Escores de cloaca e crista e morfometria testicular em galos de matriz pesada com 71 semanas de idade e três categorias de peso corporal

Abstract

In broiler breeder roosters, the weight of the testes is associated positively with daily sperm production and fertility. However, the avian testes are located into abdominal cavity, not being accessible to reproductive evaluation as mammalian testes. The reproductive evaluation of roosters is subjective and it is based on characteristics such as body weight (BW), quality of feet and legs and morphology of cloaca and comb. Scores of cloaca and comb and testicular morphometric parameters were evaluated in adult Cobb 500 Slow roosters of low (4.30kg), medium (between 4.30 and 5.25kg) and high (5.25kg) BW categories. The BW coefficient of variation was 12%. The high BW roosters have heavier testes and higher scores of cloaca and comb than the low BW roosters (P0.05). There was not statistical difference between the BW categories in gonadosomatic index, percentage of seminiferous tubule and interstitial tissue, diameter of the seminiferous tubule and height of the seminiferous epithelium. Positive, moderate and significantly correlation was found between testis weight and characteristics of BW, score of cloaca, score of comb, diameter of the seminiferous tubule and height of the seminiferous epithelium. 40% of roosters with <10g testes weight have 1 score of comb and/or 4 or 5 score of cloaca. One of six low BW roosters evaluated for histology of the testis had testicular atrophy. In Cobb 500 Slow roosters, it is conclude that the BW influences the weight and the histological quality of the testes. Besides, scores of cloaca and comb can be used with moderate potential of prediction to identify roosters with underweight testes.