Ministry of Agriculture, Food and Rural Affairs

Can I do that on Grass?

With increased interest in grass fed beef, people ask if it is possible to fatten cattle on pasture without grain supplementation. The answer is yes, with a few conditions. When grass finishing animals, remember that the market is generally not looking for as much fat cover as normally found on grain finished animals. If you are not looking to finish cattle but rather achieve maximum growth on pasture the same pasture management principals will apply.

First and foremost, what is the quality of the pasture? To achieve optimum production you need lots of good quality pasture. However, unlike with stored forages and grains, producers often don't have an accurate quality assessment of their pastures. This is because pastures grow and are utilized directly by the animal without ever being formally harvested or analyzed.

Stored forage and grains have a known quality and energy level - either from feed analysis or from a long consistent history of grading standards and nutritional analysis. Although it is often produced on farm, you still have a good indicator of the feed quality, especially in the case of grains.

With pastures, there is a wide range in species make up, including any number of mixtures of legumes and grasses, with each species having a different feeding value. There is also the maturity factor - pastures may range from lush and vegetative to those which are mature and woody. Obviously, the lush and vegetative pastures will provide much higher quality feed, and you will have far greater success finishing cattle on this than a mature, woody pasture. This range in quality has a tremendous effect on animal performance, especially with livestock requiring more than a maintenance ration.

In a research project conducted at the Ontario Agricultural College in the 1960's, forage quality at various stages of growth was determined. For alfalfa, the range was from a high of 20.8% CP (crude protein) and 70.6% IVD (in-vitro digestibility) in the younger plants to a low of 15.6% CP and 60.1% IVD in the more mature plants. For Orchard grass, the protein ranged from 13.3% to 6.6% and digestibility ranged from 74.7% to 51.8%, showing a decrease in value as the plant matured. Timothy and brome grass showed similar declines in quality as orchardgrass (Table 1). When the digestibility of forage decreases, the intake also declines. This comes as a double hit because the animals are eating less of a lower quality feed, resulting in poor performance. To finish well, cattle will need high intakes of quality forage. If pastures are managed to be grazed when the plants are in the vegetative state, with maximum animal intake, excellent growth and production results are achievable.

Table 1: The effect of advancing maturity on the quality of four forage species¹.

	Vernal Alfalfa*		Climax Timothy		Frode Orchardgrass		Saratoga Bromegrass
	%IVD	%CP	%IVD	%CP	%IVD	%CP	%IVD	%CP
Boot	70.6	20.8	70.9	10.6	74.7	13.3	75.1	13.4
Heading	65.9	17.7	64.1	8.9	71.2	11.0	69.1	10.0
Flower	63.0	16.7	56.6	6.9	61.3	8.2	59.4	6.7
Early Seed	60.1	15.6	53.1	5.7	51.8	6.6	59.7	5.8

*Alfalfa - medium bud, very first flower, full flower, early seed
¹From Research Review of Forage Production Crop Science OAC 1983, R.S. Fulkerson

The second condition required to successfully finish on pasture is good pasture management. How do you manage your pastures and your grazing to achieve these results? Staging the pastures to create a wedge of forage with the last pasture grazed being the thin edge of the wedge and the next pasture to be grazed is the thick end of the wedge. If animals are moved every one to two days they will always have fresh high quality forage available that will meet the nutritional requirements for excellent growth. To support pasture finishing, pastures should be maintained with forage grasses in the boot stage and legumes in late bud to early flower stages. By maintaining and monitoring this "wedge" you will have the opportunity to adjust your grazing program to maintain quality pasture from May through to October.

This example for a 12 paddock system shows the available feed in animal days per acre for each paddock. The animals will start in paddock 1 and by the time they get to paddock 12, the first one will have regrown to provide abundant high quality forage (Figure 1).

Figure 1: Illustration of the wedge technique for pasture management.

Animals come out of paddock 12 (the thin end of the wedge) when the forage is sufficiently grazed and moved into paddock 1 (the thick end of the wedge) where there is ample supply. Animals will rotate through the 12 paddocks so that while one is being grazed the other 11 are in a state of regrowth. Ideally, by the time animals have grazed through paddocks 1-11, and are ready to be back in paddock 12, it will have regrown enough to be the thick end of the wedge again.

Perennial pastures have minimal input costs and very low maintenance cost when compared to annual crops, stored forage or grain crops. By maintaining quality pasture throughout the grazing season, you create the lowest cost feeding program, while still achieving gains comparable to any other feeding program. It is the dollars you have left that determine your profitability, not the gross revenue. Well managed pastures are an opportunity to have a profitable bottom line and access a niche but growing market for grass fed beef.