Survey Of Ewe And Lamb Losses

Press, Volume CVI, Issue 31125, 30 July 1966, Page 10

Survey Of Ewe And Lamb Losses

“The outstanding causes of loss in production in this district are (a) dry ewes; (b) ewe losses due to sleepy sickness; (c) ewe losses at lambing due to difficult births and blood poisoning; (d) lamb losses, due, in order of importance, to (i) storms and exposure, (u) mismothering and starvation, (iii) born dead I or died during a difficult birth; and («) * < ?° 1 many good ewes being culled on age at their I peak of production rather than on constitution ' and teeth.

These are the findings of a most comprehensive survey carried out last year under the auspices of the Malvern Farmers’ Veterinary Club on ewe losses, lamb losses in the first seven days of life and docking methods and culling. Messrs G. D. Leeming and R. G. Clark, veterinarians of the club, say the main criticism that would be made of many of the comments for overcoming problems was the labour factor. It was a matter of economics. Did the loss in production due to the problem make it profitable to spend the time and money in overcoming it? For instance, shelter on a one-year basis probably did not warrant the expense of putting up shelter belts, etc., but this problem, like many others, would be with the farmer for many years to come. The labour problem was best overcome by using aids that would cut down losses before they occurred—by using improved husbandry, nutrition, vaccination and culling. “For instance, if the number of lambings you have to do are cut down by culling ewes that are difficult to lamb, then you have more time to spend on mothering up.” The veterinarians say that another important aspect that the survey illustrates is the value of good records. “The most disappointing factor in the survey is the Insufficient records that are kept, especially of lamb losses. Only 11.6 per cent of farmers knew how many lambs they lost, virtually, one in 10.” “By studying good records it is possible to see where the losses are and their extent, and from this can be calculated the economics of controlling them.”

The survey covered 277 farms and they ranged from plainsland farms in the West Melton, Aylesbury, Halkett and Sandy Knolls areas to the Rakaia Gorge, Windwhistle and foothills to Glenroy and the high country on the West Coast road inland from Springfield.

The average percentage of dry ewes in the survey area was 4.7 per cent. “In our opinion the dry ewe percentage is too high,” say the veterinarians.

The causes are put down as (1) ram infertility—epididymitis and brucellosis, scrotal mange, sheath rot, lack of sex urge and incorrect ramewe ratio; (2) nutrition—low body weight in ewes and selenium deficiency; (3) ewe conformation and genital abnormality (e.g. the Romney Breeders’ Association incriminate low tail setting and docking tail being too long) To reduce the dry ewe problem it is recommended that rams be examined by a veterinarian and they be vaccinated against brucellosis if necessary, selenium be used if selenium responsive diseases like white muscle in lambs have been diagnosed or

If selenium trials, have proved that there is a health response to selenium, and culling of dry ewes. Ewe losses between tupping and lambing averaged 0.86 per cent On one property there was a 28.6 per cent loss after a snow storm.

The most common cause of deaths in ewes at this stage was pregnancy toxaemia or sleepy sickness occurring as a problem on 38 per cent of the properties in the survey.

To overcome pregnancy toxaemia or sleepy sickness the veterinarians give advice that should now be wellknown to all farmers. They urge that ewes should have a rising plane of nutrition in the last third of pregnancy. It may often be necessary, they say, to cut back on nutritional intake after tupping. Sudden checks in nutrition should be avoided. Ewes should be exercised and parasites should be eliminated by intelligent use of dips in the case of external parasites, and in the case of internal parasites by worm drenching. Early detection and treatment of the condition was desirable. By moving sheep early in the morning early cases could be observed — these often appeared normal later in the day. Affected sheep should be put apart, treated, and given preferential treatment, such as being put on to grass. The survey average for ewe losses at lambing was 1.7 per cent Those troubles, in order of importance, that caused problems on some 40 to 50 per cent of farms, were difficult births and blood poisoning; on 12 to 14 per cent of farms bearing trouble, dead lambs, milk fever and mastitis; and those that caused problems on less than 7 per cent of farms—cast sheep, sleepy sickness at lambing, died after lambing, constitution gone, misadventure and foot abscess. Miscellaneous causes of ewe deaths included posterior paralysis (e.g., due to spinal abscess or nerve damage at lambing) and losses in snow storms.

In dealing with the main troubles, the veterinarians say that difficult birth is a matter of husbandry and breeding. Ewes should be “fit but not fat.” Sheep should be exercised on the road or given a reasonable walk between the run-off paddock and feed paddock. Ewes should be culled where they had difficulty in lambing, especially where it was associated with a narrow pelvis. There was also need for good lambing techniques with adequate obstetrical lubricant and hygiene. On blood poisoning they say that ewes should be vaccinated if losses warranted the cost Aids in combatting this disease were also good hygiene and antibiotics.

Lamb losses in the first seven days of life expressed as a percentage of ewes tupped averaged 11.3 per cent over the survey area. Storm and exposure and mismothering and starvation were found to be the causes of problems on more than 30 per cent of farms; lambs born dead and

dying due to difficult births were problems on 10 to 14 per cent of properties; and on under 7 per cent of properties causes of problems were pneumonia, mastitis in the ewe. death shortly after birth, membrane over the mouth, and navel infection. To alleviate the major cause of trouble the veterinarians recommend provision of shelter and emphasise the value of knowing that mobs are going to lamb, as with synchronised lambing, and then bringing the ewes into the most sheltered paddocks when on the point of lambing. On the treatment of lambs suffering from the effects of storm and exposure they suggest the use of infra red light and feeding by oral stomach tube. For mismothering and starvation, they recommend attention to husbandry and feeding by oral stomach tube. Entropion, or turned in eyelids, was found to occur on about 7 per cent of farms surveyed (in apparently two main areas) and with an incidence of up to 15 per cent of lambs on two farms. The veterinarians say that the condition is thought to be hereditary so that the method of control is through culling. Abortion occurred on about 3 per cent of the farms surveyed and the highest incidence was on a property where 7J per cent of the ewes aborted. Docking In a study of docking methods it was found that the most popular methods were use of rings on purse and tail. About 37.6 per cent favoured this method. Then in order of favouritism were the searing iron on tails and the rings on the purse (22.4 per cent), the emasculator 13.4 per cent), knife on tail and ring on purse (10.1 per cent), searing iron on tail and knife on purse (9.8 per cent) and knife on tail and purse (8.7 per cent). In the survey farmers who had changed their methods of docking were asked for their reasons for making a change.

“The knife has the disadvantages of haemorrhage, shock and high losses as experienced by 37.1 per cent of those who changed methods. As a cause of arthritis the knife was incriminated by 13.7 per cent of those that changed methods compared to rings by 2.4 per cent. On top of this infection caused by the knife was reported by 2.4 per cent of those that changed methods. "Rings have the disadvantage of tetanus as reported by 21 per cent of those that changed methods. However by the use of tetanus antitoxin at tailing or tetanus toxoid on all ewes before lambing this problem can be eliminated if losses warrant it

“Rings have been incriminated by 1.6 per cent of those changing methods as predisposing to blowfly strike. On the other hand rings are the only method which were complimented by 12.7 per of those changing methods. They claimed it was quicker and more efficient. “The emasculator was criticised by 2.4 per cent of those changing methods as being not positive enough. “Searing irons, as slow healing, were incriminated by 5.6 per cent of those that changed methods. It must be emphasised with this method the temperature of the iron is very important. If it is too cold it predisposes to haemorrhage and if it is too hot it predisposes to much tissue damage. Tetanus was recorded as a disadvantage of the searing iron, by 1.6 per cent of those who changed methods.”