15/03/2022
KNOW YOUR HAY
- THE BAD AND UGLY OF HAY -
Working with hay every day, you get to learn all things about hay and see a myriad of things in the bale. Some things are just plain annoying and some things that are very dangerous for your pet. As hay is a natural product that comes off from the filed, you can image what else hitches a ride in the bale. And hay is also a wild animal magnet while standing in the shed/garage. In this series, I will discuss various items that you may come across, what to look out for and to be aware of.
THE COLOUR OF HAY
I have added this point of thought here because yellow hay may not always be a ‘bad’ hay. Of all the food produced for animal feed, hay is the most variable in terms of quality. Hay quality varies due to different factors such as hay species, fertilisation, stage of maturity, harvesting practices/curing and storage.
The colour of the hay often tells us more about the curing process of the hay. Hay that is bright green was typically cut at a desirable stage of maturity and rapidly cured. It has a high protein and vitamin content. Yellow or golden colour is often a result of sun bleaching and does not seriously reduce quality. Brownish hay is usually a result of excessive moisture during the curing process, thus indicating some degree of fermentation. Dark brown or black is often an indicator that they hay was exposed to rain or high humidity and is usually accompanied by a distinctive musty odour, which is typical of mould growth. Do not feed mouldy hay to your pet.
DUST
Clouds of dust on the fields during harvest are the telltale signs that the farmers in combines, tractors, trucks and other equipment are hard at work reaping what they have sown several months ago. Airborne grain dust is a complex mixture of organic material fragments from grain, plus mineral matter from soil, and possibly insect, fungal or bacterial contamination. These particles are about 30 times smaller in diameter than a human hair. Hay with excessive dust can sometimes lead to respiratory health complications to you or your pet if concentrations are high.
Symptoms of a hay allergy can vary, and depending on the type of allergy and the amount of allergen you or your pet has been exposed to. Signs could begin as mild sneezing or a little clear nasal discharge but over time it can progress to respiratory difficulties.
MOULD & TOXINS
Now this is the real ugly of hay. Mould occurs when hay is produced during wet and humid conditions. Rain and poor drying weather can contribute to this as well and the hay in storage with elevated levels of moisture allows mould and bacteria to grow on the hay. The mould growth produces heat, carbon dioxide and water, which further damages the hay. Mouldy hay can result in dry matter and nutrient loss and produce spores and dust. These moulds can produce spores that cause respiratory problems, and under some conditions, will produce mycotoxins.
Mycotoxin is the toxic chemical products produced by fungi that affect crops. Examples of mycotixins causing human and animal illness include aflatoxin, and ergot alkaloids such as ergotamine.
AFLATOXIN B1 in animal feed and grain
Crops such as wheat, barley and oilseeds can be contaminated with aflatoxin B1 if they become mouldy in storage. The contamination levels in these crops however are much less than the levels found in corn.
Aflatoxicosis caused by aflatoxin (AF) B1 and related toxins represent one of the most serious diseases of rabbits and other animal species. Rabbits are considered of the most sensitive animals to aflatoxicosis. Ingestion of this toxin by rabbits can cause abdominal upset, poor growth and death - especially in younger animals. Long-tem low doses can cause kidney dysfunctions, liver damage and liver cancer. Animals will go off feed and water, get dehydrated and lethargic. You might even notice jaundice
ERGOT ALKALOIDS
Ergot is a fungus that grows on rye and less commonly on other grains such as wheat. Ergotism caused by Claviceps purpurea is the oldest known mycotoxicosis and is characterized cutting off circulation by constricting blood flow. There are two forms of ergotism: gangrenous, affecting blood supply to extremities, and convulsive, affecting the central nervous system. Modern methods of grain cleaning have significantly reduced ergotism as a human disease; however, it is still an important veterinary problem. After being almost neglected over the past decades, ergot and ergot alkaloids have regained scientific interest in recent years
Tip: How do you know if your hay is mouldy? You can smell the mould once it is established, or the sweet smell is gone, and you may see the black spots on the stems. If it is really bad, you will see the entire area that is black with white fuzz growing in the darkest areas. Discard mouldy hay.
