Can Grass-Finished Beef Make The Cut?

By: Lyssa Seefeldt, Marquette County

One commonly held belief of grass - fed beef is that animals finished on a non - grain diet can’t finish to a grade of choice within 24 months. As physiological maturity of the animal increases, consumer accepta- bility issues increase, especially in beef with forage based diets (i.e. meat toughness), so finishing forage - based beef prior to reaching 24 months is a priority. A 2010 study at UW - River Falls by Dr. Gary Onan evaluated the differences between grass finished beef versus beef with a more conventional feedlot diet with grain supplementation.

The trial cattle were 24 Angus crossbred steers born in April and May 2009. The cattle were split into two groups: a pasture diet group, with winter supplementation only containing haylage, and a feedlot diet group that utilized corn silage, haylage, and high moisture corn. The haylage used had a relative feed quality (RFQ) of ~ 200 . Both groups had supple mental trace minerals supplied in their diets.The pasture group was rotationally grazed over the summer while the feedlot group used an 80:20 corn to corn silage diet.

Real - Time Ultrasound was used to monitor backfat (BF) and monitoring was completed with the monthly weighing. A minimum BF amount of 0.35 inches was used as one of the criteria to deter- mine if animals were ready for harvest as this amount tends to indicate a steer should be close to mar- bling to a choice quality grade (anything below 0.35 inches usually doesn’t have enough marbling to make even a low choice grade). The other determining factor for harvesting was reaching an appropri- ate weight for the frame size of the animal. This allowed for a relatively similar end point of feedlot and pasture groups for better comparison of data between the groups. Throughout the trial, weights were monitored and at strategic points were similar between groups. Weaning weights, weight at time of pas- ture turnout, and end weight between groups were similar, ensuring that the trial was unbiased. Produc- tion and carcass data were collected to compare differences between the groups.

As you might expect, average daily gain (ADG) from weaning to market was greater for feedlot fed steers (2.89 lb.) versus pasture fed steers (2.18 lb.). Days to slaughter was greater in the pasture based group (average 317 days) versus the feedlot based steers (average 239 days). Onan noted that the last pasture steer to be marketed was sold at 22 months of age (within the ideal marketing window).

The carcass data indicated that there was greater finish on the feedlot steers (0.56 inches BF on feedlot diet vs. 0.38 inches BF on pasture diet). Subsequent marbling was greater as well (553 for feedlot vs. 451 for pasture). No differences in yield grade or ribeye area were observed. It is important to note that while there were differences in marbling, both the pasture group and the feedlot group had 80 - 85% of the animals grading at least low choice (a marbling score of 450 meets this criteria).

Key management considerations for grass - fed beef Feeding and grazing management is very important in getting pasture - based steers to a finished weight and quality grade on time. Winter feeding is critical: gains need to remain on an increasing rate, not “maintained” over winter. Dry matter intake (DMI) is crucial to keep pushing gains, so forage nutrient availability needs to be high. Energy is the limiting factor in the forage - based diet, so a high - quality leg- ume/grass based forage is needed (adequate protein of ~14% can easily be achieved with medium quali- ty forage). Fermented feed will likely increase DMI, so haylage or baleage is probably the best choice to provide adequate nutrition.

Cattle need to have adequate weight (≥800 lb.) at pasture turn - out. The reason for this is that in the Upper Midwest, there is a finite grazing period per year (~180 days). Assuming a 2.0 lb/day ADG, the maximum gain for a grazing season would be 360 pounds, so the steers need to be within 350 - 400 pounds of the target market weight. To make a grass - based diet work to the utmost potential in the Midwest, you need to start with heavy weaned calves (≥600 lb. at 205 days) for the same reason. Graz- ing management was also a factor in forage - based steers finishing adequately. Moving the animals to the next paddock daily was critical for maintaining DMI which drives ADG. Not moving animals daily de- creased DMI, impacting ADG

Other factors that may warrant consideration for pasture based beef include genetic potential for post - weaning gain, marbling ability, and milking potential. Potential for post - weaning gains are necessary to reach target weight for pasture turn - out, market weight, and aggressive ADG since you are dealing with a finite grazing period. Marbling is a highly heritable trait and is influenced by genetics to a large degree. To make a grazing based diet work to your advantage, the calves should have a high marbling tendency. This is necessary since the animals will be on a low energy density diet. Cows need to have good genetic potential for milking to help get calves to adequate weight by weaning

With the correct cattle and a good feeding program, pasture systems can meet the criteria of to- day’s market. Adequate condition and weight for frame size is crucial for meeting that market criteria. Managed properly, grass - fed beef can be profitable while making the cut

Source:uwex.edu