José Neuman Miranda Neiva

Desempenho de novilhas de corte até o parto recebendo diferentes níveis de suplementação durante o período reprodutivo, aos 14 meses de idade

The objective was to evaluate the performance of beef heifers until calving receiving different levels of supplementation on native pasture during the first breeding season, from 14 to 17 months: no supplementation; 3.5 g/kg of body weight; and 7.0 g/kg of body weight. Ninety-eight Charolais, Nellore and their crosses, with average initial weight of 255 kg, were used. Weight at the end and average daily weight gain during the supplementation period were higher for 7.0 g/kg of supplement heifers (322 and 0.701 kg) compared to those with 3.5 g/kg of supplement (302 and 0.464 kg) and heifers without supplementation (288 and 0.425 kg), which did not differ from each other. Body condition score at the end of the supplementation was different between the three treatments, being 3.03, 3.33 and 3.47 points for heifers without supplementation; 3.5 g/kg of body weight; and 7.0 g/kg of body weight, respectively. Pregnancy rate was significantly affected by supplementation level, being 35.0, 34.2 and 70.0%, respectively. Heifers of the two supplementation treatments had higher conception rate at the first half of the reproductive period. Average heifer ages at calving were of 785, 778 and 761 days, respectively. The average daily weight and body condition of the heifers of the two genetic groups were similar; however, the initial and final weight of the supplementation period was higher for Charolais bulls daughters, compared with Nellore bulls daughters, reflecting on the heat (68.8 vs. 38.2%) and pregnancy (60.9 vs. 26.5%) rates. Characteristics related to calving were not affected by the supplementation levels during the reproductive period. The supplementation during the first breeding season increases reproductive performance of heifers at 14 months of age.

Carcass physical composition and meat quality of Charolais cattle of different categories

The objective of the experiment was to study the carcass physical composition and meat qualitative characteristics of different categories of Charolais cattle, feedlot finished. Nine steers (ST), ten heifers (HE), with average age of 20 months, and ten cull cows (CO) with average age of 87 months, taken from the same herd, were used. Diet contained 13% of crude protein for ST and HE and 10% for CO, with roughage:concentrate relation of 50:50, on a dry matter basis. The animals of the three categories were slaughtered with similar degree of finishing, with average subcutaneous fat thickness of 3.8 mm. HE showed carcasses with greater pistolcut percentage (52.8%) than ST (51.0%) and CO (51.4%). The carcass physical composition was similar among the categories evaluated, with 66.5; 67.0 and 67.3% of muscle, 19.1; 18.5 and 18.7% of fat, and 14.9; 15.0; and 14.6% of bone, respectively, for ST, HE and CO. The marbling score was lower for HE (4.6 points) than ST (7.1 points) and CO (6.5 points). However, when this characteristic was adjusted for 100 kg of cold carcass, the means were similar among the categories. CO showed higher cooking losses (27.8%) than ST (21.4%) and HE (23.5%). Meat color, texture, tenderness, shear force, palatability and juiciness were similar among the categories. Charolais cows have the potential for the production of carcass and meat with quality similar to steers and heifers.

Degradabilidade Ruminal In Situ de Silagens de Capim-Elefante com Adição de Subproduto da Manga

Avaliou-se a degradacao in situ da MS, PB e FDN de silagens de capim-elefante contendo cinco niveis de inclusao do subproduto da manga-SM (0; 4; 8; 12 e 16%, com base na materia natural da massa ensilada). O delineamento adotado foi o inteiramente casualizado em parcelas subdivididas, sendo os niveis de adicao as parcelas e os tempos de incubacao as subparcelas, com quatro repeticoes. Para confeccao das silagens, foi utilizado capim-elefante cortado aos 70 dias e adicionado ao subproduto, armazenado em 20 tambores plasticos (silos experimentais) com capacidade para 210 litros. As amostras de cada silo foram pre-secas, moidas em moinho com peneira de 5,0 mm, sendo usados 3,0 g de amostra em cada saco de nailon, para incubacao no rumen por 6, 48 e 96 h em dois ovinos machos castrados, sem padrao racial de fi nido (SPRD). Os sacos correspondentes ao tempo 0 hora foram lavados em agua corrente. Nos tempos de incubacao 48 e 96 h, veri fi cou-se aumento no desaparecimento da MS e da PB quando da adicao de ate 12% de SM a silagem de capim-elefante. Para a FDN o desaparecimento nao diferiu com a inclusao de SM nos tempos 0, 6 e 48 h. Para o conjunto de parâmetros de degradacao avaliados, observou-se que o nivel de inclusao 12% do SM apresentou maiores valores para a degradabilidade potencial e efetiva da MS, PB e FDN. A adicao do subproduto da manga a silagem de capim-elefante aumenta a degradabilidade das silagens, sendo recomendado incluir 12% ou mais deste subproduto.