Joyce Jacobson, researcher; John Holland, senior  analyst AAHS; and Darrell R. Charlton Jr., researcher, © All rights  reserved
 
Introduction
 
Horse slaughter has become a hotly contested issue in the United  States in the past year. A large number of articles have appeared in the  print media claiming that the closings of the three US based horse  slaughter plants, all of which were foreign owned, in 2007 caused crisis  levels of horse abuse and neglect and even wide scale abandonment of  horses. None of these articles, however, cites any evidence for these  claims beyond opinion or the occasional anecdotal story.
The purpose of this study is to document trends that have occurred in  the wake of the closing of horse slaughter plants in the United States,  to include the numbers of horses slaughtered and where they were  slaughtered during the study period. This period was selected to include  one year before the first closings to provide a baseline. The further  goal was to establish what effect, if any, the closings of the US based  plants might have had upon the frequency of abuse and neglect. 
Background
All three of the foreign owned horse slaughter plants operating in  the United States were closed under state laws during 2007. On January  19
th, 2007, a federal appeals court overturned a lower court  decision and ruled that a 1949 Texas law prohibiting the sale of horse  meat was constitutional and valid. Although the two Texas plants  continued to slaughter for some weeks under an appeal to the Supreme  Court, they ceased operations in February when the airlines refused to  ship horse meat to their customers in Europe.
The Texas plants had been responsible for more than half of all the  horses slaughtered in the United States. Within weeks of their closings,  the Cavel plant in Illinois increased their production to take  advantage of the opportunity.
On May 24, an Illinois law prohibiting horse slaughter went into  effect. After closing briefly, the Cavel plant appealed the decision and  reopened under a TRO (Temporary Restraining Order).
At the federal level, an amendment to the 2006 Agriculture budget had  been passed with the goal of closing all US horse slaughter plants by  removing 
USDA funding for their required ante-mortem inspections. This  amendment, which should have taken affect in March of 2006, was  sidestepped by the USDA when it instituted a pay-for-inspections  program. 
The USDA program was the immediate subject of a law suit but the plan  was allowed to continue under another TRO as the suit worked its way  through the court system. The lower court decided against the USDA as  did the appeals court. The result was that the Cavel plant closed  briefly on several occasions before slaughter ended there on September  20
th of 2007 under the new Illinois law.
Data sources 
Several data sources were used for this study, including the Illinois  Department of Agriculture, the United States Department of Agriculture  (USDA), the 
Canadian Food Inspection Agency (CFIA), the Bureau of Labor  Statistics, the Illinois Department of Agriculture (ILDA) and the online  database 
http://www.pet-abuse.com/.
Limitations
There are several complicating factors in gathering and analyzing the  data available. The most comprehensive data available is from the USDA  and the CFIA. While these statistics give accurate numbers for horses  slaughtered in the US last year, as well as exports by country, the US  numbers are not differentiated between the three plants that were  operating in January of 2007. These were the Cavel plant in Dekalb,  Illinois, the BelTex plant in Fort Worth, Texas, and the Dallas Crown  plant in Kaufman, Texas.
The biggest challenge is in obtaining and properly interpreting data  on abuse and neglect. The first problem is that there is no way of  knowing directly how many equines are being abused or neglected. The  only metric available is the number of cases of abuse and neglect that  are charged. Additionally, not all cases charged result in a guilty  verdict, and the fact that a case does not result in such a verdict may  be for reasons other than culpability.
Another issue in regard to charged cases is that they can take months  or years to work their way through the court system. Therefore, this  study uses each case on the date it was charged, whether or not it  results in a guilty verdict, with the assumption that this metric will  average out to be roughly proportional to true abuse levels over time.  The study period is sufficiently brief that significant changes in law  enforcement vigilance over its course are unlikely and the data should  be valid for determining trends.
Moreover, very few states keep centralized data on equine abuse and  neglect cases charged, and those that do keep it in a variety of  formats. This study will look at one such state and analyze the  correlation between its data and other metrics including slaughter rates  and economic conditions for reasons that will become clear in the  analysis.
