Grão de soja em suplementos múltiplos para novilhas de corte em pastejo / Soybean in multiple supplements for grazing beef heifers

AUTOR(ES)
FONTE

IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia

DATA DE PUBLICAÇÃO

16/02/2012

RESUMO

This dissertation was prepared from two experiments with beef heifers submitted to different supplementation strategies on pasture. In the first experiment aimed to evaluate the effect of replacing soybean meal by soybean at different levels in multiple supplements on the nutritional characteristics and productive performance of heifers grazing in Uruchloa decumbens in the transition period water-dry. Were used 40 crossbred heifers with initial age and initial weight of 18 months and 2906 kg, respectively. The design was completely randomized with four treatments and ten repetitions. The supplements contained approximately 30% crude protein (CP) and gradual replacement of soybean meal by soybean at 0, 50 and 100%. To the animals of the control treatment was offered exclusively mineral salt ad libitum and the other treatments were given 1.0 kg/animal/day of supplement. The supplemented animals had high average daily gain (ADG) than control animals (P<0.10) and there was no difference in ADG among the supplements (P>0.10). There was effect of supplementation (P<0.10) on the intake of ether extract (EE), CP and non-fiber carbohydrates (NFC) and a positive linear effect (P<0.10) the level of soybean on EE intake. There were no differences (P>0.10) on dry matter intake (DM), DM grazing, organic matter (OM), OM pasture and neutral detergent fiber corrected for ash and protein (NDF) between treatments. There was no effect of supplementation (P<0.10) and positive linear effect (P<0.10) the level of soybean on the intake of total digestible nutrients (TDN). Supplementation improved DM digestibility and all constituents of the diet (P<0.10), with the exception of NDF (P>0.10). There was no effect of supplementation or the level of soybean on serum levels of insulin and progesterone (P>0.10). The levels of insulin and progesterone varied depending on the day of collection (P<0.10); at the end of the experiment the animals had higher levels of these hormones compared to the beginning of the experiment. Based on serum progesterone, heifers in the present experiment commenced luteal activity at around 297 kg of body weight. It is concluded that the provision of multiple supplements optimizes the performance of heifers grazing during the period of water-dry transition and that the substitution of soybean meal by soybean does not affect the productive performance of animals. The second experiment aimed to evaluate the effect of temporal replacement of soybean meal by soybean in multiple supplements on the nutritional characteristics and productive performance of heifers grazing in recreates Uruchloa decumbens in the dry season. We used 40 crossbred heifers with average of ages and weights initial of 21 months and 3256 kg, respectively. The design was completely randomized with four treatments and ten repetitions. We used two supplements with 30% CP, with a soybean meal (FS) and the other with soybean (GS) as a protein source. It was offered 1.0 kg/animal/day of supplement. The treatments consisted in the replacement of the supplement FS by GS for 0, 40, 80 and 120 days. There was no difference in ADG between treatments (P>0.10) and all remained close to maintenance. The soybean improved DM intake, grazing DM, OM, OM pasture, NDT and EE (P<0.10). There was no difference in intake of crude protein, NDF and NFC. There was no difference in digestibility of DM and its constituents (P>0.10), except for EE, a higher digestibility (P<0.10) was observed in the diet of animals that received the supplement GS. There was no significant difference (P>0.10) between supplements on urinary excretion of urea nitrogen, serum urea nitrogen and flow of microbial nitrogen compounds. The efficiency of microbial protein synthesis in animals receiving GS was lower than in animals that received FS (P<0.10). The serum insulin levels decreased during the experiment (P<0.10) and did not differ between treatments (P>0.10). It was observed quadratic time providing supplement containing soybean on progesterone levels (P<0.10) and maximum concentration of progesterone achieved was approximately 70 days supply of GS. It is concluded that the replacement of soybean meal by soybean supplements during the dry season does not change the performance of heifers. The replacement of soybean meal by soybean in multiple supplements improved nutritional characteristics of cattle grazing in the dry season and the maximum response of serum progesterone occurs with 70 days of supplementation with soybean.

ASSUNTO(S)

prenhez reprodução suplementos avaliacao de alimentos para animais pregnancy reproduction supplements

ACESSO AO ARTIGO

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