Minimising Coccidiosis Outbreaks

Coccidiosis is a parasitic disease which primarily occurs in young cattle between 3-8 months of age. Occasionally the disease is seen in animals as young as 4 weeks. Coccidia are widespread in the environment, however disease only occurs if large numbers of the parasite are ingested or if their resistance is lowered due to stress, poor nutrition, concurrent disease, or heavy worm burdens. Coccidia can survive for long periods on pasture - grazing calves on the same paddocks each year increases the risk due to significant build-up of oocysts on paddocks, especially in wet conditions.

Calves present with diarrhoea typically containing mucous and blood. They frequently strain to pass faeces, swish their tails, are often off their food and appear uncomfortable and unhappy. Faecal staining on the back of the thighs is often evident. Affected calves lose weight rapidly due to gut damage and growth rates can suffer for months after the disease. Most calf meals contain a coccidiostat which prevents the infection becoming established – however the protective effect relies on calves consuming about 1kg of meal/day. Often mobs are eating more than this on average but there are always some calves that eat less than others.

Treatment is with Toltrox (as a single oral dose) or injectable Amphoprim (antibiotic) and are usually effective, especially when instigated early in the disease. History and clinical signs are often enough for a presumptive diagnosis, however faecal samples are required to confirm and are relatively quick and cheap to perform.

Turbo Initial is also a good product to keep in mind – a dual action double combination drench (Eprinomectin and Levamisole) with added Diclazural for coccidia control. Post-weaning off calf meal, some calves will become very susceptible to coccidiosis. Calves at risk can be strategically treated with Turbo Initial once at 18-20 days after weaning off meal. This allows them time to establish an infection and gain some immunity, then treating the infection before it can cause disease.

Calf Scours in the Latter Half of Calving

We field a lot more calls about calf scours in late August and September than we do in the earlier stages of calving. When we visit calf rearing facilities that are having problems at this later stage, one of the notable issues is the accumulated deposition of infectious scours in pens. In the case of Rotavirus, it is possible to infect 10,000 calves from just 1 gram of faeces! So, when a calf pen become thick with scour, the sheer volume of viral (and bacterial) load may be enough to overwhelm good colostrum antibody immunity in what are otherwise healthy calves.

It doesn’t matter how much disinfectant is sprayed around a very heavily contaminated pen, the reality is you cannot sterilise it. Placing new calves in a heavily contaminated pen will always have a negative outcome.

Where possible avoid housing new or young calves in heavily contaminated pens. Either completely clean them out (disinfect and replace bedding) or get them outside. Straw bale outside shelters may need to be moved frequently so calves do not camp for extended periods in poo. Scours vaccines do work, but they work best when the whole herd has been vaccinated which ensures the calf pens stay cleaner for longer (partial herd or just doing late calvers is a compromise).

Remember to use Metacam to speed recovery and appetite, supply free access Optiguard as a gut protectant, and use Vet Centre Rehydrate electrolytes (we believe our formulation is the best on the market). Discuss whether antibiotic use is appropriate with your vet.

Finally ensure your hay/racks are placed high and are full to dissuade calves eating contaminated sawdust or wood chips on the ground and getting infected. Calves which are sick should never be place on OAD feeds.

Rehydrate – Calf Electrolyte

Rehydrate is an electrolyte mix that our practice formulated. Its ingredient list is far superior to that offered by many other commercial preparations but at a fraction of the cost.

• It has great palatability

• It corrects metabolic acidosis in dehydrated calves

• The formulation ensures speedier absorption of fluid fraction of solution

Downer Cows

Every dairy farm will experience some metabolic downer cow cases this spring and most are a relatively quick fix with metabolic treatment and up within a few hours.

But a significant number stay down for long periods. Any cow which has been down for over 24 hours requires good nursing to ensure a full recovery but this can be very labour intensive and time consuming.

It is important to understand that these cows are often not down due to the primary condition (i.e. milk fever) but are down due to secondary complications such as muscle injuries, nerve damage and compartment syndrome. This damage can occur within as little as 3 to 6 hours of going down, especially if the surface is hard and/or the animal is heavy. So, a cow needs to be got back on her feet quickly or managed appropriately to prevent this secondary damage.

Nursing of a downer cow should only be undertaken if the cow has a reasonable chance of recovery and a competent person is on hand, who is prepared to invest the time and energy in the care of the cow. This is an important animal welfare message. If you are unable or unwilling to provide a high level of care then euthanasia should be elected early in the piece.

Inadequate care of down cows is one of the most common animal welfare complaints from members of the public.

Research has shown that over 45% of downer cows can recover with good nursing, while 0% of cows will recover if very poor nursing is given!