The only centralized database that tracks all states is 
http://www.pet-abuse.com/. There  are significant limitations to this data source and they will be  discussed in a later section. Since these limitations could draw doubt  as to their validity, a significant effort was made to verify and  otherwise test the data extracted from the database. This will be  discussed in more detail in the section dealing with that analysis.
Historical Perspective
Before looking at the data for 2006 and 2007, it is useful to gain a  historical perspective on horse slaughter. While it is widely known that  horse slaughter was at much higher levels in 1990 than in recent years,  it is less well known that the United States has been exporting horses  to slaughter in Mexico and Canada for this entire period, and to Japan  since 1999.
Canadian and Mexican horse slaughter operations are quite different  in nature. Canadian horse slaughter plants ship most of their product to  Europe with a smaller fraction being consumed domestically. In Europe  the meat is considered a delicacy and it brings relatively high prices.  The plants tend to be similar to US plants because they must meet EU  (European Union) approval.
Horse slaughter is more common in Mexico than in the US. There are  two types of plants in Mexico; EU suppliers and domestic suppliers.  There are two EU supplier plants located in central Mexico at the towns  of Jerez and Fresnillo. In contrast there are dozens of smaller local  plants throughout Mexico that are owned by the municipalities and that  supply horsemeat for local consumption. Unlike the European consumers,  the Mexican consumers view horsemeat as an inferior substitute for beef  and it is often used as filler.
 Figure 1
                                                                            Figure 1
Figure 1 shows the number of US equines slaughtered and exported for  slaughter each year since 1989, as well as the countries to which they  were exported. There are several notable features about this data. The  most often referenced feature is the famous steep decline in total  slaughter between 1990 and 2002. There were over ten slaughter plants in  the United States in the late 1980s and only three by the 2000.
Anti-slaughter proponents have long found this decline their most  unassailable argument against the claim that slaughter protects horses  from abuse and neglect. They argue that since slaughter decreasing by  81% did not bring about a crisis of horse neglect, ending it would not  have such consequences either. This argument has yet to be countered in a  meaningful way by those who espouse the theory that only "unwanted"  horses are slaughtered. The question remains, however, whether the  decline occurred because of supply limitations, legislation, market  demand or other causes.
The possibility that the decrease was caused by limitations of supply  is easily discounted by horse population studies
1. During  this period the horse population of the US grew by 3 to 5% per year. 
The effect of legislation on this decline is minimal but should be  mentioned. Between 1989 and 1998 there were no legislative restrictions  on the slaughter of horses in the United States. In 1998, after  slaughter had already dropped from over 400,000 equines a year to under  100,000, California passed proposition 6 which banned the slaughter of  horses and the export of horses from the state for purposes of  slaughter. Since there were no slaughter plants operating in California  at the time, there was no noticeable impact on the total slaughter in  the United States. Despite many legislative initiatives, no other  legislation affected slaughter until early 2007.
We can see from the export curves in Figure 1 that the overall  decline was almost entirely driven by the decline in US slaughter and a  parallel decline in exports to Canada. This parallel tracking phenomenon  can be seen more clearly if we change the scale on the exports to  Canada as shown in Figure 2.
 
Figure 2
Exports to Canada tracked US slaughter during the precipitous decline  of the 1990s in stark contrast to exports to Mexico. Since US and  Canadian slaughter plants share the same customer base in Europe, this  leads to the implication that slaughter and export to slaughter are  driven primarily by market demand and not the supply of "unwanted"  horses. If supply had been driving the market we would have seen similar  patterns in exports to Mexico.
Finally, an Italian study
6 of horse meat consumption  confirms that it followed the same trend as US slaughter during that  study period between 1995 and 2001. This further indicates that demand  in Europe was likely the strongest determinant of US slaughter levels.  Interestingly, this study will show that there may have been yet another  component to the famous decline of the 90s.
The only other notable non-market influences on the reduction of  slaughter were the burning of Cavel West in Redmond Oregon by arson on  July 21
st, 1997 and the burning of Cavel East in Dekalb  Illinois by accidental causes on Easter Sunday of 2002. Cavel in Dekalb  was rebuilt and was back in operation by the summer of 2004.
