ABSTRACT This study analyzed seasonal variations in the testes, the concentration of sex hormones, the parameters of fresh and thawed semen, and the sexual behavior of male Alpine goats from a temperate region in a tropical climate and possible interference with fertility. The maximum and minimum temperature and luminosity were recorded daily, while seminal, hormonal, and behavioral assessments were carried out every fortnight. The maximum and minimum temperature (°C) and luminosity (h) were recorded daily always at 17.00 h. The scrotal circumference (cm), testicular volume (mL), volume (mL), appearance (creamy, milky, aqueous) and coloration (white, white-yellowish, and yellowish) seminal, turbulence or mass movement (0 to 5), progressive spermatic motility (0 to 100%), spermatic force (0 to 5), concentration (spermatozoids/mL), spermatic pathologies, hypoosmotic test (%), serum levels of FSH (mUI/mL), LH (mUI/mL), testosterone (ng/mL), and sexual behaviors were carried out every fortnight. There was a difference between the scrotal circumference evaluated monthly, testicular volume, volume and concentration of fresh semen, sperm vigor of the thawed semen, serum levels of testosterone, FSH and LH, and some sexual behaviors. Thus, the changes that occur in the quantity and quality of sperm, in the hormonal profile, and in sexual behaviors should not be regarded as an impediment to the use of male Alpine goats in tropical climates throughout the year. These variations do not lead to changes in the semen that may compromise the fertility of these animals.

RESUMO Este estudo foi realizado para determinar a relação ideal de treonina:lisina digestíveis para poedeiras leves no período de 42 a 58 semanas de idade. Foram utilizadas 240 poedeiras Hy Line W-36 com 42 semanas de idade durante 16 semanas. Os tratamentos foram distribuídos em delineamento inteiramente casualizado, com oito repetições e seis aves por unidade experimental. As dietas experimentais foram formuladas com cinco níveis de treonina digestível (0,461; 0,515; 0,569; 0,622 e 0,676%) proporcionando as cinco relações treonina:lisina digestíveis (60; 67; 74; 81 e 88%) estudadas. As variáveis analisadas foram: produção de ovos; consumo de ração, de lisina e de treonina; massa e peso médio dos ovos; eficiências de utilização da lisina por massa e ovos produzidos; conversões alimentares por massa e dúzia de ovos; pesos médios de: gema, albúmen e de casca; ganho de peso; peso corporal final das aves; e balanço de nitrogênio. As relações treonina:lisina digestíveis na dieta não influenciaram as variáveis analisadas, exceto o consumo de treonina que apresentou efeito linear. A relação ideal de treonina:lisina digestíveis na dieta para galinhas poedeiras leves de 42 a 58 semanas de idade é de 60%, que corresponde ao nível de 0,461% de treonina digestível na dieta e ao consumo diário de treonina digestível de 446mg/ave.

SUMMARY This study was conducted to determine the ideal ratio of digestible threonine: lysine in diets for laying hens at 42 to 58 weeks of age. Two hundred forty Hy Line W-36 laying hens were used at 42 weeks of age for 16 weeks. The treatments were distributed in a completely randomized design with eight replicates and six birds each. The experimental diets were formulated with five levels of digestible threonine (0.461; 0.515; 0.569; 0.622 and 0.676%) providing the five ratio of digestible threonine: lysine (60; 67; 74; 81 and 88%) studied. The variables analyzed were: egg production; feed intake; lysine intake; threonine intake; mass egg; average egg weight; lysine use efficiencies by mass and produced eggs; feed conversion per mass and dozen eggs; Average weights yolk, albumen and shell; weight gain and final body weights of birds; and nitrogen balance. The digestible threonine: lysine ratio in the diet did not influence the analyzed variables except consumption of threonine which showed a linear effect. The ideal ratio of digestible threonine: lysine in diets for white laying hens at 42 to 58 weeks of age is 60%, which corresponds to the level of 0.461% of digestible threonine in the diet and daily intake of digestible threonine 446mg/bird.