Slaughter and processing terminology for lambs and goats
tatiana Stanton, July 2012
(Cornell Small Ruminant Extension Specialist)
Regardless of what marketing channel a farm decides to work with, it behooves a lamb or goat producer to learn some basic slaughter terminology and how to calculate some of the commonly used measurements. Several factors affect these measurements.
Hanging carcass weight
Hanging carcass weight is the weight of a dressed carcass as it hangs from the rail. Different buyers will include different parts of the goat in this weight so it is a good idea to ask them for a detailed description. Often it is the weight of the carcass after the offal, internal organs, hide, head and lower shank bones have been removed. A hide off/head on carcass has the offal, organs, and hide removed but not the head while "organs hanging" means that the kidneys, liver and heart and any fat surrounding them are included in the weight. "Hot carcass weight" is the weight immediately after slaughter while "cold carcass weight" will be less because of the weight loss after chilling (cooler shrinkage).
Dressing percentage (DP)
Dressing percentage (DP) = (hot carcass weight/live weight) x 100, i.e., it's a measurement of the weight of the carcass compared to the live weight of the animal. For example, if an animal weighs 80 lbs. live and dresses out with a 40 lb. hanging carcass, the DP is 50%. Dressing percentage is affected by what parts of the goat or lamb are being included in the carcass weight. Dressing percent ages range from about 45% - 55% for market kids with the hide off/head on, while dressing percentages for nice suckling kid carcasses with hide off/ head on and organs hanging often range from 52% - 62%. Two major factors influencing DP are gut fill and carcass fat. If an animal is full of feed when its live weight is taken it will have a full gut and a lower DP than if the same animal is taken off feed for a short time prior to weighing. Suckling kids and lambs and plump kids and lambs tend to have higher DPs than weaned or lean kids and lambs.
Shrinkage or shrink
Shrinkage or shrink refers to the weight loss that occurs in live weight from the time the animal is gathered for transport until it is slaughtered. Goats or sheep coming off lush pastures will show live weight losses shortly after being taken off feed because the feed passes through them faster than dried forages and grains do. If animals are deprived of feed for 6 or more hours not only live weight but carcass weight starts to decrease and DP will also start to drop. Carcass weight loss is about 2.5%, 3- 4% and 6- 7% after a 12, 24, and 48 hr fast, respectively. Water deprivation can result in another 2% loss in carcass weight. Depending on the distance traveled, truckers report shrink losses of 3% to 10% for goats and sheep going from farm to auction.
Cooler shrinkage is the weight loss that occurs as the carcass loses moisture during chilling. It is calculated as ((hot carcass weight- cold carcass weight)/hot carcass weight) x 100. It normally ranges from 2% to 3.5% but can be as high as 4- 6% for young suckling animals or extended chilling periods.
Carcass to bone ratio
Carcass to bone ratio is the ratio of the weight of the entire carcass compared to the weight of the bones in it. Similar terms are meat to bone ratio and muscle to bone ratio. Meat and muscle are interchangeable terms for what's left after deboning the carcass and usually include carcass fat. Therefore, although we often consider carcass to bone ratio and dressing percentage to be measurements of the meatiness of an animal, they are also indicators of the body condition of an animal. Fatter carcasses will tend to have higher carcass to bone ratios and higher dressing percentages. Just like humans, some animals build short thick muscle while others have a body conformation that leans towards long lean muscles. However, despite these differences, the absolute ratio of muscle mass to bone does not vary a great deal within an animal species. As in humans, the ratio of fat mass to bone has the biological potential to vary far more.
When a goat carcass is split into halves between the 12th and 13th rib, approximately 45% of the weight will be in the hindquarters (hind-saddle) and 55% in the forequarters (fore-saddle). Lamb carcasses tend to carry more of their weight (as high as 50%) in their hind-saddle. The proportion of marketable retail cuts from a carcass can vary depending on breed, conformation, sex (intact males will generally be heavier in the neck and shoulders), animal size, and fat cover (the more fat on the carcass the more cutting losses during trimming). The shoulder, neck, rib rack, breast and foreshank are in the fore-saddle, while the loin, sirloin, flank, leg and hindshank make up the hind-saddle.