Genetic evaluation and phenotypic trend for some lactation traits of dromedary camels

Abstract There is a paucity of published work on genetic evaluation of lactation traits in camels using modern methodologies such as MTDFREML (Maximum Likelihood Restricted by Multiple Trait Derivatives Free of Maximum). The current study aimed to estimate the genetic parameters (direct heritabilities, repeatability and breeding values), and to estimate the phenotypic trend. A 302 lactation records over 10 years for a herd of dromedary camel that were bred at Matrouh Camel Studies and Production Development Center, Animal Production Research Institute, Egypt. Studied traits were lactation traits including total milk yield (TMY, kg), day milk yield (DMY, kg) and length of lactation period (LP). Actual means of TMY, DMY and LP were 1464.90 kg, 4.00 and 418.84, respectively. LP was significantly (P ≤ 0.05) affected by the year and season of calving. Additive heritability (h2a) estimates for TMY, DMY and LP was 0.25, 0.30 and 0.17, respectively. These are promising values for the potential of genetic improvement. Repeatability (t) values recorded a medium value for LP (0.19), while the values were high for both TMY (0.36) and DMY (0.43). The range of predicted breeding values (PBVs) of animals for TMY, DMY and LP were 143.07 kg, 1.5 kg and 113.9 days, respectively. Regression coefficients for she-camels showed a negative annual phenotypic trend (PT) of about − 3.58 kg and − 0.012 kg per year for TMY and DMY, respectively. A genetic improvement program should be followed that allows exploiting the higher estimates of genetic parameters by relying on animals with positive breeding values.