Source: Alberta Agriculture and Forestry
Barry Yaremcio, beef and forage specialist at the Alberta Ag-Info Centre, looks at how forage energy content impacts lactating cow rations.
“There have been many articles written over the years – Agri-News included – that have indicated that feed testing is a good way to minimize winter feeding costs,” says Yaremcio.
“But, how does over-mature, rained-on or poorer quality forage impact lactating cow feeding costs. Is there a need to adjust forage prices based on quality?”
When forage prices are low, he adds that overfeeding may not be as much of a concern for some producers.
“This year however, even with an abundance of hay, bale silage, or swath grazing in many parts of the province, quality is much lower than the 5-year average. Protein is down 20 to 40% compared to normal, and energy content of the forages is down 10 to 20%. It impacts the amount of energy and protein supplemented to keep the cows in good condition.”
One recommendation is that a lactating mature cow receives a ration that contains 65% total digestible units (TDN) and 11% protein on a dry matter basis as published in the factsheet,Beef ration rules of thumb.
Yaremcio looks at how that impacts the amount of grain that is needed to meet energy requirements when feed test results have energy contents between 55 and 63% TDN.
He uses a 1,500 lb lactating cow offered forage on a free choice basis as an example.
“The temperature is in the -20 C range. Energy content in the forage varies between 55 and 63%. Barley grain is valued at $230 per tonne, or $5 per bushel, and has an 83% TDN value.”
Using CowBytes to balance the ration, Table 1 indicates the amount of grain that is required to meet the 65% TDN requirement.
Table 1 – Grain inclusion and cost to keep a lactating cow ration at 54% TDN.
|TDN Value in forage||Pounds of barley||Cost per head per day|
He notes that lower quality forages tend to have higher fibre content than a higher quality feed.
“It takes longer for the low quality forage to pass through the digestive system, so feed intake increases as the quality increases. That is why the amount of grain required is not a linear function of TDN value.”
“The higher quality forage requires less grain supplementation than the lower quality feed. It could be a difference of 10.5 lb of grain per head per day at an additional cost of $1.09 per head per day for the extra grain.”
Hay can be sold by the bale or cents per pound, and no differential is factored in for quality.
Yaremcio looks at whether lower quality feed should be discounted with the different supplemental feeding costs.
He points to the Beef Cattle Research Council’s Feed Testing and Analysis for Beef Cattlewebpage that includes a tool to evaluate the economic value of feeds based on nutrient content.
Barley and canola meal are used as the base to estimate the value of energy – barley – and protein – canola meal. After entering the current prices for barley and canola meal, and the feed test results for the feeds in question, the calculator provides a relative value for each forage.
He uses barley valued at $230 per tonne, or $5 per bushel in Lethbridge, and canola at $293 per tonne – the price at the crushing plant – as an example. The relative value of each forage can be determined. Prices are quoted from Alberta Agriculture and Forestry’s February 14, 2020 Weekly Crop Market Review.
“Hays of different TDN and protein contents are evaluated based on feed test results. We need to look at the relative value of the forages containing different quality,” he explains. “Using 11% protein and 65% TDN forage as the standard, discounts based on nutrient content are listed in Table 2.”
Table 2 – forage price discount – dollar per tonne – based on nutrient content, with a moisture content of 15% in the forage
|Discount per dollars per tonne|
He says that the reduction in protein creates a lower discount rate compared to a loss of energy.
“The 0.5% reduction in protein reduces the value of the forage by roughly $1.45 per tonne. The 2% reduction in TDN reduces the value of the forage by roughly $4.60 per tonne.”
“Buying forage by sight without having a feed test result is gambling,” he adds. “Colour, smell and texture of the feed are all helpful when evaluating a forage, but the only way to obtain the true nutritional quality is by taking a representative sample of the forage and have it analyzed.”
“When the feed test results are evaluated, it is possible that the initial contract price of the forage will need to be readjusted based on quality. It’s no different than adjusting price when considering moisture content.”
Connect with the Alberta Ag-Info Centre:
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