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Discipline: nutrition/feeding; Key words: concentrate feeding method, total mixed ration, feed-to-yield, flat-rate, confinement
The ration of a cow is compiled from knowledge of the nutritional requirements to sustain a particular milk production. The requirements are then met by a ration containing a specific ratio of concentrate and forage (hay, silage, pasture), supplemented with protein and a mineral-vitamin premix. If it is not a total mixed ration (TMR), the concentrate part of the ration is fed separately, for example in the milking parlour during milking and split half and half during the morning and afternoon milking periods, whereas the forage part is then available for feeding or grazing during the remainder of the day. An interesting question is whether the method employed to feed the concentrate makes a difference to the performance of the cow. This was the topic of investigation by Dr P.J. Purcell and colleagues recently published in the Journal of Dairy Science, Volume 99 of 2016, pages 2811 to 2824, the title being: Effect of concentrate feeding method on the performance of dairy cows in early to mid lactation.
The objective of their study was to determine the effects of concentrate feeding method on milk yield and composition, dry matter (DM) intake (DMI), body weight and body condition score, reproductive performance, energy balance and blood metabolites of housed (that is, accommodated indoors) dairy cows in early to mid lactation. Eighty-eight multi-lactation Holstein-Friesian cows were managed on one of four concentrate feeding methods (CFM), resulting in 22 cows per CFM. The study was conducted for the first 21 weeks following calving. The cows on all four CFM were offered grass silage plus maize silage (in a 70:30 ratio on a DM basis) ad libitum throughout the study. In addition, the cows had a target concentrate allocation of 11 kg per cow per day (from day 13 after calving) via one of four CFM, consisting of (1) offered on a flat-rate basis via an out-of-parlour feeding system, (2) offered based on the individual cow’s milk yield in early lactation via an out-of-parlour feeding system, (3) 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 via an out-of-parlour feeding system, and (4) offered as part of a partial mixed ration containing a fixed quantity of concentrate for each cow in the group. In addition, all cows were offered 1 kg concentrate pellets per cow per day via an in-parlour feeding system.
The results showed no effect of CFM on concentrate intake or total DMI, mean daily milk yield, concentrations and yields of milk fat and protein, or metabolizable energy intake, nutrient an energy requirements, or balances throughout the study. There were also no effect of CFM on mean or final body weight, mean or final body condition score, conception rates to first service, or any of the blood metabolites examined. The results therefore suggest that CFM has little effect on the overall performance of higher-yielding dairy cows in early to mid lactation when offered diets based on conserved forages, which is quite surprising and maybe contrary to what one would have thought.