Goat Management ?
Feral does should ideally be at least 18 months old, and at least 25kg live weight at mating. Economics may, however, dictate earlier mating, especially when the progeny Is worth more than the dam. It is possible to mate does at around 9 months of age.
At the same time, if light-weight does have been purchased, it may pay to let them miss the first mating, as pregnancy and lactation will drag them down fur- ther, they will not do their kids well, and they will never really gain sufficient weight to do so, Angora does should be considerably heavier than feral does, but because of their value few farmers are willing to let them miss a mating, in which case specialised feeding is called for. Some Angora breeders mate their hoggets, but others prefer to wait until they are 2-tooths. There appears to be some risk of hoggets losing condition through rearing a kid to such an extent that they do not cycle the following year.
Bucks should be kept in a goat-proof enclosure until they are needed. To induce oestrus in the does a teaser buck can be used, being put out about 21 days prior to the mating sires being released. The teaser buck will increase doe fertility and ensure that the majority of does are mated within a period of about 10 days.
This technique is not essential, however, as does tend to synchronise one another, and most quiet does in good condition will come on heat at about the same time once the buck is put among them. Does do not mount one another as females of some other species do instead they seek the buck when on heat’ and tail-wagging is a clear indication that a doe is in oestrus. There is some evidence too. that poor conception rates have resulted from a young, or somewhat smaller-than-normal buck, being dominated by one or two bossy’ does. Where there is a risk of this happening, it is suggested that the buck be put out several months prior to the date on which mating is planned to commence, but this would seem to introduce the risk of the buck not being dominated and starting the mating far too early. Bucks apparently vary considerably in degree of libido. It may help though this has not been reported to put out. a teaser buck first so that the does begin tocycle, in which case they may bring the The question of when to put the bucks
out depends on when one wishes to have kids born. In deciding that, one needs to take a number of factors into account.
Does may cycle any time between December and August depending on feed supply, weather conditions, day length, etc. If one wishes to have most of the kids born around early September, then it would be necessary to put the bucks out in early April. Since does need to be in top condition when they go to the buck, they will need good feed during March. If mating is brought forward one must consider what feed conditions will be like for does with kids at foot in the period prior to September. If September is normally wet and windy and shelter is less than perfect, it may pay to kid several weeks later.
Newborn Twins Goats
Selecting a date on which to put the bucks out is at present being influenced in too many instances by live goat prices. In other words, farmers would often benefit from adopting later kidding but hesitate to do so because later kids will be smaller than those born earlier when auctions are held. Unfortunately most buyers buy on the basis of size without regard for date of birth of kids; buying on weight-for-age would be more logical. Once demand eases and buyers of live goats become more knowledgeable, it may be possible for farmers to adopt later kidding without suffering a reduction in price for their progeny. In most parts of this country kidding in late-September/early-October would seem advisable.
Embryo transplants are now a normal aspect of farming, and although the majority of goat farmers will have no need of the system, it is bound to offer apparent advantages to those who pay high prices for purebred Angora does. Eggs are taken from the doe after she has been treated to increase her fertility, and placed in surrogate mothers such as Saanen does.
There are a number of vet groups in the country which offer this service. Ruakura scientists working with eight donor does achieved the following results: 54 angora offspring from 46 recipients and 7 naturally-mated offspring from the donors.
The operation is, however, costly (about $1100/donor), and there is some risk as the number of fertile ova produced and the number of kids born live, can vary from nil to a dozen, but the average is about six live offspring in a year. The operation does not negate the possibility of the doe giving birth to a kid, or twins, of her own, and rearing them, but it may shorten her breeding life.
Straight Furrow’ reported on a new embryo transfer system developed by former vet-turned goat farmer, David Baigent. The non-surgical method involves in simplified terms, flushing eggs from the donor doe and accurate placement in the recipient does, made possible by working with a laparoscope. Mr Baigent was reported as saying that the system overcame the after-effects of surgical embryo transfer which reduces the breeding life of donor does.
Goat Reproductive Tract
Artificial insemination is also successfully employed to make maximum use of top quality bucks. The system is primarily of interest at present to breeders. As far as commercial goat farmers are concerned, AI is unlikely to be of interest immediately because of cost and because of the lower kidding rate. Improvements in the technique to ensure higher kidding percentages are being developed, and as outstanding sires are identified it is likely that AI will be used more widely.
The use of a laprascope to place thesemen directly into the uterus, is reported to improve conception rates by 50 percent compared with cervical insemination,though at double the cost. An increase in the number of kids born to a breeding flock can also be achieved by removing the kids after a day or so and hand-rearing them and putting the does back to the buck shortly after. Hormone injections can be used to induce does to come into season again. The result of this procedure is that two crops of kids are born annually.
Does can also be treated with drugs which induce super-ovulation, and the three or four kids resulting are then taken from her and hand-reared. If two sets of triplets are produced annually, the result is equivalent to embryo transplant but the cost is considerably less.
In dealing with ova transplants and artificial insemination, one comes back repeatedly to the question of identification of superior stock. Such identification is relevant also to the question of which young bucks a farmer should keep for his own use.
Subjective assessment is acceptable when staring, but once it becomes possible to concentrate on up-grading through selection and breeding, it is essential to be able to identify those bucks and does, either Angora or cashmere, which come the top 5 percent, say.
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