Including corn in crop rotations is profitable for dairy farms and does not result in greater greenhouse gas emissions at the whole farm level


The following is an abstract of a poster presented by student Véronique Ouellet, Université Laval, at the American Dairy Science Association meeting in Utah last summer.




Corn silage is recognized as a palatable and digestible source of energy for dairy cows. On the other hand, corn silage production is widely criticized as it may carry more environmental risks than perennial forages.


Our objective was to use the whole-farm model N-CyCLES to assess the effect of different crop rotations with varied levels of environmental risks on dairy farm profits, nitrogen (N) and phosphorous (P) balance, and greenhouse gas emissions, while optimizing the management practices required to achieve maximum profits. Adaptations made to the model, included modification to rotations, adjustment in the optimization constraints, evaluation of crop production cost, evaluation of forage nutritive value, and update in fertilization requirements.


Data representative of an average dairy farm from Centre-du-Quebec region in Quebec, Canada were used. Four crop rotation scenarios considered to have different environmental impact were built in the model, and compared: corn grain-soybean-corn silage-alfalfa-alfalfa (very high negative impact, +++); corn grain-soybean-corn silage-alfalfa/timothy-alfalfa/timothy-alfalfa/timothy (moderate negative impact, ++); cereal-alfalfa/timothy-alfalfa/timothy-alfalfa/timothy-naked oats (low negative, +); cereal-alfalfa/timothy-alfalfa/timothy-alfalfa/timothy-alfalfa/timothy-mixed grains (positive impact, -).


Results showed that the highest dairy farm profits (0.12 $/kg of FPCM) were associated with the (++) rotation, whereas the lowest profits (0.05 $/kg of FPCM) were associated with the (-) rotation. The lowest farm-gate to farm-gate greenhouse gas emissions allocated to milk production (0.98 CO2 eq./kg of FPCM) was predicted for the (+++) rotation, whereas the highest value (1.03 CO2 eq./kg of FPCM) was predicted for the (-) rotation. This result is mainly explained by the lack of cash crops sold and the lower NFC and higher N content in cow diets for the farm with (-) rotation. The highest N and P balances (20.1 g/kg of FPCM and 1.185 g/kg of FPCM, respectively) were predicted for the (-) rotation since more corn grain was bought (156.5 t/yr) to compensate for the absence of corn grain and corn silage produced on the farm. Moreover, the lowest N and P balances (12.8 g/kg of FPCM, 0.465 g/kg of FPCM) were predicted for the (++) rotation.


These results suggested that including corn silage in the crop rotation do not carry a greater environmental risk on the considered output than crop rotations without corn, and that growing corn silage is profitable when the whole farm is considered as a single unit of decision. Sound practices still need to be developed to improve other environmental considerations such as soil structure and erosion.

Authors:  Ouellet, V. (Université Laval), D. Pellerin (Université Laval), M. Chantigny (AAFC), and E. Charbonneau (Université Laval)


Symposium 2016 – Nutrition and Health

Symposium 2016 – Nutrition and Health

The theme “Making Sense of Dietary Patterns” aims to look at how we eat and the various ways that we eat. Nutrition experts know that it is impossible to isolate the effects of individual foods and nutrients on health and disease prevention. Rather, it is the totality of one’s diet (combinations and quantities) that has synergistic and cumulative effects over time. Simply put, overall dietary patterns are a key determinant of lifelong health.


  • Making sense of trendy diets and superfoods
  • Saturated fat and cardiovascular disease: Then and now
  • Dairy and cardiometabolic health
  • The DASH Diet: A model for healthy eating

Live webcasts will be available on our website for those who cannot attend in person.

English webcast (broadcasted from Toronto) – November 8
French webcast (broadcasted from Montreal) – November 9

Join the conversation on Twitter by using #DFCsympo before and during the event.

Register now

Dairy Cattle Symposium 2016

Dairy Cattle Symposium 2016

On October 27, hundreds of Quebec dairy farmers and industry partners will gather in Drummondville, Quebec for the 2016 edition of the Dairy Cattle Symposium presented by CRAAQ. The Dairy Research Cluster is a proud sponsor of the poster session and will be on site with its kiosk to engage with dairy farmers on research and distribute material featuring research results.

A breakfast meeting will be kicked off with an overview of the evolution of dairy production in developing countries presented by Dany-Pierre Rondeau. Throughout the day, presentations will be made by Alex Bach of the Institut de Recherche et de Technologie Agroalimentaires (IRTA) and Trevor De Vries of the University of Guelph on feeding behaviour and nutrition. The conference is being simultaneously webcast. For registration information and a copy of the full programme: Dairy Cattle Symposium 2016. ResearchInfographic_e

Stop by and see us to get your copy of the latest Dairy Research Highlights!


