Effects of Seasonal and Physiological Variations on the Serum Chemistry, Vitamins and Thyroid Hormone Concentrations in Sheep

Abstract

The aim of this study was to investigate the possible effects of the reproductive status and seasonal variations on the serum chemistry and vitamin status and their relationships with the thyroid hormones in Sakiz-Awassi crossbreed sheep. The sheep (n = 34) were divided into two groups. The first group (n = 22) was mated; the second group (n = 12) was not mated. Their serum samples were collected four times a year at the each season and under reproductive status. The periods are 1, early pregnancy (October); 2, late pregnancy (January); 3, lactation (April); and 4, dry season (July). The results of this study indicated that (1) total protein (TP), globulin, cholesterol, creatinine, uric acid and T4/T3 vary with reproductive status but not seasonal variations; (2) alanine aminotransferase, T4, fT4 concentrations in serum vary only with reproductive status; (3) the urea, creatine kinase, lactate dehydrogenase, alkaline phosphatase, aspartate aminotransferase, amylase, albumin, triglyceride, VLDL, Vit A-E, T3 and fT3 concentration could vary with both reproductive status and seasonal variations; (4) the glucose, gamma-glutamyl transpeptidase, folate concentrations were altered neither season of the year nor the reproductive status; (5) a single reference interval for folate, gamma-glutamyl transpeptidase (GGT), glucose, TP, globulin, cholesterol, creatinine, uric acid and T4/T3 can be used for both mated and non-mated sheep because of no differences were found due to the reproductive status. Taking the results together suggests that reproductive status and seasonal variations have to be taken into consideration for a correct interpretation of the serum chemistry values of sheep. Nutritional supplements are required for sheep during certain periods to avoid a decline of their performance, which would then represent consequent economic, loses.

Thyroid hormones in small ruminants: effects of endogenous, environmental and nutritional factors

“…The seasonal pattern of blood TH levels often showed maximal values during winter (cold months) and minimal during summer (hot months) (Salem et al, 1991;Webster et al, 1991;Okab et al, 1993;Menegatos et al, 2006). However, contrasting results have been reported (Kloren et al, 1993;Rhind et al, 1998; Ashutosh et al, 2001;Yokus et al, 2006). In the Sahel desert, plasma T3 and T4 levels did not change significantly from the beginning of the cool season (December) until the end of the dry warm season (May), but a highly significant rise of both hormones was observed at the onset of the humid warm season (June) (Assane and Sere, 1990).…”

Blood metabolites of extensively reared Croatian multi-coloured goats during early lactation and early gravidity

“…They are useful in diagnosing diseases and determining their prognosis, as well as in preventive programs. Comparison of biochemical results and physiological ranges is complex, because values depend on many factors, such as: breed, sex, age, nutrition, physiological conditions (pregnancy and lactation), illness and seasonal variations (YOKUS et al, 2006). Using reference intervals available from textbooks (KANEKO et al, 2008) has been shown to be inappropriate considering the large number (much more than the expected 5%) of clinically healthy animals falling outside the published intervals (VOJTA et al, 2011).…”

Plasmatic protein values in captive adult Iberian red deer stags (Cervus elaphus hispanicus)

“…Previous studies have not found seasonal variations in other ruminants such as sheep [16] or white-tailed deer (Odocoileus virginianus; [17]). In contrast, DelGuidice et al [18] described seasonal variations in total protein that are similar to the pattern observed in our study.…”