Evaluation of growth, milk and manure production in Norwegian dairy goats in one highland of Tanzania 30 years after introduction
Journal article, Peer reviewed
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OriginalversjonSouth African Journal or Animal Science. 2017, 47 (2), 202-212. 10.4314/sajas.v47i2.12
Dairy goats have been imported into Tanzania since the 1960s to improve the milk production of Small East African (SEA) goats through crossbreeding. The SEA goats have poor genetic potential for milk. Although crossbreeding programmes started in the early 1980s, most were abandoned or failed for a number of reasons, including lack of performance records, which were important for the design and management of breeding programmes for dairy goats. This study was designed to evaluate growth, lactation, and manure yield in Norwegian Landrace (NL) goats in one rural community of Tanzania. Growth was evaluated in 211 goats by birth weight (BW), weaning weight (WW), weight at six (W6M) and nine months (W9M), and average daily gain (ADG). Lactation performance involved lactation milk yield (LMY), lactation length (LL), and dry off days in 251 does. Twenty four additional goats were confined to determine manure production and chemical composition in a different on-station study. The general linear model (GLM) of Statistical Analysis System (SAS) was used in data analysis. Averages for BW, WW, and adult weight (W9M) were 3.27 ± 0.04, 12.79 ± 0.09, and 28.33 ± 0.19 kg, respectively. Average LMY of 322 litres, LL 214.5 days and dry off days of 84 were obtained. Animals with ≥75% NL genetic make-up produced more milk and showed longer LL and higher ADG than those with 50%. For example, BW was 3.38 ± 0.12 kg in 75% NL animals compared with 2.56 ± 0.12 kg in 50%, whereas LMY was 324.09 ± 16.22 and 248.67 ± 16.20, respectively. The amount of manure was 311.8 g and 218 g per day for mature and grower goats, respectively. Nitrogen was the major content, comprising 1.98% of all nutrients in manure. Compared with the early years of introducing NL goats, growth and productivity of milk have increased several fold, indicating that the development of NL goats in Mgeta is positive at the moment.