January 3, 2009

Sheep Farm Husbandry - Meat; Grading; Slaughter; Home kill

Meat from sheep: the law; grading; slaughter; home killing

By Dr Clive Dalton

Sheep meat image problem
Beef producers are fortunate as regardless of age, their animals all produce “beef”. Sadly for sheep farmers where we don’t talk about “sheep meat” as a generic term, there are three products to market - lamb, hogget and mutton.
  • Lamb poses no problem as it already has a “young” image that is easily embellished by adding words like “fresh, spring, Canterbury and New Zealand”.
  • But what about hogget and mutton? Hogget is hidden under “lamb” (see glossary), but so far nobody has come up with an attractive marketing name to improve the image of mutton.
  • Focus groups of shoppers see mutton as being old, frozen, tough and worst of all – fat! This is unfortunate, as now with modern processing, some very high quality lean meat cuts are produced from carcasses of older sheep.
  • The main messages coming back from consumers are that they don’t want fat for health reasons.
  • And they don’t want large “joints” of meat – the traditional Sunday roast that Granny cooked has gone. This is the age of small ovens and convenience foods for busy people so now 95% of lamb is cut to specification and exported packaged, labeled and ready for cooking.
Meat and the law
After over 100 years in the meat exporting business, a mass of legislation has grown up in New Zealand to protect producers, processors and exporters, so farmers need to be aware of this fact and where necessary comply with it. Remember the customer is always right! So there is:
  • The Meat Act 1981
  • The Biosecurity Act 1993
  • The Animals Product Act 1999
  • The Biosecurity (Ruminant Protein) Regulations 1999
  • The Biosecurity (Animal Identification Systems) Regulations 1999
When are animals ready for slaughter?
This is always a big concern and can be tricky because of the sheep Carcass Classification or Grading System used in New Zealand, and you would be wise to become familiar with it and seek good advice before selling anything. Here are some basic points:
  • The grading system places carcasses with similar characteristics into groups or classes.
  • It is designed to pay farmers for what the meat company considers the export market wants, and not pay (or even penalise) them for what is not wanted such as over-fat animals.
  • It allows meat to be purchased sight-unseen, and provides a channel for consumer requirements to get back to producers so they can change things if needed.
Meat fit for human consumption
  • After slaughter and processing, every sheep carcass whether for export or the domestic market is checked by a meat inspector from “Asure (New Zealand) Ltd” on behalf of the New Zealand government by the Ministry of Agriculture and Forestry, to make sure it is fit for human consumption.
  • Any carcass that fails to pass inspection is condemned and rendered down for blood and bone fertiliser.
  • After passing inspection, the carcass is weighed while still warm, and graded by a meat grader employed by the meat company and regularly audited by AusMeat.
Lambs off to meat works. Careful handling to avoid bruising and a stress-free journey is important to maximise returns.
Meat grading
  • Farmers are paid on carcass weight and grade.
  • There are two weights recorded at the meat plant – hot carcass weight (HCW) and cold carcass weight (CCW) after a period in the chiller. Farmers are paid on HCW recorded straight after dressing and CCW is used when export meat is sold.
  • Meat graders from the meat company then assesses the maturity, sex, fat cover and muscling of the carcass.
  • Fat is assessed by the “GR measurement” and is the fat depth taken at the 12th rib and 11cm from the mid line of the carcass with a sharpened ruler pushed into the meat. In other major meat exporting countries they use an electronic probe to assess fat and meat content which was invented in New Zealand but not used here. The reasons remain a mystery!
  • There are 7 fat classes for lamb from devoid of fat at one end, to excessive at the other which has to be trimmed (with added expense) before export. Carcasses that are too thin for export and damaged go into a “manufacturing” grade.
  • The general rule is that as carcass weights go up, then so does fat content. The search is always on for animals that confound this rule.
  • Beta lamb is a special class of milk-fed lamb less than 7.5kg carcass which is moderately-to-well muscled with an even but not excess fat cover.
  • Hoggets. There is a separate “hogget” grade (defined by teeth eruption) for carcasses based on weight and fat cover.
  • Rams. There is only one class covering all weight ranges with no GR specifications.
  • Muscling is only assessed on a limited range of sheep carcasses.

