The hypothalamo-pituitary-adrenal (HPA) axis interacts with the hypothalamo-pituitarygonadal (HPG) axis at several sites and there are both species and stress related differences in how a particular stressor affects the gonadal axis. In the pregnant mare, negative effects of stress on reproduction are often measured in terms of effect on plasma progesterone levels or abortion rate. In cycling m...

Matua bromegrass hay (Bromus willdenowii Kunth) is a high quality forage, but its value for mares during gestation and lactation is not well known. Intake, rate of passage, performance, and reproduction by gestating and lactating Quarter Horse mares fed the hay was investigated. In this experiment, 12, 2- to 12-yr-old gravid mares (mean BW = 553 kg, SD = 36) were fed Matua hay (CP = 11.5%) or a...

The current limitations for obtaining ovaries from slaughterhouses and the low efficiency of in vivo follicular aspiration necessitate a complete understanding of the variables that affect oocyte developmental competence in the equine. For this reason, we assessed the effect on equine oocyte meiotic competence and the subsequent in vitro cloned embryo development of 1) the time interval between...

The behavioral effects of the immunocontraceptive agent porcine zona pellucida (PZP) have not been adequately studied. Important managerial decisions for several species, including the wild horse (Equus caballus), have been based on this limited research. We studied 30 horses on Shackleford Banks, North Carolina, USA to determine the effects of PZP contraception on female fidelity to the harem ...

BACKGROUND Endometritis is a common problem in a broodmare practice, often leading to infertility. The diagnosis is based on several methods such as cytology, bacteriology and histopathology; however the outcome of these methods may be inconclusive even when used together. The objectives of this study were: (1) to investigate the usefulness of acute phase proteins as an additional diagnostic to...

Thirty-two light-horse mares were confirmed to be pregnant and assigned to one of four treatments: (1) injected with 250 micrograms of Equimate on day 70 and again on day 77 if abortion had not occurred; (2) injected with 250 micrograms of Equimate on day 70 and every 24 hr until abortion occurred (maximum four injections); (3) injected with 250 micrograms of Equimate on day 70 and every 12 hr ...

Conditions threatening pregnancy in late term mares can pose unique challenges to the practitioner. The following manuscript reviews clinical scenarios that the equine practitioner may encounter with late pregnant mares. Diagnostic and treatment options are also discussed. Author’s address: Department of Large Animal Clinical Sciences, College of Veterinary Medicine, University of Florida, PO B...

Lactation is the most energy demanding part of parental care in mammals, so parent-offspring conflict arises over milk provided by the mother. In some species females commonly become pregnant shortly after parturition of previous young. This further intensifies mother-offspring conflict due to concurrent pregnancy and lactation. In equids it has been well established that pregnant females wean ...

Controlling fertility of feral horses through the use of long-acting contraceptives or sterilization approaches has been championed as a reasonable and humane solution for addressing overpopulation problems in several western states. However, methods to accomplish long-term contraceptive efficacy of horses following a single treatment have been lacking. In fall 2002 and spring 2003, we initiate...

REASONS FOR PERFORMING STUDY Equine herpesvirus 1 (EHV-1) is one of the most common causes of infectious abortion in mares. Analysing the demography of outbreaks and detailing subsequent reproductive performance of affected mares will assist in the management of future (threatened) epizootics. OBJECTIVES To examine the epidemiology and reproductive outcomes of 2 EHV-1 abortion epizootics with...