The burning of Cavel in Illinois came just as slaughter had ebbed and  was beginning an upward trend that has continued to date. The  relationship of abuse and neglect to slaughter during the period  surrounding the burning of Cavel East was the subject of an earlier  study
2. Ironically, the burning of Cavel appears to have  saved approximately 50,000 horses while we will see later that the  closing of all of the US based plants in 2007 saved only about 22,000  horses from slaughter.
The other two features of interest in the graph of Figure 1 concern  exports to Mexico and Canada. Much has been made of the "unintended  consequences" of driving slaughter over the border to Mexico and Canada,  and later graphs will show that has indeed been the case. However,  Figure 1 exposes the little known fact that these current export levels  are not historically unique.
Particular focus has been placed on Mexican exports because of the  barbaric slaughter methods used in some of their local plants (as  documented by undercover videos by HSUS and others). While Mexican  exports accelerated dramatically after the plant closings in 2007, they  also spiked in 1994 when domestic slaughter in the US was at levels over  100,000 horses per year. Likewise, exports to Canada were higher  between 1991 and 1994 than in 2007.
Thus while it is true that the closing of the US based horse  slaughter plants in 2007 drove American horses over the borders to  Canada and Mexico, the converse is not true and domestic slaughter has  not historically protected American horses from going to these countries  in similar numbers.
Slaughter trends following US plants closures
As previously mentioned, all three slaughter plants in the US were  closed during the year 2007. The two Texas plants ceased operations in  February and the Illinois plant in late September. Figure 3 shows the  resulting slaughter patterns from January of 2006 through March of 2008.
 Figure 3
                                                                                  Figure 3
As can be seen from the red curve in Figure 3, the overall slaughter  of US horses (domestic slaughter + exports) did not drop as dramatically  as might be expected following any of the closings, even though  domestic (US) slaughter did decline steeply following both the Texas  plant closings in February and the Cavel closing in September.
The two temporary interruptions in Cavel operations discussed earlier  can clearly be seen in the dips in April and again in July. Despite  this, the industry had completely recovered to its peak slaughter levels  by late September when Cavel slaughtered its last horse.
Two things happened during this period. First, Cavel ramped up its  operations from its design capacity of 500 horses per week to well over  1,000. There is evidence that this ramp up had already begun well before  the closings and was simply accelerated. This volume offset losses  during the two interruptions and from the Texas plant closings.  Secondly, Cavel management began making arrangements to move their  operations over the border to Canada. When they were finally closed in  September it took only weeks for Cavel to begin slaughtering operations  at the Natural Valley Farms in Wolseley (SK) Canada.
The curve of Mexican exports (blue) shows an interesting and little  known fact. 
Mexican exports had already been increasing since  mid-2006, well before the Texas plants were closed. During the  months following the Texas plant closings these exports continued with  an even more rapid increase. This increase was boosted for a period of  several months as BelTex dumped thousands of horses from its feedlot in  Morton, Texas to slaughter plants over the border.
By September of 2007, the glut of horses from Texas feed lots had  been exhausted and the exports to Mexico had begun to decline. This  decline was partially offset by the continued strong flow of horses to  Canada. By March of 2008 exports to Canada were approximately 50% higher  than those to Mexico.
Figure 4 demonstrates how incredibly quickly Canada slaughter houses  absorbed US horses. Remarkably, Canada more than doubled its equine  slaughter in a single month. This was done by converting existing beef  processing plants that had been struggling to compete with US beef  slaughter plants. Some of these facilities had been built in response to  the closing of the US border to Canadian beef due to an earlier mad cow  outbreak in Canada. The number of slaughterhouses processing horses in  Canada rose from three at the beginning of 2007 to seven at the end of  the study period.
 
Figure 4
We can see from Figure 4 that Canada now depends on the US for the  vast majority of the equines it slaughters. Before the closing of Cavel  about 50% of the horses slaughtered in Canada were from the US, but  between the closing and the end of the study period, 79.5% of all the  equines slaughtered in Canada came from the US. (It should be noted that  USDA numbers for horses exported to Canada for slaughter are  considerably higher than the US import numbers released by Agriculture  and Agri-food Canada. The USDA numbers appear to be the correct ones  given their correlation with CFIS slaughter statistics as shown in  Figure 4.)