Typical meat schedule prices

Here’s an example of a typical Meat Schedule published by meat companies or available from independent websites, for a particular week for North Island lamb for the Y low-fat grade and the MX1 mutton grade. For South Island stock, take off $1.50/head/lamb.

Key points from the table
  • It lets you see what prices are this particular week, and how they have changed.
  • The skill is to predict what’s going to happen in the weeks ahead and whether you should buy or sell, taking into account the weather, pasture growth, what’s happening in the US and European economies, changes in the exchange rate, saleyard rumour and downright lies!
  • There’s a challenge for a smart young IT person to write some software for a pocket PC to predict all this– but it would take a lot of the fun out of it.
When to sell?
  • This is the hard part or the challenging part - depending on your attitude.
  • So knowing all the different criteria involved in each grade, you now have to predict which particular combination will make most return.
  • A typical decision would be whether to sell on this week’s schedule, or by looking at recent schedule trends, reading market reports and using stock agent or saleyard information, hang on for a bit longer.
  • If you do this, the stock will put on more weight for which you will get paid, but it may also mean they get fatter and could even get overfat and grade T where excess fat has to be trimmed off before export and you would get less per kg.
  • But the penalty per kg may not have much effect if you have produced many more kg of carcass. Remember the extra time on the farm and the extra feed eaten would have to be taken into account too.
  • So can you see why it would be wise to consult with a meat company meat buyer or farm consultant to seek guidance on all this. It’s very much like the stocks and share market.

Killing out or dressing percentage

  • The meat company pays you for the weight of the carcass, so now comes the question of how much of the live animal you sent to the meat plant ended up as a carcass.
  • From the newly-killed sheep the following are removed or trimmed:
  • Pelt
  • Head including tongue
  • Feet
  • Internal organs including all digestive, respiratory, excretory and reproductive organs.
  • Mammary system and cods (udder and scrotum)
  • Skirts both thick and thin (abdominal wall)
  • Tail
  • Aorta – all tissue
  • Neck trim – removed with pluck (trachea and lungs) and any tissue contaminated by blood or ingesta.
  • So you are left with the weight of the animal after its carcass has been “dressed”.
  • The terms Killing Out Percentage (KO%) or Dressing Percentage are used and are calculated by dividing the hot carcass weight by the live weight and multiplying this by 100 over 1.
[(Hot carcass weight)/(Live weight without fasting)] x [100/1]

  • If you want to predict the HCW from liveweight before the animal leaves the farm, use this formula:
  • HCW = (Liveweight kg x 0.473 – 1.92) x 1.045
The standard is taken as 43% for a 13.5kg hot carcass.
Here’s a ready reckoner table to help solve this mystery:

  • It’s important to remember that if you weigh stock before they leave the farm, they will vary greatly in the amount of “fill’ or gut contents they have, and this may come as a big surprise when you see the KO%.
  • The longer you empty stock out by leaving them on a bare paddock or yard before slaughter, the less the loss will be. See table below for the factors that can affect KO%.

