Leptin hormone concentration during the late gestation and early lactation period in Friesian cows
Abstract: A total number of ten multiparous Friesian cows at last one or two months of pregnancy were used. They were ranging from the second to the fourth parities, and their age ranged between three to six years. The average weight of cows was 459.0±43.9 kg at parturition. All cows were milked twice daily; and fat corrected milk based on 3.5% was estimated. In addition, all blood constituents were measured colorimetrically meanwhile direct single antibody radioimmunoassay (RIA) technique was performed for plasma triiodothyronine (T3) whereas leptin (Lep) analysis was; done using DRG® leptin (Sandwich) ELISA. The aim of this study was to determine plasma leptin (pLep) concentration of Friesian dairy cows throughout one month before parturition and during early lactation period till peak lactation; and its relation to body weight, body condition score, some blood metabolites, productive and reproductive status.The days postpartum (DPP) significantly affects most of plasma variables except plasma leptin and T3. Meanwhile milk leptin (mLep) was significantly affected by DPP (P<0.0528). In addition pLep concentration started to decrease one month pre-partum and reached 3.29 ng/dl at parturition and continued in low level; during postpartum period and reached its minimum at 60 DPP (2.71ng/dl). Plasma leptin concentration correlated positively with plasma cholesterol (r=0.31; P<0.0173) and negatively with milk solids not-fat percent (r=-0.34; P<0.0274), solid not-fat yield (r=-0.26; P<0.0985) and milk protein yield (r=-0.28; P<0.0695). In addition to the significant correlation between milk serum leptin concentrations and plasma glucose concentrations which was r=0.39; P<0.0415. Otherwise milk serum leptin did not show notable correlations with milk constituents. Plasma leptin concentration of the cows was higher in the second and fourth parities than that of the third parity cows. Calving intervals and days open are increased in cows in the 3rd than those in the 2nd and 4th parities. Moreover, correlation coefficients of milk yield and milk components among plasma constituents were estimated.Current data revealed that there is an insignificant negative correlation between plasma leptin and milk serum leptin concentrations (r=-0.09). Using simple linear regression, regression coefficient estimates were obtained for pLep as regressed by mLep and its reverse.
Publication year 2010
Pages PP. 116
Availability location مكتبة معهد بحوث الانتاج الحيوانى-شارع نادى الصيد- الدقى - الجيزة
Availability number 1134
Organization Name
Country Egypt
Author(s) from ARC
Agris Categories Animal physiology - Reproduction
AGROVOC
TERMS		 Blood composition. Blood proteins. Cows. Gestation period. Pregnancy. Radioimmunoassay. Triiodothyronine.
Proposed Agrovoc Leptin hormone;lactation period;
Publication Type PhD Thesis
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