Biometry and Testicular Growth Influenced by Nutrition on Prepubertal Pelibuey Lambs (original) (raw)
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TURKISH JOURNAL OF VETERINARY AND ANIMAL SCIENCES, 2016
The aim of this study was to investigate changes of serum testosterone, scrotal circumference, body weight, and semen characteristics in a Meat Institute Sheep (MIS) population during their developing period (between 3 and 17 months). Correlative relationships among parameters were also tested. Body weight and scrotal circumference were measured monthly, blood samples for testosterone levels were taken bimonthly (3-17 months), and semen samples were collected by an electroejaculator between the ages of 9 and 17 months. The analysis showed that the average serum testosterone levels ranged from 1.83 to 13.28 ng/mL and significantly depended on the age of the lambs (P < 0.05). The trend in the level of serum testosterone was characterized by pronounced variability throughout the study period. Changes in scrotal circumference and body weight were significantly dependent on age. Ejaculate volume, sperm motility, and the percentage of live spermatozoa increased with age, except for the percentage of abnormal spermatozoa, which decreased with age. Correlations among serum testosterone, scrotal circumference, and body weight were moderately to highly positive and highly significant. All parameters of semen quality were poorly correlated with testosterone and body weight, while scrotal circumference was in moderate correlation only with ejaculate volume and live sperm count (P < 0.05).
Postnatal testicular development and testosterone changes in Ghezel ram lambs
This study was conducted to investigate the histological structure of testis and hormonal changes during prepubertal Ghezel ram lambs. Histometrical evaluation of the testis was performed in 36 Ghezel lambs from one to 9 months of age. Lambs were allotted into nine groups, and surgically castrated each month from 1 to 9 months of age (n = 4 lambs per group). In addition, blood samples were taken from six animals from 1 month of age to adulthood to measure plasma levels of testosterone. With the age held constant, scrotal circumference and body weight were correlated (r = 0.960, P < 0.01). The sex cords did not have lumen up to the age of 4 months and lumenization process was completed after 8 months of age. A dramatic increase in spermatogonia cells per cross-section of seminiferous tubule was observed from 3 to 5 months of age; their number per tubule cross-section stabilized after 8 months. Spermatogenesis started when the spermatocyte cells were observed at the 4th month, and established at 8 months of age (body weight = 42.39 kg, scrotal circumference = 25.8 cm). Onset of puberty was observed to be established at 8 months of age when spermatozoa, adhered to the adluminal border of the Sertoli cells as well as in the tubular lumen. Leydig cells were visible in 4-month-old lambs. During the 5 months after birth, Leydig cell number showed a similar pattern as that observed for testosterone plasma levels. At 8–9 months of age the testosterone plasma level reached up to 2 ng/ml which contributed to the increase in testicular testosterone secreting capacity of the mature adult Leydig cells, with the accomplishment of this transition, sexual puberty is completed. It can be concluded that establishment of spermatogenesis begins a long time before puberty in 8 month-old Ghezel lambs.
South African Journal of Animal Science, 2007
The study was conducted to measure the development of several testicular characteristics and to investigate the relationship between testicular parameters with body growth, semen characteristics and serum testosterone levels in growing ram lambs. Seventeen single born Kivircik ram lambs from three to four year old ewes were used. When the rams were two months old measurements of the length, diameter and circumference of their testes and body weights started, and blood samples were collected at 20-day intervals for the next 12 months. From seven to 14 months of age semen was collected at monthly intervals. There was a gradual and linear increase in testicular dimensions from two to 11 months of age. A rapid increase in all testicular dimensions was observed between 140 to 160 days of age. All measurements of testes, live weight, age and serum testosterone concentrations were positively and significantly correlated with each other. While a significant positive correlation was found at seven and eight months of age between all testicular measurements and semen volume and motility, no such correlations were observed between nine and 14 months of age. From seven to 14 months of age no correlation was measured between serum testosterone concentrations and spermatological characteristics. These results demonstrated that testicular measurements, especially scrotal circumference, can be used as criteria for early selection of ram lambs to be used in breeding at relatively young ages.
Indian Journal of Animal Research
The present work was conducted to elucidate the relationships between chronological age, testosterone concentration and testis size of Najdi and Naemi ram lambs under desert conditions to determine the reproductive capacity of the above two breeds. The postnatal development of the seminiferous epithelium of the testes was also monitored. A total of 90 (45 Najdi and 45 Naemi lambs) aged between one and nine months, with five lambs at each month of age for each breed were used. The results showed that the testosterone concentration increased dramatically and rapidly between five and six months, followed by a period of gradual growth where testicular size was increased from 3 to 6 months of age. There was a significant (P > 0.05) difference in testosterone concentration (TC) and testis size (TS) in ram lambs between different age groups, similarly there were significant differences between body weights and lamb age between one and nine months. A positive correlation between the incr...
Small Ruminant Research, 2001
The aim of the experiment was to determine whether supplementation of the lamb-ewe unit during intra-uterine and postnatal life affects testicular stereology, particularly Sertoli cell numbers, in 120 pregnant Corriedale ewes grazed either native pastures (control group) or improved pastures grain supplement (treated group). Ewes bearing single ram lambs were maintained under the same feeding regime until lambs were castrated (99 days of age). Body weight, testosterone and FSH blood serum levels were recorded at 45, 75 and 99 days of age. Body weight was higher (P`0X01) in the treated group from birth on. Serum testosterone values did not differ between groups. Serum FSH values tended to differ at 45 days of age (P`0X06). Testicular weight and testes histology showed earlier pubertal development and a tendency for higher Sertoli cell numbers in the treated (supplemented) group. This tendency may indicate that extensively reared lambs supplemented during fetal and postnatal life have higher testicular growth and sperm production in later life. #
Small Ruminant Research, 2001
Ninety-six Awassi ram lambs, aged 2±3 months, raised and managed under a semi intensive system were used to measure development of testicular length, width, circumference and volume, and their association with development of body growth. The effects of parental size, age and body weight of lambs, production line (dairy or meat), type of birth and weight at birth and weaning on development of the four testicular parameters from weaning at 2±17 months of age were investigated. No signi®cant differences were observed between measurements of the left and right testis. The highest increase in testicular parameters occurred between 7 and 10 months of age at 34.6 kg live body weight. Only parental size, age and body weight affected testicular growth (P`0X05). Measurements of testes were correlated (P`0X01) with each other (r 0X68±0.97). They increased progressively and were correlated with body weight more than with age.
