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Johne’s Disease Calf Accreditation Program

By Department of Primary Industries - 27th October 2004 - Back to News

The Johne’s Disease Calf Accreditation Program (JDCAP) is a calf-rearing program designed to minimise the risk of spreading Bovine Johne’s Disease (BJD) from adult cattle to replacement calves within a herd. The fact that it is accredited by an approved veterinarian means that purchasers can be assured of the status of the stock being bought.

While the value of the program can be readily appreciated in herds known to be infected with BJD, its value may well be overlooked in those herds in which BJD has not been diagnosed. There is always a risk of introducing BJD into the herd through the purchase of replacements and bulls. Non-assessed herds may unknowingly be infected with BJD. It may simply not have been diagnosed.

So JDCAP will minimise the spread of BJD in herds which may be infected but which have not been diagnosed as such.
BJD is spread from adult animals to calves principally via faeces and milk.

The key principles of the program are quite simple:

• to prevent calves from coming into contact with the faeces of adult cattle and
• to reduce the exposure of calves to potentially contaminated milk.

All herds are eligible for entry into the program under the following conditions:

• the property be subject to inspection by an approved veterinarian prior to the commencement of accreditation
• all replacement calves to be separated from their mothers within 12 hours of birth
• cows to calve in areas free from dairy effluent or large amounts of manure
• the calf-rearing area to be free of any dairy effluent or faeces of adult cattle
• only clean water, (preferably tank, town or bore water) to be used for drinking by calves or for preparing calf milk-replacer
• only milk from low-risk cows or milk-replacer to be fed to calves
• calves to only graze paddocks that have not had adult cattle in them for the previous 12 months
• the grazing areas of calves to be free from any drainage or effluent.

The owner signs a Herd Owner Agreement which is endorsed by the approved veterinarian.
The veterinarian then provides the owner with a JDCAP registered Certificate of Compliance.
Further information on JDCAP can be obtained from your local DPI office or from your veterinary practitioner.

SILAGE TIPS

With silage season well underway, DPI Fodder Conservation and Pasture Specialist Frank Mickan has suggested some ways of ensuring the silage you are preparing has the correct dry matter content.

Silage should be made at the correct dry matter, if possible, to ensure a desirable lactic acid fermentation in the absence of air soon after harvesting and sealing. Undesirable and mouldy silage will be the result of silage made too dry or too wet. These silages will be less palatable, lower quality and not so pleasant to smell or handle.

For pasture silage the suggested dry matter content is 28-35% DM for pit silage and 40–55% DM for bale silage. Stemmy crops should be on the wetter end of the ranges while leguminous crops, such as lucerne, should be on the drier end of the ranges. Two simple ways to test the dry matter of your cut pasture is to use a hand squeeze technique or drying by a microwave oven.

With the hand squeeze method, take a representative sample of the pasture, cut it into 1-2cm lengths, tightly squeeze a handful for 20–30 seconds, quickly open your hands and by following the table below you will be able to discern the approximate dry matter content.

With the microwave oven method:
Collect representative samples from the crop and thoroughly mix together - sub sample to get a test sample.
Weigh out approximately 100g sample of the chopped forage excluding the weight of the container. Weigh to the nearest gram. This is the initial wet weight.
Spread the weighed forage sample on a paper tray and put it in the microwave oven.
Place a 250ml glass three-quarters full of water in the oven to prevent igniting the sample after some initial drying. Maintain water level during oven use.
Heat at 80-90% of maximum power for 4 minutes if sample is estimated to be 30-50% dry matter.
Remove the sample, mix and weigh.
Continue to re-heat for 1-2 minute intervals, re-weighing each time. To prevent burning use lower heat and 30 second time intervals as the sample approaches being dry. If the weight of the sample does not change after two or three drying intervals, it is 100 per cent dry within 1–2% units. This is near enough! This is the final dry weight. If the sample burns use the last recorded weight.

Calculate dry matter content as follows:

Final Dry Weight (gms) X 100 = % Dry Matter

Initial Wet Weight (gms) 1

e.g. 48 gms X 100 = 42.8 % Dry Matter

112 gms 1

Source: http://gippsland.com/

Published by: news@gippsland.com