The effect of dietary protein on reproduction in the mare. VII. Embryonic development, early embryonic death, foetal losses and their relationship with serum progestagen

• Published in: Journal of the South African Veterinary Association Vol. 69; no. 4; pp. 150 - 155
• Main Authors: Van Niekerk, F.E, Van Niekerk, C.H. (Stellenbosch Univ. (South Africa). Dept. of Human and Animal Physiology)
• Format: Journal Article
• Language: English
• Published: South Africa South African Veterinary Association (SAVA) 01.12.1998
• Subjects: AFRIQUE DU SUD; Animals; Data Interpretation, Statistical; DESARROLLO EMBRIONARIO; DEVELOPPEMENT EMBRYONNAIRE; Dietary Proteins - administration & dosage; Dietary Proteins - standards; Embryonic and Fetal Development - physiology; EMBRYONIC DEVELOPMENT; EQUIDAE; Equine; Female; Fetal Death - blood; Fetal Death - veterinary; FOETAL DEATH; GESTACION; GESTATION; Horses - blood; Horses - embryology; Horses - physiology; JUMENT; Lactation - blood; MARES; MORT DU FOETUS; MUERTE FETAL; PREGNANCY; Pregnancy loss; Pregnancy, Animal - blood; Pregnancy, Animal - physiology; PROGESTAGENE; PROGESTAGENOS; PROGESTATIONAL HORMONES; Progestins - blood; Protein nutrition; Reproduction - physiology; Serum progestagen; SOUTH AFRICA; SUDAFRICA; YEGUA
• ISSN: 0038-2809; 1019-9128; 2224-9435
• DOI: 10.4102/jsava.v69i4.844

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 Eight mares were withdrawn from the investigation owing to injuries or gynaecological pathology.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.