Association of offspring's birth weight considering maternal parity with offspring's survival, productive and reproductive performance and AMH concentration from birth to the first lactation period.

Offspring birth weight (BW) is an indicator of growth during fetal period and there were studies indicating its association with survival as well as productive and reproductive performance during adulthood. In this context, both light and heavy calves were reported to have inferior postnatal performance due to the lack of vigor and perinatal complications, respectively. With regard to perinatal complications, maternal experience of previous pregnancy is considered as a determinant. Therefore, we conducted the present study to investigate whether the pattern of association between offspring BW and postnatal performance differ between the offspring born to nulliparous dams versus those born to parous dams. In study I, data of BW, culling, milk yield and reproductive variables of offspring born to nulliparous (NPR) and parous (PR) dams (n = 24741) were retrieved. Afterwards, offspring were classified in various categories of BW. In study II, blood samples (n = 435) were collected from offspring in various categories of BW born to NPR and PR dams for measurement of serum AMH. Culling rate of offspring decreased by increase in their birth weight and this decrease was more evident in the offspring born to NPR dams (p ≤ 0.05). Milk production increased by increase in birth weight regardless of maternal parity (p ≤ 0.05). However, reproductive performance diminished by increase in birth weight regardless of maternal parity (p ≤ 0.05). Concentration of AMH was not associated with birth weight of offspring (p > 0.05). In conclusion, the present study showed that offspring birth weight was positively associated with their survival and milk yield, but negatively associated with their reproductive performance.