Foal

Abstract: The interacting influences of maternal size and fetal genotype on placental and fetal development in the mare were assessed by comparing conventional within-breed Thoroughbred (Tb-in-Tb, n = 7) and Pony (P-in-P, n = 7) control pregnancies established by artificial insemination (AI) with between-breed (Tb-in-P, n = 8; deprived in utero condition and P-in-Tb, n = 7; luxurious in utero condition) experimental pregnancies established by embryo transfer. All foals were born spontaneously and the mean (+/- SEM) duration of gestation in the two groups of control mares was significantly different (P < 0.001) at 325 +/- 3.0 days for the P-in-P pregnancies and 339 +/- 3.0 days for the Tb-in-Tb pregnancies, whereas the durations of gestation for the two experimental groups were very similar and midway between those of the control pregnancies at 332 +/- 2.8 days for the Tb-in-P and 331 +/- 2.7 days for the P-in-Tb. Mean (+/- SEM) foal birth weight and the mean (+/- SEM) values for the mass, gross area and volume of the allantochorion were all highest in the seven Tb-in-Tb pregnancies (53.1 +/- 2.6 kg, 3.8 +/- 0.3 kg, 12.9 +/- 0.3 x 10(3) cm(2), 3.5 +/- 0.2 l, respectively) and lowest in the seven P-in-P control pregnancies (24.0 +/- 1.3 kg, 1.7 +/- 0.1 kg, 8.3 +/- 0.3 x 10(3) cm(2), 1.8 +/- 0.1 l, respectively). These parameters were higher in the seven P-in-Tb pregnancies (37.9 +/- 2.1 kg, 2.7 +/- 0.1 kg, 10.1 +/- 0.5 x 10(3) cm(2), 2.5 +/- 0.1 l, respectively) than in the eight Tb-in-P (33.0 +/- 2.4 kg, 2.3 +/- 0.2 kg, 9.0 +/- 0.5 x 10(3) cm(2), 2.1 +/- 0.1 l) experimental pregnancies. Foal birth weight was positively correlated with the mass (r = 0.84, P < 0.001), gross area (r = 0.87, P < 0.001) and volume (r = 0.91, P < 0.001) of the allantochorion, and maternal weight was also positively correlated with both the mass and gross area of the allantochorion (r = 0.64 and 0.69, respectively; both P < 0.001). Application of stereology to multiple random biopsies recovered from each placenta produced mean values for the surface density of microcotyledons on the allantochorion (S(v)). Values were higher in Thoroughbred than in Pony mares regardless of the breed of fetus being carried. Multiplication of S(v) by the volume of the allantochorion to give the total microscopic area of fetomaternal contact at the placental interface was also positively correlated with foal birth weight (r = 0.84, P < 0.001). Foal birth weight was determined by the microscopic area of fetomaternal contact of the placenta and there were no differences in foal weight per m(2) of placenta regardless of fetal or maternal genomes. Thus, the results indicate that in equids, maternal size interacts with both the maternal and fetal genotypes to control the rate and extent of fetal growth by influencing the gross area of the diffuse allantochorion, and the density, complexity and depth of the microcotyledons on its surface.

Abstract: In an effort to identify improved methods for diagnosis of infection in the neonatal foal, clinical records from 38 septicaemic foals of less than one week of age were examined for trends in history, physical examination and clinicopathological findings. The survival rate of septicaemic foals, 26 per cent, was markedly less than the rate for all other foal admissions. Blood cultures were valuable in diagnosis and treatment of septicaemia and identified a preponderance of Gram-negative infection. Zinc sulphate turbidity test results were abnormally low in all septicaemic foals tested. The clinical course was often distinguished by severe complications and multiple organ dysfunction, leading to death. Conditions present in the mare pre-partum resulted in weak or diseased foals; bacterial placentitis, vaginal discharge and premature lactation were most common. There was no single diagnostic criterion of the septicaemic foal. Fever was not a consistent finding. The most useful white blood cell parameters were neutropenia, the presence of band neutrophils (greater than 0.2 X 10(9)/litre) and toxic changes in the neutrophil population. Hypoglycaemia, metabolic acidosis and hypoxaemia were also common findings.

Abstract: 1. Anatomy and Physical Examination of the Stallion 2. Endocrinology of the Stallion 3. Semen Collection 4. Stallion Behavior 5. Sperm Physiology 6. Semen Evaluation 7. Breeding Management of the Thoroughbred Stallion (Shuttle) 8. Breeding Management of the Warmblood Stallion 9. Hormonal Manipulation of the Mare 10. Microbiology and Diseases of Semen 11. Anatomy and Physiology of the Mare 12. Uterine Edema of the Mare 13. Breeding Management of the Mare 14. Artificial Insemination With Cooled Semen 15. Artificial Insemination With Frozen Semen 16. Embryo Transfer 17. Preservation of Equine Embryos 18. Assisted Reproductive Techniques in the Mare 19. The Early Pregnancy 20. Evaluation of the Foal In-Utero 21. Infectious Problems in the Last Trimester of Pregnancy 22. Parturition and Evaluation of the Placenta 23. The New Born Foal 24. Breeding the Post-partum Mare 25. Preventive Medicine of the Brood Mare 26. Evaluation of Reproductive Efficiency 27. Significance of the Equine Genome on the Horse Industry