There is a lot of buzz in the business right now about carcass data. For a lot of us at ground level with cows, the concept of carcass information is pretty far removed from the day-to-day activities on a farm or ranch, yet the carcass determines a large part of the ultimate end value of an animal.
The first thing that is important to understand is that carcass grades are valuable for sorting carcasses and may be used in settlement, but they do not determine value. A good example of this is the Laura’s Lean program (http://www.laurasleanbeef.com/).In this program light-weight carcasses, with little or no marbling, are the premium product. In contrast to this are the examples of Sterling Silver (http://www.sterlingsilvermeats.com/)or Certified Angus Beef (http://www.certifiedangusbeef.com/)where a controlled size and high marbling attract the premium.
Let’s start with the live animal that most of us are familiar with and verbally harvest him so to speak. The finished steer we start with will weigh 1,350 pounds live weight. This includes hair, hoof, rumen contents, guts, blood and everything else. Also removed are specified risk materials (SRMS). These materials include skulls, brains, spinal cords, eyes, etc. and are destroyed and do not enter the food chain.
When the steer is harvested the hide, guts, head, fore and hind limbs and organs are removed. This “drop” equates to nearly half the weight of the live animal but can vary greatly. This leaves a hanging hot carcass. The simple division of the hot carcass weight into live weight gives the dressing percentage. If the carcass was 837 pounds, the dressing percentage would be 837/1350 or 62 per cent.
A large portion of the value/profit in any animal lies in the “drop.” This is all of those parts and pieces that are removed prior to the hanging carcass. Those hides and organ meats are marketed and provide value to the processor. The drop is also one of the key reasons that access to an export market is so important, as much of the product is not high on the list of consumables for Canadians, but is a desirable eating experience elsewhere in the world. I doubt there are very many of us sitting down to a meal of beef tongue in the coming week.
If the animal and resulting carcass pass health inspection then the resulting carcass is chilled prior to grading. Chilling is important since our quality grade is assigned using intramuscular fat or marbling. Think of chilling in the same way as leaving a frying pan on the stove after cooking. When the grease (fat) cools, it turns white and becomes visible. A longer chill will often result in the marbling being more visible and thus the assignment of a higher quality grade. This is why cattle killed on a Friday and chilled over the weekend will often grade higher than those killed midweek and graded 24 to 36 hours later. The chilled carcass weight is lower than that hot carcass weight, and may decline up to two per cent due to loss from evaporation.
Youthful cattle are graded either in standing coolers (the grader walks between the carcasses) or from a grading stand (the carcasses are moved past the grader). The grader assesses the carcass by looking at the rib-eye between the 12th and 13th rib. Basically, the carcass is hanging head down, and has a slice placed partway through the rib section to form a V, exposing the ribeye. The grader looks at ribeye size by categorizing length and width, assesses muscle score (degree of muscling) and measures fat thickness around the ribeye. The resulting combination produces an estimated yield grade. Cattle grading under 54 per cent are yield grade 3, and over 59 per cent are yield grade 1. Those in between are scored a 2.
The yield goes up as ribeye area increases, and goes down as fat increases. This begs the question about why have any backfat at all? Some level of backfat is important to control the chilling process and resulting product tenderness. The chilling preserves the beef, but there needs to be enough time for the enzymes in the muscle cells to help break down the connective tissues and tenderize the meat. With no backfat, the carcass can chill too fast and freeze or damage the enzymes mid-process. Think of backfat as a tenderness sweater. Cattle that have no backfat or marbling are classed as B1 grade and are heavily discounted in mainstream markets.
Marbling is sexy when talking about carcasses in the mainstream marketplace. Marbling is highly related to juiciness and flavour and is somewhat related to tenderness. For the mainstream market (general supermarket) AA or AAA are the grades in demand. The white tablecloth (moderate and high-end restaurant) AAA or Prime are required. For high value exports such as the Japanese market the preference is for high end AAA or Prime carcasses.
As mentioned before, marbling is assessed visually after a chilling period. A-Grade cattle have trace levels of marbling. The ribeye basically looks red. AA cattle have slightly more marbling with visible “flecks” of marbling. Ribeyes of AAA cattle look quite mottled with white, and Prime cattle have very high levels of marbling.
From the graded carcass there are several “prime” cuts that are removed. This includes things like tenderloin, rib steaks, tri-tips, sirloins and anything else in the grocery store counter for more than $5 per pound. These largely come from the muscles along the animals back on either side of the spine and some cuts over the rump and amount to roughly 15 per cent of the carcass, with a wide range around that value. Lesser cuts such as pot roasts, blade roasts and skirts will hover around 15 per cent or so. Hamburger and stew meat accounts for over 40 per cent of the carcass. Fat and bone are generally over 20 per cent of the carcass. Then there is some cutting loss that makes up the difference. These values will vary tremendously on specific animals. For example, some over-fat animals may have well in excess of 40 per cent removed as fat and bone trim.
Hopefully this gives some start of an idea of the complexity of the animal walking around, and a bit of an idea where some of the value determination is made when assessing carcasses. While there is certainly profit in beef production it is important to realize that not all parts of the animal are worth $5 a pound.
As always there is a lot of good information online. Some of my favourite sites include the UNL muscle profiling site at http://bovine.unl.edu/bovine3D/eng/nIntro.jsp,the Canadian Beef Grading Agency at http://www.beefgradingagency.ca,and the Beef Information Centre at http://www.beefinfo.org/.