But regardless of the slightly understated conception rate of 71% the real concern was the loss of 160 fawns from May until weaning in mid-March. At the second scan in September, 78 (23%) of the 337 hinds were dry, and between September and weaning another 17 pregnant hinds died. Suspicions toxoplasmosis could have been the cause were unlikely given the Russell’s first calvers are part of a nationwide toxoplasmosis vaccine trial and the pregnancy losses were spread across treated and non-treated animals, focus farm facilitator Dave Lawrence said.
“What’s happened here is a lot higher than what has happened on other farms involved in the trial – we hope the losses from scanning to weaning is an aberration.”
Brian is quietly confident this season’s results are a one-off.
“I feel it is an anomaly. Usually our first calvers perform well. In the past we’ve scanned 97%.”
No major management changes have been implemented in light of the results although this year 400 rather than 600 R2 hinds have been mated.
The overall weaning result of 90% (hinds mated to fawns weaned) was a “credible effort” for the 1826 mated, Lawrence said. However, the 66% weaning from the 299 hinds mated to a B11 stag compared to the 95% weaning from the 1527 mated to a Red stag raised some unanswered questions.
“Something’s happened but we don’t know what,” Brian said.
This year the B11 stags were monitored closely during mating and hinds mated to them were scanned in the second week of May to identify those that had conceived.
Also for further investigation were the weaning weights of first fawner progeny. Stag fawns averaged 38.4kg and hinds 37.1kg, with a significant tail-end below 34kg.
The suspicion is that conception is being delayed for some reason and to confirm, scanning this year will be used for foetal ageing.
Although there were no guaranteed solutions to the problem of foetal loss, a proven way of increasing and condensing conception rates was through better feeding and monitoring of hind body condition in the lead-up to mating, AgResearch scientist David Stevens said.
The condition of a hind at mating significantly influenced how soon they conceived and the aim was to get them in a body condition score (BCS) range of 3 to 3.5. Hinds in better condition more readily conceived whereas a hind with a BCS of 2.4 could be 10 to 15 days later in conceiving. A lower-BCS hind was also more likely to be dry.
‘We hope the losses from scanning to weaning is an aberration.’
“If hinds calve 10 days earlier you could add another 3 to 4kg liveweight to fawns so there’s a lot of opportunity with condition scores,” Stevens said.
The 2014-15 season had proved to be a challenge for the finishing of all stock classes, Brian said.
“It’s been a problem throughout the region.”
The mixed-age hinds are usually weaned in early March and the first-calvers weaned post-rut but this year all were weaned in mid-March because of the lighter conditions of hinds and fawns.
Farm in focus
The 2015 Southland deer focus farm is owned by the Russell family who earn most of their income from deer breeding and finishing off two farms in Northern Southland.
The Dipton block, The Rock, is 845ha of mostly flat to rolling hill plus 220ha of undeveloped hill country. It’s used primarily for ewe and lamb grazing and cattle-deer finishing. The Kowhai block, 20km away, is higher-altitude semi and undeveloped hill country grazed by hinds and breeding cows.
Shareholders of the farming business are Brian and Kristine Russell, who manage the farming operation, and Brian’s parents Bruce and Annabel. A story on aerial weaning at the Russell’s farm featured in Country-Wide, April 2012.
