Farm and station Use of hay on irrigated pasture may be out

Press, 20 April 1979, Page 6

Farm and station Use of hay on irrigated pasture may be out

The only place for hay in the winter on a highly stocked irrigation farm may be as an emergency ration in a situation like a snowstorm.

In fact, making hay on a property that is highly stocked may lead to a reduction of' production at that time and to a greater requirement for hay later on to make up for the shortfall in feed in the spring. At Winchmore irrigation research station six wearier steers or 20 ewes per ha have been wintered without using hay at all and without any loss of production. Mr J. M. (John) Hayman, a scientist at the station who has been studying management of irrigated pastures for a number of years, says that management of irrigated pastures is a completely different matter from management of dryland pastures and requires a new management system to take advantage of what irrigation offers. “Hay making has been used in the past to cover up sloppy grazing management,” he comments. Mr Hayman says that they have been looking both at the system of grazing management under all grass irrigation farming and at hay making as a means of transferring surplus feed from the spring and summer into the winter. What has become perfectly clear, he says, is that as the stocking rate

is increased on an irrigated grass farm there is less and less grass left for conservation and the spring, when hay is normally made, becomes virtually the period of greatest feed shortage. If that aspect was combined with the fact that in hay making there was a loss of some 25 to 50 per cent of the feed and also the ever increasing cost of making hay. then it was obvious that the whole question of making hay' had to be looked at pretty closely. It was in the process of doing that they had found that they could winter six weaner steers or 20 ewes per ha without hay at all. and without any loss of production on fully irrigated pastures. The reason for this would seem to be that at high stocking rates under irrigation hay making resulted in the removal of feed that animals required in the spring and summer to reach maximum production. The act of hay making therefore reduced the growth rate of the cattle or the liveweight of the ewes at mating, with a consequent effect on lambing percentage, if the farm was fully stocked. A question that this raised, of course, was whether the feeding of

hay m the winter increased production in some other way, but their experience was that it did not provided that grazing management in the winter, and perhaps throughout the whole year, was adequate. At high stocking rates when feed intake could really not be reduced without adversely affecting production, the act of hay making increased the subsequent need for hay. Thus making hay reduced the amount of feed available in the spring and summer for fattening lambs. increasing ewe liveweight and accumulating autumn saved pasture. Consequently less feed

was carried into the winter in forms of autumn saved pasture or in ewe body weight reserves. But in the Canterbury scene it was necessary to transfer some feed from the spring, summer and autumn period into the winter as the requirements of stock in the winter exceeded pasture growth rate.

This could, however, be done by methods other than hay making — by medium of the body weight reserves of stock, autumn saved pasture and efficient grazing management.

In the first place ewes or other stock could eat the feed that would normally be made into hay. which would reduce the feed loss associated with hay making and also eliminate the cost of making hay, and there would be the advantage of ewes putting on extra weight which would be reflected in an improved lambing percentage. This body weight could also be used, to some extent, after tupping or mating to maintain the ewe, although a starvation system of feeding -was not advocated.

A further method of transferring surplus feed to the winter was in autumn saved pasture. Here the point was made that it was desirable to have a moderate growth on all pastures on a farm rather than''having just a few paddocks with long grow'th, and this could only be fostered by a system of summer and autumn rotational grazing, which had the advantages of building up body weight levels as well as autumn saved pasture at the same time. - The other factor that could influence the situation was grazing management through the summer, autumn and the winter periods. Rotational grazing, with as few mobs being used as possible, was essential’, so that most of the farm was, in fact, left free of'

stock to allow the grass to grow at maximum rate. About four weeks after the rams had been joined with the ewes the amount of grass allocated to the ewes should be cut back quite drastically. This involved use of a winter rotation that very strictly controlled intake and this could be achieved by using an electric fence, and shifting stock every two to four days to a new’ break, with back fencing also so that there could be .no grazing of blocks that had just been grazed.

It was recommended that this routine should be started no later than the middle of May. In MidCanterbury' in particular there was quite significant pasture grow’th in May and early June and on paddocks that had been grazed intensively and had received a shower of dung and. urine the growth in this period was of very high quality and provided the pre-lambing feed for the ewes.

It was important that the rotation should be planned before the winter began so that the feed supply did not run out a month before lambing. The lambing date should be about the time that spring growth started, which at Winchmore would be about September 10. Hay should be required only as an emergency ration to get the farmer

over a difficult winter situation rather than being part of the normal feed input.

However, for those who were not able to take the complete plunge and do without hay altogether, it should be fed only after all grass has been eaten on the rotational grazing blocks. It was permissible to deviate to some degree from the over-all plan but this should only be done to help the farmer to stick to his grazing plan and if done it was important that pre-lambing feed reserves should not be jeopardised. If it rained and the pasture became muddy Mr Hayman said that a common reaction was to spread stock, over a large area, but tins had been shown to be highly undesirable and in cases of extreme wetness it was better to reduce the size of the grazing block and shift the stock every day. With an electric fence this was a simple procedure and as a consequence only a small part of the total pasture was trampled, and by confining the sheep to a relatively small area they had little room to move and so the trampling effect was also reduced.

Mr Hayman said he had seen 3000 ewes on an area of three acres in this situation. It certainly resulted in the paddock being turned into “a mud pie,” which looked very depressing, but experience had shown that pasture treated in this way for a brief period in the winter was subsequently the best pasture on a farm. Good hard tramping of ryegrass pastures was an important requirement of maintaining high quality ryegrass pastures in Canterbury. The tramping did more harm to the weed grasses than to the ryegrass and left it more able to dominate the sward in the future.

For this sort of system, Mr Hayman said it was essential that pastures should be ryegrass-based and experienced farmers had noticed that the longer that this system, was followed the better the pastures became. Hoggets should be treated in a similar manner to ewes but should be allocated a separate block and rotationally grazed on that block. It was most important that they have a different block of adequate area. This could provide for one rotation and a half as with hoggets there w r as not the demand for high quality feed in the late winter.

Mr Hayman said that this work applying to irrigated pasture lands was also applicable to country with adequate summer and autumn rainfall, such as the' upper plains, that was not irrigated.