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Le Producteur de Lait Québécois MagazineVolume 2019Number JuilletJuly 1, 2019

How corn silage affects herd productivity

L’impact de l’ensilage de maïs sur la productivité des troupeaux
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By Maxime Leduc, agronomist, postdoctoral fellow – forage systems in collaboration with René Roy, Agr., agroeconomist, and Julie Baillargeon, Agr., Knowledge Transfer Expert, Lactanet

The popularity of corn silage as a constituent in the rations of Quebec’s dairy cows shows no signs of waning. An analysis of data collected from more than 500 dairy farms confirms that the use of corn silage has a favourable effect on milk yield and composition as well as on the feed profit margin. Further research is needed, however, to determine the overall impact of corn silage on the health and fertility of both soils and herds in addition to the environmental footprint linked to its production.

From a feeding standpoint, corn silage is valued for its palatability, consistent nutritional quality and high energy content. Likewise, from a crop perspective, silage corn provides high yields, is easy to produce at a lower cost per ton of dry matter, and requires only one harvest per year.  

To evaluate the effect of using corn silage to feed dairy herds, let’s take a look at the production statistics and economic data of the more than 500 farms for which Valacta advisors monitor feeding and ration formulation.

 An overview of the analysis

  • 543 Holstein herds in Quebec
  • 9 administrative regions
  • 2015 to 2018
  • September to August (to coincide with the harvest of fresh silage)
  • 3 grouping categories:

A) based on the proportion of corn silage included in the forage component of the ration:

  1. 0%
  2. less than 40%
  3. over 40%

B) based on the proportion of forage (grass silage, legume silage, corn silage and haylage) in the ration:

  1. less than 65%
  2. 65-70%
  3. over 70%, dry matter basis

The average daily feed intake of the herds included in the study gives a general idea of what the different categories represent in terms of quantity:

Type

Category

Daily feed intake (kg DM)

Corn silage

Forage

Corn silage / total forage

0%

0

14.2

0-40%

4.3

15.3

Over 40%

7.8

15.2

Forage/ration

Less than 65%

2.3

13.5

65-70%

3.5

14.7

Over 70%

5.5

16.4

A positive impact on production and components…

The analysis indicates that farms feeding forage composed of over 40 percent corn silage produce, on average, about 100 kg more milk (Table 1) than farms using less than 40 percent corn silage or those using none at all. Higher production on farms using over 40 percent corn silage is also associated with higher fat and protein levels, which may be attributable to the higher energy density of rations containing over 40 percent corn silage.

Table 1: Annual averages per cow for production, components and feed profit margin in relation to the proportion of corn silage included in the forage and the proportion of forage in the ration

 

% corn silage / total forage

% forage / ration

 

0%

0-40%

Over 40%

Less than 65%

65-70%

Over 70%

Milk (kg)

9 723

9 783

9 889

9 865

9 813

9 717

Fat (kg)

389.3

394.4

397.6

395.5

394

391.9

Fat (%)

4.01

4.03

4.02

4.01

4.02

4.03

Protein (kg)

320.8

325.3

329

327.1

325.5

322.5

Protein (%)

3.30

3.33

3.33

3.32

3.32

3.32

Feed profit margin ($/cow)

4 612

4 731

4 799

4 697

4 730

4 715

… and on the feed profit margin

The annual feed profit margin per cow increases as the proportion of corn silage in the ration increases (Figure 1). Using less than 70 percent forage in the ration has no effect on milk production or protein content, with an average yield of 9,813 kg of milk/cow/year and 394 kg of protein/cow/year. Annual fat yield and feed profit margin per cow are also unaffected by the proportion of forage included in the ration.  

Figure 1

A, B, C Significant difference (P <0.05) between categories.

More work to do

The findings of the study are limited by the fact that the analysis is based solely on annual averages compiled over a four-year period, and focuses exclusively on the relationship between the ration and herd productivity. The analysis does not take into account the effect of corn silage or forage intake on herd health and reproduction, nor does it consider the impact of corn silage production on health, soil fertility and the environment.

Unlike perennial forage crops, silage corn grown under conventional tillage and without a cover crop leads to a decrease in the organic matter content of the soil, making it more vulnerable to drought.

To evaluate the overall impact of corn silage, a wider range of factors needs to be considered, not only production and feeding data, but also data for soil fertility and forage management, from seeding to harvest and storage. It is thus important to continue collecting relevant and high quality data with a view to developing a more environmentally conscious dairy industry.

 

 

 

 

 

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