Trade-offs: Making Livestock and Poultry Welfare Decisions

In T. Grandin and M. Cockram (Editors). 2020. The Slaughter of Farmed Animals, Practical Ways of Improving Animal Welfare. CABI International, U.K. pp 35-48.

Chapter 3
Humane Slaughter Book
Trade-offs Balancing Livestock and Poultry Welfare Concerns
With the Commercial Reality of Slaughter
By Temple Grandin, Dept of Animal Science, Colorado State University

Summary

When working with commercial companies, it is often more effective to actually achieve 70% to 80% of the desired welfare improvements than attempting to achieve 100% perfect and accomplishing nothing. There are conditions that cause suffering that are always wrong and there is never a trade-off. Some examples would be beating animals, restraint methods that cause injury, throwing or dragging animals or breaking tails. Government officials, managers of meat buying supply chains and abattoir managers must always stop these abusive practices. However, there are often situations where there are legitimate welfare trade-offs. Stunning methods is a major area of controversy. Electric stunning induces instantaneous unconsciousness, but the handling methods to position the pigs or birds are more stressful. When controlled atmosphere stunning is used, the preslaughter handling method is much lower stress, but this must be balanced against the reaction to a slower induction of unconsciousness. During the induction phase, the animals may be exposed to aversive stimuli. This chapter will help the readers make decisions about trade-offs.
Learning Objectives:

I have been designing equipment and working with abattoirs on improving animal welfare for over forty years. My projects have ranged from huge U.S. facilities to smaller operations in Europe, South America and Australia. To make real improvements in commercial abattoirs, I learned that it is often more effective to actually achieve 70% to 80% of what I want. If I had attempted to get to 100% improvements, I may have been less likely to have achieved anything.

There have been situations where equipment I had designed made big improvements in the welfare of livestock at abattoirs. In other situations, other people who visited the plant were still highly concerned about welfare. This was due to either employees not operating the equipment correctly or the wrong type of animal was being handled in the equipment. In the late 1970's. I was hired to design a system that would replace the worst shackling and hoisting system used on cattle for religious slaughter without stunning. This U.S. abattoir was horrible. Almost every steer bellowed when it was jerked out of the box and hung up by one leg. This is still legal in the U.S. because religious slaughter has legal exceptions to protect religious freedom (FSIS/USDA, 2017). The exemptions cover both slaughter without stunning and the restraint methods.

The plant's engineering department and I brainstormed to invent a better system to eliminate cruel shackling and hoisting of 150 cattle per hour (Grandin, 1980). We did this project before I had commercially developed the center track (double rail) restrainer in the mid-1980'S (Grandin, 1988a, 1993). Newer head holder and restrainer systems are much better than my early system (Grandin, 1993). When I look back on this older system it was primitive compared to my more recent systems. The equipment was far from perfect, but it was a huge improvement compared to dragging live cattle around with chains. After the cattle were hung up, almost 100% of them were bellowing. The lesson I learned early in my career is actually achieving a 70% to 80% improvement is better than achieving nothing, by attempting to fix everything. Working on this early system also showed future clients that I was capable of designing even better systems.

Where Do You Draw The line?

This is a chapter about trade-offs. How do you draw the line to determine trade-offs from an ethical perspective? For me to participate in changing a system that is really terrible, I draw the line at a 70% to 80% improvement. I would not have used by design expertise to design a slightly better shackle and hoist system. One reason I chose the 70% to 80% cutoff was that it was attainable in this particular slaughter plant. I remember big discussions with the plant engineer. He raised Angus cattle and he told me he would NEVER bring his cattle to the old shackle and hoist system. After the new system was installed, he actually did bring his cattle to this abattoir. There was a joint decision between the engineer and I on what was acceptable. How was this decision made? Our goal was to eliminate the constant bellowing and struggling of tortured cattle. The new system achieved this. Compared to the old way, there was a huge improvement. To sell the expensive new system to plant management, we gave them an analysis on labor savings and safety for employees. To sell future systems, I documented the reduction in employee injuries.

