Changes in udder size and liveweight of West African Dwarf, Red Sokoto and Sahel goats during lactation and their phenotypic relationship with partial daily milk yield

Résumé

Changes in udder size and liveweight (LWT) of ten West African Dwarf (WAD), three Red Sokoto (RS) and three Sahel goats during lactation and their phenotypic relationship with partial daily milk yield (PDM) were studied. Udder length (UL), udder width (UW), udder circumference (UC), udder volume (UV), distance between teats (DBT), teat height to ground (THG), teat length (TL), teat width (TW), teat circumference (TC) and LWT of does were determined weekly for 12 weeks of lactation commencing from 4 days post partum. There was increase in udder size arising from increases in all udder dimensions (except THG) of WAD from 1^st - 3^rd week of lactation and RS and Sahel from 1^st- 2^nd week of lactation when they peaked and thereafter declined up to 12 weeks of lactation. Partial daily milk yield followed the same pattern as the udder dimensions, Sahel dues had the largest udder size with highest average PDM, except for TC' which was largest in RS does. The WAD does had the smallest udder size with lowest average PDM. Largest size of udder was obtained on the day of peak milk yield. The correlation between udder dimensions, LWT and PDM were obtained with UL (r = 0.23), UW (r = 0.30), UC (r = 0.52), UV (r = 0,50), DBT (r = 0.57), THG (r = -0.32), TL (r = 0.09). TW (r = 0.226), TC (* = 0.36) and LWT (r = 0.50). Since, UW, UC, UV, DBT, TC and LUT of lactating goats showed significantly high correlation to average PDM, they could be good indicators of milk yield requiring further investigation as genetic markers.