Reduced reproductive performance in calves born small for gestational age

In human medicine, the birth of small for gestational age (SGA) ba-bies with a birth weight below the 10th percentile for a given ges-tational age has been associated with negative consequences in both neonatal and adult life. The concept of SGA and its potential long- term effects on fertility have not yet been described in dairy cattle. The aim of this study was to compare the reproductive per-formance between nulliparous Holstein Friesian (HF) heifers born SGA with their appropriate (AGA) and large for gestational age (LGA, birth weight > 90th percentile) counterparts. Based on birth weight, dam parity and gestation length, 273 newborn female HF calves born on 4 dairy farms were defined as SGA (n = 44), AGA (n = 207) or LGA (n = 22). Insemination dates and pregnancy diagnoses were collected. Only 79.5% of SGA calves reached the age of artificial insemination (AI), compared to 89.4% for AGA and 95.5% for LGA calves. As a result, the odds of reaching first AI in SGA heifers tended to be only 41% compared to other heifers (p = .057). An average age at first AI of 425 ± 56.9 days was recorded and ANOVA (R function aov[]) revealed no difference between the groups (p = .77). However, SGA heifers tended to be older at conception (469 ± 61.0 days) com-pared to AGA (447 ± 71.5) and LGA heifers (424 ± 61.78, p = .074). This was associated with a larger number of AI's/conception: SGA heif-ers needed 2.3 ± 1.50 AI's to conceive, in contrast to 1.7 ± 0.98 and 1.5 ± 0.89 in AGA and LGA heifers, respectively (p = .009). The re-sults of this study indicate a reduced survival during the first year of life and reduced reproductive performance in heifers born SGA.

Jaar van publicatie:2023

Toegankelijkheid:Closed