It is Easier to Define Where There is Never a Trade-off

In my work, I find it is often easier to clearly define what is not acceptable and where there are no trade-offs (Grandin, 2014). The shackling and hoisting system described above should never be used. People who work in supply chain management buying meat, often use terms such as critical non-compliances or non-negotiables for practices that are never allowed. There are certain bad practices that must be eliminated. There should never be trade-offs. They should be banned. All the countries that participated in creating the World Organization for Animal Health (OIE, 2018) welfare standards and the creators of many other government and private standards can agree, that the following handling and transport practices are never acceptable:

Determining Cutoff Points for Trade-offs for Livestock Handling in Slaughter Plants

In other situations, the cutoff point for a trade-off is less clear. There are three variables that have an effect on livestock welfare in races and alleys. These are: (i) the skill level of the stock people handling the animals, (ii) the behavioral characteristics of the livestock, and (iii) the design of the facility. A system that could be operated with a high level of welfare in one situation may be highly detrimental to welfare in a different situation. Examples of conditions that would be detrimental to welfare would be excessive electric prod use, animals falling down beating of animals for refusing to move. In this introductory chapter, examples will be provided to illustrate trade-offs between the different components of a system.

People Want the New Piece of Equipment More Than Doing the Effort Required for Good Management

During a long career, I have found that selling a fancy new piece of equipment is much easier than getting people to operate it correctly. If I have a choice between excellent management and older adequate equipment or a new state-of-the-art facility with poor management, I will always choose the older system that has a good management. Buying new equipment is easy because it is a one-time expense. Good management requires hard continuous work. Management is never done. It requires effort all day, every day. Attention to details and monitoring of procedures must be continued every day. It is not a one-time fix, that some people think they can get with new equipment. I have a saying, "People want the new thing more than they want the management."

Trade off in Decisions on Race, Alley, and Handling Facility Design

A facility design that may work well in one situation may be really poor in another. A simple handling system that may be used with a high level of welfare for tame cattle that are trained to lead could be very detrimental for the welfare of extensively raised wild cattle with large flight zones. There have been undercover videos of extensively raised cattle or sheep being handled in slaughter facilities that had been designed for tame animals. The slaughter plant had no chutes, single file races or restraining equipment to hold the wild livestock. The lack of the right equipment resulted in animals slipping on the floor, falling and serious abuse by the people. To correct these problems would have required construction of races, chutes, and other systems shown in other chapters of this book. Abattoir designs for wild extensively raised cattle, bison, and other livestock are shown in Grandin and Deesing (2008) and Grandin (2014). A basic principle is that extensively raised cattle and sheep that have not lived in close contact with people will require more expensive and elaborate facilities for handling, restraint, and unloading transport vehicles. For tame livestock that are trained to lead, a race system may not be required.

Skill Dependent vs. less skill Dependent Handling Facilities

When stock people are highly knowledgeable of the behavioral principles of livestock handing, simpler economical facilities may be very effective and provide good animal welfare. At an abattoir, it would be difficult to train people to the skill level that is described below. The author watched six wild Karakul sheep being herded by two very skilled stock people who moved them around the perimeter of a corral and expertly restrained them for injections behind a long gate. The sheep were moved calmly by two handlers who worked the edge of the flight zone and stood at the correct positions. Their rudimentary corral system had no race and forcing pens. It would have been terrible if it had been used by less skilled people. In a place with high employee turnover or less skilled people, a system with races, alleys, and a forcing pen would have been required. There has been increasing interest in learning low stress cattle handling methods and an emphasis on using simpler facilities (Kidwell, 2011 and Burt, 2008). People who successfully adopt this approach must develop their stock handling skills to a high level. This often requires several weeks of dedicated practice. To summarize - handling facilities can be either:

Condition of Livestock or Poultry Arriving at the Slaughter Plant - No Trade-offs

To prevent suffering, both producers and livestock dealers must deliver to the abattoirs an animal that can be easily handled (Grandin, 2017). Severely debilitated or sick livestock are impossible to handle and still maintain good welfare. Michael Cockram, in Chapter 4, discusses problems with old cull cows arriving at abattoirs in very bad condition. Another type of animal that is almost impossible to handle in a low stress manner is neonatal (baby) dairy calves. When Holstein calves are a day old, they do not walk easily. Before dairy calves are shipped, they should have a dry naval cord and be able to walk easily without assistance from a person. The best way to improve neonatal calf welfare is to fatten them into larger steers or bulls that are easier to handle. Early in my career, I made the mistake of attempting to use engineering methods to handle neonatal (bob) calves that did not walk easily. Conveyors in the floor were not an effective solution. I tried this and they do not work. The solution is to bring animals to an abattoir that can walk easily. The problem must be fixed at the farm. Some of the worst animal welfare problems I observe in an abattoir are problems that must be fixed at the farm.

