The use of urea and blood meal in rations for crossbred heifers (Red and White Holstein x Guzera)
DOI:
https://doi.org/10.1590/S1678-3921.pab1974.v9.17153Keywords:
Age of first calving, feeding dry season x wet season, cost account, protein sources, confinement feeding, concentrate rations, non protein nitrogen, reproductionAbstract
An experiment was conducted in which blood meal was compared to urea as a crude protein source in rations for crossbred heifers. Sixteen 1/2 Red and White Holstein (RWH): 1/2 Guzera, and sixteen 3/4 RWH: 1/4 Guzera heifers were fed rations containing one of the protein sources for 140 days in confinement, during the dry season. After an interval of 28 days for adaptation, all animals were allowed to graze on pasture for an additional 140 days, during the wet season. It was observed that the 1/2 RWH heifers had an average age of 31.2 months at first parturition and weighed 433 kg. The 3/4 RWH heifers had an average age of 28.4 months at first parturition and weighed 395 kg. Parturition occurred throughout the year, with 65% occurring during the dry season. During the period of confinement, heifers consuming the ration containing the blood meal gained significantly (P <. 05) faster than those receiving the ration containing the urea. The 1/2 RWH heifers gained significantly (P <. 05) faster than the 3/4 RWH heifers, when fed the ration containing the blood meal, but not when fed the ration containing the urea.