To help illustrate what happened with the slaughter of American  horses, Figure 5 provides a year to year comparison of the total  slaughter of US horses for 2006, 2007 and the first quarter of 2008.
 
Figure 5
The 2006 (yellow) line represents the baseline year before any of the  slaughter plants were closed. The blue line represents the slaughter  rate during 2007, and the magenta line represents slaughter for the  first quarter of 2008. This method of comparison is commonly used in  accounting and government reporting because it provides year to year  comparisons that take into account seasonal trends.
There was a significant but largely temporary drop in the 2007  slaughter level following the closings of the Texas plants in February.  The slaughter rate then lagged below the 2006 levels until September  when it reached parity just in time for the closing of the last US based  plant (Cavel). Although slaughter again fell below 2006 levels in the  last quarter of 2007, by the first quarter of 2008 it had returned to  the same levels as both the previous years. The gap between the 2006 and  2007 curves represents the temporary reduction in slaughter and thus  the number of horses spared from slaughter.
Summary of slaughter trends
While the slaughter of US horses and other equines dipped during  2007, it quickly returned to the same levels as before the plant  closings. There were 122,459 US equines slaughtered or exported for  slaughter in 2007 compared to 142,720 in 2006, a reduction of only 17%  for the year. By the first quarter of 2008 the exports to Mexico and  Canada had entirely replaced the reductions in US slaughter.
Returning to the stated purpose of this study, the desire was to  determine whether the closing of the slaughter plants was a possible  causative factor in any subsequent increase in abuse and neglect. The  only mechanism by which this could have happened would have been if the  closings caused a significant and sustained change in slaughter volumes.  Since the resulting reduction in slaughter was quickly replaced by  exports, there is no ongoing volume impact from the closings, and  therefore no possibility it could significantly affect abuse levels.
The only increase in abuse caused by the closings has been the  longer trips and more brutal slaughter conditions that the horses are  subjected to.
Abuse, Neglect and Abandonment
At this point it has been established that any increase in equine  abuse and neglect must be the result of factors other than the  slaughterhouse closings, such as economic and weather (forage)  conditions. The year 2007 saw declines in the economy, especially in the  second half of the year and serious increases in feed and hay costs.  The question is whether these factors did indeed cause a dramatic  increase in abuse and neglect.
As discussed in the introduction, quantifying abuse and neglect is a  much less exact science than tracking slaughter. Fortunately, there is  no need to put too fine an edge on any conclusions drawn from the  available data. The stated purpose of this study is to simply establish  whether or not a "tsunami" or even a significant increase in equine  abuse had occurred as has been claimed by some articles.
Abandoned Horses
If reliable data quantifying abuse and neglect is difficult to find,  data concerning "abandoned horses" is even more problematic. This is  largely because state and local governments do not recognize such a  category. The closest data is on "Estray" horses, which reflects the  fact that it is almost impossible to determine whether a horse was  intentionally released or simply escaped, and only a few states track  even this data. As a result, almost every story must be tracked down  individually.
The first story about abandoned horses appeared in the mainstream  press just weeks after the closing of the Texas plants. The story titled  
Kentucky, Land of the Thoroughbred, Swamped with Unwanted  Horses, was written by Jeffrey McMurray, a college basketball  stringer for the Associated Press (AP). The piece was based on horses  seen free grazing on a reclaimed strip mine in Eastern Kentucky and  claimed they had been abandoned because of reductions in horse slaughter  forced by animal rights activists.
However, the slaughter rates shown in Figure 1 contradict McMurray's  claim of decreasing slaughter in the years between 2002 and 2007 and the  Texas plants had been closed for only a month when the story appeared.  More tellingly, it was determined that the "abandoned" horses were in  fact owned by Trish Hayes of Breaks Riding Stables in Breaks Virginia.  The horses had been the subject of an earlier AP story when teenaged  boys were charged with shooting some of them. But by that time the story  had gone international and many writers still reference the story as if  it were valid.
In October a second AP story appeared in the Oregonian titled 
Abandoned  Horses a Dilemma for Ranchers. That story claimed nine horses had  been abandoned on the ranch owned by a Mr. McKenzie, but the Malheur  County Incident Detail
4 (police report) later showed that the  incident had involved only one horse reported by Mr. McKenzie's  granddaughter and it was determined to be unfounded.
