Carcass and meat quality traits of rabbits under heat stress

Rabbits are very sensitive to heat stress because they have difficulty eliminating excess body heat. The objective of the current study was to evaluate the effects of heat stress on slaughter weight, dressing percentage and carcass and meat quality traits of rabbits from two genetic groups. Ninety-six weaned rabbits were used: half were from the Botucatu genetic group and half were crossbreds between New Zealand White sires and Botucatu does. They were assigned to a completely randomized design in a 2 × 3 factorial arrangement (two genetic groups and three ambient temperatures: 18°C, 25°C and 30°C) and kept under controlled conditions in three environmental chambers from 5 to 10 weeks of age. Slaughter took place at 10 weeks, on 2 consecutive days. Meat quality measurements were made in the longissimus muscle. Actual average ambient temperature and relative humidity in the three chambers were 18.4°C and 63.9%, 24.4°C and 80.2% and 29.6°C and 75.9%, respectively. Purebred rabbits were heavier at slaughter and had heavier commercial and reference carcasses than crossbreds at 30°C; however, no differences between genetic groups for these traits were found at lower temperatures. No genetic group × ambient temperature interaction was detected for any other carcass or meat quality traits. The percentages of distal parts of legs, skin and carcass forepart were higher in crossbred rabbits, indicating a lower degree of maturity at slaughter in this group. The percentage of thoracic viscera was higher in the purebreds. Lightness of the longissimus muscle was higher in the purebreds, whereas redness was higher in the crossbreds. Slaughter, commercial and reference carcass weights and the percentages of thoracic viscera, liver and kidneys were negatively related with ambient temperature. Commercial and reference carcass yields, and the percentage of distal parts of legs, on the other hand, had a positive linear relationship with ambient temperature. Meat redness and yellowness diminished as ambient temperature increased, whereas cooking loss was linearly elevated with ambient temperature. Meat color traits revealed paler meat in the purebreds, but no differences in instrumental texture properties and water-holding capacity between genetic groups. Purebred rabbits were less susceptible to heat stress than the crossbreds. Heat stress resulted in lower slaughter and carcass weights and proportional reductions of organ weights, which contributed to a higher carcass yield. Moreover, it exerted a small, but negative, effect on meat quality traits. © 2012 The Animal Consortium.

Persistent efficacy of 3.5% doramectin compared to 3.15% ivermectin against gastrointestinal nematodes in experimentally-infected cattle in Brazil

The present study aimed to evaluate the persistent efficacy of a 3.5% doramectin* (700μg/kg) formulation compared to 3.15% ivermectin** (630μg/kg) treatment, administered subcutaneously at a dose of 1mL/50kg body weight in cattle experimentally infected with gastrointestinal nematodes. Seventy-two male crossbred Holstein cattle that were negative for helminth infection were divided into nine groups. Treatments of 3.5% doramectin (Groups 2, 4, 6 and 8) and 3.15% ivermectin (Groups 3, 5, 7 and 9) were administered on days 49, 42, 35 and 28 prior to challenge with infectious nematode larvae (L3). Animals in the control group (Group 1) received saline solution on day 49 before challenge. Beginning on day zero, each animal received 50mL orally of a mixed culture containing approximately 3,000 third stage larvae (L3) of Haemonchus (60%), Oesophagostomum (20%), Cooperia (15%) and Trichostrongylus (5%) for seven consecutive days, resulting in a total challenge of 21,000 larvae/animal. Due to the large number of cattle, autopsies were performed between days 28 and 35 after the last day of inoculation. The formulation containing doramectin (700 mcg/kg) achieved persistent efficacy against H. placei and C. punctata for 49 and 35days, respectively. The persistent efficacy of ivermectin (630 mcg/kg) against H. placei lasted for 49days, but this treatment was ineffective against C. punctata. Both formulations demonstrated persistent efficacy against T. axei for 49days. The persistent efficacy of doramectin (700 mcg/kg) and ivermectin (630 mcg/kg) lasted for 49 and 42days against O. radiatum, respectively. © 2012 Elsevier Ltd.

