Programación Fetal – Impacto de paridad materna, temporada de concepción y el rendimiento lácteo en la salud y productividad de las crías hembras

Gonçalo Pereira¹, Luís Lopes-da-Costa², Ricardo Bexiga³

1-CIISA ? Centre for Interdisciplinary Research in Animal Health, Faculty of Veterinary Medicine, University of Lisbon, Avenida da Universidade Técnica, 1300-477 Lisboa, Portugal 2-CIISA ? Centre for Interdisciplinary Research in Animal Health, Faculty of Veterinary Medicine, University of Lisbon, Avenida da Universidade Técnica, 1300-477 Lisboa, Portugal
3-CIISA ? Centre for Interdisciplinary Research in Animal Health, Faculty of Veterinary Medicine, University of Lisbon, Avenida da Universidade Técnica, 1300-477 Lisboa, Portugal

Fetal programming occurs during fetal development, a critical period in which tissues and organs are created. Insufficient nutrition during this period results in permanent alterations to structural and physiological functions of the fetus. In mammals, the nutritional state of pregnant dams may induce embryo adaptations that enhance its chance of survival in the short term, but that may become detrimental in postnatal life, influencing the risk of disease. Regarding dairy cattle, nulliparous and primiparous cows differ from multiparous in terms of nutritional partitioning because nulliparous and primiparous, particularly nulliparous, must allocate their nutritional intake to their growth and development. On the other hand, since nulliparous are not lactating, they do not have the energy expense of milk production during their gestation. It could be hypothesized, that offspring of primiparous have a lesser portion of their nutritional intake partitioned for fetal development as compared with offspring of multiparous cows. Moreover, offspring of nulliparous cows may have a bigger energetic availability throughout fetal life. Additionally, among cows with the same parity, blood glucose concentrations are lower among higher-producing cows, probably induced by the high rates of utilization needed to fulfill the requirements of higher milk synthesis. Also, maternal heat stress during gestation has been associated with offspring’s reduced birth weights, reduced survival rates before weaning, and postnatal metabolic dysfunction. This impact of heat stress is particularly noticeable in countries with a mediterranean climate with hot and dry summers, like Portugal and Spain. Therefore, a retrospective study was conducted to assess the long-term effects of the conception season (spring, summer, autumn, and winter), dam’s parity (nulliparous, n = 320; primiparous, n = 220; and multiparous, n=276), and dam’s average milk yield (liter/day) during the lactation concurrent with offspring’s fetal life, on health and fertility during the offspring’s first lactation. Data was retrieved from a 700-milking Holstein-Friesian dairy cow herd in Portugal. Productivity and health events were retrieved from the herd’s management software. Variables investigated included calving to conception interval (CCI), the occurrence of postpartum disease (retained fetal membranes – RFM, metritis, acetonemia, displaced abomasum, and mastitis) in the first 60 days postpartum, culling, and 305-day milk yield. Statistical analysis was performed on SAS. The CCI was analyzed with Cox proportional hazard regression, the 305-day milk yield was analyzed by fitting a general linear model, and the occurrence of the different diseases and culling were analyzed by fitting generalized linear models with a logit link and a binary distribution. The offspring’s CCI was not affected by the dam’s parity and season of conception, but it was affected by the dam’s average milk yield during gestation (P = 0.002). The offspring of dams with higher average milk yield during the gestation was associated with worse CCI [Hazard ratio = 0.973 (95% CI 0.957-0.990) per liter increase]. The offspring’s 305-day milk yield of the first lactation was not affected by the dam’s parity and average milk yield during the gestation, but it was associated with the season of conception (P = 0.020). The offspring conceived in the spring produced less milk than the offspring conceived in the autumn (P = 0.004, – 498 liters) and winter (P = 0.016, – 356 liters). Metritis incidence was not associated with any of the studied variables. There was a tendency (P = 0.068) for a higher dam’s average milk yield during the gestation to be associated with lower RFM incidence [Odds ratio – OR = 0.939 (95% CI 0.878-1.005)]. Acetonemia incidence tended to be associated with parity (P = 0.064) and season of conception (P = 0.056). Nulliparous-born offspring tended to have a lower incidence of acetonemia compared with primiparous [OR = 0.681 (95% CI 0.437-1.062)] and multiparous-born [OR = 0.622 (95% CI 0.412-0.941)]. Similarly, offspring conceived during summer tended to have a higher incidence of acetonemia [OR = 1.641 (95% CI 1.028-2.621) vs winter-conceived; OR = 1.956 (95% CI 1.172-3.265) vs spring-conceived]. The incidence of displaced abomasum was affected by the dam’s parity (P = 0.046) with nulliparous-born offspring being associated with lower incidence [OR = 0.197 (95% CI 0.053-0.726) vs primiparous-born; OR = 0.363 (95% CI 0.093-1.419) vs multiparous-born]. The incidence of mastitis was affected by the dam’s average milk yield during the gestation (P = 0.021) with higher average milk yield during the gestation being associated with higher offspring’s mastitis incidence (OR = 1.041 (95% CI 1.006-1.078) per liter increase). Conclusion: Fetal programming was associated with the offspring’s 305-day milk yield, displaced abomasum incidence, and mastitis incidence, and tended to be associated with acetonemia incidence. Conversely, no association was observed between fetal programming, metritis, and culling rate. This work is expected to stimulate further research into the long-term effects of fetal programming in dairy cattle. This work was supported by Fundação para a Ciência e a Tecnologia project UIDB/00276/2020 (CIISA) and LA/P/0059/2020 (AL4AnimalS).