Circulating concentrations of thyroid hormones in pregnant camels (Camelus dromedarius )

Influence of seasonal variation on post-farrowing dysgalactia syndrome (PFDS) and serum biochemistry profiles in the periparturient sow

The objective of this study was to investigate the effect of seasonal variation on the frequency of post-farrowing dysgalactia syndrome (PFDS), sow body condition score (BCS), piglet survival, and weaning to estrus interval under intensive management systems. In addition, the effects of PFDS on litter characteristics and serum biochemistry, oxidative stress indices, thyroid, and cortisol profile were examined in order to identify potential biomarkers in the pre-farrowing stage. The study was conducted in summer and winter seasons in Nagaland, India, on 50 sows from 30 days before farrowing until weaning at 45 days. Sows were classified retrospectively into PFDS and non-PFDS. Although statistically, no significant difference was noted in the occurrence of PFDS between the seasons, the proportion of PFDS development was substantially higher in winter than summer (37.5 vs. 26.9%). In winter, the incidence of piglet stillbirth and sow weaning to estrus period was significantly higher (p < 0.05) and the mean litter size at weaning was significantly lower (p < 0.01). At weaning, the mean litter weight and average daily weight gain were decreased (p < 0.05) in both summer and winter, and the total number of piglets died in each litter was increased in sows afflicted with PFDS compared with healthy sows. A significant interaction effect of peripartum days and PFDS was observed in the changes of blood glucose, albumin (p < 0.05), and HDL-cholesterol (p = 0.07) concentration. Mean T₃ and T₄ concentration was influenced by peripartum days in both the season and a consistently lower T₃ concentration was detected in PFDS sows before farrowing. It is concluded that PFDS sows exhibited an increased incidence of stillbirth and scouring of neonatal piglets during the winter. A pronounced drop in mean circulating T₃ concentration in sows from 30 days before farrowing to 3 days after farrowing reflects endocrine-mediated metabolic dysfunction. Further research is warranted with more number of sows to identify the critical values of serum T₃ concentration in the immediate pre-farrowing period for prediction of sows developing PFDS after farrowing.

Pregnancy status and thyroid function in semi-intensive-kept Marecha she-camels (Camelus dromedarius): managerial implications

Pakistani Marecha dromedaries, a distinctive breed not covered in the empirical data of the literature reviewed existing for thyroidal physiology in camels, are subjected to investigate thyroid function in pregnant multiparous (n = 22) and non-pregnant nor lactating (n = 22) females. The function of the thyroid gland in pubescent she-camels has evoked discrepancies among researchers exploring this topic in different breeds evolving in divergent environments. Despite season, age, sex, reproductive status, health disorders, and stress are reported as potential modulating factors, these research studies failed to find statistically significant results supporting their hypothesis. For the current research, serum samples were obtained twice a week during one month from semi-intensive-kept Marecha she-camels and analyzed for triiodothyronine (T3) and thyroxine (T4) concentrations. Feed ingredients and additives were quality assessed to examine their nutrient profile, with special attention to protein content and exogenous calcium administration. Statistical differences in serum thyroid hormone levels were found between gravid and non-gravid females, being pregnant she-camels the subgroup with higher levels (P < 0.05). The genetic background of such phenotypic variability in thyroid metabolism in camels has to be further addressed to adapt husbandry practices for breed-specific requirements. Meanwhile, local management strategies are susceptible of accurate routines for sustainable farming.

Dromedary camel: A model of heat resistant livestock animal

Camels are highly adapted to harsh environments. The dromedary camel is adapted to a wide range of arid and semi-arid conditions. The aim of the present paper is to review some of the key adaptation characteristics of the dromedary and how they affect reproductive patterns. Special attention is given to the reproductive seasonality and interaction between lactation and reproduction. Adaptive mechanisms are described including some of the recent molecular aspects with respect to heat shock protein expression in camels.

Lipid profile and thyroid hormone status in the last trimester of pregnancy in single-humped camels (Camelus dromedarius)

Changes in lipid metabolism have been shown to occur during pregnancy. The thyroid hormones affect lipid metabolism. The present study was carried out to find out whether the last trimester of pregnancy affects thyroid hormones, thyroid-stimulating hormone (TSH), lipid, and lipoprotein profile in healthy dromedary camels. Twenty clinical healthy dromedary camels aged between 4-5 years were divided into two equal groups: (1) pregnant camels in their last trimester of pregnancy and (2) non-pregnant age-matched controls. Thyroid function tests were carried out by measuring serum levels of TSH, free thyroxin (fT4), total thyroxin (T4), free triiodothyronine (fT3), and total triiodothyronine (T3) by commercially available radio immunoassay kits. Total cholesterol (TC), triglyceride (TG), and high-density lipoprotein (HDL) cholesterol were analyzed using enzymatic/spectrophotometric methods while low-density lipoprotein (LDL) cholesterol, very low-density lipoprotein (VLDL), and total lipid (TL) were calculated using Friedewald's and Raylander's formula, respectively. Serum levels of TSH and thyroid hormones except fT4 did not show any significant difference between pregnant and non-pregnant camels. fT4 level was lower in the pregnant camels (P < 0.05). Serum levels of total cholesterol, triglyceride, total lipid, LDL cholesterol, HDL cholesterol, and VLDL did not show significant difference between pregnant and non-pregnant camels. All of these variables in pregnant camels were higher than non-pregnant. Based on the results of this study, the fetus load may not alter the thyroid status of the camel and the concentrations of thyroid hormones were not correlated with TSH and lipid profile levels in the healthy pregnant camels.

Use of real-time ultrasonography for control of follicular activity and pregnancy diagnosis in the one humped camel (Camelus dromedarius) during the non-breeding season

Ovaries of 16 adult pleuriparous, non-pregnant and non-lactating one humped female camels (Camelus dromedarius) belonging to National Research Centre on Camel, at Bikaner, India, were examined for the presence of follicular activity (< or = 0.5 cm diameter) using real-time ultrasonography during June-August, which is considered to be non-breeding season in India. Follicles > or = 1.0 cm diameter were found in eight females. These animals were mated with virile studs. In four out of eight camels pregnancy was confirmed by progesterone assay and ultrasonography. The study shows that pre-ovulatory follicle may develop in some female camels during June-August (non-breeding season in India) and successful pregnancies may be achieved after mating of individual animals during this period.

Hormonal studies in postpartum female camels and their neonates

The expulsion of the fetus from the mother at parturition necessitates reorganization of the endocrine status in both individuals. In this study, the patterns of hormonal changes were investigated in postpartum Dromedary camels and their neonates. Blood samples were recovered within a few hours after calving from 10 female Dromedary camels and their calves, and sampling was continued at varying intervals upto Day 21 post partum. Sera were assayed for progesterone, cortisol and thyroid hormone concentrations by specific radioimmunoassays. Progesterone concentrations in the dams varied between 0.5 and 2.0 ng/ml on the day of calving and declined steadily thereafter to become undetectable by Day 9; progesterone remained undetectable in the neonates. Cortisol concentrations were high (25 to 30 ng/ml) at parturition in both the dams and their calves. They declined to 6 to 7 ng/ml in the dams, but became undetectable in the neonates by Day 14 post partum. The thyroid hormones were low in the dams (T4=70; T3=1.6 ng/ml) on Day 1 post partum but then increased gradually to Day 21 (T4=110; T3=2.2 ng/ml). In contrast, thyroid hormone concentrations in the neonates were 4 to 5 times higher than those of their mothers at birth. They declined thereafter but nevertheless remained at almost double the concentrations found in the dams.