Improving lambing performance

Press, Volume CXV, Issue 33786, 7 March 1975, Page 8

Improving lambing performance

In spite of the many factors which contribute to a good lambing, it was felt that the size of the ewes was the most important at this time of the year

and that farmers should concentrate on

this aspect by feeding their stock well, savs Mr D. R. Macmillan, a farm

advisory officer of the Ministry of Agri* culture and Fisheries at Rangiora.

Mr Macmillan was discussing three field days held recently by the Ministry of Agriculture and Fisheries on farms near Cust, Cheviot and Hawarden and attended by about 250 farmers. The theme of each day was improving lambing performance. “A general decline in lambing percentages has occurred throughout North Canterbury in recent years and the field days were held in an effort to highlight those factors which affect lambing results, in the hope that this decline will cease,” said Mr Macmillan.

“The main message that came to light was the importance of the mating weight of ewes in relation to their lambing performance. “It was stressed that within a breed there is a general 6 per cent increase in lambing percentage for every 101 b increase in the mating weight of the ewes. Furthermore, for every week ewes are flushed (put on an increasing plane of nutrition) an additional 1 per cent increase in lambing is possible. This means that if ewes are increased in weight from an avenge of

110 to 1201 b in a four-week period, the lamb drop should improve by 10 per cent (6 per cent due to the weight increase and 4 per cent due to the four weeks of flushing). “At the field days it was pointed out that nearly 2000 ewes from 13 flocks in North Canterbury totalling 20,000 ewes have been weighed by Ministry of Agriculture and Fisheries advisory staff in the past four weeks. The average weights have varied from 941 b to 1351 b between flocks. This range was surprising considering the amount of feed there is about this year. This difference in weight can represent a potential lambing advantage of about 30 per cent to the heavier ewes. “In each flock weighed so far there has also been a difference of 50 to 601 b between the heaviest and lightest ewes, and it was suggested that farmers should draft them into different mobs, depending qn weight, so that each mob can be ’ fed to best advantage before and during mating.

“Many other factors, which affect lambing per-

centage, were also discussed, including mating management, pre - tup drenching, and crossbreeding and twin selection. “However, in spite of the many factors which contribute to a good lambing, it was felt that the size" of the ewes was the most important at this time of the year, and that farmers should concentrate on this aspect by feeding their stock well.

“Some North Canterbury flocks have achieved weight gains of the order of lib a dav over the past month and this represents a likely improvement in lambing of about 10 per cent,. other things being equal.

“A weight guessing competition was held on a pen of 10 ewes at each field day. Farmers were asked to guess the average weight of the 10 animals and guesses varied by as much as 40 to 501 b.

“As an accurate idea of ewe weights is important if lambing percentages are to be improved, it was suggested that farmers should use sheep weighing scales to take the guess work out of their flock management. Several types of weighing crates were on display and weighing techniques were demonstrated,” said Mr Macmillan.