Hands holding grain©Mint Images/Rex Shutterstock

Monitoring cereal quality and refining diets to reflect actual analysis can have a big impact on feeding efficiency and financial performance in all classes of farm livestock.

“The quality of wheat and barley varies significantly between years, and within years,” comments John Ward, poultry manager at Trouw Nutrition GB.

“A failure to take account of this and to instead base diets on standard figures can have cost and performance implications in both broilers and layers.

See also: How to feed young hens for maximum profit

“While many appreciate that the actual growing year has implications for quality, fewer realise that there will also be variation during a trading year, based on where crops are sourced.

“At the start of a harvest year, crops will tend to be sourced locally or regionally.

“During the year there will be a shift to crops sourced more widely, along with a general realignment of the market – including milling wheat moving into the feed market once milling requirements are formalised and import/export requirements are fixed. All will influence feeding quality.”

Analysis

To provide a more accurate picture the company has launched a service, available to poultry producers and feed companies, which monitors wheat and barley quality, focusing on starch and protein content.

John Ward

John Ward

Mr Ward says that these analyses provide accurate measures of feed value, as demonstrated in the table below, showing results for wheat for the past three harvest years.

“The results show considerable variation in starch and protein levels, and confirm that bushel weight, the traditional indicator of quality, is actually an unreliable predictor of energy content when used alone.

“Looking at 2015 wheats, the bushel weight at 77kg/hl is above the norm of 72kg/hl.

“Starch values, which are the best indicator of energy levels, are good and comparable with 2014, but wheat proteins are lower than 2013.

“Variation around the mean within the 2015 wheat harvest year is currently small, but this will alter during the year.”

Mr Ward says the situation for barley gives a similar picture, with a lower AMEn level for 2015 barley samples tested.

“The results indicate why it will be prudent to get samples analysed to ensure diet formulations are optimised. On average, a 0.1 MJ/kg variation in energy content is worth £2.50/t to £3/t in a broiler diet.

“As wheat will typically constitute about 65-75% of the feed, a 0.1MJ/kg shift in the energy value of wheat is worth about £2/t of finished feed.

“If no adjustment is made to account for variations in the energy content of the cereal grain and the energy content is lower than the value used in the feed formulation, then performance, particularly the feed conversion ratio [FCR], will deteriorate.

“For example, each 0.2MJ/kg change will lead to about 0.014 units reduction of FCR and 10g lower liveweight. Differences between wheat samples within a year can of course be much greater than 0.2MJ/kg, as the table shows.

“This year the difference in AMEn between the best and worst samples analysed is around 1.4MJ. If the diet is not fine-tuned to compensate for this, the cost in lost growth would be 70g.”

Inverse correlation

Mr Ward says there is also a very loose inverse correlation between starch and protein content. If starch levels are high, protein levels have a tendency to be low and vice versa, but this must be confirmed by analysis.

“Traditionally, nutritionists have adjusted the amino content of wheat based on protein content and made some estimate of energy content of the grain based on bushel weight alone.

“On this basis, there would be extra feed cost with low protein wheat samples and vice versa.

“Now nutritionists can have access to more accurate data on cereal quality. They can adjust the energy content based on starch and protein contents, and amend amino acid content based on analysis.

“They can monitor the nutritional quality of cereals on an ongoing basis, load by load if required, and compensate for any significant variance during the year.

“This will allow much more accurate feed formulation giving predictable performance while maximising the nutritional value of the cereal grain.”

Wheat nutrient values by harvest year

Harvest year

 

Crude protein (%)

Enzymatic starch (%)

Poultry AMEn* (MJ/kg)

Bushelweight (kg/hl)

Lysine (%)

Methionine (%)

2015

Average

10.11

56.32

12.53

77.26

0.27

0.15

 

Min

7.79

49.46

11.72

67.10

0.23

0.12

 

Max

12.59

62.96

13.15

85.10

0.34

0.19

2014

Average

10.07

56.94

12.52

75.56

N/A

N/A

 

Min

7.52

42.08

10.88

64.00

N/A

N/A

 

Max

15.45

65.54

13.42

85.90

N/A

N/A

2013

Average

10.78

57.45

12.63

74.85

N/A

N/A

 

Min

7.21

40.73

10.94

62.70

N/A

N/A

 

Max

17.88

65.49

13.56

83.10

N/A

N/A

Poultry AMEn values are based on Trouw Nutrition equations