Studies on lactating ewes at Templeton continuing

Press, 12 September 1980, Page 19

Studies on lactating ewes at Templeton continuing

j Research on lactating ewes at the Ministry of research station at Templeton, which | has led to the milking of ewes like cows for fetta i; cheese production, is continuing.

■- Mr K. G. Geenty, a Scientist at the station ‘.who has been in charge of ;the studies, said that the research into Use of sheep for dairy production had created a great -deal of farmer interest and the large number of inquiries from all partsof the country suggested that with the development of manu- . factoring facilities and the securing of overseas markets the industry, could expand considerably. ? In the last season five farmers in Canterbury milked a total of about >lOOO ewes and another two farmers in-Southland about 660 ewes and in total 22 tonnes of fetta cheese was produced, including 10 tonnes in

Canterbury and 12 tonnes ip Southland. At leasts three and possibly four, more fanners would be milking in Southland in the new season, and sheep milkers in Canterbury were looking at alternative manufacturing and marketing possibilities following the closing dowriV of the Barrys Bay factory where the milk had been processed, and were hoping to be producing again this season. In the course of some crystal gazing into the future, Mr Geenty has suggested that ultimately more than 5 million sheep may be milked and more than 100,000 tonnes, of cheese produced. This is based on 20 per cent' of ewes being milked in dis-

tricts where interest lias been shown in sheep milking and would depend on processing facilities, market returns and production technology being able to sustain, the suggested growth. The studies at Templeton into the lactating ewe began back in 1972 and were primarily directed to lamb production. Mr Geenty said that people frequently tended to over’ look the importance of milk production as a base for the country’s large export lamb industry, with exports amounting to well over 300,000 tonnes annually. If it was possible, as a result of research, to promote even a small increase in production of only about one per cent,

this would represent a very large increase nationally. In fact, Mr Geenty said he felt quite strongly that not enough research was being done in this area.

The work at Templeton, he said, had been basically aimed at increasing efficiency in conversion of grass to milk and in turn into lamb growth through nutrition and animal breeding. The early studies at the station had involved measuring the milk production of ewes rearing lambs by removing the lambs and injecting the ewes with a let-down hormone, called oxytocim, and the machine milking of the ewes thereafter.

The milk consumption of lambs had been measured by using a radio isotope, which was tritiated water. This was injected into the lamb and the rate of dilution or disappearance of the labelled water indicated the amount of milk consumed by the lamb under normal suckling conditions.

Breed differences had been found in milk production and also consumption patterns. For example, Dorset ewes produced milk in excess of what lambs could consume. Corriedale ewes produced a milk supply closer to the requirements of twin lambs, while Romney ewes did not produce enough milk for twin lambs.

To take advantage of these different patterns or relationships, Mr Geenty said it had been found that it was necessary to wean lambs at different ages — that was before milk production declined and the lambs were forced to compete with their mothers for feed. Thus lambs from low milk producing ewes needed to be weaned earliest — at around eight to nine weeks — whereas those on higher producing ewes could be weaned at older ages.

It was very important that where lambs were weaned at an early age they should be put on to good quality pasture and liberal quantities of it. The optimum weaning age, said Mr Geenty, varied from season to season depending on the season and the supply of feed that was available.

More recently the research work had been looking at nutritional factors — on the effect of different feeding levels during pregnancy and lactation, on their effect on body fatness and the effect of these factors on milk production.

They had been looking at factcr c . including the efficiency of fat as compared with lean ewes in producing milk and the ability of fat ewes to utilise body reserves for milk production when faced with a feed shortage.

Mr Greenty said that from preliminary results the feed intake of fat ewes was restricted during lactation so that leaner ewes were able to eat more and possibly produce milk more efficiently.' At the same time, however, body fat reserves could be utilised to assist in producing milk under conditions of. feed shortage. The picture was still not very clear and research work would be continuing this spring with lactating ewes rearing lambs and ewes that were being machine milked.

Turning to studies into sheep dairying that developed from the research with the lactating ewe for lamb production, Mr Geenty said that they had looked at several factors, including lamb weaning ages, ewes suckling two lambs and one lamb, milking techniques and finally nutrition. It had been found that milk production was highest where lambs were weaned from ewes earliest. In fact, production was highest where the lamb was removed at birth. It was then about 160 litres in a milking season of about five months. At the other end of the scale production was lowest where the

lamb was weaned at about eight weeks. It was then about 100 litres. At a seven per cent fat test a ewe producing this quantity of milk provided the raw material for about 20 kg of cheese — about 3 kg of cheese resulted from one kg of fat '1

It had been concluded that the optimum lamb weaning age was five to six weeks. A lamb must be at least 12 kg in liveweight at weaning and needed to be weaned on to top quality feed with a liberal quantity of this feed being provided. If lambs were removed at birth they would have to be reared artificially or fostered on to other ewes, Mr Geenty likes the idea of ewes which lose their lambs in a storm and which are otherwise unproductive being utilised for dairy production. No difference had been observed from a productive angle whether a ewe had been suckling only one lamb or two lambs before being milked for dairy production, he said.

In the course of studies of milking techniques, it had been found that where ewes were milked only once a day after being milked twice daily for six weeks there was a 20 per cent drop in production compared with milking twice a day

throughout the whole of the milking period. ■ ; '• For maximum production it had also been found that it was necessary to stimulate the udder by squeezing it at the end of milking. Mastitis had been .encountered where ewes have been machine milked and this could become a serious problem if prevalent and control measures had not been taken. These measures involved the spraying of teats following milking and early treatment of animals showing signs of mastitis with antibiotics.

To achieve a satisfactory level of milk production. Mr Geenty said that ewes needed to be fed well. They should be offered at least skg of pasture dry matter per day and they would probably eat about a half of that.

The day-to-day management of milking ewes was similar in many respects to that of dairy cows with the milking ewes needing to be shifted to fresh pasture frequently. This spring studies will be continuing with the nutritional effects of different feeding levels during pregnancy and lactation being looked at and a comparison being made between fat and lean ewes.