Copper Complacency

Over the last 10-12 years a level of complacency has developed around copper deficiency and the need to supplement. This has come about largely through the feeding of palm kernel. PKE has been a great supplementary feed source and it has the bonus of being high in the trace element copper.

However, the replacement R1’s & R2’s are away from the milking platform where they are fed a mostly pasture or crop-based diet depending on the season. Replacements, therefore, are at far higher risk of developing Cu deficiency than a milking herd being fed PKE through the season.

The extent of this problem was investigated several years ago when our practice conducted some basic surveillance work looking at copper levels in rising two-year-olds at grazing. We found that over 80% of R2 mobs sampled had individual animals deficient in copper.

Before disregarding the need to supplement copper in R1’s and R2’s consider the following points:

• Copper levels are at their lowest in late winter/early spring. This coincides with higher copper demands over this period for late pregnancy and early lactation.

• First calving heifers are often slow to start eating PKE in the shed unless they have been fed it as calves. So, feeding PKE can be an unreliable way of supplementing copper to these animals.

• Humeral fractures are a major issue on individual farms and a significant animal welfare problem. While copper supplementation is not the silver bullet to stopping their occurrence it is a key part of the prevention strategy.

The optimal time to supplement Copper in R1’s and R2’s is mid-late autumn before animals go onto winter crop.

Options to supplement Copper in R1’s and R2’s:

• Coppermax and Copaject injection. This can be safely given to cattle over 4 months of age. A 2ml dose is given under the skin of the neck. The dosage may be increased up to a maximum of 4ml if severe copper deficiency has been confirmed through liver biopsies.

• Copper bullets. These are given orally and contain copper oxide wire particles in gelatine capsules. Typically, a R1 would be given a 10 or 20g capsule and a R2 a 30 or 36g capsule depending on liveweight.

To establish the true copper status of a milking herd 5 liver biopsies are the way to go and we should never assume the copper status of a dairy herd is fine because PKE has been fed during the season. Copper levels will naturally decrease over winter especially if the herd is wintered on crop and the property has no in-line dispenser in the water system.

Whilst blood samples can measure copper levels easily, this only tells us what an animal’s copper status is on an individual day. It unfortunately tells us nothing about the animals’ copper stores in the liver which is of far greater importance going into winter.

Liver biopsies are quickly and easily performed on farm. Whilst collecting liver samples from cull cows at the freezing works is convenient on farm liver biopsies have several advantages.

• The vet is on farm so can select the animals to be biopsied.

• Accurate animal identification at sampling.

• Clear traceability of samples from collection to reporting.

February Production Drop and Heat Stress

For many of our clients (especially those more inland), late January/February saw some significant drops in production. Many farms reported cows being listless and inappetant, despite them going into some good quality feed.

I don’t have to labour the point that this summer has been hot (and humid on many days). For a period there was little reprieve as night temperatures failed to dip below 20 degrees. Friesian cows are comfortable in temperatures less than 20 degrees (Jerseys less than 24 degrees). Above these temperatures cows must work to keep their body temperature under 39.0 degrees.

Cows are essentially a large fermentation tank on legs. The rumen produces a lot of heat. This is great in the winter but in higher summer temperatures it means they will struggle to keep their body temperature low. Night time should provide some reprieve if a cow over-heats during the day, but when temperatures stay high throughout the night they may be starting the new day already in heat stress.

Cows in heat stress will open mouth breath (pant), seek shade and spend more time standing to try to reduce body temperature. Think back to when we had bountiful shelter belts as to where the cows would have been standing on these hot days. Once the body temperature raises above 39.5, cows will be less inclined to eat, will have poor immune function and production and body condition may drop.

We cannot replace tree shelter quickly where it has been lost, but other shorter term strategies may be used.

• Cool drinking water is hugely important. Install multiple water troughs in main lanes to and from the shed.

• Wet down the hot concrete before the cows come on the yard.

• Install sprinklers on the yard (these might be used morning and afternoon if the night was hot).

• Put sprinklers on the shed roof (and/or misters inside the shed).

• Try to avoid milking in the heatof the day.

• Milk smaller herd sizes to minimise the time spent on the yard.

• Let cows move at their own pace – chasing slow cows down the lane will just heat them up more.

Recording Clinical Mastitis Cases

Please record your clinical mastitis cases

The rules are getting more restrictive about being able to use whole herd antibiotic dry cow therapy (DCT). Most of you are steadily transitioning away from whole herd antibiotic DCT and are comfortable with it. However some herds will still require whole herd antibiotic DCT but there are criteria that the Vet Council are expecting us as the authorising vets to have met, to authorise the usage of whole herd antibiotic DCT. Two of the five criteria are based on the incidence rate of clinical mastitis (number of cases per 100 cows). One of these measures is the amount of dry period mastitis – this is traditionally very poorly recorded – if you did have some please record it into MINDA. Even if you are not considering using whole herd antibiotic DCT please get your mastitis records entered in MINDA as this data is also valuable for making decisions at the individual cow level.

To make the best decisions regarding a cow at drying off for selective DCT (is she a high or low risk of having an infection?) we do need data. Herd test data is the best, and the addition of her treatment history (clinical mastitis records) is likely to make a difference to an individual cow. Interestingly the proportion of cows correctly classified does not seem to have altered much (in some papers that have looked at the best decision-making rules) whether mastitis data is included or excluded, but these results are at a population level not for an individual cow. An individual cow is either infected or clean, not 70% infected, so please enter your mastitis data.

Polioencephalomalacia

We are once again seeing several cases of P.E. (polio encephalomalacia), a nervous disease seen primarily in calves and younger stock. P.E. is caused by a lack of vitamin B1 (not to be confused with a cobalt deficiency, which is associated with a vitamin B12 deficiency). P.E is thought to be nutritionally induced, when there is a sudden change in diet from stalky, higher DM diet, to a lush, low fibre diet. A high dietary sulphur intake, especially with brassicas, has also been incriminated as a cause of P.E.

Calves with P.E. appear blind, may walk aimlessly, appear wobbly, have muscle tremors and head press. If calves are treated early in the disease process with a series of vitamin B1 injections, survival rates are good. In an outbreak situation we have had good success, by prophylactically treating the remaining, unaffected calves, in the group with an oral vitamin B1 drench. This has proved a very cost effective preventative measure.

Pink Eye Update

Whilst Pinkeye can be tricky to see, it can certainly become an eyesore if left to brew away! Pink eye is caused by bacteria (Moraxella bovis). It becomes a pesky problem heading into the summer months as wind, heat, dust, flies and long grass can weaken the natural defences of the eye and cause an infection.

Pink eye is incredibly contagious and can rapidly move through a mob, so it pays to get on top of it quickly. Signs of pink eye begin with weepy, clear discharge and squinting which then can progress to discoloured/white eyes which can develop deep ulcers. If left untreated, it is very painful and uncomfortable. It can lead to nasty ulcers, blindness and reduced growth rates, as well as it being a significant welfare issue. Lesions quickly worsen for an animal and eye damage can be irreversible (partial or complete blindness).

Treatment of pink eye is either with Orbenin eye ointment OR injectable tetracyclines (Engemycin or Bivatop). If you are having particularly bad problems this year, or it is becoming an annual problem, then come talk to us to see what management factors may be of help. A single dose of Piliguard vaccine given 3-6 weeks before the risk period will significantly reduce the risk of an outbreak.