Developmental Programming of Fertility in Cattle—Is It a Cause for Concern?

Abstract

Cattle fertility remains sub-optimal despite recent improvements in genetic selection. The extent to which an individual heifer fulfils her genetic potential can be influenced by fetal programming during pregnancy. This paper reviews the evidence that a dam’s age, milk yield, health, nutrition and environment during pregnancy may programme permanent structural and physiological modifications in the fetus. These can alter the morphology and body composition of the calf, postnatal growth rates, organ structure, metabolic function, endocrine function and immunity. Potentially important organs which can be affected include the ovaries, liver, pancreas, lungs, spleen and thymus. Insulin/glucose homeostasis, the somatotropic axis and the hypothalamo-pituitary-adrenal axis can all be permanently reprogrammed by the pre-natal environment. These changes may act directly at the level of the ovary to influence fertility, but most actions are indirect. For example, calf health, the timing of puberty, the age and body structure at first calving, and the ability to balance milk production with metabolic health and fertility after calving can all have an impact on reproductive potential. Definitive experiments to quantify the extent to which any of these effects do alter fertility are particularly challenging in cattle, as individual animals and their management are both very variable and lifetime fertility takes many years to assess. Nevertheless, the evidence is compelling that the fertility of some animals is compromised by events happening before they are born. Calf phenotype at birth and their conception data as a nulliparous heifer should therefore both be assessed to avoid such animals being used as herd replacements.

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“…Pascottini et al (2022) claim the development of maladaptive mechanisms in cows in the postpartum period due to a negative energy balance, characterized by increased resistance of uterine tissues to insulin and excessive formation of adipose tissue. Another researcher, D.C. Wathes (2022), came to similar conclusions, but he also emphasizes the importance of genetic programming during pregnancy for structural and physiological modifications to the future female's fertility.…”

Efecto del nivel de energía de la dieta en el último tercio de gestación sobre el desempeño productivo y reproductivo de vacas para carne y su descendencia

“…Los mismos autores mencionaron que los resultados específicos sobre el rendimiento de las crías fueron variables, manifestándose la complejidad para obtener resultados de investigación claros. En este sentido, aspectos como los efectos de niveles de energía nutricional contrastantes en el último tercio de gestación sobre la respuesta de acuerdo al sexo de la cría y la interacción entre la nutrición prenatal y el posterior manejo nutricional postnatal de las terneras, no son claros (Barcelos et al, 2022; Wathes, 2022. La suplementación nutricional en vacas de cría en el último tercio de gestación se relacionó con aumento del peso vivo al destete de la progenie (Funston et al, 2010b), aunque sin beneficios en el peso vivo a la pubertad o sobre la reproducción (Larson et al, 2009).…”