October is when it gets really busy at our end, at the time of writing this production is starting to average 40 tonne a day and we are still four weeks away from the peak which is normally the short week after Labour weekend. While we continue to improve the capacity of the feedmill to cope with peak demand often it’s not that easy for the freight companies and they can come under some extreme pressure. Please do what you can to help them cope, have a tractor ready to go with some good forks. Thank you to the farmers who do have good forks on their tractor and who take care with our pallets, unfortunately the truck drivers tell me there are still some farmers unloading in a hurry and using a silage grab, which never ends well. We really like to get our pallets back in reusable condition, if you have some pallets to come back and truck driver isn’t very cooperative in picking them up then please send me a text.

Also a thank you to those calf rearers who text their order to me, often I am away from the office when an order is placed and sometimes it’s not convenient to stop and write the order down. With the texts when I get back to the office I can easily scroll through them trying to make sure I miss none. Just remember you have to use the 027 299 3484 number the 0800 does not receive texts even though it’s the same phone. This month I’ve asked Paul Drew from Vitec Nutrition to provide some info on coccidiosis. The following is an abbreviated version of what he sent me.

Ionophore use to prevent Coccidiosis in calves and the dangers to non-target species

Ionophore use in calf feed is important to prevent coccidiosis and to improve the rumen environment. A typical calf feed is formulated to protect the calf with sufficient ionophore to fight against coccidiosis, once the calf is eating 1 kilogram of feed. Aoraki Calf Meal includes Bovatec® (active ingredient - lasalocid) at a higher level, protecting the calf once it is eating 650 grams, an estimated two weeks earlier than typical calf feeds.

Calves become infected with coccidiosis when they ingest the oocysts (or eggs) of the Eimeria parasite. Once ingested, the parasite invades the mucosal lining and progress through the various stages of development in the cells of the intestinal lining. It’s during this period that the parasite does damage – reducing growth rates, feed intake and feed efficiency and eventually causing diarrhoea. By the time the signs of bloody diarrhoea become apparent, the damage is already done.

Coccidia are passed from calf to calf by ingestion, so good sanitation and isolation help to protect against coccidiosis. However, the oocysts are particularly resistant and can survive for extended periods of time in tough conditions. Once calves are infected, the number of oocysts in the environment increases rapidly and so even calf rearers, with good management practices, can have coccidiosis problems.

It is the reduced feed intake, poor growth rates and ill-thrift seen in sub-clinical cases which results in the greatest losses for the producer. Heifers affected by coccidiosis may never achieve their full potential for growth and milk production. Independent research has shown that at 12 weeks, Bovatec® fed dairy calves are on average 11.7% heavier than non-treated calves.

In the case of this disease, “prevention is better than cure”. Ionophores are very effective in preventing the disease as they disrupt the functioning of the oocysts in the gut lining and prevent the disease from occurring. In the case of Bovatec®, the lasalocid dosage required to prevent coccidiosis is 1mg lasalocid /kg bodyweight. However, because the required dosage for protection, changes with increasing bodyweight, it is evident that protection from cocciodiosis is dependent on Calf Meal intake and level of ionophore in that Calf Feed to provide the correct dosage dependant on calf weight.

Ionophore Toxicity in non-target species

Ionophores affect the transport of ions in the various cell membranes. This ability makes ionophores capable of controlling the parasite coccidia in chickens, calves and other animals, but it also makes it deadly for horses and dangerous for dogs. While it does affect many systems, its main impact is on the dog or horses muscles, especially the heart as it affects the flux of potassium and sodium across the muscle membranes.

Toxic signs and degree of symptoms are dependent on the age, sex, weight, health and intake of ionophore containing feed. There is also a difference in level of toxicity depending on the type of ionophore. There are two main types of ionophores used in New Zealand ruminants, Bovatec® (active ingredient - Lasalocid) and Rumensin® (active ingredient - Monensin). Lasalocid is known as the “safer” of the two ionophores by up to 10 times safer than monensin in horses.

LD50 is a figure used to indicate toxicity levels. LD50 is the dose required to kill half the members of a tested population after a specified test duration. The LD 50 of Lasalocid for a horse is estimated to be 21.5mg/kg bodyweight per day and 10-15mg/kg for a dog. LD50 for monensin in horses is 2 to 3 mg/kg body weight and 5-8 mg/kg for a dog.

A 400 kg horse will have to eat 86kg’s of a calf meal in a day containing 500 grams of Bovatec® 20% per tonne to reach the LD50 and in effect, have a 50% chance of dying. This is no recommendation that the horse or dog can eat feed containing lasalocid. Remember that the LD50 describes the level of intake where half of the tested population died (the other half lived). If a dog or horse has ingested feed containing ionophore and doesn’t die, there could still be long term damage to that animal. We recommend you follow all label cautions against feeding ionophores to dogs, horses and camelid species.

Cheers

Ken Buckingham