ABSTRACT
OBJECTIVE: Pregnant Nelore heifers (n = 417) were used to evaluate the effects of supplementation with monensin-molasses multinutrient block (B) during pre and/or postpartum on reproductive and progeny performance. METHODS: Heifers were allocated in four treatments: i) CC: heifers received control supplement (C) in loose meal form (0.06% of body weight [BW] offered daily before and after parturition; n = 108); ii) CB: received C before parturition and B (0.07% of BW offered weekly after parturition; n = 117); iii) BC: received B before and C after parturition (n = 103) and iv) BB: received B before and after parturition (n = 89). During pre and postpartum periods, concentration of metabolites/hormones and cow/calf performance was evaluated over time. Cows were synchronized twice for fixed timed artificial insemination (FTAI) using an estradiol/progesterone-based protocol. Data was analyzed by orthogonal contrasts (C). RESULTS: B increased pregnancy at first FTAI (p = 0.04) and overall pregnancy rate (C1: CC vs BB+BC+CB; p = 0.05). Supplemented cows had greater body condition score (BCS) only at parturition (D0; p = 0.04) and at D40 (p = 0.02). B increased BW (p = 0.03), glucose concentrations (p = 0.01) and subcutaneous fat thickness (p = 0.03) only at D40. Concentrations of insulin were higher in supplemented cows (p = 0.008). Calves born by cows supplemented before and after parturition (C2: BB vs BC+CB) were heavier at 80 (p<0.001), 120 (p<0.001), 170 (p = 0.002) and 210 (p = 0.02) days old. CONCLUSION: Regardless of period of treatment, block supplementation increased pregnancy at first FTAI and overall pregnancy rate. Additionality, block supplementation during both pre and postpartum periods improved progeny weight until weaning. Block supplementation can be a tool to optimize fertility and calf performance in Nelore primiparous cows.
ABSTRACT
O Brasil vive um cenário de grande demanda pelo produto carne, tanto para o mercado interno quanto para o mercado externo. Para atender a esta demanda, há o envolvimento de toda a cadeia da carne, desde os programas de melhoramento genético com o fornecimento de touros melhoradores para tais características, como as centrais de colheita de sêmen desses animais para uso em massa por meio da Inseminação Artificial em Tempo Fixo (IATF). Para que haja sucesso no uso desta biotécnica, é de vital importância a qualidade do produto sêmen aliado às outras características como ambiência e nutrição.(AU)
Brazil is now with a great demand of beef products, for the domestic and exportation markets. To delivery the demand, the entire meat chain must be involved, included genetics programs to provide and separate superior bulls, and the collection centers that collect this superior genetics bulls to be used in the Fixed Timed Artificial Insemination (FTAI) biotechnique in a large scale. In order to be successful using this biotechnology, the quality of the semen combined with other characteristics such as ambience and nutrition are extremely important.(AU)