Effect of concentrate feeding method on the performance of dairy cows in early to mid lactation.

The objective of the current 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 (i.e., accommodated indoors) dairy cows in early to mid lactation. Eighty-eight multiparous Holstein-Friesian cows were managed on 1 of 4 concentrate feeding methods (CFM; 22 cows per CFM) for the first 21 wk postpartum. Cows on all 4 CFM were offered grass silage plus maize silage (in a 70:30 ratio on a DM basis) ad libitum throughout the study. In addition, cows had a target concentrate allocation of 11 kg/cow per day (from d 13 postpartum) via 1 of 4 CFM, consisting of (1) offered on a flat-rate basis via an out-of-parlor feeding system, (2) offered based on individual cow's milk yields in early lactation via an out-of-parlor feeding system, (3) offered as part of a partial mixed ration (target intake of 5 kg/cow per day) with additional concentrate offered based on individual cow's milk yields in early lactation via an out-of-parlor 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/cow per day of concentrate pellets via an in-parlor feeding system. We detected no effect of CFM on concentrate or total DMI, mean daily milk yield, concentrations and yields of milk fat and protein, or metabolizable energy intakes, requirements, or balances throughout the study. We also found no effects 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 of this study 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.

Food intake, milk production, and tissue changes of Holstein-Friesian and Jersey × Holstein-Friesian dairy cows within a medium-input grazing system and a high-input total confinement system.

Although interest in crossbreeding within dairy systems has increased, the role of Jersey crossbred cows within high concentrate input systems has received little attention. This experiment was designed to examine the performance of Holstein-Friesian (HF) and Jersey × Holstein-Friesian (J × HF) cows within a high concentrate input total confinement system (CON) and a medium concentrate input grazing system (GRZ). Eighty spring-calving dairy cows were used in a 2 (cow genotype) × 2 (milk production system) factorial design experiment. The experiment commenced when cows calved and encompassed a full lactation. With GRZ, cows were offered diets containing grass silage and concentrates [70:30 dry matter (DM) ratio] until turnout, grazed grass plus 1.0 kg of concentrate/day during a 199-d grazing period, and grass silage and concentrates (75:25 DM ratio) following rehousing and until drying-off. With CON, cows were confined throughout the lactation and offered diets containing grass silage and concentrates (DM ratio; 40:60, 50:50, 40:40, and 75:25 during d 1 to 100, 101 to 200, 201 to 250, and 251 until drying-off, respectively). Full-lactation concentrate DM intakes were 791 and 2,905 kg/cow for systems GRZ and CON, respectively. Although HF cows had a higher lactation milk yield than J × HF cows, the latter produced milk with a higher fat and protein content, so that solids-corrected milk yield (SCM) was unaffected by genotype. Somatic cell score was higher with the J × HF cows. Throughout lactation, HF cows were on average 37 kg heavier than J × HF cows, whereas the J × HF cows had a higher body condition score. Within each system, food intake did not differ between genotypes, whereas full-lactation yields of milk, fat plus protein, and SCM were higher with CON than with GRZ. A significant genotype × environment interaction was observed for milk yield, and a trend was found for an interaction with SCM. Crossbred cows on CON gained more body condition than HF cows, and overall pregnancy rate was unaffected by either genotype or management system. In summary, milk and SCM yields were higher with CON than with GRZ, whereas genotype had no effect on SCM. However, HF cows exhibited a greater milk yield response and a trend toward a greater SCM yield response with increasing concentrate levels compared with the crossbred cows.