Livestock Behavior Trade-offs

Cattle and other livestock that have become accustomed to people walking through their pens will be much easier to handle in a low stress manner at an abattoir. The livestock producer should do some work to improve the ease of handling of their animals when they arrives at a slaughter plant. A review of the literature clearly shows that acclimatizing livestock to handling will make them easier to handle at the abattoir (Abbott et al., 1997; Geverink et al., 1998; Krebs and McGlone, 2009). The question is, how much work should the farmer be required to do to get his/her animals acclimatized to handling to prevent them from going berserk in the novel environment of a slaughter plant? Often simple procedures on the farm will improve the behavior of cattle or pigs. These include walking through pens on foot to teach the pigs or cattle to quietly move away. It is my opinion that producers can easily do this. Animal based outcome measures at the abattoir can be used to determine which producers have difficult to handle animals. Some of the measures that could be used are: 1) balking, refusing to more forward, 2) turning back, 3) falling, 4) vocalization, and 5) electric goad use (Grandin, 1998ab; Welfare Quality 2009; Losada-Espinoza et al., 2017). These assessments will be discussed further in Chapter 6.

Differences in Animals

Breed and Genetic Effects
The breed of cattle, sheep or pigs can have an effect on temperament and behavior during handling (Baszezek et al., 2006). This may make them more difficult to handle at the abattoir. Managers need to work with producers to help prevent handling problems at slaughter plants. More excitable animals exit more rapidly from squeeze chutes (crushes) and struggle more during restraint (Cafe et al., 2011) Some animals are more excitable and have a higher startle response when they are suddenly introduced into a new novel environment (Grandin, 1997). Animals with more excitable genetics may be calm and easy to handle when they are in a familiar environment on the home farm, but they may become highly agitated when brought to a slaughter plant or auction. Deiss et al., (2009)i Bourquet et al., (2010) Terlouw et al., (2012) conducted studies that showed that the novelty of the new environment at a slaughter plant caused the greatest stress in animals that were more excitable when temperament was tested on the farm. Agitation in animals during handing is caused by fear. The fear circuits in animal's brains have been mapped (LeDoux, 2012; Jones and Boissey. 2011; Morris et al., 2011; Panksepp, 2010). Breed differences in behavior during handling may be due to genetic differences in fearfulness.
Acclimating Livestock to Handling Procedures
Acclimating livestock to handling will require the producer to do some work to produce an animal that will have better welfare at the abattoir. Animal memories of previous experiences are very specific. If a horse becomes habituated to a blue and white umbrella, that learning will not transfer to an orange tarp (canvas) (Leiner et al., 2011). Taming ewes to contact with people did not generalize to other procedures such as handling, shearing, or movement through a race (Mateo et al., 1991). If an experience that an animal will have in the future is similar to a previous experience the animal may be able to generalize and be less stressed. Stress caused by moving through a loading ramp can be reduced by training pigs to go through alleys and ramps. Lewis et al. (2008), Abbott et al. (1997) Krebs and McGlone (2009), and Geverick et al. (1998) all did research that shows very clearly that pigs can be acclimated so handling which will make them easier to move in the future. Further studies with cattle showed that carefully acclimatizing cattle by moving them through yards and corrals reduced stress at the slaughter plant (Petherick et al., 2009). The reactions of animals indicate that their memories are sensory based and stored as specific images or sounds (Grandin and Johnson, 2005). Cattle differentiate between a person on a horse and a person walking on the ground. Extensively reared cattle that have been handled exclusively on horseback may have only a 1 m flight zone, but when they first encounter a person walking on the ground at an abattoir, their flight zone may expand to 10 m. This can be dangerous for a handler in a small pen because the animals may run wildly back and forth or attempt to leap the fence to get away from the person. The cattle perceive the man on foot as novel and frightening and the man on the horse as familiar and safe. Ideally cattle should be acclimatized to being moved on foot before they arrive at slaughter plants (Grandin and Deesing, 2008).

