Clustering of Dam’s Body Weight Based on Birth Weight of Lambs in Nilagiri Sheep

Abstract

The population of Nilagiri breed of Sheep is threatened and required micro breeding strategy for conservation and genetic improvement. Data on 4,619 Nilagiri lambs born during the 28 years (1993-2021) at the Sheep Breeding Research Station (SBRS), Sandynallah of the Nilgiris district, Tamil Nadu, India were utilized for this investigation. Data on birth weight of lamb along with dam’s body weight at the time of lambing were collected. Relationship between different body weights of dam was investigated in terms of lamb’s birth weight using one-way ANOVA followed by post hoc test for different dam body weight pairwise comparison. Heatmap was drawn for P values between different dam’s body weights aiding in visualization of the possible compatibility between body weights of dam. The birth weight of lambs positively correlated with that of dam’s body weight. Heat map visual analysis revealed five different clusters viz. less than 23.00 kg, 23.01-26.00 kg, 26.01-29.00 kg, 29.01-32.00 kg and greater than 32.01 kg sets of patterns. This was the first study in sheep breed for applying heatmap tool for growth trait analysis.