Producers need to do their homework before giving “funny feeds” to their drought-hit livestock, says leading sheep consultant, Geoff Duddy.
Mr Duddy, from Sheep Solutions, told a Sheep Connect NSW-organised webinar audience of farmers and advisors that because traditional drought fodders were in short supply and expensive, some producers were looking at alternate feeds such as pumpkins, potatoes, citrus pulp, almond hulls, bakery waste, grape marc and cottonseed.
These “funny feeds” could help keep hungry stock alive but producers had to know their true feed value and health risks they could pose.
The most important indicator of feed quality was metabolisable energy (ME) - measured in megajoules per kg of feed dry matter - which was important for muscle development, fat storage, maintenance and growth.
Carbohydrates (sugar and starch) were the main providers of energy but excess protein could also be a source along with oil.
Protein - important for muscle development, appetite and wool production - was measured as a percentage of nitrogen in feed.
Digestible dry matter (DDM) was the percentage of the feed that could be digested by animals (a DDM of more than 65pc indicated a high-quality feed).
Mr Duddy said sheep and cattle had minimum energy (ME) and protein requirements depending on their production state - eg, sheep on a survival ration needed much less than a lactating ewe.
A range of by-products and alternate feeds could be fed to stock but they should be used with caution.
Issues included high moisture content and low dry matter, questionable cost/benefit, low ME and crude protein levels, low digestibility and palatability, impaction of the rumen and choking (eg, with potatoes).
Other dangers were poisoning, mineral imbalances, chemical residues, moulds and rancidity.
Citrus pulp had reasonable energy and fibre, was a good calcium source but was lowish in crude protein.
Grape marc (stems, seeds and pulps left after winegrape processing) was low in ME, reasonable in crude protein (but much was unavailable because of tannins which bound up protein) and was lowish in dry matter. Other concerns were chemical residues, notably copper, and rancidity and oil impacts.
Potatoes and pumpkins were high-moisture, low-fibre feeds with reasonable ME, protein and digestibility. The main concerns were choking, constipation and rectal prolapse (caused by high moisture), chemical residues and transport costs.
A 60kg ewe needing 9.2 megajoules per kg of feed dry matter per day would require 800g of grain or around six times more pumpkin - which is a heck of a lot of chewing!
Many farmers have been turning to cottonseed as a drought feed but Mr Duddy said there were dangers.
Cottonseed had good ME, protein, fibre and digestibility but its high oil content (20pc) could inhibit rumen function.
Mr Duddy said rumens started having digestion issues if oils made up more than seven to eight per cent of total diet.
Livestock consultant, Alastair Rayner, RaynerAg, joined the conversation to discuss the risk of gossypol poisoning from cottonseed in young ruminants that did not yet have a functioning rumen.
Affected animals started scouring and then died suddenly.
“I wouldn’t be weaning calves or lambs onto it (cottonseed),” he said.
He said gossypol, a toxic compound produced by cotton plants, also affected fertility. He advised clients not to feed cottonseed to bulls and rams in the two months leading up to joining.
Cottonseed shouldn’t be fed to young growing breeding bulls and rams because of the potential impact of gossypol on the development of testicular tissue.