MANAGEMENT OF HEIFERS
Female calves after weaning are called heifers. From about 150 days, management depends on the system and season of birth.
Calves born in wet season
• Calves born in the wet season will enter the dry season at about 5 months of age.
• Calves in extensive systems should receive supplementation such as maize or sorghum bran in addition to natural pasture.
• Concentrate (3-5kg) should be adjusted according to heifer growth and condition to maintain steady growth.
• Feed pre-calving heifer well to receive the equivalent of 5.5kg concentrate and 10 kg fresh cut grass or 23 kg silage daily.
Calves born in dry season
• Calves born in the dry season will attain an age of up to 5 months before the wet season.
• Supplementary hay and concentrate should be given in dry season.
• When wet season sets in feed as above.
Adolescence
• Maturity in ruminants is weight dependant as well as age dependant.
• The onset of puberty (when oestrus cycle begins) in heifers depends on weight and rate of growth.
• Exotic animals reach maturity earlier at (40% mature weight) and indigenous animals later at (60% mature weight).
• Target weights for first service depend on breed, but should be higher than that at which the heifer achieves puberty and first oestrus. The range and variation of this depend on management and nutritional levels.
• A low age at first calving is desirable because it reduces land and forage requirements for replacement stock and reduces overall maintenance costs for young stock. It also leads to faster genetic improvement as cow will have more calves in its lifetime.
