Problems with Inbreeding in Pedigree Dogs

Introduction

     Inbreeding in pedigree dogs arises in because certain dogs, prized for exhibiting characteristics desirable for that breed, are used to sire many litters of puppies. The implications of this are that when the dogs from these litters come to be mated, some will inevitably be paired with dogs in other litters that have the same father. Over generations, more and more dogs across a particular pedigree are related to one another and the chances of relatives mating then increase. Genetic variability in domestic breeds of dogs, therefore, depends greatly on dog breeders’ decisions and practices(United Kingdom Kennel Club, 2011). Selection for particular types of animals can result in bottlenecks within the populations, leading to higher rates of inbreeding in dogs. Moreover, in dogs, the mating between close relatives is frequently used ( Ubbink et al., 1992) in the practice of line breeding. Mortality of puppies significantly increases with inbreeding (Van der Beek et al. 1999) and a positive correlation has also been shown between the frequency of some genetic diseases and the average coefficient of inbreeding (Ubbink et al., 1992). Moreover, purebred dogs often have to deal with genetic diseases and more than 400 genetic diseases are registered in dogs (Nielen et al. 2001). This paper looks at genetic diversity and the incidence of inbreeding in purebred dogs as well as the consequences of these breeding practices on the welfare of animals, in particular inherited genetic disorders.

Problems associated with inbreeding pedigree dogs

Loss of genetic diversity

     A study recently carried out by Calboli et al. (2008) investigated the incidence of inbreeding in purebred dogs. Through the development of novel approaches for examining population structure as well as using previously derived formulae  to represent inbreeding, Calboli et al. (2008) examined the electronic pedigrees of 10 breeds of dogs (a total of 2.1 million dogs) from the United Kingdom Kennel Club’s databases. Extremely inbred dogs were identified in every breed and the effective population size was estimated to be between 40 and 80 dogs for all except two breeds (Calboli et al. 2008). Distressingly, the effective population size of these breeds was several orders of magnitude smaller than the actual number of dogs registered in each breed. It was also found that in all but three breeds over 90% of unique genetic variants are lost over the course of six generations (Calboli et al. 2008). This points to the dramatic effect that breeding patterns can have on genetic diversity. While this was a large-scale study of many generations of pedigree dogs, it primarily focused on the more popular breeds.  The incidence of inbreeding and loss of genetic diversity could therefore be much higher in rarer breeds with smaller populations (Calboli et al. 2008). Such small effective population sizes mean that the chances of a dog breeding with a close relative, resulting in birth defects and genetically inherited health problems, are high.

Genetic Disorders

       Most diseases are affected to some extent by both genes and the environment. A genetic disorder is one in which a variation in the genetic make-up of the individual plays an important role in causing the condition (Canine Inherited Disorders Database, 2011). Although some disorders occur because of spontaneous mutation, many genetic disorders are inherited. These conditions are seen quite often in dogs, most of which are purebred dogs.
     The frequency of inherited conditions can be reduced through good breeding practices (Canine Inherited Disorders Database, 2011). However, for this to occur, we need to know how the disease is inherited, how to identify the condition in its earliest stages, as well as find ways to recognize carriers of the disease who are usually asymptomatic. Breeds that have a higher risk for a condition, in relation to other dog breeds, or to the general dog population are said to have a breed predisposition (United Kingdom Kennel Club, 2011) . Common sense suggests that these disorders are inherited, but for many breeds and for many disorders, the studies performed to determine how the disease is inherited or the frequency of the disease in a particular breed have not been carried out, or the results are inconclusive (Canine Inherited Disorders Database, 2011).
     One such disorder is canine hip dysplasia. Hip dysplasia is the most common inherited orthopaedic disease in large and giant breed dogs, and occurs frequently in many medium-sized breeds as well. Canine hip dysplasia is caused when the hip joint, (a "ball and socket" joint, in which the "ball”, the top part of the thigh bone or femur, fits into a "socket" formed by the pelvis) and the ligaments which help to hold them together are loose (Canine Inherited Disorders Database, 2011). This leads to the ball sliding part way out of the socket. Canine hip dysplasia is a condition that becomes progressively worse over time and your dog will become painful, lame and weak in the hind end (Canine Inherited Disorders Database).
     The mode of inheritance of canine hip dysplasia is polygenic. Polygenic traits are controlled by an unknown number of genes and in the case of canine hip dysplasia scientists do not yet know which genes or how many genes are involved (Canine Inherited Disorders Database, 2011). Because it is virtually impossible to determine the exact genotype for such traits, it is difficult to control defects with a polygenic mode of inheritance. The best attempts at control are based on a grading scheme for identification of the defect and a breed policy of recording and publishing the results for as many dogs as possible (Canine Inherited Disorders Database, 2011). Canine hip dysplasia remains a problem in most large breeds of dog, regardless of efforts to control this condition dating back to the 1960s(United Kingdom Kennel Club, 2011). Breed organizations and veterinarians in various countries have developed control programmes that rely on radiographic evaluation and a central registry of dogs (United Kingdom Kennel Club, 2011). Thoughtful selection by breeders, using this information, has greatly reduced the incidence of hip dysplasia in those breeds.
Conclusion

