Open AccessThe effect of dietary protein on reproduction in the mare. VI. Serum progestagen concentrations during pregnancy
Author(s) -
F.E. Van Niekerk,
C.H. van Niekerk
Publication year - 1998
Publication title -
journal of the south african veterinary association
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.535
H-Index - 31
eISSN - 2224-9435
pISSN - 1019-9128
DOI - 10.4102/jsava.v69i4.843
Subject(s) - reproduction , pregnancy , serum concentration , endocrinology , andrology , biology , medicine , ecology , genetics
Sixty-four Thoroughbred and Anglo-Arab mares aged 6-12 years were used, of which 40 were non-lactating and 24 lactating. Foals from these 24 mares were weaned at the age of 6 months. Non-lactating and lactating mares were divided into 4 dietary groups each. The total daily protein intake and the protein quality (essential amino-acid content) differed in the 4 groups of non-lactating and 4 groups of lactating mares. The mares were covered and the effect of the quantity and quality of dietary protein on serum progestagen concentrations during pregnancy was studied. A sharp decline in serum progestagen concentrations was recorded in all dietary groups from Days 18 to 40 of pregnancy, with some individual mares reaching values of less than 4 ng/ml. Serum progestagen concentrations recorded in some of the non-lactating mares on the low-quality protein diet increased to higher values (p < 0.05) than those of mares in the other 3 dietary groups at 35-140 days of pregnancy. A similar trend was observed for the lactating mares on a low-quality protein diet at 30-84 days of pregnancy. No such trends were observed in any of the other dietary groups. High-quality protein supplementation increased serum progestagen concentrations during the 1st 30 days of pregnancy. Lactation depressed serum progestagen concentrations until after the foals were weaned.