Original Research

The effect of dietary protein on reproduction in the mare. VI. Serum progestagen concentrations during pregnancy

F.E. Van Niekerk, C.H. Van Niekerk
Journal of the South African Veterinary Association | Vol 69, No 4 | a843 | DOI: https://doi.org/10.4102/jsava.v69i4.843 | © 1998 F.E. Van Niekerk, C.H. Van Niekerk | This work is licensed under CC Attribution 4.0
Submitted: 13 July 1998 | Published: 13 July 1998

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F.E. Van Niekerk,
C.H. Van Niekerk,

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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.


Equine; Pregnancy; Protein Nutrition; Serum Progestagen


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