Fatty acid, amino acid and mineral composition of milk from Nguni and local crossbred cows in South Africa
This study was conducted to determine fatty acid, amino acid and mineral composition of milk from Nguni and crossbred cows in South Africa. Milk samples from 8 Nguni and 8 crossbred cows grazing on rangeland were collected once per lactation phase, i.e. early lactation (January), mid lactation (April) and late lactation (June) in 2009 for milk composition analyses. Nguni cows had higher (p<0.05) protein content, methionine, threonine, tyrosine, glycine and proline levels and n-6:. n-3 ratio, and lower (p<0.05) milk yield, fat and total solids content, potassium levels and total mono-unsaturated fatty acids (MUFA) than crossbred cows. Phosphorus levels were higher (p<0.05) in milk from Nguni cows in the early lactation compared to crossbreds. In the early and mimd lactation stages, milk from Nguni cows had higher (p<0.05) essential amino acids (arginine, phenylalanine, histidine, isoleucine and leucine), calcium levels and polyunsaturated fatty acids to saturated fatty acids (PUFA/SFA) ratios compared to crossbreds. Milk from crossbred cows in the mid and late lactations had higher (p<0.05) C12:0, C14:0, C16:0 and C18:0 levels than Nguni cows. It was concluded that milk composition of Nguni cows is more desirable for the calf and human consumption, especially in the early-to-mid lactation compared to that of crossbreds. © 2011 Elsevier Inc.