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.

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.

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.

Cholinesterase activity in Thysaniezia giardi (Cestoda, Anoplocephalidae).

The activity of cholinesterase was determined separately in the mature and gravid proglottids of Thysaniezia giardi and its significance is discussed. The mean values of the enzyme in mature and gravid proglottids were respectively 225.60 +/- 28.55 and 75.00 +/- 11.64 units per gram of wet weight.

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

Blood samples from 15 Murrah buffalo bulls, (10- to 15- years-old) were collected during the summer, monsoon and winter seasons. The serum samples were analysed for thyroxine (T4) and triiodothyronine (T3) by RIA. Semen samples from these bulls were evaluated for various attributes. Sexual behaviour of these bulls was also recorded during the different seasons and was expressed as reaction time and refusal response. T4, T3, (T4 + T3) level and T4:T3 ratio did not reveal significant difference between seasons. Similarly, seminal characteristics did not exhibit any seasonal variation except for the percentage of live spermatozoa. However, the refusal response (no interest in mounting and ejaculating) was highest during summer months. T4 was significantly correlated to T(3) (r=0.53). Overall, T4 showed a positive correlation with seminal volume and initial motility while T3 exhibited a positive correlation with total sperm concentration and percentage of live spermatozoa. T3 was negatively correlated with refusal response only during the monsoon season. Correlation with other seminal and behavioural characteristics were not significant. The results indicated that although the sexual interest of buffalo bulls is reduced during the summer, the bulls can produce semen throughout the year under appropriate feeding and management conditions.

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.

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.

Relationship of serum guanase levels with economic characters in Zebu purebred and temperate x Zebu crossbred dairy cattle.

Serum guanase levels of Indian Zebu (Hariana) cattle and its crosses with different exotic levels of temperate breeds of dairy cattle were estimated in 527 animals, and their associations with economic characters were determined. The overall mean value of serum guanase level was 13.46 +/- 0.45 IU/ml of serum. An inverse relationship between the concentration of the enzyme and the frequency of cattle falling within a definite range was observed, as over 75% of the animals possessed 1 to 20 IU/ml of serum guanase. An analysis of variance revealed significant differences (P less than 0.01) in enzyme levels among different genetic groups under study. Hariana (Zebu) purebreds had significantly higher enzyme levels (19.60 +/- 1.85) than any of the crossbred groups, whose enzyme levels ranged from 8.99 +/- 1.41 in Red Dane F1 half-breds to 14.30 +/- 1.11 in Brown Swiss F1 half-breds. The correlation and regression coefficients were significantly positive for reproductive traits such as age at first service and age at first calving, and significantly negative for production traits such as lactation yield and lactation length. These results suggest that selection of dairy cattle based on low serum guanase levels might result in correlated improvements in dairy cattle productivity.

Plasma monoamine oxidase levels in mammals.

Plasma monoamine oxidase (MAO) levels in ruminants and non-ruminants including man are reported. The mean MAO levels in units are, goat 6699.7+/-367.4; cattle 6272.9+/-9.257.4; camel 5166.0+/-666.8; sheep 4831.4+/-543.8; buffaloe 4045.8+/-387.3; rabbit 837.0+/-19.3; dog 441.8+/-55.5 and man 20.0+/-2.8 respectively.