Body condition, parasitism, trace elements and managing metabolic disease in cows are all issues beef farmers could be thinking about heading into winter, particularly those in drought-affected regions.
Speaking on an Autumn animal health podcast, Wormwise programme manager and vet Ginny Dodunski goes through the various classes of beef cattle with recommendations on animal health management and treatments.
Weaners
Cooperia can be an issue in cattle younger than 15 months, so as a rule of thumb, Levamisole should be included in any drench. Ginny says Cooperia is universally resistant to the ‘mectin ‘drenches hence the importance of using Levamisole right through until the cattle are well over a year old.
“Don’t stop Levamisole too early, especially with smaller weaners.”
Older weaners coming off their mothers at around six months are less likely to be under a worm challenge and therefore might not need drenching every 28 days, especially if weaned onto low parasite challenge feed, or wintered on crop. Smaller dairy cross weaners on contaminated pasture may need drenching more regularly.
As with sheep, the gold standard drench for younger cattle is an oral triple combination in that the more actives in combination, the less likely worms are to survive.
Ginny says just choosing a triple is not enough.
"We are seeing numerous cases of triple resistant Cooperia in young cattle systems now"
She advises testing the efficacy of any drenches used and says it is useful to carry out drench checks in young animals until mid-winter. This involves carrying out a faecal egg count 10-14 days after young cattle have been drenched.
R1s
Under allocating feed tends to be the most common cause of underperformance in this class of cattle. Ginny suggests that before farmers go looking for trace element deficiencies or administer another drench, they look at their feeding regime to ensure their animals’ nutritional needs are being met.
Dry R2 cattle
Don’t waste winter feed on these animals if they are being held back by parasitism or copper deficiency, although copper deficiency is relatively rare in this stock class. The highest copper requirements occur during periods of fast organ and bone growth (think late pregnant cows and R1 cattle).
Ginny says farmers need to ensure their cattle are not taking a worm or fluke burden into winter. Ostertagia rather than Copperia is the worm of concern in this class of cattle.
Ostertagia will burrow into the lining of the fourth stomach and can become a problem. An injectable ‘mectin’ drench is generally effective at controlling Ostertagia.
Pregnant heifers and breeding cows.
Ostertagia can also be a problem in breeding stock, particularly after a drought. Lighter breeding cows are particularly at risk, so again, injectable ‘mectins’ are the most effective treatment.
Liver fluke is a region by region and farm by farm issue. Pregnant cattle need their livers to be functioning at 100% and Liver Fluke will compromise liver function by thickening the walls of the bile duct. This can result in ill-thrift or death.
Outside of their host, the Liver Fluke life cycle stops once grass temperatures drop below 12 degrees, so a clean-up drench in late autumn should ensure breeding cows and heifers get through winter without becoming reinfected.
Metabolic issues
Ginny says the underlying factor in metabolic disorders outside of the calving period is usually underfeeding. Under feeding or a change in diet can result in magnesium deficiency which can cause symptoms such as staggers.
Farmers should discuss the most appropriate magnesium supplementation with their vet.
Trace elements
Trace element deficiencies in pregnant cows can impact on calf survival or re-breeding performance.
Copper deficiency is the most common issue as soil copper levels drop over winter. Cows should go into winter with good copper levels in their system. Selenium is required by cows in late pregnancy and in the birth process.
Vitamin B 12 is not an issue in adult cattle in New Zealand.
To check on the trace element status of their herds, Ginny encourages farmers to get the livers of dry cows checked for trace elements at slaughter.
“Get it done every year, so you know where you are at.”
Body Condition Scoring
Ideally, going into calving, beef cows should be at a Body Condition Score of 5. This is based on a scale of 1-10 with 10 being obese.
If hill country farmers have an annual struggle to calve their cows at BCS of 5, Ginny suggests they could consider changing their calving date or their farm system.
“You need to start paying attention to this early; the fatter they are at weaning the better as it provides a buffer over winter.”
Lower BCS cows (under 4.5) tend to be the ones that fall down gullies, get stuck in bogs or lose calves to misadventure and they are going to be a cost in spring with poor lactation and calf growth rates.
Farmers carrying lighter cows through winter could consider splitting the herd and priority feeding light cows. At a minimum, calving light cows in safer paddocks can help.
Lifting feeding three weeks before calving will not result in calving difficulties. Ginny says the size of the calf is predetermined by genetics irrespective of the cow’s diet.
“If feed levels lift in the three weeks before calving there will always be a benefit in survival, lactation and growth rates.”
To listen, go to Autumn animal health with Ginny Dodunski. Part 2: Cattle