Coccidiostats in calf feed explained

The end stage of coccidiosis causes a bloody scour, but before this stage the parasite has already impacted the gut of the animal, causing poor weight gain and ill-thrift. The parasite lives in the environment so it is hard to avoid. Calves pick it up as they are grazing and then it makes its home in their gut, laying eggs and establishing an infestation. Using coccidiostats in our calf rearing system is an important way to break the life cycle of the parasite and prevent the disease developing. Most milk powder and hard feed will contain a coccidiostat, which is great, but it’s good to understand how to use these products for the best outcome on farm as they can be toxic to non-target species such as our canine companions. The three main coccidiostats used in New Zealand in calf milk replacers and hard feed are Decoquinate (known as Deccox® or Coccistop®), lasalocid sodium (known as Bovatec®) or monensin sodium (known as Rumensin® or Rumenox®).

Lasalocid sodium and monensin sodium are both toxic to non-target species including dogs, horses and alpaca and they can cause death in these animals if enough is consumed. Monensin sodium is more toxic than lasalocid sodium, so it causes more harm at lower levels when consumed by non-target animals. Bags of calf feed are required by law to have clear labelling on the front to warn users of non-target animals at risk of consuming the product. Dogs are often at the foot of calf rearers as they go about their busy days, so it’s important we keep our canine friends in mind. Decoquinate is a safer coccidiostat to use around dogs and horses, and we are seeing this in calf milk replacers more often to offer piece of mind to calf rearers. The Reliance range of calf feeds available at Farmlands have historically contained the coccidiostat Bovatec, which has served the range well for a long time, but with changing times we have decided to move to using decoquinate in the milk powder and hard calf feed of the Reliance range from spring 2026, to offer more choice to calf rearers that want to avoid the other coccidiostats.

Decoquinate also offers a great option for calf rearers looking to meet the requirements of some niche beef export markets that specify only decoquinate can be used as a coccidiostat. ACVM labelling of coccidiostats had a recent review by MPI which saw the addition of a statement to labels, which is then required to be put on any products that contain them. The statement is ‘must not be used for the purpose of promoting growth or increased yield’. This statement is important to understand, but is often misinterpreted by those keen calf rearers reading that fine print on the back of a bag. It could be assumed that this statement means the feed cannot be fed to calves since we are feeding them to grow them. However, when rearing calves we are using the coccidiostat to aid in the prevention of coccidiosis for health and development of our calves rather than for growth promotion, so it is therefore very much acceptable by MPI to use the coccidiostat in this way, despite the prohibition against production enhancement.