A Dead Cert : Experiment 1
1. Pony mares abort following surgical manipulation
University of Cambridge, Department of Physiology
A team of researchers at Cambridge used 23 pregnant pony mares to study sugar metabolism in the unborn foal. All of the pregnant animals – some of whom were very near to giving birth – were starved for 18 hours before undergoing invasive surgery. Intravenous anaesthesia was used, rather than the considerably safer inhalation anaesthesia.
All of the mares underwent abdominal surgery to expose the uterus, in which a series of cuts were made so that the researchers could reach the unborn foals. A leg of each foal was exposed and a catheter inserted in a vein and artery, and then threaded towards the heart. The surgical incisions were sutured with the catheters remaining inside the foals. These catheters were then connected – through a small opening in the abdominal wall of the mare – to a bag secured to the flank of the mare. A week later, the actual experiment began, whereby two test substances (glucose and arginine – both involved in sugar metabolism and pancreatic function) were injected directly into the foals through the catheters. Blood samples were taken at various intervals and the data recorded.
Of the original 23 pregnant pony mares, nine produced dead or dying foals. The authors could not explain some of these events. The foals’ response to the injected test substances produced no surprises and the authors merely documented the physiological responses that would normally be expected from the kind of intervention to which they had been subjected. However, the authors did conclude that the development of foetal pancreatic cells could be affected by over-exposure to steroid drugs. The fact that pregnant animals should not be given such drugs has long been documented and is already well known in veterinary medicine.
This research received financial support from the Horserace Betting Levy Board.
Fowden AL, Gardner DS, Ousey JC, Giussani DA, Forhead AJ. Journal of Endocrinology2005, 186:467-473. Maturation of pancreatic B-cell function in the fetal horse during late gestation.