MVSc

Blood samples collected from goats maintained in the farm under All India coordinated Research Project on Goats for Milk of Kerala Agricultural University, Mannuthy, formed the materials for this study. These blood samples were typed employing horizontal starch – gel – electrophoresis to study the polymorphism of haemoglobin, transferrin, albumin and amylase. In all 188 goats comprising 40 Malabari, 72 Saanen x Malabari (halfbred) and 76 Alpine x Malabari (halfbred) were involved in the study. Inter and intra population variability was studied. Genetic interrelationship among some growth, production and reproduction traits viz. body weights at birth, 3 months, 6 months and 12 months, age at first kidding, first lactation yield (120 days), peak yield and interkidding interval was determined.
Two haemoglobin variants, the faster HbA and slower HbB with two phenotypes HbAA and HbAB were observed. The gene frequency of HbA in Malabari, Saanen halfbred and Alpine halfbred goats was 0.9750, 0.9792 and 0. 9671 respectively and that of HbB in these three genetic groups was 0.0250, 0.0208 and 0.0329 respectively. The frequency of HbA allele was higher in all the populations.
Four transferrin phenotypes TfAA, TfAB, TfBB and TfAC controlled by three co – dominant alleles TfA , TfB and TfC were observed. The fast moving variant was designated as TfA followed by TfB and TfC. In Malabari goats TfAC was not observed. The frequency of TfAB type was higher in all the genetic groups. The gene frequencies of TfA, TfB and TfC in Malabari goats were 0.4500, 0.5500 and zero respectively. TfC allele was not observed in Malabari goats. Three Tf alleles namely TfA, TfB and TfC were revealed in the crossbred populations with a preponderance of TfA allele. The frequencies of TfA, TfB and TfC alleles in Saanen halfbreds were 0.5278, 0.4236 and 0. 0486 and in Alpine halfbreds were 0.5329, 0.4539 and 0.0132 respectively.
The allelic frequencies of haemoglobin and transferrinloci were suggestive of Hardy – Weinberg equilibrium in all the three population or goats. Magnitude of inter population variability among the three genetic groups was negligible.
The autosomal co – dominant mode of inheritance for Tf alleles was demonstrated by analysis of segregation patterns observed in pedigrees.
Significant association was observed between the TfAA phenotype and economic traits such as birth weight, first lactation yield and peak yield.
Polymorphism was not observed for the albumin and amylase systems.
Maximum heterozygosity was observed at the transferrin locus. Highest average heterozygosity was exhibited by the Saanen halfbred goats.
Among the four biochemical of blood studied, transferrin reflected a great scope for serving as a genetic marker to be used in selection of goats for improved milk production.