Repeat Breeding in Dairy Cattle.:The most Challenging task in Dairy farming in India
Cows that are cycling normally, with no clinical abnormalities, which have failed to conceive after at least three successive inseminations.
In practice, some will have been inseminated at the wrong time, others may have pathological changes in the bursa or oviduct that are difficult to palpate, or undiagnosed uterine infections.
Repeat breeders can be divided into two groups:
1.Early repeats
Cows that come into heat within 17-24 days after AI.
In these animals the luteal function has been shorter than normal or typical for the physiological oestrus cycle in non bred cow. In these cows the most probable event is either failure of fertilisation (delayed ovulation, poor semen quality etc.) or early embryonic death (delayed ovulation, poor embryo quality, unfavourable uterine environment, precocious luteolysis)
- Late repeats
Cows that come into heat later than 25 days after AI. In these animals the luteal function was maintained for longer than the physiological luteal phase in non bred cows. Fertilisation and initial recognition of pregnancy probably took place but for some reason (inadequate luteal function, inadequate embryo signalling, infectious diseases, induced luteolysis) luteolysis was induced and pregnancy lost. Treatment of Repeat breeders Repeat breeders should be carefully evaluated in order to define the most probable reason for the failure to conceive (early repeats) or failure in pregnancy maintenance (early and late repeats).
Principles of treating a Repeat Breeding Cow includes
=correcting the nutritional defeciency
=correcting the uterine infections
=better heat detection and proper AI
=correcting the hormonal defeciencies
=use of assisted reproduction techniques => Nutritional treatments
1.Diets containing higher concentration of inorganic iodine from 8-12 days before estrus improve the stimulation of the pituitary gland
2.Deficiencies of Copper and magnesium have been associated with infertility, anemia or immune suppression.
3.Beta-carotene, precursor of vitamin A, has recently been investigated for its involvement in the formation and function of CL, it is suggested that beta-carotene improves the progesterone synthesis and reduces the luteal hypofunction
4.Deficiencies of phosphorus and zinc are linked to low levels of progesterone, which could be the cause of failures in fertilization or early embryonic death. In conclusion, it is important to consider the nutritional imbalance in Repeat Breeding Cows, However, it is not practical to analyze the mineral or chemical composition in blood. It is better to administer 50g of mineral mixture/cow/pay orally in order to avoid disruptions to the reproductive function.
Dr.Chandrakala sinha, TVO, Hazipur,Bihar.
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