Desempenho de novilhas de corte super precoces suplementadas a pasto

• Autor(a) principal: Martins, Leandro Soares
• 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/123456789/5770
• topic: Fêmeas bovinas; Suplementação a pasto; Heifers; Supplementation on pasture; CNPQ::CIENCIAS AGRARIAS::ZOOTECNIA::NUTRICAO E ALIMENTACAO ANIMAL

For the preparation of this dissertation it was conducted three experiments with the Nelore heifers under different supplementation strategies to pasture. In the first experiment the objective was to evaluate the effect of different levels of crude protein supplement on performance, intake, digestibility and also in microbial efficiency of animals. For this were used 40 newly weaned heifers, with an initial average age of 8 months and an initial average weight of 230 + 3,39 kg. The experimental design was completely randomized. The experiment contained five treatments and eight replications. The treatments were: mineral mix provided ad libitum, supplement containing 10%, 20%, 30% and 40% crude protein (CP), representing the treatments PB10, PB20, PB30, PB40, respectively. The supplements were provided in the amount of 1 kg / animal / day. There was a higher final body weight and weight gain in the supplemented animals compared to non-supplemented (P <0.10), these two parameters did not differ between animals supplemented with different levels of CP. The intake of dry matter (DM), organic matter (OM), crude protein (CP), total digestible nutrients (TDN), digested dry matter (DDM) and dry matter in g /kg of body weight were higher (P <0.10) for the supplemented animals compared to non-supplemented. The crude protein intake had increased linearly with increasing levels of CP in supplements. The digestibility of DM, OM, CP and TDN were higher (P <0.10) for the supplemented animals compared to non-supplemented. There was a quadratic effect on digestibility of CP with increased levels of CP in supplements. The production of microbial nitrogen (N mic), serum urea nitrogen (NUS) and reason urea nitrogen in the urine/creatinine nitrogen (NUU/Ncre) were higher (P <0.10) for the supplemented animals. Quadratic effect was observed in the production of Nmic, microbial efficiency (Emic), NUS and NUU/Ncre with increased levels of CP in multiple supplements. It was concluded that multiple supplementation provides higher weight gain and final body weight in the period after weaning from Nellore females. The second experiment aimed to evaluate the effect of replacing soybean meal by cottonseed meal 38% in supplements containing 15 and 30% of crude protein (CP) on performance and nutritional parameters of beef heifers. It 40 Nelore heifers was used, initial age of 12 months and average weight of 250 + 3,97 kg, which were conducted for five paddocks evenly formed with Brachiaria decumbens Stapf. The experimental design was completely randomized. The experiment contained five treatments and eight replications. The treatments were: Supplement containing soybean meal, with 15% CP (S15), supplement containing cottonseed meal, 15% CP (A15), supplement containing soybean meal, with 30% CP (S30), supplement containing cottonseed meal, 30% CP (A30) and treatment control receiving mineral mix ad libitum. Supplemented heifers had higher daily weight gains and final body weights also increased (P <0.10) when compared to the control treatment. The animals that received multiple supplementation also had higher intakes of all nutrients evaluated (P <0.10), as well as the digestibility of the same when compared to animals in the control treatment. The animals receiving supplements containing 15% CP had lower digestibility of DM, OM, CP, TDN and neutral detergent fiber corrected for ash and protein (NDFap), compared with those who received supplemental containing 30% CP (P <0.10). Treatments containing cottonseed meal provided greater digestibility of DM (P <0.10). It was concluded that supplementation of grazing heifers provide better performance productive and nutritional and the soybean meal can be substituted for cottonseed meal. In the third experiment, it was evaluated the effect of two additives, as well as their combination, on performance, intake, digestibility and also the efficiency of microbial synthesis. It was used a total of 40 Nelore heifers with age and weight of 16 months and 308 + 4,79 kg, respectively. These animals were divided into five paddocks evenly covered by Brachiaria decumbens Stapf. The experiment had five treatments and eight replications and was conducted during the transition rainy season dry season. The experimental design was completely randomized. The treatments were: ad libitum fed mineral mixture (MM), no additive supplement (SUP), supplement containing enzyme complex (Allzyme ® SSF) (SE), supplement containing live yeast (Yea-Sacc ®) (SL) and supplement containing both (SEL). The average gain and also the final body weight were greater for the supplemented animals, when compared to the MM treatment. These parameters were also higher for animals receiving yeast as an additive, when compared to animals in SUP treatment. The supplemented animals showed higher intake of all nutrients (P <0.10) compared to animals fed MM. The addition of additives did not influence intake between the supplemented animals. When contrasted treatments SE and SL showed higher DM intake, dry matter of forage (DMf), OM, organic matter forage (MOf), DM g / kg of body weight, DMf g / kg of body weight and NDFap g / kg of body weight for animals in SL treatment. The digestibility was higher for animals receiving supplementation for all nutrients. It was observed the effect of yeast presence (SL) in increasing the digestibility of DM, OM and CP comparing to treatment without additives. It was also observed higher microbial production, serum and reason urea nitrogen in the urine/creatinine nitrogen for animals receiving supplementation for animals in MM treatment. It was concluded that multiple supplementation improves better performance and nutritional parameters of heifers, as well as the addition of active yeast enhances this effect, during the transition rainy season dry season.