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High relative humidity and ambient temperature are one of the constrains to efficient thermoregulatory responses of rabbits in the tropics during the early-rainy season. The study investigated the effect of age on diurnal thermoregulatory responses in rectal (RT), ear (ET) and skin temperatures (ST) of rabbits during the early-rainy season. Seventeen apparently healthy rabbits were divided into three groups of 5 weaners, 6 growers and 6 adults. Physiologic parameters of RT, ET and ST of the rabbits were recorded concurrently with thermal environmental parameters of dry-bulb (DBT) and wet-bulb readings, at 07:00, 10:00, 13:00, 16:00 and 19:00 h, once per week for three weeks. Result revealed that RT, ET and ST were higher in adult compared to weaner or grower rabbits. The RT and ST were higher in adult than weaner rabbits at 13:00, 16:00 and 19:00 h. The ET was higher in adult than the weaner rabbits at 07:00 h. However, there was no significant (P > 0.05) difference in physiological parameters between the weaner and grower rabbits. The DBT positively correlated with ET in all age groups (Weaners r = 0.960, P < 0.01; Growers r = 0.975, P < 0.01; Adult r = 0.942, P < 0.05). The ST of weaner (r = 0.904; P < 0.05) and grower (r = 0.997; P < 0.01) rabbits positively correlated with DBT. It was concluded that there was age- dependent effect on diurnal thermoregulatory responses and RH negatively impacted on heat dissipation ability of the rabbits. It is recommended that adequate ventilation should be provided in rabbit house to reduce the negative impact of high RH on heat dissipation ability of rabbits during the early-rainy season. L'humidité relative élevée et la température ambiante sont l'une des contraintes aux réponses thermorégulatrices efficaces des lapins sous les tropiques pendant la saison des pluies. L'étude a étudié l'effet de l'âge sur les réponses thermorégulatrices diurnes dans les températures rectales (RT), de l'oreille (ET) et de la peau (ST) des lapins pendant la saison des pluies précoces. Dix-sept lapins apparemment en bonne santé ont été divisés en trois groupes de 5 sevrés, 6 cultivateurs et 6 adultes. Les paramètres physiologiques de RT, ET et ST des lapins ont été enregistrés en même temps que les paramètres environnementaux thermiques des lectures de bulbe sec (DBT) et d'ampoule humide, à 07:00, 10:00, 13:00, 16:00 et 19:00 h, une fois par semaine pendant trois semaines. Le résultat a révélé que rt, ET et ST étaient plus élevés chez les adultes par rapport aux lapins sevrés ou de producteur. Le RT et le ST étaient plus élevés chez les lapins adultes que chez les lapins sevrés à 13 h, 16 h et 19 h. L'ET était plus élevé chez les adultes que chez les lapins sevrés à 7 h. Cependant, il n'yavait aucune différence significative (P > 0.05) dans les paramètres physiologiques entre le sevreur et les lapins de producteur. Le DBT était en corrélation positive avec l'ET dans tous les groupes d'âge (Sevreurs r = 0.960, P < 0.01; Producteurs r = 0.975, P < 0.01; Adulte r = 0.942, P < 0.05). Le ST du sevreur (r = 0.904; P < 0.05) et producteur (r = 0.997; P < 0.01) lapins positivement corrélés avec DBT. On a conclu qu'il y avait un effet dépendant de l'âge sur les réponses thermorégulatrices diurnes et que l'HR avait un impact négatif sur la capacité de dissipation thermique des lapins. Il est recommandé d'assurer une ventilation adéquate dans la maison du lapin afin de réduire l'impact négatif d'une HR élevée sur la capacité de dissipation thermique des lapins pendant la saison des pluies

This study was conducted to evaluate the performance of two lines of broiler breeders under selection. The traits of interest were fertility, body weight and survival rate. A total of 120 day-old broiler chicks were hatched from two lines of broiler breeder chickens under selection (Sire and Dam lines). The chicks were hatched from a population of breeder hens and cocks with a mating ratio of 1 broiler cock to 6 broiler hens (1:6). Eggs were collected and pedigreed according to the lines and sire information. The eggs were weighed on a Camry model digital sensitive scale in grams. Eggs were set and hatched in a Buckeye incubator. Each hatched chick was tagged and weighed at hatching and then weekly up to 8 weeks. Data were analyzed using general linear model (GLM). Correlation and regression analysis were based on pooled data from both lines. Results showed that the lines differed with respect to fertility (67.67% and 83.00%), hatchability (77.79 and 49.00) and survival rate (77.78 and 94.14). Also changes in body weight increased as their ages increased with the dam line being superior. There was a low R2 value of between 0.05-0.33 when egg weight and hatch weight were pooled and considered as independent variables. In conclusion the lines were superior to each other differently as the sire line had better egg weight and hatchability while the dam line was better in fertility, survival rate and body weight performance. This variation in traits can be used in selection for hybrid strain in the broiler.

The study was conducted with the objective of evaluating the effect of egg size (small, medium and large) and lines on egg and hatch weight, fertility, hatchability, embryonic mortality and infertile eggs of broiler breeders under selection. A total of 120 broiler chicks were hatched from three different egg sizes (40 chicks per egg size as indicated) from breeder parents at 40 weeks of age. The broiler breeders were mated in a ratio of 1:6. Data obtained were subjected to analysis of variance in a complete randomized design. The result showed that significant (p