Veterinary World, 2018
Aim: The aim of the present study was to define the onset of puberty in Tazegzawt ram lambs, an Algerian sheep breed in endangered status with a small population in its local area. Materials and Methods: Body growth (body weight and thoracic perimeter), scrotal circumference (SC), penis development stages, and seminal parameters (volume, concentration, and motility) were measured. Data were recorded at fortnightly intervals in 10 animals from 9 to 49 weeks of age. Results: On the basis of seminal analyses, puberty occurred between 29 and 45 weeks of age. At 29 weeks of age, 30% of lambs reached puberty, and at 45 weeks of age, puberty was observed in 100% of the analyzed animals. Body weight appeared as the most determinant factor, and the onset of puberty was observed when animals reached 43.2±6.4 kg body weight with 25.8±3.7 cm of SC. Seminal analyses revealed that all parameters increased regularly from puberty onset except for sperm concentration. The mean semen volume during the study period was 0.48±0.33 mL with 0.84±0.6 mL at 37 weeks of age. Sperm concentration evolved similarly as semen volume; at 29 and 43 weeks of age, the sperm concentration was 942×10 6 and 1904×10 6 spermatozoa/mL, respectively. Kinematic parameters including the percentage of motility, the percentage of progressive motility, and gametes velocities as determined by Computer-Aided Sperm Analyzer showed the highest values at 49 weeks of age. Conclusion: The current results revealed that, in Tazegzawt ram lambs, puberty occurs between 29 and 45 weeks when animals reach 43.2±4.6 kg body weight.
Czech Journal of Animal Science, 2005
Forty-seven Kivircik ram lambs, aged 2 months, raised and managed under an intensive system were used to measure the development of testis diameter and length, and scrotum circumference, length and volume, and their association with the development of body growth. The effects of age and body weight of lambs, type of birth and dam age on the development of the five testicular parameters from weaning at 2-6 months of age were investigated. In ram lambs, the respective least-squares means of testis measurements: testis diameter,
Reproduction, 1994
The effects of nutrition on the hypothalamo\p=n-\pituitary\p=n-\gonadal axis were studied in three groups of six mature Merino rams that were fed for 56 days with a ration that maintained their initial live mass (intermediate diet: 675 g chaff plus 175 g lupins), the same ration with a lupin supplement (high diet: 675 g chaff plus 825 g lupins), or about half of the intermediate ration (low diet: 475 g chaff plus 125 g lupins). Lupin seed provides a highly (95%) digestible source of energy and protein. Plasma concentrations of LH, FSH, testosterone and inhibin were measured in blood samples collected over 24 h on the day before dietary treatments began (day \m=-\1), then on days 0, 1, 5, 14, 28 and 56. Compared with the intermediate diet, the high diet significantly increased live mass within 14 days and testicular size within 28 days, and these differences increased steadily throughout the experiment. Plasma FSH concentrations and LH pulse frequency increased within 5 days, but these effects were maintained for only 14 days. Decreasing the nutritional status reduced live mass and testicular size within 7 days, led to a low LH pulse frequency that persisted throughout the experiment, but did not affect FSH concentrations. Significantly less testosterone was secreted over 24 h in the low dietary group than in the intermediate or high group until day 28. The high group tended to secrete more than the intermediate group, but only at the beginning of the experiment when LH pulse frequencies differed between these groups. The testosterone response to each endogenous LH pulse, or following an injection of ovine LH i.v. (200 ng kg \m=-\1live mass), was not related to testicular size or dietary treatment at any stage of the experiment. Similarly, plasma inhibin concentrations were not related to change of diet, despite large differences in testicular size. We concluded that the effects of nutritional status on testicular size in mature rams are at least partly mediated through changes in gonadotrophin secretion. Both increases and decreases in food supply affected LH pulse frequency, suggesting the involvement of hypothalamic mechanisms. However, the lack of an effect of a decrease in nutritional status on the secretion of FSH and inhibin and the inconsistent long-term relationship between LH pulse frequency and testicular size suggest that the effects of diet on testicular growth also involve mechanisms that are independent of changes in gonadotrophin secretion.
Developmental changes in testicular interstitium in the Najdi Ram Lambs
Saudi journal of biological sciences, 2014
This experiment was designed to study the relationship between growth rate and sexual development in Najdi ram lambs. Forty-five Najdi ram lambs were used in nine age groups (1-9th month age), keeping 5 lambs in each group. Results show that mean testis size and scrotal circumference increased at a constant rate, reaching a maximum value of 392.00 ± 2.00 g and 25.00 ± 0.32 cm respectively, at the age of 9 months. A similar trend of growth was observed for the mean body weight, reaching a maximum value of 40.2 ± 0.20 kg at the age of 9 months. There was a positive correlation between the increasing rates of body weight and size of the testis. There were significant differences (P < 0.05) in testis size, scrotal circumference and body weight of lambs between all ages (1-9 months). The histological section of testis showed that a small number of mature sperms appeared in the eighth month of age and their numbers increased in the ninth month. In conclusion, the current findings indic...