Open AccessThe effect of dietary protein on reproduction in the mare. VII. Embryonic development, early embryonic death, foetal losses and their relationship with serum progestagen
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.v69i4.844
Subject(s) - lactation , pregnancy , ovulation , biology , luteal phase , zoology , reproduction , andrology , endocrinology , medicine , physiology , ecology , genetics
Sixty-four Thoroughbred and Anglo-Arab mares aged 6-12 years were randomly allocated to 4 dietary groups and fed diets that differed in the total protein content and quality (essential amino-acids). Forty mares were non-lactating and 24 lactating. Eight mares were withdrawn from the investigation owing to injuries or gynaecological pathology. An overall conception rate of 94.6% and a foaling rate of 80% was achieved. Five of 14 (35.7%) mares (Group 1) fed a low-quality protein diet suffered from early embryonic loss before 90 days of pregnancy compared to 3 of 41 (7.3%) mares in the remaining groups that received the higher-quality protein in their diets. Serum progestagen concentrations of mares in Group 1 that suffered foetal loss were indicative of luteal function insufficiency during the 1st 40 days post-ovulation. Non-lactating mares in all 4 groups gained on average approximately 30 kg in mass during the 90 days before the breeding period. Lactating mares in Group 1 (low-quality protein) lost on average 25 kg in mass during lactation, with no weight loss observed among the lactating mares in the other 3 groups. No difference in the diameter of the embryonic vesicle was found between dietary groups until Day 35 of pregnancy.