Producers looking at using crops as a livestock feed source need to consider animal health before they start grazing.
Central West Local Land Services (LLS) regional veterinarian Dr Jillian Kelly, Coonamble, said there were a number of risks associated depending on the type of crop being grazed.
“Canola is riskier than most crops. It has been the topic of most the inquiries people are making,” she said.
“A big problem is stock grazing a monoculture, or all one plant species, that may be un-palatable.
“Some poisonous plants may be more palatable, particularly in canola, meaning stock may consume these rather than the crop.”
Recently presenting a webinar through Sheep Connect outlining how to manage and avoid animal health issues, Dr Kelly said it was important to consider withholding periods and export slaughter intervals (ESIs).
“Crops that have been sprayed or are going to be sprayed may have a withholding period and ESIs to be conscious of,” she said.
“Sprayed out crops will wilt and be more attractive resulting in animals eating more, increasing risks and toxins.”
The transition onto crops should be smooth to allow the animal’s rumen to adapt rather than experience a sharp dietary change in energy or protein intake.
Providing roughage before and during grazing is important to ensure rumen adaptability, to provide an additional feed source and to make sure stock are not hungry when they are being put onto the crop.
Livestock behaviour trends indicate it is safer to introduce crops to animals in the afternoon when they are fuller and likely to consumer less.
Dr Kelly said producers should consider the vaccination and drench status of the animals to ensure diseases were prevented or managed.
“Susceptibility to diseases, such as pulpy kidney, from a high carbohydrate diet could increase therefore even if stock are up to date, extra booster should be given before going onto crop,” she said.
Minerals should be provided to ensure the stock requirements are being met and animals are not becoming deficient. Salt and calcium are important, particularly on cereal crops.
Dr Kelly said it was also advisable not to join stock on a crop. “This is because the crop is high in protein meaning the liver is working overtime to metabolise all the protein,” she said.
“The liver is responsible for ridding body of progesterone, therefore more progesterone is being processed and there may not be enough for maintenance of pregnancy.”
She said if any animals look unwell, remove all stock immediately.