NOTE: There are numerous articles on the internet about mould and toxins in hay. A lot of the information is based for problems that occur in the Northern Hemisphere. In Europe hay is generally harvested quite late in autumn with cooler climates. It also rains more frequently there, so higher moisture content is generally a problem. In the Western Cape hay is baled from Spring to midsummer where we generally have a dry south-easterly wind which is are ideal conditions for drying and our hay very seldom has mould, and as a result with fewer incidents of toxins in the hay. Also, we have high levels of UV in South Africa, which kills bacteria and viruses quite effectively. So hay grown in South Africa during the growth and curing process has significantly lower fungal spores.
Tip: if you deep hay-pile the run or cage during winter (keep adding fresh hay on top) for warmth, make sure that the hay at the bottom is not getting mouldy. Rabbits love to burrow and could inhale the mould spores.
HAY POISONING
Hay poisoning can occur when your pets eat hay that is contaminated by a decaying animal. Botulism can occur when animals accidentally get baled in hay during harvest. The decomposing carcass is an excellent anaerobic incubator for botulism spores present in the intestinal tract of the dead animal or bird. Improperly dried hay with high moisture content provides optimal conditions for the production of botulinum toxin which contaminates the hay.
Also, animals consuming hay that is spilled on the ground and then allowed to be mixed with soil and faeces are at increased risk for botulism.
The botulism toxin however, is a protein than can be killed (denatured) through exposure to sunlight (1 – 3 hours) or 12 hours of exposure to air.
Mice and guinea pigs are sensitive to the toxin, rabbits less susceptible and horses are the most sensitive to the toxin. Symptoms are poor function of cranial nerves which leads to the dropping of the head. It can also be accompanied by weakness in the limbs and decreased reflexes.
INSECTS
MITES
Is you hay biting you? Do you have red, itchy welts on your tummy? Then your hay is most likely infected with mites. Of all the hay “uglies” this one is quite annoying especially during hot, humid summers.
The bites are from mite known as Pyemotes tritici. Commonly known as the grain itch mite or straw mite. There are 20 species of the Pyemotes genus which is a parasite of small arthropods, infesting dried plant material, particularly grain, dried beans and peas, straw, hay and other dried grasses.
Mites are actually beneficial because they attack pest insects that feed on stored grain; however they often pose a problem for pets, livestock and people working with hay. They live on the larvae of several stored product pests such as the Angoumois grain moth (see below) , the saw-toothed grain beetle, the pea weevil and the cowpea weevil. Because of their feeding behaviour, they are considered ectoparasites. They show up in hay or grain when a pest infestation is present (like moths). When we enter the infested areas or work with infested materials, the mites attempt to feed on us. This results in numerous itchy bites.
You may feel a prickling sensation on your arms at the time of being bitten – and the ‘full force’ of the bite will be evident with large, red itchy welts on the back, neck and abdomen, particularly around the waist and on the arms. There is no evidence that these mites transmit any pathogens, but their bite can lead to severe skin reactions. Hay itch mites inject proteins when they bite and the reaction to the bite will depend on sensitivity to the protein.
An infested oat hay bale with straw itch mite can affect other bales around it. Lucerne however is not readily a host, but can be infested if stored next to the infested stack of hay.
Pyemotes tritici is an extremely small mite of 0.2mm long. These mites develop from an egg to a larva, nymph and adult. The life cycle usually takes two to four weeks but this depends on the species and the weather. Straw itch mites do not breed on mammals, and if infested produce is avoided for several days, the condition will subside. Symptoms of hay mites on pets could include patches of dandruff or flaky skin, excessive grooming of any area, patches of hair loss and head shaking .
Tip: If you are using straw bales at an event or party, make sure it has been fumigated, or your guests will only remember itchy and scratchy. Once the party is over, it is best to use the straw as mulch in the garden and not as animal feed.
NOTE: There are many other species of mites that could affect your pet. Other mites known as “walking dandruff” are of the Cheyletiella species. These mites can be picked up from the environment, from other pets or from other household pets and bedding. When in doubt always consult your veterinarian.
