Reproductive behaviour of Mangalarga and Breton Maiden Mares

Abstract

In the present report, the reproductive performance of Mangalarga and Breton young maiden mares was studied throughout nineteen breeding seasons. The experimental design was completely randomized. The age at the first conception for 77 females of the Mangalarga Breed and 89 Breton was 36.94 and 38.35 months (P < 0.01), respectively. The gestation lenght for 66 Mangalarga was 340.30 days and for 76 Breton was 318.18 days (P > 0.05); the age at first foaling for the same number of maiden mares was 47.94 and 49.31 months (P < 0.01), respectively; 53.03% of 66 foals of the Mangalarga Breed were female, on the contrary, 54.79% of the 73 Breton foals were males. Pregnancy rate for 95 Mangalarga maiden mares was 84.90% and for the 113 Breton it was 81.58%. The abortion rate for 78 Mangalarga pregnancies was 7.69% and for 89 of the Breton was 8.99%; the foaling rate was 92.31% and 91.01%, respectively. Facing these data, the autors, considering the up to date knowledge of the problems related to reproduction on this species, believe that on breeding farms tecnically managed with criterious detection of oestrous and sucessive rectal palpations, the productivity of this important class of mares (maiden and young) can be more significant than what is shown by the literature.