These are broad estimates of minimal likely factors which may not all act independently. So watch you don’t double count them, e.g. in dry seasons light lambs may be leaner and also have full fleeces.
  • Meat company buyers who come to your farm are very experienced at looking at live animals and predicting their carcass weight. However, having an on-farm live weight is a great help for both them and yourself, and at least reassures you that you are not being ripped off (if you dared to doubt the buyer!).
  • The killing sheets from the meat company give you the final true picture including the killing charges. This is always interesting but sometimes frustrating to see on these sheets what defects like bruising and old injection abscesses may have cost you, especially if these were not of your doing!
Presentation of sheep for slaughter
  • Again because of legal requirements, meat companies have strict standards about stock accepted for slaughter, so they meet the very strict standards set by the overseas markets. As a result the companies require an “Animal Status Declaration” (ASD) form similar to that required for sheep sold at the saleyards or transferred between owners after January 1 2006.
  • So in summary:
  • One form travels with the stock from the old to the new owner.
  • The new owner keeps the form as they own the animals plus 1 year.
  • One form is retained by the seller or supplier. It must be kept for 1 year.
  • One copy is kept by the organising agent.
  • The copy received by the processor must be kept for 4 years.
  • If you have any pangs of frustration when filling this in, just remember we have no choice as sheep farmers are in the food business, and red meat is a health food. You’ve got to believe it!
  • The question asking if the animals were born on your property and if not have you had them for 60 days or more is very important here. If you have just purchased the stock, you should have obtained an Animal Status Declaration form from the previous owner.
  • If you didn’t, then “the worst case situation” applies which means the meat company cannot slaughter them for a 60-day withholding period. This can cost you extra feed and they may also get overfat.
Presentation grades
Meat companies also have two or three “presentation grades” for acceptance of stock for slaughter. Here are the key issues on these:
  • Dags and dirt. Sheep should have no dags and have clean fleeces. Dags are a big health and hygiene hazard.
  • Emptied out. Sheep should be emptied out (in yards or on a bare paddock) for a minimum of 4 hours to reduce the risk of contamination with faeces which can then get on the wool and then the carcass when the pelt is removed.
  • Wool blind. Sheep should be able to see so may need to be eye-wigged before acceptance at the meat plant.
  • Free of distress and injury. Distress caused by transport and injury can affect meat quality.
  • Washing. Stock should be clean and free from dirt prior to slaughter and if they are not, then the meat company will have to wash them. Hopefully they will only require one wash but they can be washed twice if necessary. Then they have to be given time to dry prior to slaughter and this is also stressful for the sheep.
  • Wool length. Wool should not be more than 4cm long which equates to approximately 0.7kg. Short wool is preferred in winter as it dries more quickly.
Black fibres
This is an interesting processing problem which arises because black sheep have black fibres! Then after processing if any of these black or coloured fibres have adhered to the carcass –they can be easily seen whereas stray white fibres cannot.

So be aware of this if you keep pigmented sheep. It’s still a problem but nothing like what it used to be, thanks to big improvements in processing equipment.

Identifying sheep before sending to the works
When you send sheep for slaughter to a meat plant, it’s important for everyone that they are clearly identified to save time and reduce cost. Here’s the basis of some acceptable and well-understood codes used by farmers and processors. The basis of it is to use standard coloured raddle on standard parts of the sheep shown in the table below.

You can use any combination of these such as BH for blue head and YR for yellow rump. If you have different mobs, use contrasting colours and not yellow and orange for example. Put enough raddle on to last, but not too much as it has to be scoured out of the wool after slaughter.

Transporting sheep to slaughter
Prime lambs for slaughter are a quality export product so remember the following:
  • At least a week before transport, draft out stock for slaughter into their new groups to give them time to settle and sort out their new social order.
  • This is to avoid stress which affects the pH of the meat, which then reduces shelf life when sold as a higher-value chilled product in supermarkets rather than just frozen.
  • Ideally meat should have a pH of around 5.5 and it’s acceptable up to 5.8. This will produce good red meat that will be excellent to eat. In a range from 5.8 to 6.2, the meat begins to be unacceptable and tough. Above 6.2 and up to pH of 7.0, the meat will be relatively tender but will go a dark colour and will spoil quickly and have little flavour on cooking. Dark meat when displayed in a supermarket has little customer appeal and shoppers assume it is “going off”.
  • After sorting or any vet treatment, put stock on good pasture to build up their glycogen levels.
  • On the day of transport, muster them quietly and let them empty out on a bare paddock or yard with water for at least 8 hours without disturbance. This will keep them cleaner in the truck and reduce the effluent that may contaminate the highway.
  • If the transporter is late - don’t let your stock be sacrificed by rushing them, in a bid to make up lost time.
  • Load stock quietly without sticks or dogs and only minimal use of an electric probe if needed. Check for any protruding nails or bolts that will damage pelts and bruise meat when loading and fix these before the truck arrives.
  • Ensure the loading ramp is safe and the truck can back up squarely to it, leaving no gap for legs to get down and cause injury so they cannot be sent for slaughter.
  • By law, animals must be able to take their full weight on all four feet to be acceptable for transport. Any animal that cannot will require a veterinary certificate before the truck operator or meat works will accept it.
  • A meat processing plant does not accept defective stock or what used to be known as “mercy kills” such as stock with broken legs. Such animals now have to go for pet food.
  • All stock must also be accompanied by the correct documentation before the truck driver will pick them up.
  • Only use reliable transport operators who will give your stock a quiet ride to the meat plant. If transport staff are rough with your stock, don’t use them again and tell the company why. You have been preparing a high quality product for perhaps 4-12 months and to have it ruined by poor handling on its last day is unacceptable.
  • Make sure the truck is clean before your stock are loaded - it is supposed to be.

