Effect of climate region and stocking density on ostrich (Struthio camelus) productive performances.

The effects of three climates (hot and dry, mild and humid and Alpine) and three flock densities (<100, 100-300 and >300 m2 ) on ostrich reproductive and productive traits were studied. Data were compared with the benchmark target sets by the World Ostrich Association (Ostrich benchmark Performance Targets. Version 2, May, 2008) for reproductive qualifications of ostrich. No significant difference was observed on egg production, weight, fertility, hatchability and day-old chicks weight among the three climate conditions; however, the Alpine climate had a lower performance trend. Mild and humid climates had a significant effect of age at sexual maturity for both males and females as well as on the duration of egg production season. Stocking density did not show significant difference on egg production, hatchability, age of male and female at sexual maturity and on duration of egg production season, while an area >300 m2 showed a reduction in egg weight and day-old chick weight. Further, an area <100 m2 led to a weaker ostrich fertility rate. Results showed that the ostrich would have a better performance under hot and dry and mild and humid climates as compared to Alpine climate with a stocking density of 100-300 m2 area per breeder bird. Thus, climatic intervention strategies at Alpine regions may be carried out for maintaining optimal reproductive qualification of ostrich so as to improve the productivity in this sector.

Effect of Testosterone Administration and Spiking on Reproductive Success of Broiler Breeder Flocks.

Age negatively affects reproductive success of broiler breeder flocks. One of the main hormones involved in the change of fertility with the age is testosterone (TT). The introduction of young males at later production stages of broiler flocks is known as spiking and is expected to reduce the fertility decline with age. The aim of this study was to determine the effect of injection of different levels of TT and the effect of spiking on reproductive fitness of broiler breeder flocks. Two experiments were conducted on Ross 308 breeder flocks for 10 weeks (41-50 weeks of age). The experiment 1 included a control and three treatments corresponding to three doses of TT (0.1, 0.2 and 0.3 cc), while the experiment 2 included a control and one treatment corresponding to spiking. The lower dose of TT (0.1 cc) and the spiking clearly slowed down the decline in hatchability. Therefore, either the external administration of TT to the males when the natural concentration of TT starts to decline or spiking the breeder flock with young roosters could contribute to improve reproductive success in later stages of the production cycle in broiler breeder flocks.

Effects of dietary supplementation with astaxanthin and ß-carotene on the semen quality of goldfish (Carassius auratus).

This study was conducted to investigate the effects of two carotenoids (astaxanthin and ß-carotene) on the sperm quality of goldfish Carassius auratus (Linnaeus, 1758). For this purpose, six diets containing concentrations of 50, 100, and 150 mg/kg of synthetic astaxanthin and ß-carotene were added to a basic carp diet. One group of fish was also fed with a control diet (no added carotenoids). Osmolality, spermatocrit value, and sperm concentration significantly increased in the treatment supplemented with 150 mg/kg of astaxanthin (296.6 ± 1.1 mOsm/kg; 29.2 ± 0.6%; 17.2 ± 0.4 × 10(9) cells/mL, respectively) and ß-carotene (295.2 ± 2.1 mOsm/kg; 32.5 ± 1.6%; 17.9 ± 0.5 × 10(9) cells/mL, respectively). The highest concentration of astaxanthin (10.4 ± 1.4 mg/kg) was recorded in the treatment of A150 (P < 0.05) and did not differ between ß-carotene treatments. The highest motility was observed in the A150 and B150 treatments, and the lowest was observed in the control group (P < 0.05). The artificial fertilization of the treated males with the similar females (fed with the control diet) showed that the fertilization rate in the A150 treatments was higher than in the other treatments (P < 0.05). In conclusion, dietary supplementation with 150 mg/kg of astaxanthin improves osmolality, motility, fertilization rate, and sperm concentration.

Productivity of steers of different genotypes: forecast based on interior indicators / [Produtividade de novilhos de diferentes genótipos: previsão com base em indicadores internos]

Meat productivity and quality of beef are determined by a number of factors, including pedigree traits of animals. Meat productivity is closely related to the biological patterns of their growth and development. Considering the patterns that affect meat productivity enables effective growing and fattening of livestock and obtaining commercially viable beef. To predict economically useful traits in beef cattle breeding, interior indicators can be used, as they reflect the metabolic picture of the animal's body. The research studies in physiology and biochemistry of livestock aimed at revealing the persistent mechanisms of a growing animal organism make them relevant. The article identifies a correlation between the interior indicators and the fattening indicators of three experimental groups of steers. The main forecasting factors of meat productivity indicators have been substantiated. Regression coefficients have been found and show how much the live weight varies depending on the determining factors. Meat productivity predicting procedures have been modeled with respect to the protein content in blood serum.(AU)

A produtividade e a qualidade da carne bovina são determinadas por diversos fatores, incluindo características de pedigree dos animais. A produtividade da carne tem relação íntima com os padrões biológicos de seu crescimento e desenvolvimento. A consideração dos padrões que afetam a produtividade da carne possibilita o crescimento e engorda eficazes dos rebanhos e a obtenção de carne bovina comercialmente viável. Para prever características economicamente úteis na criação de gado de corte, indicadores de interior podem ser usados, visto que refletem a imagem metabólica do corpo do animal. Tornam-se relevantes os estudos de pesquisa em fisiologia e bioquímica da pecuária com o objetivo de revelar os mecanismos persistentes de um organismo animal em crescimento. O artigo identifica uma correlação entre os indicadores internos e os indicadores de engorda de três grupos experimentais de novilhos. Os principais fatores de previsão dos indicadores de produtividade de carnes já foram comprovados. Coeficientes de regressão foram encontrados e mostram o quanto o peso vivo varia em função dos fatores determinantes. Os procedimentos de predição da produtividade da carne foram modelados em relação ao conteúdo de proteína no soro sanguíneo.(AU)