    In light of the many problems associated with inbreeding actions to either maintain or increase genetic diversity in the populations of purebred dogs should be a high priority for the health these dogs. Possible actions include limits on the use of popular sires, encouragement of matings across national and continental boundaries, and even the relaxation of breed rules to permit controlled outcrossing( McGreevy et al, 1999; McGreevy, 2008).

References

F.C. Calboli , J. Sampson, N. Fretwell, D.J. Balding. 2008. Population Structure and Inbreeding from Pedigree Analysis of Purebred Dogs. Genetics. 179: 593-601.

Canine Inherited Disorders Database. Canine Hip Dysplasia. Accessed September 28, 2011.

P.D. McGreevy, F.W. Nicholas . 1999. Some Practical Solutions to Welfare Problems in Dog Breeding. Animal Welfare. 8: 329-341.

P.D. McGreevy. 2008. Sick as a dog: Outraged by the health problems pedigree dogs suffer. New Scientist. 200:2677.

A.L. Nielen,S.  van der Beek, G.J. Ubbink, B.W. Knol. 2001. Population parameters to compare dog breeds: differences between five Dutch purebred populations. Vet. Q. 23: 43–49.

G.L. Ubbink, B.W. Knol, J. Bouw. 1992. The kinship between homozygosity and the occurrence of specific diseases in Bouvier Belge des Flandres dogs in the Netherlands. Vet. Q. 14: 137–140.

United Kingdom Kennel Club. Dog Health: Summary results of the Purebred Dog Health Survey for all breeds. Accessed September 29, 2011.

S. Van der Beek, A.L. Nielen, Y.H. Schukken, E.W. Brascamp. 1999. Evaluation of genetic, common-litter, and within-litter effects on preweaning mortality in a birth cohort of puppies. Am J. Vet. Res.60: 1106–1110.

Turning Good Ideas into Good Projects

This is most definitely the hardest blog entry to try and write to date. Not only do I have no ideas of my own, Google has also failed me with few useful results on the topic. So what to write about this topic?

Alright so if I was going to start a project the process I might roughly follow would look something like this:

Project idea -      Objectives -      Identify Problems-      Develop a method-    Carry out activities-      Results

I also think that for a project to be successful the idea needs to address real problems that are facing our communities today, otherwise what is the point of going any further with the idea. Also I think that you need to be realistic with what your objectives are for the project(ie. what are you really going to do and what are you realistically going to get out of this project). I also think that you need to be able to look further down the road, into the future if you will, and consider if what you are proposing will be able to be sustained. Oh, and budget. How could I have forgotten that. I think realistically that this is a HUGE factor in determining if your idea makes it through to the project stage. Your idea could be the best in the world and solve an important problem, blah, blah, blah. However if it will cost a small fortune to get it up and running, you may be finished before you even begin(I know, I hate clichés too, so this will be the only one I promise). After all money doesn’t grow on trees (Okay I lied and technically money does grow on trees).

