Comparative evaluation of lactation performance of West African dwarf and red sokoto goats raised in a hot-humid environment

Abstract

The milk yield and compositions of twelve lactating does comprising six each of West African Dwarf (Fouta djallon) and Red Sokoto (Maradi) were compared in a 21-week study. The does in their second parity were monitored over a full lactation. The goats received daily basal grass and browse fodder in addition to a concentrate supplement in a 2 × 3 factorial experiment. The does were hand milked and milk yield (g/d) was quantified daily. Milk samples were analyzed weekly for total solids (TS %), butter fat (BF %), solids-not-fat (SNF %), crude protein (CP %) and total ash (TA %). Lactose concentration (LC %) was analyzed daily immediately after sampling. Macro-minerals in milk samples were determined by dry ash extraction method specific for each mineral element. Milk yield was influenced significantly (p<0.05) by both breed and stage of lactation. The WAD produced more milk (97.34 g/d than RS (87.01 g/d). For both breeds, the average mid lactation milk yield (119.04 g/d) was significantly (p<0.05) different than either early (88.35 g/d) or late (69.14 g/d). The highest milk production was by WAD does in mid lactation (125.10 g/d) and the least was by RS in late lactation (47.07 g/d). The TS, BF, SNF, CP and LC concentrations in milk were not influenced (P>0.05) by breed. The TA was significantly (P<0.05) higher in WAD milk (0.89 %) relative to RS milk (0.88 %). Also, stage of lactation significantly (P<0.05) influenced the concentrations of TS, BF, TA and LC in WAD and RS goats milk. Total solids was significantly (P<0.05) higher in late (13.47 %) than in early (12.53 %) lactation for both breeds. The BF and LC in milk followed similar trend, recording 4.45, 3.89 and 4.13 and 3.98 % in late and early stages of lactation respectively. On the other hand, The TA decreased with advancing lactation and the highest value was obtained in the early (0.92 %) than in mid (0.89 %) and late (0.86 %) lactation in both WAD and RS goat milk. TA was highest in WAD milk in early lactation (0.92 %) and least in RS milk in late lactation (0.85 %). All macro minerals were influenced (p<0.05) by lactation stage and breed differences, except potassium (K) and sodium (Na) which were only influenced by the stage of lactation. The milk of both WAD and RS goats yielded more calcium (Ca) than K, which was attributed to the nutrients in the diets.

Keywords: West African Dwarf goats, Red Sokoto goats, milk yield, milk composition, milk macro-mineral concentration