Carlos Frederico de Carvalho Rodrigues

Utilização de carneiros de raças de corte para obtenção de cordeiros precoces para abate em plantéis produtores de lã

RESUMO - Sessenta e nove cordeiros filhos de ovelhas das racas Ideal ou Corriedale cobertas com machos das racas Suffolk, Ile de France, ou da mesma raca materna, foram usados para avaliar o seu desempenho e as caracteristicas de carcaca. Os animais permaneceram em pastagem ate o desmame (60 dias), foram confinados por 90 dias e alimentados com racao a base de silagem de milho e concentrado. Foi usado delineamento completamente casualizado em esquema fatorial. O uso de machos de corte sobre femeas lanigeras nao causou efeito sobre o peso ao nascer e ao desmame das crias, porem aumentou o peso e a compacidade das carcacas, sem alterar as proporcoes de traseiro e costilhar. A espessura de gordura subcutânea nao foi influenciada pelo genotipo, apresentando-se maior para femeas. A area de olho de lombo nao apresentou diferenca entre genotipos. As medidas de carcaca mostraram diferenca entre genotipos, sendo as do cruzamento com Suffolk mais compridas, seguidas pelos mesticos de Ile de France.

Parâmetros bromatológicos e fermentativos das silagens de milho e girassol

At the Instituto de Zootecnia, APTA, Sao Paulo StateBrazil, it was carried out an experiment to evaluated the chemical quality and ruminal degradation for dry matter (DM), neutral detergent fiber (NDF) and protein (CP) of sunflower and corn silages. For chemical evaluation of the silages, a total randomized design with nine replicates was used. For in situ degradability was used a split-plot design with three replicates, in which the plots were the times of incubation and the subplot the silage. Sunflower silage showed higher concentration of crude protein (11.6 vs 9.4%), ether extract (10.1 vs 3.2%), acid detergent fiber (42.7 vs 31.9%) and lignin (9.4 vs 3.7%), and lower concentration of dry matter than corn silage (22.0 vs 34.6%), respectively; and also higher concentration of ammonia nitrogen (10.7 vs 5.8 %) and acetic acid (3.0 vs 0.79%) and lower concentration of lactic acid (3.7 vs 11.3%) than corn silage. The effective degradation rates of DM, NDF and CP were lower in the sunflower silage. Corn silage showed more favorable characteristics for ensiling process.

Avaliação de dois métodos de diagnóstico precoce de gestação em ovelhas: ultra-sonografia transretal e detector de prenhez para pequenos ruminantes (DPPR-80®)

No periodo de marco a maio de 2001, foram realizados os exames ultra-sonograficos em 88 ovelhas do Nucleo de Pesquisas Zootecnicas Sudoeste - Instituto de Zootecnia. Os animais foram examinados entre o 19o e 33o dia de gestacao pela ultra-sonografia transretal com exames executados em dias alternados, e do 25o ao 45o dia pelo detector de prenhez para pequenos ruminantes (DPPR-80O). O diagnostico foi considerado positivo pela ultra-sonografia transretal por meio da visualizacao do saco gestacional e embriao. Apos o 25o dia de gestacao foi observado tambem o batimento cardiaco embrionario, cuja frequencia e de 160 a 200 batimentos por minuto. Esta observacao foi dada como diagnostico de gestacao. Os nascimentos confirmaram os resultados dos exames. Dentre 88 femeas acasaladas, 3 abortaram durante o experimento e foram retiradas do grupo. Das 85 femeas restantes, 64 pariram. O diagnostico de prenhez por meio da ultra-sonografia transretal apresentou 35,29% de acuracia no 19o dia de gestacao, culminando em 82,35.00% no 31o dia de gestacao. Pelo detector de prenhez, a acuracia foi de 24,71% no 25o dia de gestacao e 34,12.00% no 45o dia. Foi possivel visualizar os batimentos cardiacos do embriao pela ultra-sonografia transretal a partir do 21o dia de gestacao e os primeiros placentomas foram observados ao redor do 25o dia de gestacao. A ultra-sonografia transretal mostrou-se um metodo superior ao detector de prenhez para pequenos ruminantes, para diagnostico precoce de gestacao em ovelhas.

Desempenho de cordeiros alimentados com silagem de girassol ou de milho com proporções crescentes de ração concentrada

Two experiments were conduct to evaluate the effect of dietary nutritive value and performance of sheep fed corn- or sunflower silage-based diet with increasing concentrate proportion (20, 40 and 60%). A factorial design (2x3) was used to evaluate nutritive value and digestibility coefficient of two silages with three concentrate levels and three sheep for each treatment. For lamb performance, a randomized block design in a factorial arrangement (2x3) was used to evaluate lamb performance, with five Suffolk lambs/treatment. Apparent digestibility coefficients of DM, OM, CF, NFE, NDF, ADF and cellulose were smaller for sunflower than for corn silage. Corn silage-based diets showed higher values of daily dry matter intake (709.5 x 609.7 g), daily live weight gains (181.8 x 108.2 g) and lower values of feed:gain ratio (3.82 x 5.53 kg DM/kg LW gain) than sunflower silage-based diets. Sunflower silage-based diets showed lower nutritive values than corn silage-based and smaller lamb performance. Lambs fed sunflower silage-based diets need more concentrate ration to obtain performance similar to those fed corn silage-based diets.

