Comparisons of Serum Somatotropin, 3,5,3′-Triiodothyronine, Thyroxine, Total Protein and Free Fatty Acid Levels in Newborn Sakiz Lambs Separated from or Suckling Their Dams

Abstract

Objective: To determine the effects on serum somatotropin, 3,5,3′-triiodothyronine (T₃), thyroxine (T₄), free fatty acids (FFAs) and total protein levels of different feedings and age in Sakiz sheep that have a high twin-bearing rate supported by estrous synchronization. Methods: 20 newborn lambs were used in the study. Lambs were divided into 2 equal groups. The lambs in 1 group were separated from their dams following parturition, and those in other group were kept together with their dams. Separated lambs were fed commercial cow’s milk for 2.5 weeks. After that, they were fed a milk substitute, hay and concentrated supplement for 2 months, and from the end of the 2 months they were fed hay and concentrated supplement. The lambs in other group were kept together with their dams only during the day and in addition were fed hay and concentrated supplement. After 2 months, they were maintained feeding only on hay and concentrated supplement. Blood samples were taken from vena jugularis of lambs at 12 and 24–48 h, and 14, 28, 42 and 56–90 days after parturition. Serum samples were analyzed for somatotropin by enzyme immunoassay, for T₃ and T₄ by radioimmunoassay, and for total protein and FFA by a spectrophotometric method. Results: Serum somatotropin levels were insignificantly different between the lambs with and without their dams. Serum T₃ levels were generally lower in the separated lambs than those in other group. Serum T₄ levels were significantly lower in the separated lambs 48 h and 90 days after parturition than those in other group. Serum FFAs were insignificantly different between 2 groups. Serum total protein concentrations were lower in the separated lambs than lambs kept together with their dams (significantly at 12 and 48 h and 14 days). Conclusion: Ingestion of colostrum and dam milk markedly affected serum total protein levels, but body weight and serum somatotropin levels were insignificantly affected. Also serum T₃ and T₄ levels markedly decreased with advancing age. Serum FFA levels were not affected by the trial.

Age‐related changes in thyroid hormones, some serum oxidative biomarkers and trace elements and their relationships in healthy Saanen goat kids during the first three month of age

“…Throughout the study, T4 was above ARI, while T3 concentration reached to the level of ARI at the end of the third month of life. These observations were in accordance with the results obtained in buffaloes (Pandita et al, 2016), calves (Medica et al, 2020; Paulíková et al, 2011; Rowntree et al, 2004), lambs (Firat et al, 2005; Novoselec et al, 2009) and foals (Malinowski et al, 1996). Although the age‐related decreasing trend of thyroid hormones has also been reported in goats (Igbokwe & Ezeasor, 2017; Nazifi et al, 2002; Panday et al, 2014), these reports had compared the serum level of thyroid hormones in different age groups including kids, juveniles and adult goats.…”

“…Since colostrum contains higher level of lipids, protein and energy compared to milk (Rauprich et al, 2000), concentrations of T4 and T3 are higher at birth. This downward trend can also be associated with increased growth rate and subsequent increase in hormone metabolism (Fırat et al, 2005).…”

“…The thyroid activity begins in the prenatal period and towards the end of gestation, the foetal concentrations of thyroid hormones gradually rise (Igbokwe & Ezeasor, 2017). Previously, the high level of thyroid hormones has been reported in neonates calves, buffalos, lambs and goat kids (Eshratkhah et al, 2010; Fırat et al, 2005; Medica et al, 2020; Pandey et al, 2014; Pandita et al, 2016), which can be attributed to their higher growth rate and the initiation of thermogenesis (Schmaltz, 2012). Thyroid hormones are essential for acquisition and maintenance of passive immunity in neonates.…”

Morphological and functional events associated to weaning in rabbits

“…In early weaned rabbits, they were substantially reduced 7 days after the weaning, whereas in those weaned at 35 days of age, such differences were not observed. Similar tendencies were reported in lambs, separated from dams immediately after birth and fed cow milk – significant reduction in blood T4 (as early as the 48th hour) and total protein (by the 12th day) vs. control lambs (Firat et al., ). In our experiments, mean blood T3 levels were statistically significantly higher in normally weaned vs. early weaned rabbits.…”