Many avian species are considered sexually monomorphic. In monomorphic bird species, especially in young birds, sex is difficult to identify based on an analysis of their external morphology. For nestlings, sex identification is usually impossible by morphological examination. Sex identification in avian species is one of the key points of avian breeding and evolutionary studies. Through the knowledge of sex identification genes, poultry breeding programmes can be applied more successfully. Vent sexing, laparoscopy, steroid sexing and karyotyping are methods for sex identification used in monomorphic birds. However these methods are unreliable, time-consuming, and expensive while some of them could be painful and even lifethreatening for birds. The sex of an individual is established from the genes located on sex chromosomes. Female birds carry one copy of both Z and W, and male birds carry two copies of Z avian sex chromosomes. However, there are many DNA techniques, the most reliable one is amplifying sex specific CHD1 gene by P2 - P8 primer pairs.

Background: Yellow-legged gulls (Larus michahellis), commonly found in Istanbul and their surroundings, have a monomorphic plumage, like other gull species. For this reason, sex determination cannot be made externally. In this study, a total of 60 adult Yellow-legged gulls, 33 males, and 27 females, collected from the coastal areas of Istanbul, were examined. Discriminating functions were developed to classify males and females using birds that were previously sexed by DNA analysis and abdominal dissection.Results: Head length and bill depth were selected to build the discriminant function by the stepwise analysis. The function classified male gulls with an accuracy of 97.0% and females with an accuracy of 92.6%. Head length alone is the most accurate predictor in terms of the percentage of correct sex determination (90.9% for males, 92.6% for females).Conclusions: Functions that can easily determine sexual dimorphism for the population ofLarus michahellisgulls around Istanbul have been put forward for the first time.

Inherited diseases are caused by recessive alleles proceed from increased inbreeding in Holstein cattle population. Bovine leucocyte adhesion deficiency (BLAD), deficiency of uridine monophosphate synthase enzyme (DUMPS), complex vertebral malformation (CVM), factor XI deficiency (FXID) and bovine citrulinaemia (BC) are the most frequent inherited diseases in Holstein cattle population. The prevalence for carriers of BLAD, DUMPS, CVM, FXID and BC diseases were reported highest in Denmark (21.5%), USA (1.2%), Japan (32.5%), Turkey (18%) and Australia (13%) respectively. Moreover the highest prevalence for carriers of BLAD, CVM and FXID were reported as 2.2%, 3.4% and 18% respectively in Turkey so far. Neither DUMPS nor BC carriers were identified in Turkey so far. However further studies are required in order to identify the provinces that have risks for mutant alleles of inherited diseases in Turkey. Determining the carrier animals and exclude them from breeding is the only solution for eradication studies of inherited diseases.

Avanus K, et al. J Vet Sci. 2017 Dec;18(4):465-470. https://doi.org/10.4142/jvs.2017.18.4.465