The work of the late Sir Joseph Barcroft and his collaborators (see Elsden & Phillipson, 1948) left little doubt that, in ruminants, the end products of the bacterial dissimilation of dietary carbohydrate included large amounts of the steam-volatile fatty acids—acetic, propionic and butyric acids. More recently, el Shazly (1952a, b) has shown that the steam-volatile fatty acids also arise together with ammonia during the bacterial breakdown of amino-acids in the rumen. Studies by Pfander & Phillipson (1953) and Schambye (1955) further indicate that the acids are absorbed from the digestive tract in amounts that suggest they make a major contribution to the energy requirement of the animal. Quantitative data relative to the amounts absorbed, however, are difficult to obtain. Carroll & Hungate (1954) have calculated that in cattle some 6,000-12,000 Cal. of energy are available from the acids produced by fermentation in the rumen. With sheep, Phillipson & Cuthbertson (1956) have calculated from the results of Schambye (1951a, b; 1955) that at least 600-1,200 Cal. of energy in the form of steam-volatile fatty acids could be absorbed every 24 hrs. Since the fasting heat production of the steer is about 6,500 Cal./24 hrs. and that of the sheep about 1,100 Cal./24 hrs. it is clear that if the fatty acids can be utilised efficiently by the body tissues, they could make a major contribution to the energy requirements, at least those for maintenance.

The uneven seasonal growth of herbage is the main obstacle to the more efficient utilisation of grassland. There is an abundance of growth in late spring and early summer and a scarcity during a summer drought and in winter. Heavy stocking in spring followed by lighter stocking in summer is a suitable management for fattening sheep and cattle because they can be sold fat from June onwards, but a constant number of livestock has to be maintained throughout the year on many farms which carry breeding or growing animals. On these farms grassland, besides giving summer grazing, is expected to provide the bulk of the fodder for over-wintering. It is doubtful whether the results of grazing experiments which evaluate summer grazing only can be applied to these farms.

On hill farms where breeding cattle are kept there are advantages in retaining until the following spring at least a proportion of the surplus calves. The ability to winter them presents wider scope in choice of markets, while the sale of calves in spring, in addition to the dung produced, can provide a greater profit margin if wintering costs are minimised. Grass used efficiently in autumn offers an opportunity to reduce the requirement of the relatively expensive hay, silage, other crops and purchased feed. The value of extended grazing throughout autumn and winter months has been demonstrated by Smith (1953-4) for Blackface ewe hoggs, and for store stock and in-calf heifers by Hughes (1954) and Corbett (1954). In the case of calves, however, the period when late grass can be utilised depends on the continuance of moderate temperatures and availability of shelter from wind and rain, and therefore in most seasons will be relatively short. With these considerations in mind it was decided to compare the performance of two groups of weaned calves, one of which was housed and fed in courts immediately after weaning, while the other remained on grass for several weeks prior to court feeding.

Subcutaneous implantation of the synthetic oestrogens, hexoestrol and stilboestrol is known to increase the daily rate of live-weight gain and to improve the efficiency of food utilisation in lambs (see review by Averill, 1955; Wilkinson et al., 1955; Gill et al.,1956; Jordan & Croom, 1956).

A critical review of these reports shows that despite the numerous experiments testifying to increased and more efficient weight gains as a result of implantation it is not known how much of this extra gain is represented by products saleable for human consumption. Further there is only limited information relating to the chemical composition of the increased live-weight and none concerning the precise nature of the increased efficiency of food conversion in units other than live-weight.

The need for the improvement of carcass quality in bacon pigs is generally accepted; the means whereby this improvement may be brought about is open to argument. Many experiments, particularly in Great Britain those of McMeekan (1940-41) and Mansfield, Trehane and Peacock (1937), have shown that carcass quality may be improved by the restriction of food intake during the later stages of fattening. However, Lucas and Calder (1956) conclude, from a comprehensive survey of published feeding experiments and their own results, that only small improvements in fat measurements and body length can be achieved by restricted feeding unless the age at slaughter is delayed by periods which are unacceptable to the farmer.

While there is no exact definition of sleep acceptable by all authorities, it is generally accepted that ordinary sleep is characterised by a loss of critical reactivity to events in the environment, an increased threshold of general sensibility and reflex irritability, and the ability of being aroused or brought back to a state of wakefulness (Kleitman, 1929). There are many physiological changes in sleep such as fall in blood pressure, decrease in heart rate, reduction in pH of the blood, reduction in urine secretion, decrease in metabolic rate, slow and regular breathing, muscular relaxation and the disappearance of deep reflex actions, but almost any of these physiological changes may be absent in a sleep which is normal in all other respects. It is therefore more accurate to refer to the physiological accompaniments than to the physiology of sleep (Gillespie, 1929).

The disposal of the surplus milk produced in the spring and early summer months is becoming a problem. Blaxter (1950) suggested that the conversion of milk protein into meat protein in the form of veal would be an ideal method of dealing with the surplus.

In March 1955, the Fatstock Marketing Corporation and the Milk Marketing Board jointly announced a scheme designed to divert surplus milk from the overloaded butter and cheese manufacturers to veal production at a time when home-killed meat is normally in short supply. From the beginning of April until the end of July, a minimum price of 3s. per lb. dressed carcass weight for Grade I calves in the weight range 60-100 lb. and 2s. 9d. per lb. between 101-125 lb. was offered by the Fatstock Marketing Corporation.

The pattern and character of Northern Ireland farming is to-day very different from what it was a century ago. The farms, although still relatively small, were then very much smaller, and the output of farm products was very low. The changes in farm organisation consequent upon the gradual increase in the size of farms made it possible for the occupiers to keep more stock. Indeed, the tendency to-day for consolidation of holdings into larger units is being accentuated by economic conditions and developments in farm mechanisation.

Climatic conditions have also played a big part in the expansion of stock farming. While the rainfall cannot be regarded as excessive, at least in the east, it tends to be unduly persistent in the harvest months so that crop production, especially of cereals, is a risky business. In the west, with a higher rainfall, it is even more so. This enforced limitation of cropping has induced farmers to concentrate more on the production of livestock and their associated products.

Before dealing with the marketing of livestock I will mention briefly the current arrangements for the disposal of our two main livestock products—milk and eggs. Milk is marketed through a Producers’ Marketing Board which operates on very much the same lines as the Milk Marketing Boards in Great Britain.

In the marketing of eggs we have a unique system for the control of egg quality. The eggs are collected in the normal way by packers, or collectors acting on their behalf, and are graded on a quality basis in the packer’s store. The producer is paid on the result of this grading, deductions being made for second quality eggs, cracked eggs, soiled eggs, etc. The grading and packing are supervised by officers of the Ministry of Agriculture who also carry out further checks on the standard of packing and quality of eggs being shipped to Great Britain. These further checks are carried out at the ports of shipment, random samples of eggs being subjected to further quality tests.