Thirty-five buffalo heifers were tested daily with fertile males to ascertain the age and live weight at first possible oestrus and conception. Patterns of sexual behaviour were recorded while rectal palpation was carried out to define the conditions of the ovaries and to diagnose pregnancies. The mammary gland development, as well as the intensity of lactation, were noted post partum.1. Pubertal matings were allowed with less certainty than adult matings. The signs of oestrus were intensified by the recurrence of heat and association with the male. Homosexuality was only observed in the first and second oestrus.2. The average age of first oestrus, first conception and first calving were 406, 647 and 963 days respectively. The body weight at first oestrus and first conception were 198 and 319 kg. respectively.3. The number of services/conception ranged from 1 to 7 with an average of 4·25. The number of silent heats/female ranged from 1 to 4 with an average of 1·65. The period elapsing from first oestrus to first conception ranged from 52 to 438 days. Before conception, there was a period of anoestrus which ranged from 115 to 314 days, this was probably due to weak oestrus symptoms.4. The live weights at 28, 84, 140, 196, 252 and 308 days were correlated with the age and live weight at first oestrus as well as the live weight at first conception.5. All the buffalo-cows except two which showed oestrus conceived. Fourteen animals calved normally while fourteen aborted after 131–318 days. The gestation period ranged from 312 to 321 days with an average of 316 days. The birth weight of young ranged from 33 to 40 kg. Seven animals were not lactating while seven gave 1–2 kg. of milk.6. Puberty phenomenon is a gradual phenomenon and is attained in steps: sexual desire, ovulation, oestrus, conception, pregnancy then lactation.
The Correlation of Mammary Gland Development of Heifers with Their Body Weight and the Milk Production of Their Dams
