Data from: Maternal nutrition during pregnancy affects testicular and bone development, glucose metabolism and response to overnutrition in weaned horses up to two years

Pregnant mares and post-weaning foals are often fed concentrates rich in
soluble carbohydrates, together with forage. Recent studies suggest that
the use of concentrates is linked to alterations of metabolism and the
development of osteochondrosis in foals. The aim of this study was to
determine if broodmare diet during gestation affects metabolism,
osteoarticular status and growth of yearlings overfed from 20 to 24 months
of age and/or sexual maturity in prepubertal colts. Twenty-four saddlebred
mares were fed forage only (n=12, group F) or cracked barley and forage
(n=12, group B) from mid-gestation until foaling. Colts were gelded at 12
months of age. Between 20 and 24 months of age, all yearlings were overfed
(+140% of requirements) using an automatic concentrate feeder. Offspring
were monitored for growth between 6 and 24 months of age, glucose
homeostasis was evaluated via modified frequently sampled intra veinous
glucose tolerance test (FSIGT) at 19 and 24 months of age and
osteoarticular status was investigated using radiographic examinations at
24 months of age. The structure and function of testicles from prepubertal
colts were analyzed using stereology and RT-qPCR. Post-weaning weight
growth was not different between groups. Testicular maturation was delayed
in F colts compared to B colts at 12 months of age. From 19 months of age,
the cannon bone was wider in B vs F yearlings. F yearlings were more
insulin resistant at 19 months compared to B yearlings but B yearlings
were affected more severely by overnutrition with reduced insulin
sensitivity. The osteoarticular status at 24 months of age was not
different between groups. In conclusion, nutritional management of the
pregnant broodmare and the growing foal may affect sexual maturity of
colts and the metabolism of foals until 24 months of age. These effects
may be deleterious for reproductive and sportive performances in older
horses.