Exploring the relationship of STAT5A gene with milk fat and protein yield in Holstein Friesian crossbred cattle

Signal transducers and activators of transcription (STATs) arbitrate signals of various cytokines and hormones. STAT5A is a crucial intermediary of prolactin signalling mechanism which set in motion the transcription of milk protein genes. This research study was amied to explore the relationship and/or effect of STAT5A/AvaI gene with milk fat and protein content in a North Indian crossbred cattle herd of Holstein Friesian. Milk composition data of 535 adult HF crossbred cows was collected for over a period spanning 12 years from the records available at Guru Angad Dev Veterinary and Animal Sciences University, Ludhiana, Punjab. Thereafter data of first lactation length of 222 animals was selected for further analysis. Data correction was applied for non-genetic factors i.e SoC :season of calving, PoC : period of calving, SoC*PoC :the interaction effect of season & period of calving & AFC: age at first calving. Corrected high and low milk fat and protein yields was used to form two groups. Forty animals were selected for further blood collection and laboratory assessment. AvaI restriction enzyme was used for digestion of the 215bp STAT5A gene. Animals of both groups exhibited a uniform monomorphic pattern with DNA fragments of 181bp and 34 bp. The results indicated presence of a fixed locus for STAT5A gene in the studied population. Considering the results, more exploratory studies need to be conducted to further explicate the profound role of STAT5A in various milk related traits among the bovine species.