A similar problem can occur in pigs or cattle that are raised indoors. The animals differentiate between a person in the alley and a person walking through their pens. To produce calm animals that will be easy to load onto trucks and handle at an abattoir requires people walking through their pens during the entire fattening period. This will get the animals accustomed to moving quietly away when a person walks through them. Pigs that first experience a person in their pens on the day they are shipped are more likely to be difficult to handle. They may bunch together and squeal. Acclimation to a person walking through them is especially important with more excitable genetic lines. In the U.S., the large integrated pork companies have a standard procedure that instructs people to walk through the finishing (fattening pens) every day.

Handling Bulls
Another factor that can affect animal handling is whether or not animals are socialized to other animals. Intact bulls that have been reared on small farms where they are always kept tied by a halter will often fight and mount each other when they are put in group pens. Fighting and mounting may be more severe compared to bulls reared in groups. Bulls reared together in a group pen or on pasture can be penned together with their herdmates at the slaughter plant. Fighting and mounting may be severe if bulls from different rearing pens are mixed. Bulls with low fear had more mounting than bulls with higher fearfulness (Mark Deesing, 2013, personal communication).

Livestock Breeding for Productivity Trade-offs Affect Welfare

Producers have been breeding animals and using production methods to achieve greater amounts of meat or milk. Pushing the biological limits for more and more productivity can cause handling and welfare problems at the abattoir. At what point has pushing productivity gone too far? I suggest using outcome measurements at the abattoir such as lameness (mobility) scoring and panting scoring for heat stress (Grandin, 2017, Welfare Quality Network (2009). Outcome measurements will be discussed in more detail in Chapter (CHECK WITH TEMPLE).

Genetic abnormalities can also contribute to handling and transport problems. Murray and Johnson (1998) report that pigs with the PSS (porcine stress syndrome) gene: The death losses during transport were 9.2% in homozygotes, 0.27% in heterozygotes and 0.05% in PSS gene free animals. Problems with the stress gene will vary in different countries. In the U.S., a very low percentage of pigs carry the stress gene. Ninety-three percent of midwestern U.S. markets were homozygous negative (Ritter et al., 2007). Indiscriminate selection for production traits such as rapid growth may result in a failure to select against structural leg defects. At a slaughter plant, the author made observations that half of the market weight pigs were lame (Grandin, 2014). The lameness was due to hereditary poor leg conformation. The pigs had either straight post legged legs or their ankles were collapsed and they were walking on their dew claws. Ten years later, observations at the same abattoir indicated that the leg problems had been corrected. They achieved this by eliminating one of their hybrid boar lines. The pigs I observed weighed between 270 and 290 lbs. (123 to 132 kg) and all the pigs at this abattoir were ractopamine (beta agonist) free. They walked easily and were willing to trot during truck unloading. Selection for small feet in pigs to satisfy a specialized Asian market may also increase the percentage of lame pigs.

Trade Off: Growth Promotants Versus Welfare

Both research and the author's own observations show that high doses of beta agonists such as ractopamine and zilpaterol may also cause handling problems. Marchant­ Forde et al. (2003) reported that pigs fed high doses of ractopamine were more difficult to handle. Ractopamine at high doses can also cause hoof lesions in pigs and fighting in pigs (Poletto et ai, 2009, 2010). Further research has shown that problems with ractopamine in pigs is related to both high dosage and physical exertion. When pigs are fed doses over 5 mg/kg per day, they may be more difficult to handle (Ritter et al., 2017). The percentage of nonambulatory pigs may increase when pigs fed 20 mg/kg are handled in an aggressive manner (Ritter et al., 2017; James et al., 2011; Peterson et al., 2015). The author has observed feedlot cattle at the slaughter plant that were both lame and heat stressed that had been fed beta agonists (Grandin, 2015; 2010). Cattle fed ractopamine for 28 days at a dose of 400 mg/day had a higher percentage of lame cattle arriving at the abattoir (Hagenmaier, et al., 2017ab). This experiment was conducted during hot summer weather. The temperature was 31 degrees C. Other research has also shown that cattle and sheep fed beta agonists had signs of heat stress and higher body temperatures (Vogel et al., 2011 and Marcia Cruz et al., 2010). In one very severe case, feedlot cattle fed high doses of zilpaterol had their outer hoof shells fall off (Thomson et al., 2016). The author learned that the cattle originated from a feedlot that fed both high doses of zilpaterol and a diet high in potato starch. Heat stress symptoms and lameness were sometimes more likely when the outdoor temperature was over 32 degrees C (90 F). Loneragan et aL (2014) reported that feeding beta-agonists increased death losses during the warmer summer months. The author has observed that the detrimental effects were very uneven. A few animals in a group had severe heat stress and were reluctant to move. However, many of the other animals behaved normally. This may be due to either uneven feed mixing or some cattle eat more. Some animals may have received a much higher dose.