Understanding Pro$ and the Lifetime Profit Curve

August 2016 marks one year since the introduction of Pro$ as one of Canada’s national genetic selection indexes. Since its inception, Pro$ has been well received by both producers and industry personnel. As a genetic selection tool, Pro$ maximizes genetic response for lifetime profitability, leading to realized daughter profit on farm. The accumulated profit a cow achieves over her lifetime depends on several contributing factors, all of which are reflected in the Pro$ index. Let’s take a closer look to better understand how Pro$ can help Canadian producers develop a herd of profitable cows.

 Lifetime Profit Curve

From the day a heifer calf is born, she starts to incur costs, the majority of which are related to feeding. With an average age at first calving near 26 months, the cost of heifer rearing is roughly $2,800 for Holsteins. Once calved and lactating, a dairy cow starts to generate her primary source of revenue – milk and its components. At the end of each lactation, no revenue is generated during the dry period but expenses continue. This concept of describing how a cow’s profit accumulates over time is its lifetime profit curve, which is shown in Figure 1 for the typical Canadian Holstein. This lifetime profit curve covers the first six years of life since this was the definition of lifetime profit used by Canadian Dairy Network (CDN) to develop Pro$.


For the typical Holstein in Canada, the complete repayment of costs incurred from birth is achieved by 40 months of age, at which time she is in her second lactation (Figure 1).

Looking closely, it can be seen that each new dry period and subsequent calving leads to higher levels of accumulated lifetime profit compared to the scenario of a cow having only one calving followed by years of consecutive production. Normally, prior to reaching six years of age, the typical cow will have had four calvings, including three dry periods, and is in progress on her fourth lactation. This underlying cycle of reproduction and production is fundamental to the dairy enterprise since heifer calves are required as future replacement animals for the milking herd. On average, about one-third of all lactating Holsteins in Canada stay in the herd to at least the age of six years. Those that do, typically end up with about 40 months of productive life in lactation along with six months for dry periods.

When producers aim to maximize herd profitability, it is important to think of the factors contributing to each cow’s lifetime profit curve, which include:

  • Age at first calving since prior to this point a heifer only incurs costs. The earlier an animal first calves, the sooner it can start paying back those rearing costs.
  • Production levels of milk, fat and protein since these are the primary sources of revenue but they are also associated with some expense, mainly feed costs.
  • Days in lactation since this is the only period during which revenue is generated.
  • Days dry, which is longer with poorer reproduction.
  • Ability to stay in the herd, which reflects a multitude of possible factors.

When examining Pro$ values, higher bulls are expected to produce more profitable daughters compared to lower Pro$ bulls. This means that the average lifetime profit curve for daughters of high Pro$ sires will be somewhat different, and higher, compared to daughters of poorer Pro$ sires. CDN recently conducted an analysis to help demonstrate how the key factors contributing to a cow’s lifetime profit curve vary between sires that are higher or lower for Pro$. To conduct this analysis only older sires could be used since their daughters would have to have been born early enough to have had the opportunity to reach six years of age. Table 1 provides various statistics describing the performance of daughters of the sires that were in either the top 10% for Pro$ of the group included in the analysis, or the bottom 10% for Pro$, relative to the daughters of the middle 10% of sires for Pro$.

screen-shot-2016-09-27-at-4-47-46-amRelative to daughters of the middle group of sires for Pro$, 7.4% more daughters of the top Pro$ sires and 6.0% fewer daughters of the bottom Pro$ sires stayed in the herd to six years of age. Evidently, longevity is a crucial component of lifetime profitability. By looking specifically at the daughters that stayed in the herd until at least six years of age, we can illustrate the profitability differences, beyond longevity, that exist between the two sire groups based on Pro$. For example, daughters of the top group for Pro$ calved younger, had more days of productive life and produced more milk, fat and protein than daughters of average Pro$ sires. On the other hand, daughters of the bottom sire group for Pro$ had an older age at first calving, fewer days in production, spent more days dry and produced significantly less than daughters of average Pro$ sires.

Since all these performance measures impact profitability, there is a clear difference in the average accumulated profit to six years of age, based on all daughters, for each of the two sire groups by Pro$. Daughters of the top sire group for Pro$ generated an extra $1,300 profit to six years than daughters of the middle sire group, while daughters of the bottom sire group generated $1,200 less profit to six years than daughters of the middle group. Bottom line is that selecting sires based on Pro$ produces daughters with higher lifetime profit curves and improved herd profitability.

  • Authors: Brian Van Doormaal, General Manager, CDN and Lynsay Beavers, Industry Liaison Coordinator, CDN