March 2018 Monthly Management
Spring Feeding, How to Manage Cryptosporidium Problems on Your Farm
While we hope that spring kicks into gear this week and that growth/ground conditions improve, an alternative plan needs to be in place in case it doesn’t. A difficult autumn and a cold wet start to the spring has all led to reduced availability of grass and silage on farm. At this time of year, it is critical to ensure that that feed intake and energy demands of the herd are being met.
- Walk the farm regularly to assess ground conditions and grass covers.
- Plan when your first round of grazing will finish, it will be later on all farms this year. For example, if you predict the first round will finish in 30 days, take the total area available to be grazed in this time and divide by the number of days to the end of the first round. E.g 60 acres are available for grazing divided by 30 days gives a 2 acre day allocation for cows. This does not take account of cow numbers or grass availability but allocates a percentage of the farm each day to the end of the round.
- Ensure you have adequate fertiliser out; target for mid March is to have 70 units N out per acre.
- Graze lighter covers sooner – these paddocks will recover faster and allow a higher percentage of the farm to be grazed and back growing again for the start of the second round - grazing will also wake the sward up.
- Use all spring grazing techniques especially when weather is challenging to avoid grass being wasted. Use On/Off grazing - giving cows 2-3 hour allocations of grass, spur roadways and a back fence to avoid cows eating regrowths or causing extra damage.
- Graze heavier covers on drier days if possible
- Midway through your first round you need to look at the paddocks first grazed to assess regrowths. During the first round you need to look behind you as much as ahead of you. Decide if these paddocks will have an adequate cover of grass for the start second round. If they won’t you will need to increase supplementation and extend the first round.
- For those measuring grass, average farm cover should not fall below 500kg DM/ha at any time, otherwise grass growth will be compromised.
Silage will be required during the first round if growth rates remain low. The amount depends on weather and growth. Every farm is different but if you feel that you don’t have enough there are a few options listed below:
- If feeding silage by night, ensure the herd has an appetite to graze once let out – either cows should have no silage left in front of them for a few hours before being turned out to graze or held for 2 hours after milking. This can reduce silage demand and increase grass utilisation.
- Get cows and younger stock out to grass as soon as possible – even heavier farms may have drier fields, the key is to walk the farm
- Concentrate feeding levels – if meal feeding levels are already high (4kg/head at each milking) then a midday feed of 2-3 kilos of a cost-effective mix will reduce cows pull on silage and improve overall performance. Care needs to be taken to avoid digestive upsets when on high feeding levels
- Milking earlier in the evening will allow more time after milking to get cows out for a couple of hours grazing and back in again.
These points are just some of the areas that will assist over the next few weeks however it is not a one size fits all approach. If you require any assistance contact you advisor.
How to Manage Cryptosporidium Problems on Your Farm
Neonatal scours are the most common cause of death in calves in the first 4-6 weeks. Calf scours can be caused by a variety of pathogens, but in many cases, Cryptosporidium parvum is the most frequently isolated bug found.
How calves get infected
C.parvum is a small, single-celled parasite. It produces so-called oocysts: small eggs, with a thick wall, that are very difficult to kill. If oocysts are ingested by a calf, they infect the gut wall and cause severe damage to the gut lining. The gut wall cannot then absorb nutrients, so the calf stops growing and develops diarrhoea. After infecting the gut cells, the Cryptosporidium parasite will start to produce additional oocysts which are shed through the faeces. These can survive in the environment for a very long time, resulting in a high risk of infection to other calves present on the farm.
Clinical Signs & Diagnosis of Cryptosporidium
Most calves get infected when aged between 2-5 days and show signs of diarrhoea between 5 and 15 days of age. The clinical symptoms include a yellow/pale scour that has watery and slimy texture.
If calves are infected only with Cryptosporidium, they usually develop mild diarrhoea which does not respond to treatment, but which does resolve within 10 days. However, the infection will have caused permanent damage to the lining of the gut, and as a result, these calves will not thrive as they should. Later in life they will fail to perform well and will have difficulty coping with other diseases.
Mixed infections, particularly with rotavirus, are very common. These cause diarrhoea that is more severe, often characterised by marked weight loss, emaciation and even death. Without correct intervention, calves can become weak and dehydrated rapidly. For a conclusive diagnosis, you must test the faeces of a few animals that have exhibited clinical signs.
A product called Halocur™ can be used preventatively in new-born calves at risk of C. parvum infection. It significantly reduces the severity of scours caused by C. parvum and reduces the excretion of infectious oocysts. Outside of this treatment, C .parvum parasites are not susceptible to any vaccines, antibiotics or coccidiostatic treatments (Vecoxan™, Baycox™, etc..).
Most calves will survive the infection, but they do need intensive supportive care. Sick calves should be moved to a clean, warm and dry environment. They need fluid therapy to treat dehydration and nutritional support to give them energy to recover and repair their bodies.
A protocol to prevent the spread of infection is critical once C. parvum has established itself on a farm. Any protocol must include a combination of measures both to increase resistance/immunity in the calf and reduce infection pressure in the environment.
Increasing Immunity & Resistance in The Calf
Appropriate feeding of at least 3 litres of high quality colostrum immediately after birth is crucial to establishing a healthy immune status for the calf. Exposure to stress should be reduced as much as possible – feeding schedules should be constant, i.e. regular quantities, temperature and feeding times. Stress should be kept to a minimum when carrying out sensitive procedures like weaning and dehorning.
Reduce Infection pressure
Calves are most often infected by ingesting oocysts from the environment. It is important to realise that infected calves will begin to shed oocytes a few days before any signs of diarrhoea show. These calves should be separated from the group and treated accordingly.
Many of the disinfectants commonly used by farmers (such as chlorine bleach) are ineffective against oocysts. Recommended products like Keno™Cox are proven to be effective against C. parvum. Pressure washing at temperatures above 65°C will also work.
Oocysts can survive for several months in cool and moist conditions. Survival time in dry conditions is much shorter.
Cryptosporidium parvum is the most common cause of scours. On its own, it causes mild diarrhoea, but mixed infections (particularly with those with rotavirus) are very common and will lead to diarrhoea that is much more severe. Calves that recover will have permanent damage to the gut, which in turn will have a serious negative impact on their growth and future production.