the previous week. In addition, all cows received 0.3 kg straw in the mixed ration part of the diet and 0.5 kg of concentrate twice daily in the milking parlour.
The mean concentrate intakes over the study period were similar at 11.5 and 11.7 kg of dry matter per cow per day for group and individual cows respectively, although the pattern of intake within each treatment differed over time. Milk yield did not differ either, respectively 39.3 and 38.0 kg per day for group and individual cows, also not milk composition, milk constituent yield, body weight or body condition score. The milk yield response curves within each treatment were largely aligned with the concentrate dry matter intake curves. Cows on the individual cow treatment had a greater range of concentrate dry matter intake and milk yields than those on the group treatment. Cows on the individual cow treatment had a higher pregnancy rate to first and second service than cows on the group treatment. Overall though, the study demonstrated that concentrate allocation strategy had little effect on production performance which supports the findings of the previous study discussed.