Work on sheep farms is largely regulated by the seasons.
In winter, most sheep farms carry their lowest number of stock. In the high country and harder hills, farmers feed hay and silage to supplement the animals’ diet. On easier country, sheep are break fed (a feeding method where animals are fenced into part of a paddock) on fodder crops and saved pasture. Farms that specialise in finishing sheep for meat production continue to supply the butchers’ market and the export trade.
Ewes are scanned to check for pregnancy. Barren ewes are culled, while those carrying twins or triplets are given preferential feeding.
Farmers who rely on wool as a main source of income shear their ewes before lambing, as the stresses of bearing and raising lambs can weaken the wool and lower its value. In colder regions, sheep are shorn with blades or a cover-comb, leaving enough wool for protection from storms.
Farmers try to time lambing to match the first flush of grass growth, as ewes need good feed to produce milk. On rough country, farmers allocate a certain number of ewes to each paddock or block and leave them to lamb unattended. On easier country, farmers often shift the lambing mob daily, leaving behind the ewes that have recently given birth and their lambs. In this way ewes with lambs are given the best feed available.
A week or two after lambing, ewes and lambs are taken to the tailing yards, where the ewes are separated from the lambs and drenched with an anthelmintic to kill intestinal worms. Each lamb is caught, vaccinated against clostridial diseases (bacterial diseases such as tetanus), and given a worm drench and an ear mark to identify its farm. Then its tail is docked with a sharp knife, searing iron or rubber ring which stops the blood supply. Ram lambs are castrated using a knife or rubber rings. Finally, before the lamb returns to its mother, its rump is sprayed with a chemical to prevent fly strike (flies laying their eggs on a living animal).
Lambs are weaned off their mothers at about three months of age. The ewes and lambs are mustered into the permanent yards and drafted (separated into groups). On lowland farms and easy hills, some of the lambs will be ‘prime’ – ready to be killed for meat. The main mob of weaned lambs are drenched, dipped against fly strike and put onto the best pasture available, which on better country might include specialist crops for finishing the animals. Over the summer the lambs are brought in every few weeks and the prime animals drafted off for the freezing works. On hard hill and high country, lambs not required to maintain the flock are sold as stores (animals to be fattened for slaughter) at weaning or grazed for a month or so, before being sold to farmers to be finished on better country.
At weaning the ewes are culled, with the older sheep and poorer types being sold off. Old ewes from hard hills and high country are often bought by farmers on easy country, kept for a year or two, and mated to a terminal sire to breed prime lambs.
Telling a sheep’s age
Lambs are born with four pairs of incisors. At about a year they start growing their adult teeth – first a pair of incisors, so a one-year-old sheep is known as a two-tooth. After this, they grow a pair of incisors every year until they have four pairs. So a two-year-old sheep is a four-tooth and a three-year-old is a six-tooth. When it has all its incisors the sheep is said to have a ‘full mouth’.
Ewes are mated in autumn. Before mating they are ‘flushed’ – given better feeding to lift their body weight – to increase their fertility. Ewes are usually crutched before mating – the discoloured wool and dags from around the tail are removed. On some farms the belly wool is also shorn so the sheep can move about more freely in wet and muddy conditions.
Ewes and rams are often selectively mated, with the rams chosen to improve particular qualities that the ewe might lack, such as density or fineness of wool, or body size.
Most farmers leave rams with the ewes for up to six weeks. Some farmers fix harnesses with coloured crayons on the rams – as he mounts the ewe the crayon leaves a coloured patch on her rump. After mating, the ewes’ feeding is controlled at a level that maintains their body weight, so farmers can use their feed efficiently and save any surplus for winter.