To this day stories continue to surface in respectable publications  that contend there is an abandoned horse crisis in America. Yet research  into individual cases
3 has determined that very few are  accurate and even then they involved fewer horses than reported.
Only a few sparsely populated western states even keep records of  estray horses. Of the states that do keep accurate records, the trends  are mixed but largely flat. The largest documented increase found in  Estray horses was in Arizona
5 which reported a 16% increase  from 2006 to 2007. As a matter of reference, that translates to an  increase of only about 16 horses statewide or 8 more than the three-year  average.
The picture that emerges for horses is very different than that for  dogs and cats, where abandonment is common. Any owner who would simply  release a horse from its pasture is aware that there is a significant  liability if that animal causes a traffic accident, and dropping a horse  off at a distance from its home requires the ownership of a horse  trailer or the collaboration of someone who does own one. It is not an  easy crime to commit or conceal.
As a result, true horse abandonment appears to be rare. The more  common method of abandoning a horse is to simply leave it to forage in  its pasture without medical care or supplemental feed. Thus it was  determined that the focus of this study would be on abuse and neglect  where there is at least some statistical evidence.
Abuse and Neglect
Again, the analysis of trends in abuse and neglect was complicated by  the fact that data is not available in a consistent manner from  different sources. The picture that emerged, however, was that while  some areas had indeed seen significant increases in abuse and neglect  cases, others had, in fact, seen declines.
For example, there was a severe drought in much of the South during  2007, which drove hay prices up in some areas by 100% and more. Texas on  the other hand, which had experienced several years of devastating  drought, hay shortages and wildfires, enjoyed an abundant hay crop in  2007. More over, there have been significant fluctuations in the economy  during the study period.
One of the states where good data was available and where a notable  increase in abuse and neglect cases had occurred was, ironically,  Illinois. Illinois was the only state in the US where slaughter occurred  for most of 2007. In 2006, a study of the relationship between abuse  and neglect in Illinois and total slaughter in the US 
2 found that  on average more slaughter was accompanied by more abuse. The variation  was so great year to year, however, that the study concluded there was  no meaningful relationship between the two.
Figure 6 revisits this comparison with the hindsight of two  additional years of data. If a reduction in slaughter caused an increase  in abuse and neglect, we would expect the two curves to be mirror  images of each other. Looking at the two curves in Figure 6, it is clear  that there is no consistent correlation between the sets of data.
There are two notable features to the curve of abuse cases (blue); a  remarkable increase in abuse between 2000 and 2002, and another steep  increase in 2007. The Cavel plant in Illinois burned on Easter Sunday of  2002. The next year the abuse rate flattened. Had this slaughter been  preventing abuse we would have expected the curve to increase in  steepness. The original study done in 2006 speculated that the changes  in abuse were more likely the result of economic or weather conditions,  but did not attempt to establish this correlation partially because the  data set was limited at that time. 
 
Figure 6
If, however, we now look at the abuse and neglect data from Illinois  with respect to unemployment in the state, we see a very interesting  correlation between upward trends in the two sets of data (Figure 7).
Figure 7
Although the upward slopes of the abuse and unemployment data have an  uncanny correlation in the periods between 2000 and 2002, and in 2007,  the downward trend of unemployment between 2003 and 2006 does not appear  to be mirrored by a corresponding downward trend in abuse and neglect.
At first this lack of downward correlation appears to cast doubt on  just how strong the relationship is, but that is due (at least in part)  to a distortion in the way the government tracks unemployment.
A person is only considered to be "unemployed" while he or she is  receiving unemployment compensation. People whose benefit period has  expired before they get a new job are removed from the "unemployment"  roles and from the statistics just as if they had found a job.
This trick of accounting biases the numbers by amplifying downward  trends (good news) in unemployment. In other words, the downward trend  in unemployment is exaggerated and may in fact be nonexistent. For  example, if nobody at all got a job, every large increase in  unemployment would be followed by an equal downward trend as benefits  ran out.
Therefore, in reality, the shape of the true unemployment curve would  probably be even more like the shape of the abuse and neglect curve.
