Influence Of Ewes' Milk On Growth Rate Of Lambs

Bay of Plenty Beacon, Volume 12, Issue 97, 20 September 1948, Page 7

Influence Of Ewes' Milk On Growth Rate Of Lambs

Correlation between the "milk supply of Romney ewes and rates of growth of their lambs to weaning shows that,, on the average, about one-half of the rate of growth is dependent on the milk. All other factors, such as health, amount of grass eaten, weather conditions, birth-weight, and “inherent tendency to grow,” amount to only about one-half of the total , influence on growth rate. The assumption that milking capacity of the ewes is .the most important factor influencing the growth-rate of lambs can be made from the milking records of over 200 ewes taken over a five-year period at Massey Agricultural College. The typical lactation curve for a Romney ewe under “fat lamb” conditions shows that the milk volume increases slightly until about four weeks after lambing (at this peak it varies from about 40oz to 80oz per day, with an average of about 550 z), and -this is followed by a decrease in yield until weaning. Romney ewe’s milk is much richer than cow’s milk. The percentage of fat was found to be very variable, as samples ranging from two to 15 per cent have been recorded, the average being six per cent. Solids other than fat account for about 11 per cent, which includes from five to five-and-a-half per cent, of protein. At the end of lactation the milk is even more concentrated. During a lactation period of about 12 weeks ewes with single lambs secrete between 12 and 30 gallons of milk. This surprising range in yields indicates the desirability of selecting ewes according to their milking abilities, but much preliminary work is required before even an investigation into this problem can be made. Ewes with twins secrete about 40 per cent teiore milk; that is-each twin lamb gets about 70 per cent of the amount singles obtain, and consequently they grow more slowly. It is generally agreed that lambs “fattened off their mothers” are most profitably produced. Little information has been available in New Zealand, however, regarding the relationship between milk yield and quality and lambs’ growth-rate, nor have there been any ayailable records of the composition of normal ewe’s milk, nor of the factors responsible for variations in composition and yield of this product. (