Cull Cow Body and Carcass Composition
|Written by:||Don Blakely - Beef Quality Assurance Program Lead/OMAFRA|
Canada's grading system categorizes cull cow carcasses into grades
D1, 2, 3 and 4 based on the following:
D1 - excellent muscling, with less than 15 mm of firm, white or amber coloured backfat
D2 - medium to excellent muscling, with less than 15 mm of white to yellow backfat
D3 - deficient muscling with less than 15 mm of backfat
D4 - deficient to excellent muscling with greater than 15 mm of backfat
Unlike the grading system for fed cattle, the cull cow grading system does not grade cows for marbling nor is it well used for establishing payment for cull cow carcasses. While live auction markets may describe D1, D2 cow prices, it is terminology adopted to describe live cows predicted to have the highest carcass value, even though the cow carcasses have not been graded.
In Canada body condition scoring is a visual rating of fatness on a scale of 1 to 5, with 1 being the extremely lean cow and 5 being the extremely fat one. In the U.S. the scoring is on a scale of 1 to 9. BCS does not describe muscling and is terminology often used to describe cow condition for managing feeding systems. It is safe to predict that a BCS 1 cow would, using the cull cow carcass grading system grade D3 and a BCS 5 cow would grade D4.
Cull cow body composition varies considerably in terms of carcass weight and percentages of fat, muscle and bone. The percentages in Figure 1 are ranges where the majority of animals will fall, but there are always individual cases that will be outside these ranges.
Use the information in Figure 1 to predict the weight of saleable
lean meat. Start with the live weight, make estimates of body fill,
fat thickness and muscling, and then apply these predictions to
the percentage ranges listed in Figure 1. Results should be within
a couple percentage points of actual muscle and fat content.
Figure 1. Predicting carcass components of cull cow.
Carcass content of cull cows
Products and estimated weights are shown in Figure 2.
Figure 2. Products and estimated weights of products derived from an example cull cow.
Equivalent of Graphic
Figure 3. Retail meat cuts derived from wholesale cuts of a cull cow carcass.
At slaughter the hide, head, feet, blood, entrails and their contents are removed from the cull cow carcass. A weight difference exists between beef and dairy cows for the udder, which is removed with the hide. Understandably, dairy cows have a much higher udder weight. Edible products from the removed components are the heart, liver, lungs, tongue, cheek and oxtail. Any animal deemed to be 30 months of age or greater must have Specified Risk Materials (SRM) removed from the carcass. SRM include the skull, brain, eyes, tonsils, spinal cord, and clusters of nerve cells connected to the spinal cord and part of the small intestines. SRM cannot be used in any by-products such as pet foods and must be disposed of.
Prior to and following slaughter qualified persons carry out health inspections. Carcasses that pass health inspection are chilled rapidly to ensure control of any pathogen loads. Hot carcass weights are recorded before cooling and after an overnight chilling cold carcass weights are recorded and carcasses graded if required. Carcasses are then fabricated by completely deboning.
The majority of the carcass is sold as trimmings for grinding. Fat is included with trim as fat carcasses will be balanced out with lean carcasses. Most of this will be sold in products such as ground beef burgers, meat balls, meat loaf, taco filling, etc. (See Figure 3.)
Carcass deficiencies can reduce the value of cull cow carcasses. Canadian National Beef Quality audits show injection site lesions, bruising and condemnations as contributing factors in reducing the value of carcasses.
To achieve maximum returns when marketing cull cows, it is vital that producers have knowledge of cull cow body and carcass composition, and the edible and non-edible products that can be marketed from the carcass. Knowing weights, body condition and muscling, a producer can predict the value of saleable products from the cull cow carcass.