The Illinois data supports the obvious conclusion that bad economic  conditions lead to more abuse and neglect. This should come as no  surprise, but the fact that slaughter does not affect abuse and neglect  in a positive way (if any at all), may be surprising to the advocates of  the "unwanted horse" theory about slaughter's beneficial contribution  to the negation of abuse.
Measuring Nationwide Abuse and Neglect
The final question that remained to be answered was whether or not  there was a major increase in abuse and neglect nationwide in 2007. The  only source of such data nationwide is the online database of  pet-abuse.com.
The data on this site is well organized for research, but there are  significant limitations to its use. Data is entered as abuse cases are  flagged from other media sources. If a case is not mentioned in the  media immediately, it might not be represented in the data until months  or even years after charges are first placed. The data thus has a  tendency to "back fill" and one can safely assume that the more recent  the data is the more likely it is to be understated.
The usefulness of this data becomes lower as one attempts to  determine recent trends or to determine trends over shorter periods.  Additionally, in any given month the data may consist of only a dozen or  fewer cases, making short term trends more difficult. These  difficulties and assumptions will be discussed further when the data is  presented.
Several tests were performed to determine the data distortion caused  by latency and backfilling of the data in the database. The period  between September 2007 and January 10
th 2008 was initially  analyzed within days after the end of the period. It was again analyzed  at two occasions a few months apart. Based on this comparison it was  determined that the backfill issue was statistically insignificant after  three months. Final data collection was performed three months after  the end of the study period.
The journalistic nature of the data also presented issues. For  example, some cases did not include the exact number of equines, but  instead used variable terms (e.g., "several"). For purposes of  uniformity, these descriptions were converted to numbers using a defined  constant. For example, the word "several" was replaced with the number 6  and the word "dozens" was translated as 24. In any event, these cases  were not common enough to significantly skew the results.
Both the number of cases and the number of equines involved in those  cases are presented. It can be seen that the two roughly track each  other. Again, the analysis of abuse was only used to determine if there  had been a dangerous rise in abuse and neglect overall.
Finally, only cases of owner abuse and neglect were included in the  statistics. Cases involving third party abuse were not included as the  motive for such abuse is outside the purposes of this study. The results  of this search yielded the graph in Figure 8.
 
Figure 8
As expected, the data was somewhat inconsistent on a month to month  basis, but one obvious conclusion can be drawn. 
There clearly was NOT  a catastrophic increase in abuse and neglect during 2007. Other  conclusions that might be drawn are a bit more risky since they might  possibly be putting too fine an edge on the analysis. There appears to  have been a slight drop in abuse after March and a slight upturn at the  beginning of 2008.
 
Figure 9
Finally, it is useful to test this graph against the nationwide  unemployment rates to see if the unemployment rates could have predicted  something close to what we saw from the pet-abuse.com database. Figure 9  shows that comparison. A drop in the unemployment rate is apparent in  late 2006, and from June onward there was an upward trend to  unemployment.
There are obvious reasons why the nationwide unemployment number is a  less than perfect barometer for nationwide equine abuse even if the two  are closely correlate on a regional level. For example, the average  unemployment does not take into account the fact that some states have  larger horse populations than others and unemployment varies  significantly between states. Weighting each state was beyond the scope  of this study.
Even so, there are some interesting similarities between the  unemployment curve in Figure 9 and the abuse case rate as determined  from Pet-Abuse.com. A drop in unemployment occurred slightly before a  similar drop in abuse. (Note that a drop following a relatively flat  period is less likely to be an artifact than one following a recent up  surge). Except for a spike in cases that occurred in March, the  comparison would have been even clearer, but as previously stated the  abuse data is very noisy when observed short term. Similarly, a general  upward trend in unemployment later in 2007 seems to have preceded the  upward trend in abuse during the last quarter of the study (first  quarter of 2008).
The Illinois comparison was performed on a year to year basis which  did not expose this lag of a few months. The identified lag is logically  to be expected since most neglect cases take several months to become  apparent (horses don't starve overnight) and then to be acted upon by  authorities.
