COOLER temperatures and repeat rainfall events during a longer than usual harvest season have kept sorghum moisture relatively high, increasing the risk of potentially damaging mycotoxins.
Mice have significantly added to the problem. In addition to the deterioration and palatability of feed ingredients because of urine and faces and their carcases, mice also carry a range of pathogens which pose a major threat.
Mycotoxins are recognised as part of a mould's natural defence system. Moulds develop readily, particularly where the moisture content of the feed is above 14 per cent, temperatures are greater than 16 degrees Celsius, and suitable aerobic conditions exist.
Essentially, the longer crops stay in the field, the more stress they are susceptible to, and the more mould is produced.
In sorghum, ergot is caused by a fungus that occurs during flowering. Other notable mycotoxins include aflatoxins, fumonisins, zeralanone and the most severe of all - deoxynivalenol.
Moulds fall into three broad groups - aspergillus, penicilliums and fusariums.
They are particularly dangerous to livestock because the toxins they produce attack an animal's rumen function and ultimately, its immune system.
Moulds and mycotoxins are so common, they are considered unavoidable. They can also be found on most grains, silages, hay and other by-products used as feeds.
Identifying the problem
Often the first signs of a problem is only seen when the animals being fed experience reduced growth rates and/or increased production costs are noticed.
Cattle fed highly-contaminated feeds can also suffer from digestive disorders, lower feed intake, immune challenges and abortion.
Feedlot cattle typically display symptoms including reduced feed intake and ill thrift, excessive saliva and poor growth rates.
A compromised immunity system can also limit the animal's ability to fight disease and infections such as bovine respiratory disease.
Silage is also currently presenting a particular challenge as mice are destroying the protestive plastic layers on round bale or pit silage.
This opening able oxygen to enter the silage, allowing moulds and their mycotoxins to thrive.
One very effective treatment is Alltech's Mycosorb A+, which contributes to managing the control and the impact of mycotoxins. 1-2kg per tonne of finished feed has proven effective. The cost is about 12c-24c/head/day.
With feedstuffs affected by mice, diarrhoea can be a problem, particularly in calves. Diarrhoea can be caused by both viral or bacterial infections, with E.coli and salmonella pathogens often involved.
Deactivating pathogens
Alltech's Actigen works by deactivating the pathogens, slowing the population from developing. This makes the gut more efficient improves immunity levels.
Actigen is recommended at 4g/head/day. The cost is about 6.4c/head/day.
- TOBY DOAK is a livestock nutrition specialist with Alltech Lienert Australia.
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