Revista Colombiana de Ciencias Pecuarias

Ejaculate traits of ram lambs with different rectal temperatures under heat stress conditions

Jorge Humberto McCormick Palacios — 2024-12-06

Background: Heat stress reduces semen quality in rams. Objective: To evaluate the productive and reproductive responses of rams and ram lambs with different rectal temperatures under heat stress conditions. Methods: The animals (n = 12, Dorper × Katadhin × Pelibuey crossbreed, aged 235 to 730 days) were assigned to one of three experimental groups: ram lambs with low rectal temperature (RLLRT), ram lambs with high rectal temperature (RLHRT), and Rams. Results: Afternoon rectal temperatures were higher (p ≤ 0.05) in the RLHRT group, and there was no difference (p > 0.05) between the Rams and RLHRT groups. Ejaculate volume and sperm concentration were higher (p ≤ 0.05) in the Rams group than in the RLLRT and RLHRT groups. Mass motility and sperm concentration were lower (p ≤ 0.05) in the RLLRT group than in the RLHRT and Rams groups. Average daily weight gain did not differ (p > 0.05) between the RLLRT and RLHRT groups. Conclusion: The selection of ram lambs with low rectal temperature under heat stress conditions did not provide any benefit in terms of average daily weight gain or ejaculate traits.

Agronomic characteristics of Tamani grass under different defoliation frequencies and intensities

Francisco GS Alves — 2024-10-23

Antecedentes: Estratégias de manejo podem afetar o crescimento das plantas e as características da pastagem. Assim, o entendimento do impacto pode ajudar a definir manejos mais adequados. Objetivo: Avaliar o efeito de diferentes intensidades e frequências de desfolhamento sobre as características estruturais, os componentes da biomassa e o potencial de uso do NDVI (índice de vegetação de diferença normalizada) em pastagens com Megathyrsus maximus cv. BRS Tamani. Métodos: Adotou-se o delineamento de blocos casualizados em esquema fatorial 2 × 3, com duas frequências de desfolhamento (85 e 95% de interceptação da radiação fotossinteticamente ativa (IPAR)) e três intensidades de desfolhamento (índice de área foliar residual (LAIr) de 0,8, 1,3 e 1,8). Resultados: A frequência de desfolha afetou o índice de área foliar pré-desfolhamento, a altura, a biomassa forrageira total colhível (HTFB) e a lâmina foliar colhível (HGLB), com maiores valores para pastagens manejadas com 95% de IPAR. O efeito da intensidade de desfolha foi observado nas variáveis HTFB e HGLB, onde pastagens com menor LAIr apresentaram maiores valores de biomassa. As pastagens manejadas com 95% de IPAR e maior LAIr atingiram o nível de saturação do NDVI mais rapidamente. As pastagens manejadas com uma combinação de 95% de IPAR e LAIr de 0,8 apresentaram maior produção de biomassa de colmo verde e biomassa de forragem morta colhível. A combinação de 95% de IPAR com LAIr de 0,8 ou 1,8 possibilitou um maior número de novas folhas vivas quando comparado às pastagens com 85% de IPAR. Conclusões: O capim Tamani deve ser manejado com uma frequência de desfolhamento de 95% de interceptação da radiação fotossinteticamente ativa, mantendo um índice de área foliar residual entre 0,8 e 1,3.

Effect of feeding carrot flour on performance and profitability of broilers

Janeth Jácome Gómez — 2024-12-11

Background: The quality of chicken meat, essential for consumer satisfaction, is influenced by skin pigmentation. The lack of carotenoids in conventional diets has driven the search for costeffective alternatives to enhance these aspects in poultry production. Objective: This study assessed the impact of partially replacing commercial balanced feed with different levels of carrot flour (Daucus carota subsp. sativus) on productive parameters and the pigmentation of broiler chickens. Methods: Sixty-four Cobb 500 birds were randomly assigned to four experimental diets, each with eight replicates of two birds. The control group (T0) received a standard diet, while the experimental groups received a diet with 10% (T1), 15% (T2), and 20% (T3) replacement with carrot flour (CF). Variables such as feed consumption, weight gain, feed conversion, mortality, skin pigmentation, and profitability were evaluated. Results: Treatments with 15% and 20% CF resulted in significantly higher feed consumption (p < 0.05) compared to the control group. Although weight gain did not show significant differences between groups (p > 0.05), a trend towards higher gains was observed in the experimental groups. The feed conversion ratio increased non-significantly (p > 0.05) with higher CF concentrations. No mortality was observed in the experimental groups, whereas the control group had a mortality rate of 12.5%. Regarding pigmentation, CF influenced skin color as its concentration in the diet increased. In terms of profitability, the 15% replacement treatment stood out by generating higher income and a superior cost-benefit ratio. Conclusion: Orange cultivar CF can be a viable dietary source of natural pigment for broiler chickens. It may also be beneficial in promoting weight gain and reducing mortality, translating into economic advantages.