767
Single nucleotide polymorphisms in the DRD2 and XKR4 genes may be beneficial to Missouri beef cattle grazing endophyte-infected tall fescue
Decreased growth, fertility and lactation can be observed in beef cattle grazing endophyte-infected tall fescue. Polymorphisms in the DRD2 and XKR4 genes may modulate these responses. Adjusted birth (ABW) and 205 day weights (A205) were calculated for 1,697 calves from 390 dams, over a span of 14 years, at the Forage Systems Research Center located near Linneus, Missouri. These represented two herds (fall- and spring-calving) of Angus-crossed beef cattle grazing endophyte-infected tall fescue. Fall-born calves had lighter ABW and A205 than spring-born calves (p<0.0001). Dam genotype at DRD2 and XKR4 influenced A205 (p=0.0015 and p=0.0152 respectively). There was an interaction noted between DRD2 and season; spring calves from AA and AG dams had higher A205 (p=0.021). No genotype effect on ABW was observed. Dam genotype at these loci may affect calf growth when stock are consuming endophyte-infected tall fescue, possibly through modulation of lactation.
Keywords:
DRD2
XKR4
fescue toxicosis
