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Dairy Forages: What‘s New in Genetics and Management?


Dairy Forages: What's New in Genetics and Management?


It is clear that both seed genetics and producer management affects forage quality and potential dietary inclusion levels along with impacting daily feed cost and intangible factors such as rumen health and function. However, the relative contribution of genetics versus management (environment) must be considered. In our cow populations, genetics establish the base for milk production potential while environment (feed, housing) dictates the absolute yield. This is also true for forages where growing environment and harvest management often trumps genetics when it comes to yield and quality. High quality forage does not ensure high milk production (cow comfort is equally important) but low quality forage almost certainly will guarantee low milk production (or very expensive rations). Pennsylvania State University research (Buza et al., 2014) refutes the importance of feed cost per cow per day, with data showing that profit margins are affected more by the quality rather than the cost of the feed. That said, once forage genetics are chosen and planted, there are four major areas over which dairy producers have some control in optimizing quality: (1) harvest maturity/moisture, (2) particle size, (3) storage/feedout and (4) nutritional profiling.

The amount of forage in the dairy diet today is primarily dictated by the need to maintain rumen health (and milk components) and the economics of forage production (influenced by yield and cost for harvest, storage and transportation logistics) compared to the availability of other non-forage, co-product fiber sources. It is not unusual today to find diets containing 55-70% forage on a dry matter basis. Much of what has allowed this to happen is improvement in forage genetics, producer management of those genetics and a better understanding of how to analyze and feed high-forage diets.

The quantity of forage that can be consumed by a dairy cow depends on the interactions among bodyweight, level of intake, rumen fill, passage rate, specific gravity (buoyancy), neutral detergent fiber (NDF) content, particle size, particle fragility/tensile strength and the pool size and digestion rates of potentially digestible NDF (pdNDF) versus indigestible NDF (iNDF) fractions. Improvements in forage genetics (e.g. BMR corn, reduced-lignin alfalfa, drought-tolerant corn), coupled with improved rumen models (e.g. NDS, CPM) and forage analyses, uNDF240,) are helping provide higher quality forages and the understanding of how to capture their full value in the diet.

High-forage intakes are possible by producing and feeding higher-quality, lower-NDF (and iNDF) forages. The classic multi-forage meta-analysis by Oba and Allen (1999) suggests that a one-percentage point increase in NDF digestibility can increase daily dry matter intake by 0.37 lb., resulting in a daily increase of 0.55 lb. of 4% fat-corrected milk. Chase and Grant (2013) offered these guidelines for herds considering higher forage rations:

  1. strive for consistent quality because variations in forage quality will have more effect on milk production as the level of forage in the diet increases,
  2. closely monitor forage inventory and considerations for required changes in the cropping (or sourcing) program,
  3. allocate the highest-quality forage to appropriate animal groups,
  4. frequently analyze forages (including particle size and digestibility) to keep the feeding program on target,
  5. monitor rations closely to determine if adjustments are needed based on frequent forage test results (including dry matter),
  6. target forage management, including silage face management, aerobic stability and palatability, feed delivery and the need for pushups and
  7. track the need for more mixes per day or the need for a larger mixer given that high-forage rations will be bulkier and not as dense (pounds per cubic foot).

Shifts in Forage Production

It is interesting to note that the top 10 forage production states in 2013 (WI, CA, NY, TX, PA, MN, ID, IA, MI, SD) also represent 8 of the top 10 dairy production states (CA, WI, ID, NY, PA, TX, MN, MI, NM, WA) (Progressive Dairyman, 2014). Forage production in the United States has increased dramatically over the past century (Figure 1) with the major trend of reduced alfalfa production and increased corn silage production. The benefits of high dry matter yields, high starch, consistent fiber digestibility, a single harvest time and the ability to utilize manure has driven higher corn silage inclusion rates responsible for the current corn silage trend.

U.S. Forage Dry Matter Production 1919-2013.

Figure 1. US Forage Dry Matter Production 1919-2013 (Newell, 2014)

The current alfalfa trend started in the 1990‘s, partly due to the corn silage shift, and accelerated downward due to increased corn acres for ethanol production under the Renewable Fuels Standard Western Dairy Management Conference created under the Energy Policy Act of 2005. Alfalfa production was also affected by the broad regional droughts in 2011 and 2012 which led to declining hay production and shortages that drove up hay prices and increased hauling distances for hay. In response, acres devoted to alfalfa increased in some Western states where corn is less prevalent, but not enough to offset the overall loss of alfalfa acres. The Upper Midwest remained in alfalfa deficit through 2013 due to winter damage and stand loss. 2013 alfalfa production was below trend, and hay market prices continue to remain somewhat elevated. The increase in availability of distillers grains as a mid-protein source replacing alfalfa-protein is also a key factor in alfalfa production and utilization trends. There may be a rebound in alfalfa seedings over the next few years if competing crop prices decline or alfalfa prices stay relatively elevated but total acres could remain stagnant, because average stand age has grown excessively long in some regions where producers delayed new seedings in favor of grain crops. If a higher stand replacement rate unfolds, a younger average stand age could help support a production rebound (Newell, 2014).

