a1 Department of Soil, Plant, Environment and Animal Production Science, University of Naples “Federico II”, via Università 100, Portici, NA 80055 Italy
a2 Department of Animal Science, University of Sassari, via De Nicola 9, Sassari, 07100 Italy
a3 Associazione Nazionale Allevatori Specie Bufalina, Via F. Petrarca 42-44 Località Centurano, Caserta, 81100 Italy
a4 Istituto Sperimentale Italiano ‘Lazzaro Spallanzani’, Via Einstein, Cascina Codazza, LO, 26900 Italy
The aim of this study was to evaluate possible associations between three SNPs at the oxytocin locus (AM234538: g.28C>T; g.204A>G and g.1627G>T) and two productive traits, milk yield and milkability, in Italian Mediterranean river buffaloes. Effects of parity, calving season and month of production were also evaluated. A total of 41 980 test-day records belonging to 219 lactations of 163 buffalo cows were investigated. The allele call rate was 98·8% and the major allele frequency for all the investigated loci was 0·76. The OXT genotype was significantly associated with milk yield (P=0·029). The TT genotype showed an average daily milk yield approximately 1·7 kg higher than GT buffaloes. Such a difference represents about 23% more milk/d. A large dominance effect (−1·17±0·43 kg) was estimated, whereas the contribution of OXT genotype (r2OXT) to the total phenotypic variance in milk yield was equal to 0·06. The TT genotype showed higher values also for the milk flow, even though the estimated difference did not reach a level of statistical significance (P=0·07). Such an association, among the first reported for the oxytocin locus in ruminants, should be tested on a population scale and possible effects on milk composition traits should be evaluated in order to supply useful indications for the application of marker-assisted selection programmes in river buffaloes.
(Received September 16 2011)
(Accepted November 23 2011)
(Online publication January 27 2012)