• Ideally the down cow is sheltered and on clean, dry and soft bedding. Normally this means putting her in a calf shed. While the majority of down cows are nursed in the paddock, this is not ideal and she should at least have a cow cover put on her.

• Clean water and good feed should always be available. A cow should drink 40 litres a day and have at least 12-15kg of DM. A 1 litre bottle of Calstart or Headstart is equivalent to a kg DM.

• Longer acting anti-inflammatories such as Metacam and Rimadyl will definitely improve cow comfort and prognosis.

• Move the cow from side to side every 3 hours to ensure her weight is not always to one side and flex and extend the hind limbs each time the cow is moved

• Regularly milk the udder out by hand stripping, check she is not developing mastitis.

• Encourage the cow to rise, use hip clamps to get her to her feet only, never leave cows hanging in hip clamps.

• Regularly re-assess her progress and diagnosis. If you have any doubts ask for help.

Preventing Metritis and Endometritis

Last year we saw a number of herds with a high incidence of health alerts picked up in cows during the first 14 days post-calving. This coincided with high rates of metritis and endometritis in these herds. Once we see these alerts kicking off it may be hard to prevent the problem in cows that are already within 10 days of calving (springers). Five common causes are :

1) Cows calving down too fat – these mobilise high levels of NEFA suppressing the immune system

2) Cows calving down too skinny – these are also immune compromised due to energy status

3) Cows having inadequate dietary protein in the final 3-4 weeks of pregnancy – protein is required for production of antibodies and this may be preferentially drawn on by the calf when in short supply

4) Clinical or sub-clinical milk fever – slows the involution of the uterus 5) Selenium deficiency – reduces the immune function and increases the chances of retained membranes.

Optimal dietary protein intakes are regularly compromised in the last weeks of pregnancy when cows remain on Fodder Beet crops with low leaf yield together with low protein supplements. Ensuring that the springer diet is meeting the energetic needs and no more is also vital.

If metritis and endometritis has been a problem in the past – discuss transition cow prevention steps with your prime vet.

Balancing the Winter Diet

Fodder Beet

A cow in the dry period typically requires 10-11% dietary crude protein as a minimum to remain healthy and gain muscle mass as well as body fat. This requirement (for udder development, colostrum production, rapid phase calf growth) starts to rapidly increase in the final 3 weeks of gestation reaching an optimal 16% in the final 10 days before calving. Fodder beet (FB) is usually low to marginal in protein. The leaf yield of the crop is a prime determinant in the total available crude protein. Crops that have low leaf yield or have had minimal nitrogen application/depleted soils will generally be low. Careful consideration needs to me made around the form of supplements to complement a FB diet. Where the CP levels are low, addition of a good quality grass or lucerne silage/bailage will aid in restoring to optimal levels, whereas a poor-quality hay or straw will worsen the situation. Getting crops tested for crude protein is a good place to start when calculating supplement balance.

Fodder beet may be low in Phosphate (but not always) and is commonly low in Calcium. Phosphate levels in beet in the Waitaki area are not as low as those reportedly found in other areas in Canterbury. With Calcium the leaf typically contains 5-7 times the concentration than the bulb. Thus, having a healthy leaf yield is a good way to ensure cows are not deprived. Testing for these two macro-minerals is a good start point to decide on the requirement for supplementation. Lucerne is a good matching supplement for FB as it is generally high in protein and very high in calcium.

Where is it is possible to provide calcium on FB I suggest you do it. 50g/day of DCP plus an additional 50g/day of limeflour will meet most requirements. Some crops are quite low in salt. Mixing salt with limeflour/DCP can encourage intakes. Most Fodder beet ‘loose lick’ type products benefit from an additional calcium boost.

Selenium levels are always very low, so ensure cows are well supplemented while on crop or going on and coming off. High rates of soil ingestion can deplete liver copper stores so keep this in mind particularly with R1s and R2’s.

Kale/Giant Rape

Generally, kale will have adequate crude protein to support pregnancy - ~15% crude protein, but this is not always the case if it has been nitrogen deprived (it can measure sub 10%). Most of our brassicas are high in Calcium so require no additional supplementation – they can be quite good at replenishing bone stores.

Kale however contains goitrogens which can bind up dietary iodine. Consider supplementing with iodine, particularly with R2’s as deficient heifers are more prone to still births.

Kale diets usually result in the body consuming more Selenium and Vitamin E (vitamin E deficiency is also associated with still births and RFMs). For Vitamin E restoration try to get back onto 5kgDM plus of grass 10 plus days before calving and ensure selenium supplementation pre and post going on the crop.

It is recommended that a maximum of 75% of the diet be kale, the rest silage/hay.