In cattle, open mouth breathing is a sign of severe heat stress (Mader, et al., 2005).

As panting increases and the tongue becomes further extended, the internal body temperature of cattle rises (Gaughan and Mader, 2016). Cattle with black hides get hotter during hot weather compared to cattle with light colored hair.

Making Sensible Decisions on Beta-Agonist Use

There is a trade-off between welfare and sustainability. Beta-agonists reduce the feed required to fatten an animal (Boles et al., 2012). Some importing countries have banned beta-agonists. From a welfare standpoint, outcome measures of lameness and heat stress should be used. This is essential to prevent producers from using doses that are too high. This is especially a problem when the weather is hot.

In beef, the use of either ractopamine or zilpaterol will make meat tougher (Lean et al.,2014). If the entire animal is doing to be used for hamburger or meatballs this would not matter. In countries where beta-agonists are permitted, people working in the lairage should be monitoring cattle for lameness or reluctance to move. A simple four point scoring system can be used (Grandin, 2015; Edwards-Callaway et al., 2017): 1) normal, 2) lame, keeps with walking group, 3) lame - does not keep up and 4) almost a downer.

Scientific studies, observations by the author, and reports from lairage managers all indicate that welfare problems in cattle are related to hot weather, high doses of beta­ agonists, and physical exertion. In pigs, problems are related to high doses and physical exertion. Cattle on beta-agonists should also be monitored for heat stress. Cattle at rest in a lairage should breathe with their mouths closed. If the mouth is open, they have severe heat stress (Gaughan and Mader, 2016).

Productivity Trade-offs and Preventing Bad From Becoming Normal

The animal's biology has been pushed too far with either genetic selection or growth promotant substances if 1) death losses increase, 2) handling becomes more difficult, 3) a higher percentage of animals are lame or 4) greater percentage of animals show signs of heat stress. Everybody needs to be careful to prevent bad conditions from slowly increasing and nobody notices it. I call this "Bad Becoming Normal" Surveys of dairy producers showed that they often underestimated the percentage of lame dairy cows by half. In the U.S., beef cattle are being fed to heavier weights at younger ages. This may have increased the small percentage of beef cattle that die of heart failure before slaughter. At what point has pushing the animal's biology gone too far?

Electric Stunning Versus CO2 Stunning Trade-off for Pigs and Poultry

When animal welfare is being evaluated at a slaughter plant, both the stunning method and the handling methods associated with it should be evaluated as an entire system. (Grandin, 2014) There are trade-offs between the different parts of the system (Velarde and Raj, 2017). A good example is methods for stunning and handling pigs and chickens.

In both species, electrical stunning will produce instantaneous unconsciousness (Croft, 1052; Lines et al., 2011; Gregory and Wotton, 1990) but handling to position the animal is more stressful. When chickens are electrically stunned, each bird is handled by a person and hung on a shackle. Hanging birds inverted on a shackle is highly stressful (Beddanova et al., 2007; Kannen, et al., 1997). There is a new European system where the shackles are eliminated but each bird still has to be individually handled at the slaughter plant. From a handling standpoint, controlled atmospheric stunning is far superior. The birds enter the stunner in the transport containers and handling by people at the abattoir is eliminated. Since the gas used for stunning does not induce instantaneous insensibility, the question is:

How much stress and discomfort does the animal have before it loses consciousness?

