We continue to be a little fox obsessed. Foxes are our major predator here and they seem to be in plague proportions. Everywhere we drive there are dead foxes beside the road. Today I counted five travelling the 50 Klms into Canberra. We will need to be well prepared for lambing in September or will suffer big loses. It is time to plan our first baiting programme.
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Our poor sheep have been standing in the rain for almost ten days now and there is more to come. Sheep endure this type of weather but it interferes with eating, resting and joining. They also use energy just keeping warm, fortunately we don't have any lambs to be concerned about.
We have been asked about "flushing" and what it means: In the normal flock it is achieved by putting the ewes onto better feed to create a rising plane of nutrition, this can be done by feeding suplements such as lupins, which are high in protein, or giving them access to high quality pasture prior to joining. The point of this is to increase conception rates, with the hoped for result of more lambs at weaning. Which improves the bottom line of the enterprise. In embryo transfer programs, "flushing" means chemically stimulating the ovaries to produce a larger number of ova, for fertilising and transplanting. With the large number of wet days, we have had to delay the weaning of our lambs. This has had two effects, the ram lambs are close to being sexually active and need isolating. But of more immediate importance is the ewes are down in condition, and joining is rapidly approaching.
What we must do now is to "flush" the ewes, this means they need a rapid rise in nutrition, ideally with a boost in protein intake. Even in normal circumstances this will give an increase in the number of twins. Koenie's visit is over and our joinings have begun. It has been a wonderful opportunity to be able to discuss, pull apart, look for strong points, and make the joining decisions, with the help of such an experienced eye. We only need to wait till August/September to see how well we did.
Finally managed to get the lambs weaned, better late than never. The biggest worry is that with the dorper ram lambs, they are keen to work from such a young age, that you don't want them joining their mothers.
This week we'll be having another South African Dorper inspector to visit, as we are keen for him to look at our weaner lambs and to give us some guidance with our ram selection for joining later in the month. One of the breeding strategies that breeders use in their studs is corrective mating: this is where animals are combined where one animals excels in an area where the other is weak, with the goal of correcting the weak point and creating more uniformity within the flock. An example of this is selecting a ram with a very good head that conforms in a superior way to the breed standard and using that ram to improve the quality of all the heads in the flock. The same principle can be used to improve other traits such as shedding. However, the breeder must always be careful not to focus on one single trait at the expense of another. Line breeding is also used in most studs to increase the incidence of good genetics, where animals are bred that have related ancestors. The aim of this is to increase the uniformity of the progeny. Line breeding creates the most genetic gains in a flock, but has the problem that, in attempting to increase the incidence of good genes, there may be some defective genes that also accumulate and this can result in problems with future generations. Hence the old saying: "It is called line breeding when it works and inbreeding when it doesn't". If the line breeding is too close it can also impact negatively on growth rates and fertility. This weekend is the planned date to wean our lambs, but we are having some trouble getting enough straight hours to process the sheep.Martin has installed the weigh bars under the new sheep handler,preparing to weigh all our lambs. We do this for our own interest interest as well as enabling us to send the weights to "Lambplan". This indicates to us a measure of the genotype of our sheep. The Dorper inspectors help maintain a good phenotype,(visual qualities), and performance recording gives us information about genotype,(genetic potential). The morning started well with just a light drizzle, which eased up once we had the sheep yarded. We were moving along quite well when the first storm came through (about half the lambs processed), it wasn't long then we were able to get back into it. Then dramatic thunder storms started with abundant lightening. There was so much energy in the air that I saw the drafting gates spark. This necessitated a retreat to the shed. We then got a another break before the heavens opened up (with 15 sheep to go), at which point we gave up. With the lambs wet and miserable and the sheep yards flooding there was no going on. Oh well, back to it this morning.
Ideally lambs should be weaned into a clean worm free paddock. But on our other block, we only have 3 main ones that are large enough. One has our crossbred flock, one our stud ewes and lambs, and the other is being rested.
We will wean at the end of January, so one option is to put the ram lambs, (which will soon start working) in the fresh paddock, then put the stud ewe lambs with the crossbred mothers, and the crossbred ewe and wether lambs with the stud ewes. There is an additional advantage in this, the weaners settle much quicker when they are running with the adults, and we like to feed a few sheep pellets at this time, so that the adults teach the lambs to come for these, useful in times of drought. It is a more natural way, not, say, having a town with only teenagers, "Lord of the Flies" style. I guess we are flogging a dead horse, but probably the most important thing at this time of year is vigilance against Barbers Pole worm. They frequently cause sheep to die, sheep in prime condition, - often snake bite is blamed.
A female worm lays up to 10,000 eggs/day.They pass out in the dung, where they hatch if weather is warm and moist, go through 2 larval stages feeding on bacteria in the dung. In ideal conditions they can become the infective L3 larvae in 7 days. Rain & Dew wash these onto the grass where they are eaten by the sheep. Once in the sheep, they immediately moult and migrate to the abomasum (4th stomach). IT TAKES 21-28 DAYS FROM LARVAL INGESTION TO EGGS PASSING IN DUNG. (sorry for shouting, very important). This means an effective drench can help clean a paddock over this interval by taking up larvae but passing no eggs. The 4th stage larvae & adult worm can remove 0.05 ml blood per worm per day ie: 1000 worms 50ml/day resulting in anaemia ie no stamina, pale gums and conjunctiva, even bottle jaw, constipation , and death. Even with no visible signs of infestation, worms can reduce milk production and weight gain by 30%. Now that the joining season is nearly upon us, it is important that when buying in rams or ewes that they come from disease free stock. Rams from accredited studs can be introduced without testing, but, without blood testing rams from an unknown source can pose a risk to the whole flock and result in significant economic loses. Ewes should be isolated for one month if not in lamb, however pregnant ewes need to be isolated and not rejoined for 4 months.
Johnes disease does not show until the sheep are older, so it is important to purchase from vaccinated flocks, as it is becoming a problem in all areas that do not vaccinate, being a soil born disease. It is good practice to have in place a small quarantine paddock to isolate recently purchased stock and it can also be used as a hospital paddock for sick stock from within your existing flock. Any stock that you bring home should be drenched and given a top up 6 in 1 vaccine. This is to reduce the risk of resistant worms being introduced to you farm as well as giving the new animal some protection as it enters a new environment. People often ask why we shear a shedding sheep, a valid question.
As we mentioned on our post on "shedding" the dorper sheep is primarily a meat sheep, and muscularity is of prime importance. If we concentrate too much on shedding we would produce a carcass more like some of the hair breeds and inferior to our 'competition" in the lamb industry. The muscling is best seen when the sheep is shorn, and if you learn to look, you can see the degree of shedding and the type of cover. If you look at a dorpers conformation, notice the muscle above the elbow, a bulge here indicates good mucle through the whole animal. A nice flat topline and smooth shoulder are also important. |