Comparative milk production potential of Indigenous and Boer goats under two feeding systems in South Africa

The aim of the study was to investigate the milk potential of Boer goat and South African local Indigenous goat does, under intensive and extensive nutritional regimes. Thirty-six Multiparous does (18 Boer and 18 Indigenous) were allocated to intensive (complete diet) and extensive (natural pastures) environmental groups, following kidding. Does were hand-milked twice weekly and the milk production recorded. Body weight changes, milk fat, solid non-fat (SNF), lactose and protein contents of the milk were determined weekly. Overall Boer goat and Indigenous does produced more (P < 0.05) milk under the intensive, compared to the extensive nutritional regime (3.1 +/- 1.51 per day versus 0.8 +/- 0.71 per day and 1.4 +/- 1.41 per day versus 0.7 +/- 0.61 per day for the Boer and Indigenous does, respectively). The intensively reared Boer and Indigenous goat does reached peak lactation earlier (week 5). Level of nutrition had a significant (P < 0.01) effect on milk production, with the intensively fed does producing more milk. The intensive Indigenous does produced milk with the highest mean fat content (7.5 +/- 3.2%) at a milk yield of 1.4 +/-1.41 per day. Milk lactose content tended to decline as the lactation period progressed and milk yield decreased. Milk protein content tended to increase with advancement of the lactation period (mean of 4.2 +/- 1.0; 5.0 +/- 3.0; 5.0 +/- 2.0 and 4.5 +/- 2.8% for Boer and Indigenous goats under intensive and extensive environments, respectively). Solid non-fat content was negatively correlated to milk yield. Breed had a significant (P < 0.01) effect on SNF content, with Boer goat does producing a higher SNF. In the intensively maintained groups, feed intake was significantly (P < 0.01) correlated to milk production, irrespective of the breed. Boer goats had the highest mean live weight (45.0 +/- 8.7 kg) and also produced the most milk. Principally the Boer goat doe can fulfill the function of providing milk to the rural, poorer communities in South Africa or alternatively be used to upgrade the Indigenous goat for increased milk production-especially under improved nutritional management systems. (C) 2004 Elsevier B.V. All rights reserved.