HEMATOCRIT VALUES AND MORTALITY FROM ASCITES IN COLD-STRESSED BROILERS FROM PARENTS SELECTED BY HEMATOCRIT

A hypothesis that the relative hematocrit value of broilers is inherit ed and can serve as an indicator of partial resistance to the ascites syndrome in cold-stressed broilers was shown to be valid in a field tr ial. Hematocrits were determined for male and female grandparent breed ing stocks. Matings were then made between low (LL), low-medium (LM), medium-high (MH), and high (HH) hematocrit parents: LL x LL, LM x LM, MH x MH, and HH x HH. The progeny of HH parents had higher hematocrit values than the progeny of lower hematocrit parents (P < 0.0001). Expo sure of the progeny from all the parental groups to an ascites-predisp osing cold environment caused higher losses from ascites in the progen y of the HH parents (P < 0.0001). The progeny of LH parents had an inc reased mortality from causes other than ascites (P < 0.0001). This wor k suggests that elimination of birds with HH in broiler breeding progr ams may be desirable where cold-induced ascites is an important proble m.