V.K. Agarwal

Changes in profiles of serum sex steroids of male buffaloes from birth to maturity

Age-related changes in testosterone, progesterone and estradiol 17-beta were determined by radioimmunoassay (RIA) in the serum of 155 male buffalo calves of varying ages. The calves were classified into 17 age groups. The mean weight of calves increased from 33.6+/-9.6 kg at one week of age to 531+/-41.4 kg at 42 months. The testosterone levels were less than 100 pg/ml from birth until 15 months of age, followed by peak concentrations of 422+/-79 pg/ml at 24 to 30 months and 793+/-193 pg/ml at 42 to 48 months (corresponding to puberty and maturity, respectively). The progesterone levels were higher in newly born calves and mature bulls. Otherwise, the levels continued to be low throughout the period of growth and development. Estradiol 17-beta was significantly higher in postnatal calves up to two months of age. The testosterone revealed a positive correlation with weight and age while E2 17-beta showed a negative correlation with age. These results do not support a direct role of peripheral progesterone and estradiol 17-beta in the onset of puberty and sexual maturity of buffalo bulls.

Circulating levels of estrogen and progesterone in female camel (Camelusdromedarius) during pregnancy

Abstract Monthly blood samples from 16 pregnant camel were collected commencing from 60 d post service until the last month of gestation. Two animals aborted and two did not conceive. The average length of gestation was 398 ± 13 and 372 ± 11 d in camels carrying male and female fetus, respectively, with a mean of 383 ± 9 d. Sera were analysed for estradiol-17 beta and progesterone by radioimmunoassay. The mean estradiol levels increased progressively from a basal level of 20 pg/ml at 2 to 3 mo of pregnancy to about 450 pg/ml at the final stages of gestation. The camel bearing a male fetus had relatively lower estradiol concentrations (76.5 ± 10.8 pg/ml) as compared to those carrying a female fetus (112.3 ± 19.6 pg/ml). The mean progesterone levels fluctuated between 4 and 5 ng/ml throughout pregnancy except for a slightly lower value (2.5 ± 0.27) at 9 to 10 mo of gestation. On an average, the camels carrying a male fetus had higher progesterone levels (5.13 ± 0.69 ng/ml) than those carrying a female fetus (3.45 ± 0.28). The data suggested that the steroid hormone levels are influenced by the stage of pregnancy and sex of the fetus. Cases of unnoticed abortion and unsuccessful conception could be identified.

A twenty-four hour temporal variation in peripheral levels of testosterone and thyroid hormones in male buffaloes.

Hourly serum samples from four adult Murrah buffalo bulls of 5 to 6 years of age were analysed for testosterone, thyroxine and triiodothyronine by radioimmunoassay during a period of 24 hours. All four bulls exhibited three episodic peaks for testosterone with some variation in the time, duration and peak concentration of the hormone. The average testosterone concentration varied from 0.30 to 3.50 ng/ml of serum. Thyroxine levels varied from 20 to 40 ng/ml of serum among the four bulls. One clear-cut peak was observed between 2 and 5 a.m. in three of the four bulls. One animal showed a characteristic peak at 10 p.m. Triiodothyronine levels ranged from 1 to 2 ng/ml of serum and followed a similar trend as that of thyroxine except for an additional small peak between 6 and 9 p.m.

CIRCULATING CONCENTRATIONS OF THYROID HORMONES IN PREGNANT CAMELS (Camelus dromedarius)

Blood samples from 16 female camels were collected at monthly intervals commencing from 60 d post. breeding until the last month of gestation. Two camels failed to conceive and two had unnoticed abortions. The average gestation period was 398+/-13 and 372+/-11 in camels bearing male and female fetus, respectively, with an overall mean of 383+/-9 d. Sera were analyzed for thyroxine (T(4)) and triiodothyronine (T(3)) by radioimmunoassay. Mean T(4) and T(3) concentrations varied from 76 to 116 ng/ml and 0.73 to 1.32 ng/ml, respectively, during various stages of gestation. In general, the T(4) and T(3) levels were higher during early pregnancy, with lowest values in the tenth month. T(4):T(3) ratio showed minor, nonsignificant fluctuations. Age of dam of sex of fetus had no effect on hormone levels. Similarly, hormone levels were not affected by failure of conception or by abortion.

Seasonal variation in serum levels of steroid hormones and their relation with seminal quality and libido in buffalo bulls.

Blood samples from 15 breeding male Murrah buffaloes were collected during the winter, summer and monsoon seasons. Seminal characteristics and sexual behaviour were also studied. Serum samples were analysed for testosterone, progesterone and estradiol-17beta levels by radioimmunoassay. The studies showed significantly lower values for testosterone during winter (0.53 +/- 0.06 ng/ml) than during summer (1.22 +/- 0.19 ng/ml) and monsoon (1.06 +/- 0.12 ng/ml). The progesterone level was lowest during monsoon (84 +/- 9 pg/ml), intermediate during winter (115 +/- 14 pg/ml) and highest during summer (224 +/- 24 pg/ml). The mean level of estradiol-17beta was almost double (9 +/- 0.7 pg/ml) during monsoon as compared to winter (5 +/- 0.1 pg/ml). The correlations between hormone levels, seminal characteristics and sexual behaviour were of low magnitude.

Serum thyroid hormone levels in male buffalo calves as related to age and sexual development

A total of 155 male buffalo calves were classified into 17 groups according to chronological age. The body weight was recorded on a balance or computed. Sera samples were analysed for thyroxine (T(4)) and triiodothyronine (T(3)) by radioimmunoassay. Highest concentration of thyroid hormones (T(4), 87.6+/-17.6; T(3), 3.1+/-0.07 ng/ml) were seen during the first week after birth followed by a gradual decline until two months of age. Later, the mean T(4) and T(3) levels fluctuated between 30 and 40 ng/ml and at around 1.0 ng/ml, respectively, except for a mild peak at 12 to 15 months of age. T4:T3 ratio did not vary significantly among various age groups. Both T4 and T3 were negatively correlated with age.