The present study aimed to determine whether developmental patterns, adiposity level and fatty-acid composition of fetuses exposed to maternal malnutrition are driven by their sex or their genotype, or both, as these may modulate the adaptive response to the intrauterine environment independently of the maternal genotype. We used a single maternal genotype (purebred Iberian (IB) sows), which was inseminated with heterospermic semen (obtained by mixing semen from Iberian and Large White (LW) boars), to obtain four different subsets of fetuses (male and female, purebred (IB×IB) and crossbred (IB×LW)) in Iberian purebred sows. Analysis of fetal phenotypes indicated a better adaptive response of the female offspring, which was modulated by their genotype. When faced with prenatal undernutrition, females prioritised the growth of vital organs (brain, liver, lungs, kidneys and intestine) at the expense of bone and muscle. Moreover, the analysis of fat composition showed a higher availability of essential fatty acids in the female sex than in their male counterparts and also in the Iberian genotype than in crossbred fetuses. These results are of high translational value for understanding ethnic differences in prenatal programming of postnatal health and disease status, and show evidence that prenatal development and metabolic traits are primarily determined by fetal sex and strongly modulated by fetal genotype.

Bovine viral diarrhoea (BVD), one of the most important infectious diseases affecting bovine production systems, is thought to show a subclinical course in most cases, especially in regions that have suffered high BVD prevalence for a long time. However, few studies have assessed this rigorously under non-epidemic conditions. Here we assessed how often active BVD infection in a herd, defined as at least one antigen-positive animal, is associated with clinical signs. Surveying and sampling methods were used to detect BVD infection based on clinical picture. Analysis of 1203 samples of individual animals from 167 herds clinically suspected of BVD infection showed that 33.7% of dairy farms, 30.6% of beef cow-calf farms and 40% of feedlots contained at least one animal positive for BVD viral antigen. Prevalence of BVD infection was 7.7% at the animal level, much higher than the prevalence of 1–3% reported in the literature. This suggests that clinical picture can be useful for detecting active BVD infection, and that infections show a variable clinical course. On dairy farms, the presence of at least one antigen-positive animal was associated with a tendency towards lower fertility and higher rates of stillbirths and calf health problems (P < 0.1). On feedlots, such presence was associated with a tendency to a higher of calf health problems. In beef cow-calf systems, however, the presence of an antigen-positive animal was not associated with any particular sign. These results suggest a higher association of active BVD infections spreading in a herd and clinical pictures at the herd level, particularly in dairy herds.