Early Pregnancy Test Results

The key measures of optimal reproductive performance are the 6-week in-calf rate (ICR) and the final not-in-calf rate.  To achieve the industry target of a 78% 6-week ICR, you need >90% 21 days SR and >60% CR.

The 6 week ICR rates to date have been very variable, with the average 6 week ICR for our area, dropping around 4% to 63% compared to last season (15/16) which was 67% - remembering last season was also down on the 2014/15 season.  Many farms have seen a 5-10% drop this season in 6 week ICR.  With most farms now settling in on a 10-11 week mating period, we can expect empty rates to be once again higher than desired.  Many farms experienced a drop in Submission Rate (SR) this season, and some farms experienced an unexpected drop in Conception Rate (CR) as well - a number of farms' CR dropping 5-8%.

Yersinia

Each summer we investigate several cases of calves souring post weaning.  While there are many causes of diarrhoea in weaned calves i.e. parasitic enteritis, Salmonella, and BVD, we regularly diagnose Yersinia, which is a bacteria that causes diarrhoea.  We often see Yersinia 'roll' through a mob of calves - with a small number of calves being affected at any one time.  Treatment is aimed at correcting dehydration and administration of antibiotics.  Prognosis is usually good except in advanced cases.

There is circumstantial evidence that Yersinia is often associated with concurrent disease i.e. BVD, parasite burden, low trace element status - especially selenium and copper.  Remember - that Yersinia (both Y. pseudotuberculosis and Y. enterocolitica) are zoonotic - and hence are a common cause of food poisoning in people.  Keep the hygiene standards high if you are dealing with scouring animals!  Please contact the clinic if you are concerned about ill thrift or scouring in your weaned calves.

When lame cows get out of control

We are visiting a few farms at the moment where lame cow numbers have got out of control.  The smart money is on picking up a foot ASAP and correcting any lesions before they get too bad.  If lame cows are left they're likely to eat less, produce less milk, have lower repro rates, and ultimately have a greater risk of being culled.

On some farms, however, we are seeing lame cow mobs of 30-100+ cows.  By this stage farmers are struggling with time, and the problem often seems insurmountable. Human nature takes over, and so these cows are often left in a close paddock under the "wait and see" treatment regime, rather than being picked up and treated.  If you are in this boat, or want to avoid getting there then we have three options to help:

• Staff Training - we can come out and teach your staff members about how to treat lame cows.  This can help spread the workload across more people on farm.
• Vets to Treat - we can send out a team of vets (if available) to treat enough cows to get the mob down to a manageable level.  To enable multiple vets to work at a time these animals would need to be treated on the platform/herringbone (rather than a race).  Budget on a treatment rate of around 4-6 cows per hour (per vet).
• Healthy-Hoof Lame Cow Prevention Training - Andrew, Luke and Ryan are all trained Healthy Hoof providers and can come out on farm to teach staff about how their actions (i.e. gate use, animal handling) can increase or decrease lameness.  We have had some amazing results on farms following these courses, with dramatic reductions in lameness just from a change in staff attitude and knowledge around cow handling. A more in-depth package is also available looking at diagnosing track and shed issues that are having an influence.

The hidden costs of lameness can quickly mount up, and only get worse the longer they are left. Traditionally we've used an industry figure of around $200 per lame cow. However DairyNZ recently proposed a figure of $500 if you have to start taking cows out of the vat. If you think your lameness issues may be spiraling out of control then give one of our vets a call and we can work out how we can best help you get back on top of the situation.

Making the Most from Mating

Recommended mating lengths of 10 weeks are considered optimal to ensure all cows are calved by the 10th of October (if the PSM was the 23rd of October) to retain a healthy calving spread.  In this scenario a 10 week mating period would have bull removal occurring on the 1st of January.

The number of lactation days is one of the key economic drivers of your farms profitability.  Therefore success of mating should be measured in how quickly they get in calf (3 and 6 week in-calf rate) as well as the empty rate.  The reality of a 10 week mating period is that cows have just over 3 cycles to get back in calf.  The average cow has a ~50% chance of getting in calf at each cycle.  If given every opportunity she would have a 12.5% chance of being empty after 3 cycles.  However if she was to miss the first round of AI she will have a 25% chance of being empty.  Likewise if a heat is missed in the second round she has a 50% chance of being empty!

If your 3 week submission rate is tracking below the >90% target, review your heat detection practices immediately and look to get non-cyclers examined and treated.  Ideally all eligible non-cyclers (calved >40 days) should be mated inside of 3 weeks.  This involves hormonal treatment by day 11 of mating at the latest.  Failure to take proactive action will result in not only a protracted calving spread but also a higher empty rate.

All eligible cows not mated after day 24 of mating should also be examined and treated accordingly.

It is bloat season again....

A large number of farms have experienced deaths from bloat in the last week.  This has coincided with the introduction of high protein, low fibre second round pasture which generally has an increased clover content.

Risk factors for bloat:

• Swards where clover content is greater than 30%.
• Dew on grass at morning shift.
• Short swards.
• Warm windy conditions especially in the evenings.
• Young cows.
• Potassium to sodium ratios in pasture greater than 20 (this can easily be tested for at Feed Labs - known as the bloat index).

Factors which will reduce bloat risk include:

• Feeding longer length pasture.
• Feeding long chopped silage, hay or straw before introduction to a new paddock or break.
• Preferentially grazing older cattle (older herd) on at risk pastures - older cows have adpated grazing behaviour i.e. they do not gorge themselves.
• Feeding salt at 30gm per cow per day.

Rumensin bloat capsules should be considered in situations where dosatron type systems are not available or peta trough dispensers are not practical.  Alternatively if a dostron is available use Rumensin TT or Bloatenz Plus.  Rumensin products have been shown to reduce the risk of bloat by 80%, plus they give the added benefit of extra milk production.