Different researchers have reported different results. The stress of anesthesia induction has to be balanced against the reduction in stress by eliminating handling of individual birds at the slaughter plant. The author's opinion is that some discomfort during anesthesia induction such as gasping and head shaking may be acceptable as a trade-off to greatly lower handling stress. If the animals show escape movements and attempt to climb out of the container, the distress of induction is so severe that the system should not be used.

For poultry, five stage CO2 systems, where the level of CO2 is slowly raised are being used commercially. Gerritzen et al. (2013) concluded that welfare of the chickens was overall improved compared to electrical water bath stunning. To reduce the aversiveness of the CO2 the container containing the chickens moves through five stages at 20%, 30%, 35%, 40%, and 60% CO2. There are commercial systems with more steps. Some commercial systems use 90% CO2 at the final stage to insure death of all the birds. I have observed anesthesia induction in two of these systems and it is my opinion they are a good trade-off. The entire cycle to move the birds through the system is 6 minutes. Commercial systems must be closely monitored to prevent the time in the system from being speeded up. Speeding up movement through the machine could be very detrimental to animal welfare.

Gas mixtures that cause escape movements are not acceptable. In an abattoir, the II reactions of poultry or pigs should be observed and monitored. Either a video camera or windows can be used. There are genetic differences in how pigs react to CO2, Purebred Yorkshires have a peaceful induction (Forslid et al., 1987) and some genetic lines violently attempt to escape when they first contact the gas (Grandin, 1988b). After the animal loses posture and the ability to stand, it has lost consciousness (Benson et al., 2012). Kicking and convulsions after loss of posture are not a welfare concern.

In pigs, group CO2 systems can reduce handling stress because pigs do not have to line up in single file races. This makes it possible to totally eliminate electric prods. Electric prod use, jamming and other aversive events during the last five minutes before slaughter increase lactate levels and lead to poorer pork quality (Edwards et al., 2010ab). Cattle are a species that will walk naturally in single file, but pigs may become more stressed when they have to line up. When single file races are used for pigs by highly skilled stock people, the use of electric prods can be reduced to 5% to 10% of the animals (Grandin, 2012). In this situation, welfare may be acceptable. The trade-off is that electric stunning causes no discomfort, but the handling system may be more stressful for the pigs compared to group handling with CO2 stunning. Both the stunning method and the handling system should be evaluated together. The stress of handling has to be balanced against the aversiveness of the stunning method.

Animal Welfare Trade-offs Electric Versus Controlled Atmosphere Stunning of Pigs and Poultry
Electric C02, LAPS or other gas
Low purchase cost (both species) High purchase cost (both species)
Unconscious is instantaneous (both species) Unconscious is not instantaneous (both species); The trade-off in pigs and poultry is behavior during anesthesia induction must be balanced against the improved handling
Preslaughter handling is more stressful (both species) Preslaughter handling is less stressful (both species)
Lower maintenance and operating cost (both species) High maintenance and operating cost (both species)
Requires more supervision of employee behavior (both species) Requires less supervision of employee behavior (both species)
More blood spots in the meat of pigs Requires careful monitoring of gas concentration or LAPS operation
High amperage electric stunning more meat damage in broiler chickens Meat damage varies with controlled atmosphere method (poultry)
Post publication update: Preliminary research by Dorothy McKeegan, University of Glasgow showed that LAPS should not be used on pigs due to ear pain.

High Amperage Versus Low Amperage Electric Stunning Systems for Poultry

From an animal welfare standpoint, an electrical stunning system that simultaneously induces both unconsciousness and kills the animal by cardiac arrest is preferable to a system that induces a temporary period of unconsciousness. This is why both the European Union and the OIE require 100 milliamperes per bird for broilers (OIE, 2018) EC Council Regulation 1099/2009). Use of the EU standards will result in inducing cardiac arrest (Bourassa et al., 2017; Berg and Raj, 2015; Gregory and Wotton, 1987).

In many countries, such as the U.S. and Brazil, lower amperages are used to prevent hemorrhages in the breast meat (Sirri et al., 2017). The author has visited poultry slaughter plants in both Brazil and the US. At one abattoir, the stunner had settings labeled export with high amperage settings and domestic with lower settings. Electric stunners that do not induce cardiac arrest are also used for Halal (Muslim) slaughter (Sa bow et al., 2017). Muslim religious authorities want the bird to due to the throat cut.

