12th September 2022

Variety choice drives ROI

NEWS_Choosing varieries which put more nutrients in the clamp will increase the ROI of maizeMr Richmond says that a change in focus when selecting varieties could have significant benefits for many farmers.  He points out that as costs of production at around £800/ha are largely fixed, crop success is best measured in terms of how effectively it is harvested and the quality of feed produced.

“Maize on livestock farms is only grown to produce feed, so the quality of feed produced is of paramount importance and has a significant bearing on the economics of the crop.”

Mr Richmond says the most important selection criterion must still be to select varieties suited to the site class, arguing that selecting a variety that may not ripen adequately or may result in a problematic harvest is unwise and can increase the cost per tonne of dry matter produced.

“Early maturing varieties require fewer heat units to reach maturity which gives them a particular advantage in short seasons, allowing them to be harvested at the optimum time.  Waiting for late maturing varieties can present problems at harvest.”

He says that in September crops typically accumulate dry matter at around 4% per week but this falls to 2% per week as the weather cools in October, so the later the variety that is grown, the greater the risk of extending harvest date beyond what would be considered reasonable.  At the same time the risk of a drop in feed quality is increased.

“There is a significant difference in days to harvest between early and late maturing varieties.  On the BSPB/NIAB Descriptive List, early varieties are typically ready to harvest at least 15 days earlier.  This can be the difference between a successful harvest and a struggle to get the crop in the clamp, while the 15 days can make a huge difference to the quality and feed value of silage produced.”

If farmers want to reduce costs of production, Mr Richmond says the focus must be on producing quality forages.  In terms of maize, this means higher energy derived from starch content and high cell wall digestibility (CWD) to maximise the utilisation of the feed value contained in the vegetative parts of the plant.

Most early maturing varieties tend to be slightly lower yielding than the later maturing ones, but have higher starch content improving feed quality. However, only a few early varieties such as Activate and the new variety Reason combine this with improved fibre digestibility that will result in a higher quality feed better suited to producing milk at a lower cost per litre.

In addition to helping increase energy yield from the crop, Mr Richmond says Danish research confirms the importance of selecting varieties with high CWD.

“Each 1% rise in CWD increases total dry matter intake by 0.17kg/day due to superior rumen function. In the trial this additional intake resulted in a yield increase of 0.25 litres per cow per day. By selecting varieties with a good balance of starch and CWD, farmers will increase production from forage and reduce purchased feed requirements.”

NEWS_Varieties such as Reason which combine high strach with excellent cell wall digestibility will produce more milk poer hectareMr Richmond advises farmers to look closely at starch content, CWD and energy yield when refining their initial variety shortlist, saying there is a significant difference in milk yield per hectare between average and top varieties ranked on energy yield.

“A high quality variety like Reason will supply sufficient energy to produce an extra 800 litres per hectare compared to the average variety.  This equates to a concentrate feed saving of 360kg/ha, or £80.  For a farm growing 30ha of maize, selecting Reason over the average variety would save £2400 off the purchased feed bill with no increase in growing costs.  At the same time, its superior CWD will support at extra 0.2 litres/cow/day as a result of increased intakes.

“Variety selection is central to driving economic production of maize, by which I mean the yield of nutrients that find their way from the field to the rumen.  The focus needs to move from thinking in terms of tonnes of dry matter and instead focussing on the yield of nutrients, particularly energy, and minimising the risk of a lower quality crop.

“Cost effective diets require consistent quality forage, rather than potentially higher yields of a lower quality feed.  In practice, this will mean an increased emphasis on early maturing varieties which can deliver better feed value more consistently.  When selecting varieties, the key parameters will be maturity date, starch content and fibre digestibility.  It is the combination of good starch content and high digestibility which drives feed value.

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