Effect of reduced energy density of close-up diets on dry matter intake, lactation performance and energy balance in multiparous Holstein cows

Abstract

Energy intake prepartum is critically important to health, milk performance, and profitability of dairy cows. The objective of this study was to determine the effect of reduced energy density of close-up diets on dry matter intake (DMI), lactation performance and energy balance (EB) in multiparous Holstein cows which were housed in a free-stall barn and fed for ad libitum intake. Thirty-nine dry cows were blocked and assigned randomly to three groups fed a high energy density diet [HD, n = 13; 6.8 MJ of net energy for lactation (NEL)/kg; 14.0% crude protein (CP) ], or a middle energy density diet (MD, n = 13; 6.2 MJ NEL/kg; 14.0% CP), or a low energy density diet (LD, n = 13; 5.4 MJ NEL/kg; 14.0% CP) from d 21 before expected day of calving. After parturition, all cows were fed the same lactation diet to d 70 in milk (DIM). The DMI and NEL intake prepartum were decreased by the reduced energy density diets (P < 0.05). The LD group consumed 1.3 kg/d (DM) more diet compared with HD group in the last 24 h before calving. The milk yield and the postpartum DMI were increased by the reduced energy density diet prepartum (P < 0.05). The changes in BCS and BW prepartum and postpartum were not affected by prepartum diets. HD group had higher milk fat content and lower lactose content compared with LD group during the first 3 wk of lactation (P < 0.05). The energy consumption for HD, MD and LD groups were 149.8%, 126.2% and 101.1% of their calculated energy requirements prepartum (P < 0.05), and 72.7%, 73.1% and 75.2% during the first 4 wk postpartum, respectively. In conclusion, the low energy density prepartum diet was effective in controlling NEL intake prepartum, and was beneficial in increasing DMI and milk yield, and alleviating negative EB postpartum.

Effect of dietary net energy concentration on dry matter intake and energy partition in cows in mid‐lactation under heat stress

“…This is in agreement with Huang et al . () who reported that DMI of dairy cows within 5 weeks postpartum decreased by an average of 0.9 kg/day in high energy diets (6.8 MJ/kg) compared to low energy diets (5.4 MJ/kg). The decrease of DMI in high energy diets may be caused by dietary fat.…”

“…Recent reports (Huang et al . ; van Knegsel et al . ) reflected that dietary energy content may affect energy metabolism of cows.…”

“…However, few studies concerning net energy requirement and energy partitioning of dairy cows under heat stress has not been reported. Recent reports (Huang et al 2014;van Knegsel et al 2014) reflected that dietary energy content may affect energy metabolism of cows. Therefore, the objectives of the present study were to examine the effects of dietary energy concentration of Holstein cows in mid-lactation on milk yield, energy partitioning, efficiency of milk yield, and net energy requirements during medium heat load conditions by the combination of comprehensive experiments, regression analysis, and total collection plus gas exchange methods.…”

Reduced energy density of close‐up diets decrease ruminal pH and increase concentration of volatile fatty acids postpartum in Holstein cows

“…Complete details of animal management and diets were the same as our previous research (Huang et al . ).…”

“…; Janovick & Drackley ; Huang et al . ) have shown that over‐consumption of energy prepartum often results in a slower increase in DMI postpartum compared with cows which had low energy consumption. These papers focused on the effect of prepartum energy intake on DMI, energy balance, milk performance, body weight (BW) and body condition score (BCS) change, energy metabolism, gluconeogenesis, adipose tissue mobilization or incidence of health diseases.…”