Other hay in NASS reports includes warm-season grasses like bahiagrass, bermudagrass, sudangrass and teff, several species of clovers and other legumes, and cool season grasses of many species. Hay species in this large category are often grown for their adaptability in geographies not suitable for row crops and as such, their acres should continue providing substantial hay production (Newell, 2014).

Sorghum and sorghum-sudangrass silages are often more successful than corn under heat and drought stress where rainfall and/or irrigation is limited. Their use is relatively minor from a broad US perspective, but can be locally important, particularly in the semi-arid plains and in the southwest (Newell, 2014).

Forage Environmental Implications

One potential concern with high-forage diets is an increase in methane emissions. There is little that can be done to changes this biological fact and methane may simply be the price for balancing "starch for humans" versus "fiber for ruminants". Manure accounts for about 25% of dairy farm methane emissions, with the remaining 75% from enteric emissions, representing between 6% and 10% of the total gross energy intake of lactating cows (Chase 2010). In December 2009, the U.S. Department of Agriculture and the Innovation Center for U.S. Dairy signed a memorandum of understanding to work jointly in support of the goal to reduce dairy industry greenhouse gas emissions 25% over the next decade (Bauman and Capper, 2011). The areas they have identified that directly affect methane emissions are: (1) rumen function (including microbial genomics/ecology) and modifiers, (2) enhancing feed quality and ingredient usage to improve feed efficiency, (3) genetic approaches to increase individual cow productivity, (4) management practices to increase individual cow productivity and (5) management of the herd structure to reduce the number of non-productive cow-days (Tricarico, 2012).

The U.S. dairy industry has had a remarkable record of advances in productive efficiency and environmental stewardship over the last half-century, with annual milk production per cow increasing by more than 400% with a corresponding two-thirds reduction in the carbon footprint per unit of milk (Bauman and Capper, 2011). It is also important to maintain a global perspective on the goal of reducing methane emissions. The U.S. provides about 16% of the world‘s total milk production but only about 8% of total greenhouse gas emissions (Chase, 2010). North America and Europe currently have the lowest greenhouse gas emissions per unit of fat-protein-corrected milk. The highest level is in sub-Saharan Africa and the majority of the increase in global livestock production over the next 35 years will occur in the developing world (Mitloehner, 2010).

Research from Wageningen University (Dijkstra, 2013) suggests that improving feed efficiency and reducing methane output required an interdisciplinary, fundamental approach and that direct methane inhibition through the use of dietary lipids, nitrates or tannins typically does not improve feed efficiency. They advised approach to improve feed efficiency and reduce methane emission intensity is to increase milk production levels and improve forage quality.


As concluding "food for thought", listed below are field comments the author has solicited from DuPont Pioneer colleagues and interactions with consulting nutritionists when they were asked about the important forage-related areas dairy producers should keep in mind:

1) reduce fermentation and feed-out losses as a way to improve water utilization,

2) have someone in the operation who makes a priority of managing the agronomics and harvesting of forage crops,

3) optimize locally grown energy sources – anchor the diet with corn silage and reasonable levels of alfalfa,

4) consider all factors if switching from corn to sorghum due to water limitations - shorter maturity hybrids planted at lower populations may provide more energy per acre than sorghum,

5) focus on ration consistency and reducing variation in forage inventories,

6) be mindful of the huge varietal differences in sorghums and decide at what production level sorghum in the diet makes economic sense,

7) focus on economics of growing versus purchasing forages,

8) establish legal contracts for purchased forages with clear incentives around quality parameters (starch, kernel processing),

9) investigate ways to feed cows with less alfalfa by using alternative forage sources,

10) look closely at new silage technologies to improve forage feeding such as enzyme-producing inoculants, oxygen-barrier film, facers, rumination monitors and on-farm NIRS,

11) remember that forage quality cannot drive economical production without consistency and cow comfort,

12) consult with trusted academic and industry specialists to help separate "fact from fiction" when it comes to new forage technologies,

13) utilize new forage analysis methods to proactively predict the associative effects of combining various forage and supplements into a lactating diet and

14) keep abreast of agronomic advances allowing for prediction of yield, quality and harvest timing of forages as the growing season advances.

Literature Cited

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Bauman, D.E. and J.L. Capper. 2011. Sustainability and dairy production: challenges and opportunities. Proc. Cornell Nutr. Conf., Syracuse, NY.

Bolinger, D. 2010. Personal communication.

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Coors, J. G. 1996. Findings of the Wisconsin corn silage symposium. In: Proceedings Cornell Nutr Conf. Rochester, NY.

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Presented at the 2015 Western Dairy Management Conference, Reno, NV.


The foregoing is provided for informational purposes only. Please consult with your nutritionist or veterinarian for suggestions specific to your operation. Product performance is variable and subject to a variety of environmental, disease, and pest pressures. Individual results may vary.
Bill Mahanna

What's New in Genetics and Management?

Dairy Publication Articles

Read various forage related dairy publication articles written by Bill Mahanna, DuPont Pioneer Nutritional Sciences Manager.