To prevent meat damage, low amperage systems that do not induce cardiac arrest are a commercial reality. The author has worked with abattoirs that have these systems. To prevent birds from regaining consciousness, the automatic bleed machine was moved close to the stunner exit to shorten the stun to bleed time. This solved many problems with birds regaining consciousness. Research has also shown that using both higher electrical frequencies and amperages can reduce meat damage (Girasole et al., 2015). Frequencies of 750 hz to 650 hz were effective (Siqueira et al., 2017; Girasole et al., 2015). Frequencies under 600 hz will be most effective (Girasole et al., 2016). These methods will have a shorter period when the bird remains unconcious (Siqueira et al, 2017).

Trade-offs Between Environmental Sustainability and Animal Welfare Concerns Long Distance Shipping

There is great controversy today about shipping live cattle and other livestock to other countries for slaughter. This creates two problems - the stress of long distance transport and poor slaughter facilities at the destination. In these situations, the trade is driven by both customer preferences and economic factors. It may be possible to change customer preferences but some of the economic factors will be difficult to overcome. A good example is the shipment of young Australian cattle to Indonesia for both fattening and slaughter. Live cattle have the advantage of not requiring refrigeration in a country that has little infrastructure. Shipping refrigerated or frozen meat to countries such as Japan or Korea is economically viable because the customer is paying for a premium product. It is also easy to find a back haul such as electronics to fill the refrigerated shipping containers when they are returned. Customers buying premium meat products may also prefer to ship the meat by air.

The Indonesian situation has complex trade-offs. Rural ranchers in Australia are engaging in sustainable production of cattle on pastures in the arid outback. Grazing animals are one of the best methods for raising food on their land. Shipping the cattle for final fattening in Indonesia increases the number of cattle that can be produced in a sustainable manner on the Australian outback. This land is too arid for growing crops. Grazing can be done with a favorable net carbon balance at moderate stocking rates (Bray et al., 2014) Again, there is another trade-off. If the system is pushed too hard by increasing stock density on the pasture, the sustainability benefits may be lost. To make shipping refrigerated beef to Indonesia economically feasible would require finding a good back haul for the empty refrigerated containers. The most readily available back haul would be palm oil. This is really bad from an environmental standpoint. Rain forest is being destroyed for palm oil plantations. The best approach may be to ship the live cattle to Indonesia and have them go to a modern slaughter house run by Australian managers This solution is not ideal for animal welfare, but it may be best from the standpoint of carbon foot print sustainable agriculture, and, degradation of the environment. A reasonable level of animal welfare could be attained by enforcing rigorous standards for shipping and slaughter.

Trade-offs on Feed Consumption

To improve animal welfare, some poultry growers are using slower growing chickens. Use of the slower growing strains will often cut death losses in half (Thorton, 2016). From a sustainability standpoint, the slowest growing birds require much more feed. Up to 20% more feed may be required to produce the same amount of chicken meat (Thornton, 2016) This means that 20% more land would be required to grow the feed. A sensible compromise may be to use a slightly slower growing bird and then breed to prevent problems such as lameness. The author has observed that the poultry industry is already doing this. Unfortunately, they do not publish their research.

Nutritional Environmental Trade-offs Beta Agonists

Recently there have been problems with broken legs and other bones during transport and handling at the slaughter plant. This is due to reducing minerals such as phosphorus in the ration to reduce phosphorus in the manure. Specimens sent to a diagnostic laboratory from pigs raised in the U.S. have shown that 19% animals had rickets, an old vitamin deficiency disease (Canning et al., 2017). This is due to reducing costs of the ration. Behavioral research indicates clearly that pigs should receive roughage for rooting and chewing (Van der Weerd ref). Many producers are reluctant to feed roughage because it increases the amount of manure. Again, there is a trade-off of welfare versus sustainability issues related to manure.

Trade-offs Commercial Versus Research Welfare Assessments

Animal welfare evaluation systems used in a commercial abattoir and in a research setting are different. To be effective, an assessment system for commercial use must be much simpler (Grandin, 2010). The reality is that auditors and managers have to be able to be trained in a day and a half workshop. After the workshop, they have several shadow audits with an experienced auditor.

