Do haematological profiles of cows in drought prone areas differ with conformation?

Abstract

Aim of study: Severe and frequent droughts have resulted in loss of thousands of rangeland cattle worldwide. The objectives of the current study were to assess the reduction in dimensionality of seven conformation traits and to determine the relationships between extracted constructs and haematological parameters associated with drought resilience in beef cows.Area of study: Muzarabani district, Zimbabwe.Material and methods: Fifty multiparous Mashona cows kept on natural rangelands were used. The collinearity of seven conformation traits of the cows was reduced using principal component analysis. The relationships between the principal components and hematological profiles of the cows were subsequently determined using regression analysis.Main results: First extracted principal component described body capacity (body depth, flank circumference, chest girth). The second component described the frame size (stature and body length) of the cows and the third component was comprised of sheath height and dewlap size. Cows characterised by deep bodies, large flanks and chest girths had low percent haematocrit (HCT), mean capsular haemoglobin concentration (MCHC) and red cell distribution (RDW) (p<0.05). Small-framed cows were associated with low mean platelet volume (MPV), HCT, MCHC and RDW levels in blood (p<0.05). As principal component 3 of conformation traits increased, white blood cell count, mean corpuscular volume, RDW and MPV decreased (p<0.05).Research highlights: Small-framed cows with large thoracic capacities, large dewlaps and belly bottoms far away from the ground surface are able to maintain haematological normalcy under rangelands in drought prone areas.