Efeito do sistema de manejo sobre o comportamento em pastejo, desempenho ponderal e infestação parasitária em ovinos Suffolk

Grazing behaviour, ponderal growth and level of parasitic infestation were studied in Suffolk breed sheep, from 1994 to 1995, in Nova Odessa, Sao Paulo. Two management systems were compared: restricted grazing, where the animals were released to the pastures at 9:50 a.m. and confined at 5:30 p.m., and 24 hour grazing, where the animals were maintained all the time in the paddocks, but with access to shelters. Thirty-four adult ewes were used in the summer period (17 under restricted grazing and 17 full-time grazing), and 42 ewes in the winter period (21 with restricted grazing and 21 full-time grazing). Also, for both seasons, 12 tracer animals, six in each grazing system, were used to obtain worm counts from their digestive tracts. For three consecutive days, grazing behaviour, that is, whether grazing or not, was observed in January/February (summer) and July/August (winter) at 30 minute intervals from 7:00 a.m. to 5:30 p.m., also whether the animals stayed in the sun or shade, irrespective of whether they were grazing or not. The level of parasitic infestation was evaluated under each system by eggs per gram countings (EPG) of the herd and the tracer animals, as well as by larvae count. It was concluded that restriction of grazing time by itself does not provide any effective control of parasitic infestation in sheep, however a better control was obtained in the summer period. Restricted grazing time was compensated by the greater activity of the animals during the hotter hours of the day, however, this behaviour affected the animal performance, resulting in lower weight gains. Greater forage availability in relation to estimated consumption may explain the similarity between the grazing times observed in both management systems, either in the summer or in the winter.

Ovarian response of Suffolk ewes to estrous synchronization using short-term protocol

The efficacy of estrus synchronization using short-term protocol was evaluated by ultrasound exams in Suffolk ewes during the pre-breeding season. The control Group (n = 12) was synchronized by treatment for 12 days with vaginal sponges impregnated with medroxyprogesterone acetate, and 400 IU eCG at sponge withdrawal. Experimental groups I, II and III kept the sponge in place for 4 days, and 100 µg of PGF2a was administered at sponge withdrawal. Additionally, Group I (n = 12) had 0.1 mg of estradiol benzoate (EB) administered during sponge placement and 50 µg of GnRH 48 hours after sponge removal. Group II (n = 6) had 35 mg of progesterone (P4) injected, and 0.1 mg of EB administered during sponge placement, 400 IU eCG at withdrawal and 48 hours after, 50 µg GnRH were administrated. Group III (n = 12) had 35 mg of P4 and 0.2 mg of EB administered at sponge placement, 400 IU eCG at withdrawal, and 50 µg of GnRH was administrated after 56 hours. Ovaries were monitored through ultrasound scanning. Concerning the first wave, no difference was detected between the control group and the experimental groups. However, the characteristics of ovulatory wave were significantly different between the groups. The duration of the follicular wave was shorter for Group III than for Group II. The follicle in Group I reached its maximum diameter before the Group II. The diameter of the follicle at the sponge withdrawal in the control group was larger than in Group I. After sponge withdrawal, the follicular growth rate was smaller in the control group than in Group III. The maximum diameter of the follicle in Group II was larger than in the other groups. The short-term protocol in which estrogen was used did not synchronize the emergence of the wave of follicular development.

Kinetics of epsilon antitoxin antibodies in different strategies for active immunization of lambs against enterotoxaemia

Enterotoxaemia, a common disease that affects domestic small ruminants, is mainly caused by the epsilon toxin of Clostridium perfringens type D. The present study tested four distinct immunization protocols to evaluate humoral response in lambs, a progeny of non-vaccinated sheep during gestation. Twenty-four lambs were randomly allocated into four groups according to age (7, 15, 30 and 45 days), receiving the first dose of epsilon toxoid commercial vaccine against clostridiosis with booster after 30 days post vaccination. Indirect ELISA was performed after the first vaccine dose and booster to evaluate the immune response of the lambs. Results showed that for the four protocols tested all lambs presented serum title considered protective (≥0.2UI/ml epsilon antitoxin antibodies) and also showed that the anticipation of primovaccination of lambs against enterotoxaemia conferred serum title considered protective allowing the optimization of mass vaccination of lambs.

Cana-de-Açúcar Desidratada Enriquecida com Silagem de Soja

Desenvolveu-se o presente estudo com o intuito de avaliar algumas caracteristicas nutricionais de dietas compostas por feno de cana-de-acucar enriquecido com silagem de soja perfazendo os seguintes tratamentos: T1=20% de silagem de soja + 80% de feno de cana-de-acucar; T2=40% de silagem de soja + 60% de feno de cana-de-acucar; T3=60% de silagem de soja + 40% de feno de cana-de-acucar; T4=80% de silagem de soja + 20% de feno de cana-de-acucar. Foram analisados os teores de proteina bruta, fibra em detergente neutro, fibra em detergente acido, lignina, digestibilidade in vitro da materia seca e materia mineral. O delineamento estatistico utilizado foi inteiramente casualizado, com quatro repeticoes. O teor proteico da dieta elevou-se em 259% quando o nivel de silagem de soja passou de 20% para 80%, ou seja, o valor passou de 3,7% para 13,3%, respectivamente. O conteudo mineral das dietas passou de 2,7% para 5,4%, respectivamente para os fenos enriquecidos com 20% e 80% de silagem de soja. Nao foi constatada significância dos niveis de silagem de soja sobre as variaveis fibra em detergente neutro, fibra em detergente acido e digestibilidade in vitro da materia seca, cujos valores medios foram, respectivamente 37,2%, 25,1% e 67,3%. Conclui-se que associar a silagem de soja ao feno de cana-de-acucar e uma alternativa para obter volumoso com melhor valor nutritivo, pois quanto maior a participacao da silagem de soja junto ao feno de cana maior o teor proteico e mineral da dieta. DOI:10.15528/2176-4158/rcpa.v12n2p146-149