Short communication: Effects of milk removal on teat tissue and recovery in Murciano-Granadina goats

The aim of this work was to study how machine milking (MM) carried out in appropriate conditions affects teat wall thickness and canal length and their return after milking to premilking conditions compared with other milk removal methods considered biological referents: kid suckling (KS), catheter removal (CATH), and hand milking (HM). Three Latin square experiments were designed, each divided into 2 periods. In the first period, the left glands of each animal were machine milked and the KS, CATH, and HM treatments were applied to the right glands in experiments 1, 2, and 3, respectively. Subsequently, in the second period, the removal methods were interchanged. Teat wall thickness, teat wall area, teat end wall area, and teat canal length were measured from the ultrasound images. Milk removal using the reference methods (KS, CATH, and HM) and by MM caused increases in teat wall thickness and teat canal length, which were greater with MM. The time needed for the teat walls and canal to return to their physiological conditions before milk removal was greater than 10 h in the reference methods and following machine milking.