The trend in writing animal welfare guidelines is to use outcome measures that are animal based instead of specifying exactly how a facility is designed (Wray et al., 2003; Grandin, 2010; Mullan et al., 2011; Velarde et al., 2012), and (Welfare Quality, 2009). Examples of outcome based measurements are body condition score, lameness, bruises, panting score for heat stress, cleanliness of the animals, death loss, sickness, vocalization during handling, falling during handling, and others. Grandin (2017) contains a review of welfare indicators that can be assessed at the abattoir. Producers, transporters, and slaughter plant managers should track progress in reducing lameness, dirty animal's lesions and other problems, by scoring these variables. On each numerically scored variable, cut off points have to be determined for minimum acceptable levels. The cutoff points should be set where the best 25% of producers can attain them (Grandin, 2010ab). The other producers will need to be given time to bring their practices up to the standard. How did I decide where the cutoff point should be? This cutoff point worked well in previous work on assessing abattoirs on stunning and handling (Grandin, 2010). I have been on many welfare committees for many different species of animals. Unfortunately, I observed problems where the worst producers got on the committees so they could set acceptable levels of lameness way too low. This enabled the worst farms to pass the audit.

Trade-offs and Equipment Design

There are been many cases where expensive, difficult to maintain pieces of equipment has been installed in a developing country. The local people did not have the skills or resources to maintain it. Some examples of equipment that is only suitable for technologically advanced areas are, controlled atmosphere stunning systems with complex conveyors or hydraulic lifting floors in livestock trucks. If the people cannot maintain the equipment, it is useless. In these situations, equipment with fewer difficult to maintain mechanical parts is more appropriate.

The corral, stockyard, and race systems shown in this book and Grandin and Deesing (2008) can all be built by local people with easily available materials such as steel, or concrete. They also have the advantage of being low maintenance and they do not require automated or mechanized parts. In many developing countries, there is a lack of loading ramps for loading and unloading animals onto farm trucks. Loading ramps can be easily built from either metal or concrete. Moving parts are not required.

Economic Factors Can Either Improve Welfare or Make it Worse

When producers have to pay for bruises, they work to greatly reduce them (Grandin, 1981). If losses are passed on to the next segment of the marketing chain with no financial accountability, bruises and damage to livestock usually increases (Grandin, 2015). Several studies have shown that cattle and sheep that pass through auctions have more bruises compared to livestock sold directly to a slaughter plant (Cockram and Lee, 1991; McNally and Warris, 1996). The payment method for employees can also affect the quality of handling. Paying stock people based on the number of animals handled per hour may provide an incentive to handle animals roughly. Stock people should be paid based on the quality of handling by providing incentive pay for low levels of injuries or bruises.

How to Make Trade-off Decisions

In my own work, to make decisions, I have used a combination of data collected during audits and my own observations from over 200 abattoirs in over 20 different countries. For example, how did I make the decision on the trade-off between elimination of electric prods for pigs and elimination of shackling live birds and escape attempts from gas stunning system. Escape movements is a well-defined behavior that both auditors and plant managers can easily observe. Everyone who cares about animal welfare can agree that escape attempts from the container are not acceptable. It is more difficult to make a definitive statement about which is worse - 15% of the pigs getting poked with an electrical prod or four or five gasping movements before a pig falls over and loses posture in CO2, This would require additional research. I also put management factors into my decisions. From my experience in slaughter plants, I have learned that supervising employees to keep electric prod use at low levels is more difficult than managing a group handling CO2 machine. To explain the trade-off in simple terms - The CO2 machine is expensive and more difficult to maintain, but day-to-day management of the people handling the pigs is easier. Electric stunning systems are economical to buy, easy to maintain, but require much more supervision of the people handling and stunning the pigs.

Conclusions

Making ethical decisions on trade-offs is sometimes difficult. There are trade-offs between productivity and welfare and sustainability and welfare. At what point has welfare been compromised? Welfare has been compromised if animals have higher death losses during transit, lameness, or sign of heat stress. There are abusive practices which are always wrong and there is never a trade-off. Numerical objective outcome measures should be used to evaluate welfare.

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