ANIMAL RESEARCH PROBLEMS

Press, Volume LXXIV, Issue 22431, 18 June 1938, Page 11

ANIMAL RESEARCH PROBLEMS

METHOD OF APPROACH OUTLINED

DR. HAMMOND’S OBSERVATIONS

The collection of statistical material by districts as a means of attacking animal research in New Zealand is recommended by Dr. J. Hammond, of the Animal Nutrition Research Council, Cambridge, in an article in the New Zealand Journal of Science and Technology. Some of the problems that he came across, says Dr. Hammond, were capable of being dealt with by individual research workers, but others would demand co-operative attention.

“In guiding the course which research should take it would be advisable in the first place to make a survey of the causes of losses in the different animal industries and to find out as far as possible the conditions under which these losses are most prevalent,’’ the report states. “The New Zealand Herd-testing Council already has a survey of dairy cow wastage in hand, and when completed (or perhaps before) the Animal Research Bureau and its specialist workers’ committees might consider it and discuss in how far the various causes warrant further experimental research, and the ways in which this research should be made. Indications of the latter might be obtained from the conditions under which the disease is most prevalent—e.g., in high and low yield herds, or in herds purchasing or only using home-bred stock for replacements, if details as to these have been collected in the survey.

“Useful information to supplement this might also be obtained from freezing works returns of the diseases found in the carcases of slaughtered dairy cows and. so far as tuberculosis is concerned, from condemnation of the heads of bacon and pork pigs. If this were done by districts much valuable information might be obtained which would be of use when preventive measures were to be inaugurated. “Concerning some of the mo e prevalent causes of wastage, more detailed surveys might be made by using the appropriate tests (if data do not already exist) of the prevalence of mastitis, contagious abortion, and tuberculosis on farms in different areas. If details of the relevant management conditions—e.g., hand or machine milking, etc.—existing on the 'arm were also collected at the time the tests were made, some indication might be obtained of the likely causes and these could be tested experiment, ally. In figures so obtained, re. 1 3,1ships should be observed between the prevalence of contagious abortion in a herd and the amount of sterility exiting. The frequency of sterility in bulls could also be obtamed and steri’e bulls could be collected for studies at research institutes on methods of curative treatment. Sheep Wastage

“Similar studies should be undertaken in selected flocks kept under different conditions (back country North and South Island, cull ewe flocks mated to Down rams under grass-feed and under rape-feed conditions, etc.) in different districts over a number of years, again with a view of the conditions existing on the farm at the

time (such as the nutritional state of the ewes during pregnancy, management, weather, and state of the feed, etc.). Analysis of these results would show not only + he main causes of the losses occurring, but also the circumstances under which they occurredThis would give a clue to the pea s required for prevention, which could then be tested experimentally. Figures collected from freezing works' (by districts) would also indicate the prevalence of diseases (such as arthritis, caseous lymphadenitis, hydatid cysts ip livers, etc.) causing loss by rejection of carcase and their relative prevalence under different conditions. These would suggest the lipes on which experimental work might be successful. A survey of the causes for carcases being placed in the second grade (by districts) would show the necessity for work being done in these districts on production problems. Qne of these causes—yellow fat—seems to be more prevalent in some districts than others, and whether it is due to a recess! "e genetic factor (as it is in rabbits), or to feeding, or to disease should be investigated with a view to its elimination. Some indication of which it is could be obtained by survey methods.

Fertility Problems “The keeping of breeding-stock which is unproductive is not only uneconomic in itself, but (especially in times of the year when there is a shortage of feed) also reduces the thrift and wellbeing of those that'are productive. Any steps, therefore, which can >e taken to reduce barrenness in stock will lower the costs of production. The following seem to be the main problems to be ■ solved: — “The fertility jf sheep flocks in the back country is low US compared with the lambing percentages of similar sheep on the hats. Moreover, in certain parts of the back country the fertility appears 1 to have declined in recent years. It is known that the fertility is determined largely by the feed conditions just before and during tupping time, and experiments are required on how it is possible tq improve tips by measures, such as temporary movement of the ewes, treatment of the soil, mineral feeds, or perhaps by weaning the lambs Slightly earlier -p as to allow the ewes to get into better condition before tupping (this would also be an advantage in getting the lambs to the flats earlier for fat-lamb rreduction). Even with flocks kept on low grpuhd the level of fertility i§ often lamentably low; Those who practise hand Service know that some ranis are sterile. The inclusion of one of these sterile rams among four or five turned put with a flqck of pwes is puffin cipnV fo cause barrenness in a num-

bar of ewes, fpr if‘the sterile ram is ai particularly powerful one (as they often are) he will keep away the fertile rams from a certain numbr of ewes. Means are required of testing rams for fertility before they are turned out with the ewes. By use of the artificial vagina method of collecting semen and by measuring the opacity, counts of sperms, and/or respiration teats it should be possible to dp this. “For stud breeders with valuable animals it is also necessary to know how sterile rams can be cured and what is the cause of their going sterile so that steps can be taken to prevent it. It is known »that the purpose pf the scrotum is to keep the tests at a lower temperature than that of the body, and that high 'temperatures kill O-T! the sperm in a short time. Experiments are required to' find out whether keeping tfie wool clipped short in this region will improve matters and whether the presence of a feverish condition pf the animal may not some, times be the cause . of. some of |h§ feqyble. ! *