My question for this topic would be: How do you figure out if your idea will be sustainable in the future?

How to make a Bad Presentation

So the riveting topic for this weeks blog is (drumroll please): What makes a good presentation. Who comes up with this stuff anyways? Well since I took ALES 204(a whole class on communication) in which we exhausted this topic ( and because it will simply be more fun) I will look into how to make a bad presentation instead.
     Surprisingly, or maybe not so surprisingly, there is alot out there on how to make bad presentations. One prof at Berkely (Prof.David Patter) even came up with a list of commandments to be followed to ensure a bad presentation. They are as follows:

1. Thou shalt not be neat -Why waste research time preparing slides? Ignore spelling, grammar and legibility. Who cares what 50 people think?
2. Thou shalt not waste space -Transparencies are expensive. If you can save five slides in each of four talks per year, you save $7.00/year!
3. Thou shalt not covet brevity -Do you want to continue the stereotype that engineers can't write? Always use complete sentences, never just key words. If possible, use whole paragraphs and read every word.
4. Thou shalt cover thy naked slides -You need the suspense! Overlays are too flashy.
5. Thou shalt not write large -Be humble -- use a small font. Important people sit in front. Who cares about the riff-raff?
6. Thou shalt not use color -Flagrant use of color indicates uncareful research. It's also unfair to emphasize some words over others.
7. Thou shalt not illustrate -Confucius says ``A picture = 10K words,'' but Dijkstra says ``Pictures are for weak minds.'' Who are you going to believe? Wisdom from the ages or the person who first counted goto's?
8. Thou shalt not make eye contact -You should avert eyes to show respect. Blocking screen can also add mystery.
9. Thou shalt not skip slides in a long talk -You prepared the slides; people came for your whole talk; so just talk faster. Skip your summary and conclusions if necessary.
10. Thou shalt not practice -Why waste research time practicing a talk? It could take several hours out of your two years of research. How can you appear spontaneous if you practice? If you do practice, argue with any suggestions you get and make sure your talk is longer than the time you have to present it.

 

     This just goes to show that it is not just good presentations that take a lot of skill to pull off, bad presentations require skill too. The guy in this YouTube video( http://www.youtube.com/watch?v=wXILI9Q1jIw)  seems to have distilled bad presentations down to an art form. I loved this video as it is fun after taking a communications class (not that you need one to be able to see what he is doing wrong) to pick out all the things he is doing wrong in a presentation. Go ahead an try it yourself! Besides it can be very informative-and entertaining!- to learn from others mistakes.

Industry Issue

The Expected Outcomes and the Unintended Consequences for Human and Animal Health due to the banning of growth promoting antibiotics in the EU

Introduction  

     Regulatory authorities throughout the EU have suspended the use of some antibiotics as growth promoters in animal feed. The controversy surrounding this topic results from the issue of whether the use of antibiotics as growth promoters in animals presents a genuine threat of increased antibiotic resistance in human pathogens, and therefore a risk to human health. Supporters of the ban point to falling rates of resistance in animal and human isolates as a direct result of the ban (World Health Organization, 2003). Critics however question whether there is actual evidence supporting a link between the use of growth promoters and resistance in human pathogens and talk about a decline in animal health among the undesirable effects.

     In 1986 Sweden implemented a ban on all growth-promoting antibiotics in food animals(World Health Organization, 2003). This was followed by Denmark, in 1995, banning the use of avoparcin and virginiamycin and the European Union (EU), in 1999, banning the use of four remaining antibiotics used for growth promotion ; bacitracin, spiramycin and tylosin, and virginiamycin (World Health Organization, 2003). The motivation behind these bans is thought to be a combination of both consumer and political opinion, in addition to scientific concerns that antimicrobial resistance in animals may be transmissible to humans.

