title: Heterophil/lymphocyte ratio as a selection criterion for heat resistance in domestic fowls.
abstract: 1. Two experiments were conducted to examine the Heterophil/Lymphocyte ratio (H/L) as criterion for selection for resistance to heat stress and some aspects of general resistance in domestic fowls. 2. The first experiment on a small sample (n = 64) of light breed Iraqi local fowls showed that this ratio could be used as an indicator of heat stress resistance. 3. The second experiment on a large sample (n = 1160) of heavy parent stock confirmed the results. It showed that there was a different H/L ratio for the two strains and that there was much individual variability in the H/L ratio within-strain that could be utilised for individual selection for heat resistance. 4. The H/L ratio was highly heritable; Resistant and Sensitive groups, defining all individuals with an H/L ratio over the upper 95% confidence limit as 'Sensitive' and those below as 'Resistant' produced progeny with significantly different H/L ratios. 5. There were indications of differences in mortality between the progeny of the Resistant and the Sensitive groups. 6. The H/L indicator could be used as a criterion to select for heat stress resistance.
authors.affiliation: Department of Veterinary Public Health, College of Veterinary Medicine, University of Baghdad.
authors.forename: W K
authors.initials: WK
authors.lastname: al-Murrani
authors.forename: A
authors.initials: A
authors.lastname: Kassab
authors.forename: H Z
authors.initials: HZ
authors.lastname: al-Sam
authors.forename: A M
authors.initials: AM
authors.lastname: al-Athari
mesh_terms: D000818:Animals; D001833:Body Temperature Regulation / Q000235:genetics / Q000502:physiology*; D001947:Breeding; D002452:Cell Count / Q000662:veterinary; D003141:Communicable Diseases / Q000401:mortality / Q000662:veterinary; D005260:Female; D006098:Granulocytes / Q000166:cytology*; D006358:Hot Temperature; D007493:Iraq; D008214:Lymphocytes / Q000166:cytology*; D008297:Male; D010058:Oviposition / Q000502:physiology; D011200:Poultry / Q000097:blood* / Q000235:genetics / Q000502:physiology*; D011201:Poultry Diseases / Q000401:mortality; D012641:Selection, Genetic; D012727:Sex Characteristics