# Regression analysis to evaluate the effect of pulsation rate on the morphological structures of cow teats

Galina Dineva, Kancho Peychev and Dimitar Georgiev

*Trakia University, Faculty of Agriculture, Department of Agricultural Engineering, 6000 Stara Zagora, Bulgaria*
**Dineva, G., Peychev, K. & Georgiev, D. ** (2020) Regression analysis to evaluate the effect of pulsation rate on the morphological structures of cow teats. Bulg. J. Agric. Sci., 26 (Suppl. 1), 212-215

In a previous study (Dineva et. al., 2019) an ultrasound examination of the following morphological structures of the cow teats was performed: the length and diameter of the teat canal, the teat wall thickness, the teat diameter in the region of Furstenbergâ€™s rosette, the diameter of teat cistern in its middle part and the cistern diameter at the teat base. The scan was performed before milking, immediately after milking, at the 1st and 2nd hours after milking. During milking two types of milking units (with a cylindrical shape of the pulsation chamber and the so-called tri-circle) were used in combination with different frequency modes. The present study is a continuation of the above by performing statistical processing of the obtained data to determine the coefficients of variation, correlation and correlation ratio, the regression equations are derived to determine the influence of pulsation rate on the observed morphological structures of cow teats. The obtained regression models allow extrapolation and estimation of the change in the structures of the milk papilla outside the experimental gradations of the pulsation rate.

*Keywords: *cow; correlations; pulsation rate; regression equations; teat health

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