Using dietary heat increment to alter energy use in dairy cows during hot weather
Pacetti, Lani Melissa
MetadataShow full item record
Thirty-two lactating Holstein cows averaging 169 ± 35 DIM were used to determine changes in energy use due to ration heat increment (HI) content under heat stress conditions. Dietary treatments were high HI ad libitum (HA), low HI ad libitum (LA), and low HI at restricted caloric intake (LR). The LR cows were paired and restricted to HA daily NEL intake (Mcal/100 kg BW). The high HI diet was formulated with more forage and fibrous byproducts, whereas the low HI diet contained more starch and fat from byproducts. Milk yield, milk composition, and energy-corrected milk yield were similar for treatments. Milk yield and energy-corrected milk yield per kg DMI were greater for LR compared with HA. Total energy efficiency was greater for LR than for HA and LA treatment groups. Data indicates that HI is useful for reducing heat stress and improving energy efficiency in dairy cattle during heat stress.