Thursday February 27, 2014

Day 53..

Dual wheels - that's what we fitted to the big Massey Ferguson tractor this morning! A dual wheel is an "extra" wheel, which has the same height as the original wheel but not necessarily the same width. One of the benefits of Dual Wheels is the reduction of ground pressure and improvement of the soil structure, especially on soft surfaces, as the surface that touches the ground is twice as large. Thus, increasing traction and reducing compaction. 
We started off by driving the tractor on to wooden blocks (the side that the dual wheels were being fitted too) then to fit there is no need to rotate the dual for alignment with the tractor wheel because the tractor was already fitted with eyenuts (these replacing the original nuts) so we fitted a hook end to the eye nut and an over-centre clamp to the dual wheel power rail, securing the tension with two metal tubes that fitted over the clamp handle for better torque. Once the clamps were correctly tensioned, we locked them in position with 'R clips' for additional security. The tractor was then driven around the yard turning the steering wheel severely in both directions before re-checking the clamp positioning. A couple of the clamps were not entirely in-line - which means extra pressure would be placed on the system and could cause the clamp or a nut to break, therefore, we undid the clamp and repositioned to ensure these were on squarely. Once completed,  we used the air compressor to make sure all the tyres were the same pressure (measured in psi - pounds per square inch) where in this case they all needed to be 14psi. Using the compressor gage we either inflated or deflated the tyres accordingly. Incorrect tyre pressures mean tractors can waste 20-40% of engine power through tyre slip and rolling resistance!!
 
Animal lecture afternoon.. this was started with a dvd - a guide to lambing. Lambing is divided into several phases. In the first phase, the cervix dilates and the birth canal is prepared for delivery. This phase lasts for approximately 12 to 24 hours. At the end of this phase, a clear-whitish discharge will appear. The presence of the mucous discharge means that lambing has begun. In the next phase, uterine contractions will increase. As labour progresses, the ewe will spend more time lying down on her side with her head turned in the air. Eventually, a large "bubble" or water bag will appear, break, and expel the water. At this time, the tip of the nose and front feet of the lamb can be felt. The lamb is expelled. As ewes often have multiple births, the same sequence of the rupture of the water bag and expulsion of the lamb will be repeated for the delivery of each lamb. Ewes will vary in the time taken to complete lambing. The last stage of lambing includes the expulsion of the afterbirth or placenta. The placenta is usually expelled 30 to 60 minutes after the delivery of the last lamb. If the placenta is not expelled after 24 hours, there may be a problem. The ewe will eat the placenta because her instincts tell her to hide evidence of lambing to protect her offspring from predators. The placenta should be discarded to prevent the spread of disease and scavenging by dogs.
We finished off the lesson discussing endoparasites - a parasite, such as a tapeworm, that lives within another organism.