Biosecurity on the Dairy Farm

Biosecurity means

• effective control of the diseases which occur on your farm.
• keeping other diseases off your farm.
• producing a wholesome product for the consumer

 

What poultry and pig farmers do

The points below illustrate how seriously intensive biosecurity is taken on modern pig and poultry units. 

Access control

• Security fence around unit
• Gates locked
• Vehicles deliver feed and load pigs from outside the security fence – i.e. they do not enter unit
• Strict control on who enters the unit 

Hygiene

• Restrict visitors
• Visitors shower in and shower out
• All in - all out systems i.e. buildings are emptied completely and thoroughly cleaned and disinfected BEFORE the next batch of chickens or pigs are placed in the building.

Further Control

• Pets
• Feral cats
• Birds eg. mossies
• Artisans tools
• Injection needle hygiene

On less sophisticated pig farms the four most important control measures are:

• Perimeter fence
• All in – all out as far as possible
• Each worker wears boots and overalls which stay on the property at night. If taken home, they could pick up diseases from backyard pigs and then bring them into the piggery.
• Boot dips at strategic places 

Dairy Farms

Which of these methods can be applied on dairy farms?

It is obvious that on a pasture based dairy farm only some of the above methods can be applied but those which are applicable include:

• Parlour hygiene: milkers, clothing, clusters
• Control rodents
• Syringe and needle hygiene
• Hygiene in calf rearing system
• Restricting access to the calf rearing area. Visitors must foot-dip their footware!
• Screening of introductions i.e. before purchase (see Appendix 1)
• A vaccination programme planned for your farm in consultation with your veterinarian
• Ensuring good calf immunity by good colostrum management

Threats to Biosecurity

• Purchased animals (see Appendix)
• Other animals
• Dogs: afterbirths (CA/BM) Leptospirosis
• Rodents: Leptospirosis
• Wild birds: TB, Avian influenza
• Monkeys & baboons : TB, Salmonella, E.coli
• Fomites (equipment which could carry virus eg. FMD)
• Vehicles

APPENDIX to Biosecurity

Herd Health: Tips on the purchase of dairy animals

Cows and Heifers

Before purchasing heifers or cows establish the following:

Vaccinations

• Have heifers been vaccinated for CA? (Brucellosis/Besmetlike misgeboorte)
• If so, at what age?
  With which vaccine - S19 or RB51 or both?
• By whom
• What other vaccinations? Dates?

TB and CA

• Is herd tested for TB and CA regularly?
• Are certificates available?
• When last were there positive cases of TB or CA on the farm?

BVD

• A skin notch from an ear can be tested for BVD to ensure a heifer is not persistently infected with BVD.

EBL (Enzootic Bovine Leukosis)

• This disease will increase in importance and EBL-free animals will command premium prices.

Other Tests

• There are numerous other diseases for which one can test e.g. Leptospirosis, Johnes, Neospora, Salmonella, Cryptosporidium.

Ticks

• Ticks on some farms are resistant to acaricides (dips). This could cause huge problems on an unwary buyer’s farm.
• Ensure cattle are tick-free on arrival and try to establish whether resistance is a problem on the seller’s farm.

Uterus and ovaries

• How many calves has she had?
• Is number of calves satisfactory in relation to her age?
• What is status of reproductive organs? i.e. is she in calf? Infected uterus?
• How often does vet do fertility examinations on the dairy herd?
• When last were the cows that you are keen to buy checked by a vet, what were his findings and what treatments did he administer?

Udder

• How many quarters are functional?
• Fibrosis (hardening) of quarters present?
• Mastitis history?
• Previous SCC?

Teeth

• Badly worn?

Milk Production

• What has she yielded in previous lactations?

General 

Dairy cows are an expensive investment. Unless the above-mentioned questions can be answered satisfactorily you may be buying trouble. The potential problems should be obvious yet very few farmers protect themselves by seeking the answers!! Individual cows sold out of hand are usually other people’s problem cases - don’t buy trouble!! You seldom get good dairy cows cheaply, so beware. A sound rule is to buy only hefers and never buy cows. 

Bulls

Trichomonas and Vibrio are two important venereal diseases. Ensure bulls are tested before purchase.
Testing is especially important if you hire clean up bulls at the end of your AI programme. Bulls must also be tested for EBL, BVD and Johne's diseas. 

 

Specific Threats 

Enzootic Bovine Leukosis [EBL] (Read more)

Mastitis (Read more)