MOTHS
Moths can end up in your pet’s hay. Although rather annoying, it is not toxic. Common to South Africa is the Rice Grain Moth or Angoumois grain moth. They like to eat seeds and grain of the oat plant in warm and humid conditions.
Adult moths lay eggs near food sources. They lay their eggs between the oat hay grain themselves and hatching at a later time and often during the processing, packaging, transportation or storage stages. These eggs are white and very small and it is difficult to see them with the naked eye. After hatching, the caterpillars have the ability to chew or wriggle through plastic bags to reach the food. A typical life cycle is 35 - 50 days, but under optimal conditions it can be as short as 28 days, but cooler winter months prohibit this.
Moth population control is difficult to manage after discovery due to the speed of the insect’s life cycle, the flying habit of adults and the challenge of storing hay bales, however, maintaining sanitary conditions, sweeping and cleaning loose hay, avoid leaving lights on at night near the hay so that the adult moths are drawn elsewhere. Fumigation and insecticidal sprays on or near the hay is not recommended.
Tip: If you are handling bales to take home, it is wise to shake the bale so that any harbouring moths, mice, spiders and snakes can scatter away (and not reside at your place).
Tip: Always store hay in a dry, well-ventilated area, away from humidity and direct sunlight. Keep it off the floor either on pallets, in baskets, in a plyprop bag (breathable bag), in an open tub or tote.
Recources:
https://wagwalking.com/horse/condition/hay-allergy-Are you or your pet allegic to hay?
https://www.fortair.org/the-impact-of-harvest-activities-on-air-quality/
https://www.ag.ndsu.edu/news/newsreleases/2011/july-25-2011/don2019t-risk-hay-fires/view
https://www.business.qld.gov.au/industries/farms-fishing-forestry/agriculture/land-management/health-pests-weeds-diseases/livestock/residues-animals/aflatoxin
Tropical and Subtropical Agroecosystems E-ISSN: 1870-0462 [email protected] Universidad Autónoma de Yucat
Tropical and Subtropical Agroecosystems E-ISSN: 1870-0462 [email protected] Universidad Autónoma de Yucat
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4202174/
https://afs.ca.uky.edu/content/botulism-deadly-disease-can-affect-your-horse
https://extension.sdstate.edu/sweet-clover-poisoning #:~:text=The%20problem%20is%20when%20sweet,livestock%20to%20hemorrhage%20(bleed).
https://extension.sdstate.edu/sweet-clover-poisoning
https://pets.stackexchange.com/questions/4408/how-can-botulism-occur-in-hay-and-is-it-hazardous-to-my-pet
http://www.medirabbit.com/EN/Neurology/Differentials/Head_down.htm
https://www.noble.org/news/publications/ag-news-and-views/2010/may/hay-quality-impacted-by-five-factors/
https://horseandrider.com/horse-health-care/five-things-to-know-when-buying-hay
https://extension.okstate.edu/fact-sheets/evaluating-hay-quality-based-on-sight-smell-and-feel-hay-judging.html
https://www.farmersweekly.co.za/farm-basics/how-to-crop/the-influence-of-weather-on-lucerne-hay-quality/
https://soquelvet.com/blog/94518-external-parasites-in-rabbits
https://www.agric.wa.gov.au/feeding-nutrition/straw-itch-mites
https://www.vets4pets.com/pet-health-advice/rabbit-advice/mites-and-your-rabbit/
http://bohart.ucdavis.edu/uploads/5/6/2/5/56256413/note_43_hay_itch_mites.pdf
https://www.yumpu.com/en/document/read/11290371/common-mites-of-your-rabbit-and-small-animal-cumberland-
https://www.uspharmacist.com/article/pyemotes-the-mysterious-itch-mite
https://extension.sdstate.edu/straw-itch-mites
ttps://en.wikipedia.org/wiki/Angoumois_grain_moth
Professor Dirk U Bellstedt. Emeritus professor Dept of biochemistry University of Stellenbosch.
Article compiled by Renate Jacobs - March 2022