Home killing on the farm

  • It’s very important to have your home killing done by a licensed “home kill service provider” Operators are required to be licensed under the Animal Products Act 1999 and can provide their service on their own licensed premises or on your property.
  • The welfare standards for home killing must conform to those given under the Animal Welfare (Commercial Slaughter) Code of Welfare 2006.
  • Home killing of livestock is subject to legal restrictions because of concerns that home-killed meat (which has not been inspected by an approved government inspector in a licensed slaughtering facility) may get into the export meat trade and threaten market standards.
  • Our export markets view this as a risk, and farmers who kill sheep for home consumption need to fully appreciate this. The risk is not so much with those who understand and stick to the law, it’s the illegal operators who are the worry and those who are tempted to buy “cheap meat”, some of which is of very suspect origin and without doubt is a human health risk.
  • “Home kill” is the slaughtering and butchering of your own animals, either by yourself or by a licensed home-kill butcher for your own consumption which includes your family and household.
  • A “family” normally includes parents, children and grandparents and does not include an extended family living elsewhere.
  • A “household” are the normal occupants of a house and does not include an institution or tourist accommodation.
  • Only animal owners who are actively engaged in the day-to-day maintenance of an animal, or keep animals of the same kind for a period of 28 days, may use home kill. In other words – someone making a serious attempt to farm them and not just dealing in stock.
  • Home killed meat cannot be sold, raffled, or bartered for goods or services. It would not even be wise to give it away.
  • You can feed home kill meat to your staff if they are regular employees, and they can feed it to their families. You cannot feed casual workers or contractors or your vet, accountant or bank manager, and you cannot feed home kill to paying guests.
  • It’s very important to use a home kill butcher with a good reputation for producing top meat. A freezer full of tough meat is not a good prospect, nor is the nagging concern that you may think you didn’t get all your own sheep back from the butcher!
  • It is very important to realise that under the Animal Welfare Act 1999 all animals must be slaughtered in a humane way without causing any pain or stress to them or their flock mates.
  • Some operators will bury the offal on your farm or will take it away for disposal in an approved site. This will be part of the charge.
  • Anyone offering home-kill services is required to be listed under the Animal Products Act 1999 as a “homekill service provider”. They can provide their service at their own licensed home-kill premises or on the owner’s property. The welfare standards for home kill animals should conform with those given under the Animal Welfare (Commercial Slaughter) Code of Welfare 2006.
  • Check with MAF for the latest regulations and for regulations to provide meat for Marae and ethnic and religious groups.
  • Realise the potential hazards with home killing of meat. You would do well to consider sending a sheep off the farm to a licensed slaughter facility to be killed and processed. Then at least you have no human safety concerns, animal stress or food safety issues to be concerned about.
  • If you kill your own sheep – see information on euthanasia and slaughtering.
  • Before you fill the freezer, check to make sure it’s reaching the correct temperature and tape the plugs into the socket. Also lay some rat poison near it as they love the plastic on the cable and you don’t want to come back from holiday and find a freezer full of nice pink water with your meat floating in it!
Curing sheep skins
If you want to cure a sheepskin, see the recommended further reading list for a good recent reference. (Martin 2004).

This material is provided in good faith for information purposes only, and the author does not accept any liability to any person for actions taken as a result of the information or advice (or the use of such information or advice) provided in these pages.

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