Expected Outcome

Benefits to Human Health

     The EU ban has succeeded in the complete removal of the antibiotics previously used as growth promoters which was the main goal of the ban. For example where Denmark previously used in excess of 105 metric tonnes of antibiotics for growth promotion in 1996, in 2000 the use of antibiotics for growth promotion fell to 0 metric tonnes (Danish Integrated Antimicrobial Resistance Monitoring and Research Programme, 2001).

     There has been data showing the termination of antimicrobial growth promoters in Denmark has dramatically reduced the food animal reservoir of enterococci resistant to these growth promoting antibiotics, and therefore a reduced reservoir of resistance genes that defer antimicrobial resistance to a number of clinically significant antimicrobial agents in human medicine (World Health Organization, 2003). There are also some signs that the termination of antimicrobial growth promoters in Denmark may be associated with a decline in the prevalence of streptogramin resistance among E. faecium from humans (World Health Organization, 2003).

Unintended Consequences

 Animal Health

     The ban on these antibiotics originally used for growth promotion has revealed that these antibiotics were important in the prevention of many infections in food animals. It could even be said that the decrease in the resistance pool in animal and human microorganisms has had the cost of a decrease in animal health and consequently animal welfare. Denmark has already reported an increase in both the morbidity and mortality among the swine population (Wegener, 2002) . Most of these have been associated with enteric infections (Verner et al., 2002). Reduced weight gain and frequent bouts of diarrhoea have been seen in 11 percent of finishing pigs and most of the recurring problems of chronic infections in weanling and post weaning pigs are due to Lawsonia intracellularis (Callesen, J., 2002; Verner et al., 2002).

     The poultry industry in Denmark has also experienced problems due to the withdrawl of antibiotics, in particular bacitracin (Wicker et al., 1977). One example is the emergence of clostridial necrotic enteritis, which had been previously shown to be suppressed by bacitracin, which is requiring producers to use antibiotics in a therapeutic capacity (Tornee, 2002).

Increased use of Therapeutic Antibiotics in Food Animals

     There has been a significant increase in therapeutic antibiotic use due to an increase in infections in food animals since the ban was implemented (Muirhead, S. 2002). After the ban of antibiotics as growth promoters an increase in sales of therapeutic antibiotics rose from 383 tones in 1999 to 437 tones in 2000 (Veterinary Medicines Directorate, 2002). The 7 percent increase in therapeutic antibiotic sales in the swine industry has been attributed by critics to the EU ban as well as to the presence of diseases such as porcine dermatitis and post weaning multi-systemic wasting syndrome (Veterinary Medicines Directorate, 2002). In Denmark alone there has been an increase from 48 to 94 tones in the period between 1996 and 2001 (Veterinary Medicines Directorate, 2002). This increase in therapeutic antibiotic usage has occurred in spite of efforts to improve other critical aspects of animal husbandry to make up for the loss of the growth promoters (The National Committee for Pig Production, 2002).

Conclusion

     A great deal of attention has been paid to antibiotic use in food animals including antimicrobial growth promoters because they have the potential to add to problems with antibiotic resistance in humans. Antibiotic resistance is undesirable in any situation including animal husbandry because it has the potential to reduce efficiency and animal productivity (DANMAP, 2009). Knowledge about antimicrobial use in humans must be applied to all settings. Animals require antibiotics for the same reasons humans do and strategies need be put in place to ensure their continued efficacy. This necessitates veterinarians and farmers to unite together with medical professionals to improve the use of antibiotics and subsequently control the spread of antibiotic resistant bacteria (DANMAP, 2009). Antibiotics should be an integral part of disease preventive methods.

