Topic:Broodmares
Broodmares are adult female horses that are used for breeding purposes. They play a vital role in equine reproduction, contributing to the continuation of specific bloodlines and the development of desirable traits in offspring. The management of broodmares involves various aspects, including nutrition, health monitoring, and reproductive care, to ensure successful conception, gestation, and foaling. Horses, as a broader category, include both males and females and encompass a wide range of breeds and disciplines. The study of broodmares and horses encompasses reproductive physiology, genetic considerations, and husbandry practices. This page compiles peer-reviewed research studies and scholarly articles that explore the management, reproductive health, and genetic aspects of broodmares, as well as general equine care and breeding strategies.
Estrus, ovulation, and serum progesterone, estradiol, and LH concentrations in mares after an increased photoperiod during winter. On December 11, 1974, 15 seasonally anestrous mares were assigned at random to 1 of 3 experimental groups: outdoor-control, indoor-control, or indoor light-treated (a 16-hour photo-period). This experiment was terminated on April 21, 1975. The five mares in the indoor light-treated group ovulated 59.0+/-6.9 days later, which was 74 days earlier (P less than 0.01) than 2 of the 5 outdoor-controls (the other 3 ovulated after April 21 during a subsequent experiment) and 50 days earlier (P less than 0.05) than the indoor-controls. Durations of the 1st estrus for the 3 groups of mares were 13.3+/-3...
Levels of luteinizing hormone and progesterone during the estrous cycle and early pregnancy in mares. Jugular venous blood was collected from 16 mares at daily intervals throughout the estrous cycle. Twelve of these mares were bred to fertile stallions. Of the twelve, four were palpated daily throughout the estrous cycle, four were palpated daily during estrus and four were not palpated. The remaining four mares were not palpated or bred and blood samples were collected at 6-h intervals during estrus. Serum was harvested from all blood samples by centrifugation. The serum samples were analyzed for luteinizing hormone (LH) and/or progesterone by radioimmunoassay. Levels of LH in serum increased...
[Plasma progesterone in mares showing oestrus during early pregnancy (author’s transl)]. Sixtyfour mares were examined 3 and 6 weeks after mating. Progesterone was measured in 22 mares 3 weeks after mating in order to see if this could be of any help in the oestrous diagnosis. None of the pregnant mares had plasma progesterone below 2 ng/ml. Pregnant mares that did not show oestrus had higher levels of plasma progesterone than pregnant mares showing signs of oestrus 3 weeks after mating. Clinical findings in pregnant and nonpregnant mares 3 weeks after mating is compared, and oestrus in pregnant mares is discussed.
Early pregnancy testing and its relationship to abortion. A total of 487 Standardbred and Thoroughbred mares at two studs were manually tested for pregnancy at 20 to 24, 30 to 34, and greater than 42 days after service and the abortion rate compared to that obtained in previous years when only the greater than 42-day test was performed. The results indicated that early manual pregnancy testing does not increase the abortion rate if undertaken carefully and enables non-pregnant mares to be re-mated earlier in the same season.
A review of the influence of nutrition upon the oestrous cycle and early pregnancy in the mare. Attention is drawn to the beneficial effect of improved nutrition during winter and early spring on the ovarian activity of mares. Furthermore, the necessity of an adequate plane of nutrition during early pregnancy to prevent embryonic resorption is stressed.
Development of the equine fetus and placenta. Prenatal specimens from mares with known breeding dates were used to characterize morphological changes in the fetus and placenta of pony mares. Prenatal characteristics and the day on which each was first found and weights of different components of the equine conceptus are summarized.
Endocrine patterns of the mare at term. The levels of progesterone and total progestins increased during late pregnancy and then fell dramatically during the last few days before parturition, although birth occurred in the presence of significant amounts of plasma progesterone. Oestrogen levels decreased slowly but insignificantly until birth occurred, and then remained at a low level until the post-partum oestrus 10 to 12 days later. Total 11beta-hydroxycorticosteroids were unchanged from Day 45 before to Day 15 after birth. The endocrine pattern of one ovariectomized pregnant mare during the last month of gestation was similar to ...
Effects of artificial light on the oestrous cycle of the mare. Two groups, each of seven pony mares, were maintained from 17 October to 15 February (120 days) in the University Biotron where temperature and daily photoperiod were regulated to simulate normal conditions for that period (control group) or those normally applicable from 1 March to 1 July (treated group). Follicular growth, ovulation rate and oestrous behaviour were determined daily by rectal palpation, and by teasing with a stallion. By Day 69 of treatment, all ovarian end-points (number of follicles greater than 10 mm, number of follicles greater than 20 mm, average follicle diameter and di...
Ovarian changes during early pregnancy in pony mares in relation to PMSG production. The ovaries of twenty pregnant mares were examined daily, per rectum, for the first 4 months of gestation and note was made of their estimated size and follicular content. Serial blood samples from sixteen of the mares were assayed for PMSG. A marked seasonal effect was noted on ovarian size, follicular content and ovulation rate during pregnancy but there was no such effect on PMSG production. It is concluded that PMSG is synergistic with gonadotrophins of pituitary origin and that the latter hormone are the primary stimulus on the ovary of the pregnant horse.
Plasma progestins in pregnant, postpartum and cycling mares. Jugular vein plasma from 13 mares was extracted with diethyl ether and chromatographed on Sephadex LH-20 columns (.5 × 9 cm) after which progesterone and 17α-hydroxyprogesterone (170HP) were quantified by a competitive protein binding radioassay. During pregnancy, progesterone increased (P < .05) from 1.1 ± .4 ng/ml (mean ± SE) on day 0 to 7.5 ± 1.2 ng/ml on day 8 followed by a transient (nonsignificant) decrease to 4.8 ± .4 ng/ml on day 28. From days 28 to 44 progesterone again increased (P < .05) attaining a maximum concentration of 15.2 ± 1.4 ng/ml on day 64. Thereafter progesterone ...
Progesterone concentrations in the peripheral plasma of the mare during pregnancy. Progesterone concentration was measured by a protein-binding assay in peripheral plasma samples taken from 8 thoroughbred mares throughout pregnancy and for 2 days after parturition. There were considerable differences between individuals at any one time in gestation but, on average, levels rose during the first 60 days of gestation, fell to a minimum at about 180 days when the accessory corpora lutea regress and finally reached their highest mean value of 11.5 mg/ml±1.2 (S.E.M.) during the period 270 days to term, significantly higher than the mean, 7.6 ng/ml±0.5 (S.E.M) for the whole of ge...