ABSTRACT
Native sheep breeds have satisfactory reproductive activity throughout the year, but nutritional and climatic factors such as high temperature during the dry period can affect the semen quality, causing a decrease in sperm motility and an increase in the percentage of morphologically abnormal sperm. To protect itself against the deleterious effect of high temperature, the testicle has a complex mechanism of thermoregulation sites. The scrotal skin has an important function in the maintenance of testicular temperature, since it is thin, poor in subcutaneous fat, relatively hairless and has a well-developed blood and lymphatic system, facilitating thermal loss by radiation and evaporation. This study aimed to evaluate the effect of scrotal temperature on sperm quality in Morada Nova sheep. Temperature was measured with a laser thermometer and three classes of average testicular temperature were established: class 1 = 28ºC to 31ºC, class 2 = 31.01ºC to 33ºC and class 3 = >33ºC. The ejaculate of each animal was collected using an artificial vagina for further evaluation of volume, aspect, whirling, motility and sperm vigor. Then the sperm concentration and morphology were determined by examination of moist slides. Means were compared by the t-test and chi-square test using the SAS software (SAS Inst., Inc., Cary, NC). There was no difference (P>0.05) for whirling (3.42±1.08%)
O artigo não possui resumo em português.
ABSTRACT
Native sheep breeds have satisfactory reproductive activity throughout the year, but nutritional and climatic factors such as high temperature during the dry period can affect the semen quality, causing a decrease in sperm motility and an increase in the percentage of morphologically abnormal sperm. To protect itself against the deleterious effect of high temperature, the testicle has a complex mechanism of thermoregulation sites. The scrotal skin has an important function in the maintenance of testicular temperature, since it is thin, poor in subcutaneous fat, relatively hairless and has a well-developed blood and lymphatic system, facilitating thermal loss by radiation and evaporation. This study aimed to evaluate the effect of scrotal temperature on sperm quality in Morada Nova sheep. Temperature was measured with a laser thermometer and three classes of average testicular temperature were established: class 1 = 28ºC to 31ºC, class 2 = 31.01ºC to 33ºC and class 3 = >33ºC. The ejaculate of each animal was collected using an artificial vagina for further evaluation of volume, aspect, whirling, motility and sperm vigor. Then the sperm concentration and morphology were determined by examination of moist slides. Means were compared by the t-test and chi-square test using the SAS software (SAS Inst., Inc., Cary, NC). There was no difference (P>0.05) for whirling (3.42±1.08%)
O artigo não possui resumo em português.
ABSTRACT
One of the main characteristics to evaluate in selective breeding is semen quality. However, factors related to the animal itself, such as age, and the environment can influence reproductive traits. Good semen quality assures a faster return on investment in sheep farming by allowing better selection of males used as breeding stock to enhance reproductive efficiency of the herd, since males with good sexual performance and high fertility probably will beget a greater number of ewes in a shorter period of time. This study aimed to evaluate the effect of age on the semen quality of rams of the Morada Nova breed. The experiment was conducted at the Instituto de Zootecnia de Nova Odessa in São Paulo state, Brazil, in the period from March to May 2014. Twenty-four rams were used for monthly evaluation, with ages of 18±2 (n = 12) and 30±2 months (n = 12). The ejaculate from each animal was collected with an artificial vagina with the aid of a female in estrus, for further evaluation as to the volume, aspect, whirling, motility and sperm vigor. Then the sperm concentration and morphology were determined in wet slides. Means were compared by the t-test and chi-square test using the SAS software (SAS Inst., Inc., Cary, NC). There was no difference (P>0.05) for volume, concentration/mL, total concentration, coiled tails, decapitation and distal protoplasmic droplets. The variables whi
O artigo não possui resumo em português.
ABSTRACT
One of the main characteristics to evaluate in selective breeding is semen quality. However, factors related to the animal itself, such as age, and the environment can influence reproductive traits. Good semen quality assures a faster return on investment in sheep farming by allowing better selection of males used as breeding stock to enhance reproductive efficiency of the herd, since males with good sexual performance and high fertility probably will beget a greater number of ewes in a shorter period of time. This study aimed to evaluate the effect of age on the semen quality of rams of the Morada Nova breed. The experiment was conducted at the Instituto de Zootecnia de Nova Odessa in São Paulo state, Brazil, in the period from March to May 2014. Twenty-four rams were used for monthly evaluation, with ages of 18±2 (n = 12) and 30±2 months (n = 12). The ejaculate from each animal was collected with an artificial vagina with the aid of a female in estrus, for further evaluation as to the volume, aspect, whirling, motility and sperm vigor. Then the sperm concentration and morphology were determined in wet slides. Means were compared by the t-test and chi-square test using the SAS software (SAS Inst., Inc., Cary, NC). There was no difference (P>0.05) for volume, concentration/mL, total concentration, coiled tails, decapitation and distal protoplasmic droplets. The variables whi
O artigo não possui resumo em português.