Sixty mature Friesland cows were divided into six comparable groups of 10. Groups 1, 2 and 3 grazed spared veld during the winter from 15 May and received the following supplements: Group 1, a lick plus NPN, Group 2 the same lick as Group 1 plus maize silage to provide 50% of their nitrogen requirements. Group 3, the same treatment as 2 except that volatile fatty acids were added to the lick. Groups 4,5 and 6 were penned over winter and received maize silage containing adequate nitrogen for maintenance. The following additional supplements were provided: Group 4, phosphate and salt lick, Group 5, a lick consisting of salt, phosphate and urea and Group 6 the same lick as Group 3. Group 1 lost most weight (P < 0,01 cf. 2 and 3). Groups 2 and 3 lost a minimum of weight while Groups 4,5 and 6 only lost 3% of weight. For efficient wintering of cows on spared veld, nitrogen supplementation is essential and further supplementation with silage from mid- June prevents further weight loss. The addition of volatile fatty acids had no significant beneficial effect.
"Experientia docet" - Experience is the best teacher