A week ago, I recounted my relentless search for three essential vaccines that must be given to day-old chicks to prevent them from lethal infections.
These are Marek’s disease, infectious bronchitis and New Castle Disease.
I’d never administered these vaccines before because I always sourced already vaccinated chicks from a reputable hatchery in Naivasha. However, this time, I’d hatched my own chicks for a customer and I needed to ensure she got the best.
If you recall, I couldn’t get the aerosolised (spray-type) New Castle-Infectious bronchitis vaccine combination from my supplier in Nairobi. It’s normally given within the first 24-hours as a spray.
Instead, the agrovet advised me to use another combination that is usually mixed with water but given only after the third day. I then paid Sh400 for 200 doses.
Unfortunately, for Marek’s disease, the minimum vaccine available was 1,000 doses for an equivalent number of young birds. In my case, I only needed 100 doses.
Another thing was that a bottle of 1,000 doses retailed at Sh3,500, which was too expensive. It would cost Sh35 to vaccinate one chick, and once the vaccine is reconstituted, it must be administered within one to two hours and cannot be stored for later use.
To better understand the cost to benefit ratio (the value for money if I vaccinated or not), I called my vet Dr Omari to seek professional opinion.
His answer was a wake-up call to my fledgling hatchery business. “Marek’s a highly contagious and prevalent cancer-causing viral disease in chickens,” he said emphatically. “It occurs in chickens between three and four weeks or older but is most prevalent between 12 and 30 weeks of age.”
After the call, I recalled sometime in June last year when my batch of 500 Kalro chicks suddenly developed general body weakness, limb paralysis and were unable to walk.
When I enquired, the vet expressed concern that I could’ve been dealing with Marek’s disease and he advised me to get in touch with Kalro to confirm if they’d administered the vaccine.
In fact, I lost 29 chicks with paralysed limbs due to suffocation when they were trampled on by others (Seeds of Gold, July 1, 2017).
Ochieng’ assured me that they’d administered the vaccine. “There are several causes of lameness —weakness/paralysis — in chickens.
SPECIFIC TO AVIAN SPECIES
These include viruses (viral arthritis and Marek’s disease); bacteria (mycoplasma and staphylococcus). There are also nutritional causes like rickets and cage layer fatigue syndrome,” he stated.
He mentioned that the only remedy for Marek’s disease is a vaccine administered to day-old chicks through a subcutaneous inoculation or directly into the egg (by in vivo inoculation) when they are being transferred from the incubator to the hatchery on day 18.
He cautioned that after vaccinating the chicks, immunity develops within two weeks meaning that the disease could still be transmitted earlier.
Further, I learnt that Marek’s, named after a famous Hungarian veterinarian called József Marek from Slovak, is one of the most widespread poultry diseases in the world. Besides lameness and paralysis of the limbs and wings, it can also impair vision (blindness) in chickens and make hens to stop laying eggs. Another thing is that it causes between 20 and 30 per cent mortality in infected flocks.
And can the virus be transmitted from humans to animals and vice-versa. The good news is that Marek’s disease is specific to the avian species meaning that humans will not contract it by eating eggs or chicken meat from an infected bird (sick birds should not be eaten).
I also learnt that the vaccine should never be injected directly into the muscle but under the skin (subcutaneous).
“Pinch the skin at the back of the neck and using a needle, inject 2ml per chick,” Dr Omari intimated.
He also cautioned that the virus is hardy and can survive in the environment for years (Seeds of Gold, May 27, 2017).
Besides vaccinating, observe strict farm bio-security practices (infection prevention) to keep the diseases at bay (see My checklist to ward off those deadly diseases available online).
Here’s my advice, before buying day-old chicks, confirm if they’ve received the necessary vaccines. Too often, I’ve heard farmers argue (out of ignorance) that day-old chicks are immune to diseases and often forget to ask if shots have been given at the hatchery.
Unlike other vaccines for poultry ailments like New Castle Disease that can be administered later as booster doses, Marek’s vaccine doesn’t work after 24-hours.
I informed Irene that I had not administered the Marek’s vaccine. My plan is to source around for smaller doses or increase the size of my hatchery to make it economical to vaccinate 1,000 birds.