Estratégias de suplementação para novilhas de corte em pastejo nos períodos de seca e transição seca-águas

• Autor(a) principal: Ortega, Román Enrique Maza
• Data de Publicação: 2013
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/5793
• topic: Desempenho; Fêmeas; Forragem; Suplementos; Performance; Females; Forage; Supplements; CNPQ::CIENCIAS AGRARIAS::ZOOTECNIA::NUTRICAO E ALIMENTACAO ANIMAL::AVALIACAO DE ALIMENTOS PARA ANIMAIS

This research was conducted from two experiments with beef heifers offered different supplementation strategies on pasture. The first experiment aimed to evaluate nutritional characteristics and productive performance of the effect of replacing soybean meal by cottonseed meal in multiple supplements of beef heifers reared in pastures of Brachiaria decumbens in the dry season. 24 beef heifers nelore were used with age of 8 months and initial weight of 210±6 kg, respectively. The experimental design was completely randomized with four treatments and six repetitions. The supplements contained approximately 30 % crude protein (CP) and progressive replacement of soybean meal by cottonseed meal at 0, 50 and 100 %. The animals of the control treatment were provided only mineral mixture ad libitum and the other treatments were provided with 1.0 kg/animal/day of supplement. There was no difference in ADG between animals supplemented and control animals (P>0.10). No effect of supplementation (P>0.10) was observed on dry matter intake (DM), dry matter on pasture (MSP), organic matter (OM), ether extraction for fat (EE), non-fiber carbohydrates (NFC), neutral detergent fiber corrected for ash and protein (NDF) , indigestible neutral detergent fiber (iNDF) and total digestible nutrients (TDN) between treatments. Only crude protein (CP) showed a difference (P<0.10). The substitution level of soybean meal by cottonseed meal did not affect (P>0.10) intake in the supplemented animals. The supplementation increased the digestibility coefficients (P<0.10) of OM, CP and TDN CFN except EE and NDF (P>0.10). A positive linear effect was observed (P<0.10) with the level of substitution of soybean meal by cottonseed meal on the digestibility of DM, OM, NFC and TDN. No effect was found on supplementation and replacement level (P<0.10) on urea nitrogen and serum urea nitrogen in the urine. Also, no effect was detected of supplementation and replacement level on the flow of microbial nitrogen to the gut (NMIC) and efficiency of microbial protein synthesis (EFM) (P>0.10). Decreasing linear effect was observed (P < 0.10) on the substitution of the relationship microbial nitrogen / nitrogen intake (NMICR). The second experiment aimed to evaluate the nutritional characteristics and productive performance of providing different levels of multiple supplements on heifers grazing Brachiaria decumbens in the transitional period dry-wet season. 24 beef heifers were used aged 11 months and average initial weights of 243±6 kg, respectively. The experiment was completely randomized with four treatments and six repetitions. A supplement with approximately 25 % CP was used. The treatments consisted of four quantities of supplementation of 0; 0.5; 1.0 and 1.5 kg respectively. All treatments received mineral mix ad libitum. A positive linear effect was observed (P<0.10) on ADG and final body weight (PCF) with supplementation quantity. An increasing linear effect (P < 0.10) in intake of DM, OM, CP, EE, NFC and TDN was identified on the increasing quantities of supplements. Opposite effects were observed on consumption of NDF. The quantities of supplements improved linearly (P<0.10) on the digestibility of OM, CP, EE, NFC and TDN. A quadratic effect was observed (P<0.10) on the estimates of digestibility of OM, CP, NDF and TDN between quantities of supplements. A cubic effect (P<0.10) on apparent digestibility of OM, CP, NDF, NFC and TDN levels between supply multiple supplements was clearly detected. A positive linear statistics (P<0.10) on the urinary excretion of urea nitrogen (NUU), serum urea nitrogen (SUN) and flow of microbial nitrogen (NMIC) was found with quantities of supplements. No difference was observed (P<0.10) quantities of supplements on microbial efficiency. The quantities of supplements decreased linearly (P<0.10) on the NMICR. It is concluded that the replacement of soybean meal by cottonseed meal in multiple supplements during the dry season does not affect the productive performance of beef heifers. The provision of higher quantities of multiple supplements during the transition dry-rainy season improves performance and nutritional characteristics of grazing beef heifers.