Invermay researchers carry out various studies on the stock with the support of Mr Knowler and his staff.
These include a monitored residual feed intake trial for 200 sheep, and sheep reproductive trials.
There are also parasite studies and genetic evaluation trials with deer; the present study is looking at seasonal growth in the progeny from sire stags selected to have potential for different seasonal growth patterns.
''The weaners will be ad-lib fed pasture at all times through the winter, with the stags being killed once they reach good weights in late spring, and the hinds will continue on ad-lib until mating in April.''
He said some of the key focuses on both research farms include animal welfare, sediment loss prevention and reducing nutrient loss.
''Soil management is a priority. Winter crops are the single biggest cause of the loss of sediment and nitrogen.''
He balances the need to feed stock with reducing the amount of winter crops grown to prevent nutrient loss, and as well as using fenced setbacks from gullies, grazing crops from the top down greatly reduces the potential for sediment loss.
The deer self-feed silage pad has been identified as a ''hot spot'' for nitrogen loss, so the silage has been fed on pasture for the past two years, and nutrient containment will be needed if used in the future.
During very wet periods, the sheep are taken off the crop and are put on set-aside paddocks with more than 3000kg/DM for up to four days on one break, so there is no pasture damage, and they are well-fed, drier and happier, which means less soil movement on the crop paddock.
He estimated that in one 20ha deer-farmed catchment, more than 200 tonnes of sediment had been captured in the wetland area during the past 40 years.
''Around half the farm has been put in new pasture during the past four years, and along with the refencing, has led to a better animal performance but not at a cost to the environment.''
-By Yvonne O'Hara
Farm facts
AgResearch's Invermay 579ha research farm and commercial operation, Mosgiel.
* Research farm managed by Kevin Knowler for the past four years. Before that he managed Woodlands research farm, near Invercargill, which he still oversees.
* Has 255ha for sheep, 179ha for deer, 90ha in forestry and remainder as campus, laneways and creeks.
* Grows 24ha of fodder beet and swedes, and kale has been grown for the sheep and deer. Runs 540 breeding hinds (500 AI'ed), 110 R2 hinds and 360 R1 hinds/stags and 28 breeding stags.
* The Central Progeny Test (CPT) programme runs 820 ewes (all AI'ed), 500 ewes and 300 ewe hoggets involved in reproduction trials and another 500 ewes run as a commercial flock.
* Lambing percentages range from 145% to 175% (composite sheep flock at Woodlands).
In the past four years more than $100,000 has been spent to fence deer out of gullies where water may run even for short periods during the year.
* In addition, based on extensive soil testing, phosphate is applied only where needed (Olsen P range 10 to 45), sulphur applied at maintenance and lime used to achieve 5.8/6 pH. Potassium levels are good and potash is only applied on paddocks cut for silage.
* Short tree breaks planted in the most suitable/driest part of paddocks so stock can access all sides for shelter or shade.
* 15 areas (11ha) fenced off, which will be planted in natives, shade trees and hardwoods.
Southern Rural Life