References

Callesen, J. 2002. Effects of termination of AGP use on pig welfare and productivity. Page 6 in  Abstracts of the International Invitational Symposium: Beyond Antibiotic Growth Promoters in Food Animal Production., Copenhagen, Denmark.

Danish Integrated Antimicrobial Resistance Monitoring and Research Programme. 2001. Consumption of Antimicrobial Agents and Occurrence of Antimicrobial Resistance in Bacteria from Food Animals, Food and Humans in Denmark. Danish Veterinary Laboratory, Copenhagen, Denmark.

DANMAP. 2009. Use of antimicrobial agents and occurrence of antimicrobial resistance in bacteria from food animals, foods and humans in Denmark. Accessed September 11, 2011. http://jas.fass.org/site/misc/JAS_Instruct_to_Authors_2011_2-24-2011.pdf.

S. Muirhead. 2002.Therapeutic use of antibiotics on rise in Denmark. Feedstuffs. 74:1–5.

The National Committee for Pig Production. 2002. Danish Slaughterhouses. Accessed September 11,2011. www.danskeslagterier.dk/smcms/ LU_engelsk/Research_ar

Tornee, N. 2002. Consequences of terminating AGP use for broiler health and usage of antimicrobials for therapy and prophylaxis. Page 6 in Abstracts of the International Invitational Symposium: Beyond Antibiotic Growth Promoters in Food Animal Production.,Copenhagen, Denmark.

Verner, J. Wheelock. and C. Foster. 2002. Food Safety and Pig Production in Denmark. Report commissioned by the Danish Bacon and Meat Council. Verner Wheelock Associates Ltd, Skipton, UK.

Veterinary Medicines Directorate. 2002. Sales of antimicrobial products used as veterinary medicines, growth promoters and coccidiostats in the UK in 2000. Accessed September 12,2011. http://www.vmd.gov.uk/general/publications/amrrpt2000v51.htm

H.C. Wegener. 2002. Banning antimicrobial growth promoters in Europe: where does it make a difference? Abstract for Session 195 in 42nd Interscience Conference on Antimicrobial Agents and Chemotherapy., Washington, DC, USA.

D.L. Wicker, W.N. Isgrigg , and J.H. Trammell. 1977. The control of necrotic enteritis in broilers with zinc bacitracin. Poultry Science. 56: 1229–1231.

World Health Organization. Impacts of antimicrobial growth promoter termination in Denmark. 2003. Report number WHO/CDS/CPE/ZFK/2003.1. Accessed September 14, 2011.http://www.keepantibioticsworking.com/new/Library/UploadedFiles/Impacts_of_Antimicrobial_Growth_Promoter_Termi.pdf

Turning Good Questions into Good Answers

" You can tell whether a man is clever by his answers. You can tell whether a man is wise by his questions."- Naguib, Mahfouz

Has it ever occured to you just how many questions children ask? It seems to matter not where they are or who they’re with or what they are doing, they inevitably seem (much to adult irritation) to have questions. This is understandable as questions are a significant part of the way children learn about their world (right up alongside putting things in their mouth and up their nose). It seems, to me anyways, that as we grow older we begin to lose our desire and passion to question. We have, tragically,  learned to stop asking questions. Questions, those things which are critical to gaining knowledge and understanding. For it is only by asking questions that we are forced to discover the answers. It is only by questioning that we venture down unfamiliar paths and it is often down these paths that we find ( or accidentally bump into while stumbling around in the dark) new ideas or information. 

But alas I digress (well what did you expect this is my first blog after all). We are, I think, supposed to comment on getting good answers out of good questions. That to me seems to imply that all questions are good. For that matter are all questions good? To know what is good you must experience evil or to know what hot is you have to experience cold. I think questions work kind of the same way. You have to have bad questions so as to know what a good question is otherwise what is there about the question that makes it good? Well lucky for us the notes tell us what makes a good question. Or do they? as all the answers appear to be in the form of questions themselves. Oh dear.