Consumo, digestibilidade aparente de nutrientes e balanços de nitrogênio e hídrico de ovinos alimentados com silagens de cultivares de capim-búfel

The objective of this present experiment was to determine intake and apparent digestibility of dry matter and nutrients, nitrogen (NB) and water balances (WB) of sheep fed with buffel grass silages. The buffel grass cultivars used were Tanzania, Buchuma and Biloela. 21 male, castrated, crossbred Santa Ines x Non defined genotype sheep, with initial body weight of 31.8±3.16kg were used, kept in metabolic cages. The experimental design was completely randomized with seven replicates. No differences were observed in dry matter intake in g/day (919.2) and % of body weight (2.9). In general, digestibility coefficients of dry matter varied from 37.7% to 60.0%. The NB and WB were positive, with higher NB values in sheep fed with Tanzania (5.1g/day) and Biloela (3.9g/day) and higher WB in animals fed with Buchuma (1.38kg/animal/day) and Biloela (1.42kg/animal/day). All cultivars of buffel grass evaluated (Tanzania, Buchuma and Biloela) presented adequate chemical composition, where the silage of buffel grass used corresponded to 60% of the total daily water intake by sheep.

Efeito da inulina e de probióticos sobre a digestibilidade dos nutrientes e balanço do nitrogênio em leitões

This study aimed to evaluate different inulin and probiotic levels as supplement in diets for piglets on nutrient digestibility and nitrogen balance. Twenty four crossbred barrows (Pietráin × Landrace × Large White), with initial average weight of 18.00 ± 0.38 kg, were individually housed in metabolic cages. The experimental design was a completely randomized block, in a 2 × 3 factorial scheme (probiotic levels: 0.30 and 0.60 %; inulin levels: 0.00, 0.25 and 0.50 %), with four replications. The probiotic used was a mix of Lactobacillus acidophillus, Streptococcus faecium and Bifidobacterium bifidum. The inulin was the prebiotic used in this study, characterized as an indigestible carbohydrate formed by fructooligosaccharides. Inulin levels provided a quadratic effect (p<0.05) on the digestibility coefficients of dry matter, organic matter and ether extract, and the better responses were obtained supplementing 0.194, 0.185 and 0.188 %. Quadratic effects were observed for the nitrogen excreted in feces, total nitrogen excretion, nitrogen efficiency use and nitrogen digestibility. The inulin levels of 0.194 and 0.216 %, in piglet diets, were the better for dry matter digestibility and total nitrogen excretion, respectively.

Desenvolvimento corporal de novilhas leiteiras suplementadas com minerais inorgânicos e orgânicos em pastejo na época das águas

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Comparison of factor-analytic and reduced rank models for test-day milk yield in Gyr dairy cattle (Bos indicus)

We analyzed 46,161 monthly test-day records of milk production from 7453 first lactations of crossbred dairy Gyr (Bos indicus) x Holstein cows. The following seven models were compared: standard multivariate model (M10), three reduced rank models fitting the first 2, 3, or 4 genetic principal components, and three models considering a 2-, 3-, or 4-factor structure for the genetic covariance matrix. Full rank residual covariance matrices were considered for all models. The model fitting the first two principal components (PC2) was the best according to the model selection criteria. Similar phenotypic, genetic, and residual variances were obtained with models M10 and PC2. The heritability estimates ranged from 0.14 to 0.21 and from 0.13 to 0.21 for models M10 and PC2, respectively. The genetic correlations obtained with model PC2 were slightly higher than those estimated with model M10. PC2 markedly reduced the number of parameters estimated and the time spent to reach convergence. We concluded that two principal components are sufficient to model the structure of genetic covariances between test-day milk yields. © FUNPEC-RP.

Estimación de parámetros genéticos para producción de leche en el día de control en búfalas de primer parto

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Resistência às infecções artificiais por Haemochus contortus de cordeiras Santa Inês, Ile de France e de cordeiras produtos do cruzamento entre raça Santa Ines e as raças Dorper, Ile de France, Suffolk e Textel

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Efeito da suplementação com semente de girassol na performance reprodutiva de fêmeas bovinas de corte: Mariângela Bueno Cordeiro. -

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Óleo de Neem: tratamento parasitário em ovinos e desenvolvimento ponderal

Pós-graduação em Ciência Animal - FMVA

Caracterização ultrassonográfica das estruturas flexoras músculo-tendíneas e ligamentares da porção distal dos membros de bovinos

Pós-graduação em Cirurgia Veterinária - FCAV

Produção de quimeras embrionárias bovinas mediante a agregação de embriões diploides (Bos indicus) e tetraploides (Bos indicus)

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Variação da temperatura corpórea em ovinos sob diferentes condições de manejo

Pós-graduação em Ciência Animal - FMVA

Aditivos químicos na ensilagem e fenação de capim-tifton 85

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Estudo quantitativo da infecção por Babesia bovis e Babesia bigemina em diferentes grupos genéticos de bovinos de corte

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)