SERUM AND URINARY GONADOTROPHIN LEVELS IN PREGNANT PONIES AND DONKEYS

Estimations of serum and urinary gonadotrophins have been made in two ponies and two donkeys during each of three pregnancies. Results of assays were expressed in terms of the international standard for pregnant mare's serum gonadotrophin [PMSG]. Serum gonadotrophin levels in ponies and donkeys were generally lower than in pregnant mares of larger breeds. This was especially so in the case of donkeys. Gonadotrophic activity was detected in the urine of all four animals. Values in urine were much lower than and bore no obvious relationship to serum levels. Marked variations in serum and urinary gonadotrophin readings and in values for renal clearance occurred between pregnancies in the same animal and between animals. The renal clearance of gonadotrophins was low, the mean figure in both ponies and donkeys being 0·1 ml./min. A pregnancy diagnosis test in small ponies and donkeys based on urinary gonadotrophin estimations cannot be recommended.