The fact that unemployment is a general barometer of trends in equine  abuse and neglect is not surprising as it has long been known to have  the same relationship to domestic abuse and child abuse. In the case of  horses, however, it gives us a historical view into the probable number  of horses that were at risk of neglect and thus "unwanted" by the  definition of slaughter advocates. Unemployment is thus also an  approximate barometer of the number "unwanted" horses and this fact  allows us to see if slaughter has historically increased when this  barometer was rising. 
 
Figure 10
Figure 10 explores the relationship between horse slaughter and the  unemployment barometer of abuse and neglect. To have a beneficial  effect, slaughter would have to rise following increases in unemployment  but during this decade it has done just the opposite. The same  antithetical relationship existed in the 1980s and until about 1993.
However, from 1993 through 2000, the unemployment rate began a  continuous decline during a well known period of prosperity. It is  entirely likely that this decrease, combined with the increasing number  of horses being kept in the population put supply side pressure on the  slaughter industry just as demand was faltering. There were plenty of  horses, but their owners were not willing to sell them at slaughter  prices, and new owners probably outbid kill buyers for surplus horses  from racing and other horse industries. The result was a "perfect storm"  for the horse slaughter industry which produced the famous long  decline.
The implication is that the horse slaughter industry may operate on a  thin margin on supply side price. This implication was recently tested  when Pure Thoughts Horse Rescue (PTHR) attended the famous Sugar Creek  slaughter Auction in Ohio. At most their weekly auctions the bulk of the  horses go to slaughter, but PTHR, financed by a benefactor, was able to  outbid the kill buyers on every horse. The average price paid was $432,  not significantly above the average price seen for slaughter horses.
Conclusions 
Despite the difficulties posed by the data limitations discussed,  several conclusions about slaughter and abuse and neglect trends can be  stated with confidence:
1. While the supply of low priced horses is essential to the  slaughter industry, it does not determine the number that will be  slaughtered. That number is set by the demand for horse meat in Europe.  Slaughter therefore is useless as a tool for controlling the unwanted  horse population and instead simply creates a low end market that  competes with potential buyers of low end horses and encourages a  continuous supply.
2. The rate of slaughter of US horses was only temporarily affected  by the closings of the US based slaughter plants in 2007, and the  slaughter rate has since returned to its previous levels. There was  therefore no mechanism by which these closings could have impacted abuse  and neglect.
3. There was clearly no epidemic of abuse and neglect in 2007  following the closings of the US based horse slaughter plants. None was  predicted by the unemployment numbers and none was found in the database  of cases. 
In other words, on the question of whether the closings  were the cause of a pronounced increase in abuse we find that neither  the cause nor the effect actually happened.
4. While US slaughter rates are clearly driven by the demand for  horse meat in Europe, it appears the industry operates in a relatively  narrow window of supply price. If we are to accept that horses sent to  slaughter are "unwanted" then we can define an unwanted horse not as one  with zero value but one whose value is greater to the slaughter  industry than to a potential owner and that average value is probably  under $500.
5. Abuse and neglect is largely determined by economic conditions. An  upturn in unemployment seen in late 2007 appears to have translated  into the beginning of an upturn in abuse and neglect in early 2008. As  of the end of the study period, abuse and neglect did not appear to have  exceeded norms for the baseline year of 2006, but to the extent that  the economic conditions continue to deteriorate, this trend may become  more worrisome in the months to come. 
References
1.      Oklahoma Cooperative Extension Service Study, David W.  Freeman, Oklahoma 
Horse Industry Trends, Historic Estimates of Horse  Numbers in US and OK. 
http://pods.dasnr.okstate.edu/docushare/dsweb/Get/Document-2087/CR-3987web.pdf
2.      
A Study of the Relationship Between Horse Slaughter and  Reported Cases of Abuse and Neglect. John M. Holland, 23 January  2006
3.      
Deleting the Fiction: 
Abandoned Horses http://www.commonhorsesense.net/index.php?option=com_content&task=view&id=25&Itemid=1 Terry  Torrence, John Holland and Valerie James-Patton
4.      Malheur County Sheriff Office, Incident # 01-2007-05662,  Wolfe, Brian E, 11/27/2007
5.      Email correspondence with Ed Hermes, Public Information  Officer Arizona Department of Agriculture
6.      Characteristics of Horse Meat Consumption and Production in  Italy, F. Martuzzi, A.L. Catalano, C. Sussi