 Newsletter 1 January 2018 Dear dog breeding enthusiasts
Due to academic commitments, I have not been able to write any newsletters over the past 18 months. That is now behind me and I shall make amends. Our newsletters shall also take a more professional look and past and current newsletters shall also be available on our website http://www.rantendal.co.za. If you do not wish to receive these newsletters then use the buttons below to unsubscribe. Our new-look website also explains all the services we render with special reference to reproductive services. Semen can now be frozen on demand at our premises with as little as 1 weeks’ notice. Contact Gigi at reports@rantendal.co.za to make a booking. The topic of my PhD study was all aspects of caesarean section in the bitch. It is therefore prudent that my first newsletter deals with the first aspect of caesarean section. Need for caesarean section
Introduction To a large extent the need for caesarean section (CS) is a man-made problem. Likewise, we as veterinarians are complicit in the problem. This is because we help propagate the very genes that causes the problems in the first place. For instance in brachycephalic breeds (cant breed and cant whelp) we assist in AI as well as planning CS for them. Please see conclusions for possible solutions to the problem. The research I performed was aimed at solving my immediate problem at hand namely to plan CS during normal working hours by determining accurate predicted dates of labour and determining the safety of performing CS on a fixed time and date using such predicted dates. This planning is vital for breeds such as English bulldogs and French bulldogs that almost have a 100% CS rate and for many other breeds where the CS rate is high and risk of stillbirths is very high or not acceptable by owners. In other breeds, difficulty in labour (dystocia) occurs in approximately 5% of all whelpings in dogs of a variety of breeds (general obstetric population), but may be considerably higher in some dog breeds. Conservative obstetric treatment (oxytocin, drip and glucose and calcium) does not always succeed in delivering all the foetuses and may be associated with stillbirths. Bitches treated conservatively for dystocia may still require CS. In fact of all dogs that show problems at labour 60% to 75% of them will end up in CS. Also when bitches have difficulty at labour, 31.9% of their puppies on average will be stillborn. A prompt decision for CS will considerably improve the prognosis for survival of the puppies. Therefore, a strong argument can be made for CS at first indication of dystocia in high-risk pregnancies. High-risk pregnancies are considered those occurring in English Bulldog bitches and some other brachycephalic (short faced) breeds, those with a history of dystocia, those with known large litters, those with singletons, those with small litters (in large breeds) and those with a history of prior CS. These arguments are at the core of the decision to plan an elective CS. In my first chapter, I conducted a number of studies which examined the following, Study 1: Prevalence of CS in South Africa across breeds (excluding GSD and English bulldogs) Study 2: Prevalence of CS in German Shepherd Dogs in South Africa Study 3: Odds of stillbirth in Boerboel bitches allowed to whelp normally Study 4: Likelihood of CS following a prior CS Study 5: Probability of stillbirth when delivery method is by elective caesarean section as opposed to emergency caesarean section The results of the respective studies were as following: Study 1 Prevalence of CS in South Africa across breeds (excluding GSD and English bulldogs) See table below of the proportion of bitches per breed that ever required a CS in her lifetime as per countrywide survey conducted in 2014-2015 in South Africa. Please note that I did not determine what percentage of bitches required a CS at any one pregnancy. I determined what percentage of bitches had at least one CS or more in her breeding lifetime. You will see that the French bulldog and English bulldog does not appear in this table as they were not included in this survey. This is because it is generally accepted that these breeds have a 100% CS rate anyway and because the risk of dead puppies when attempting natural labour in them is just too high.
1) Table 3.2
a Rank of breed with regards to number of puppies registered in South Africa during 2016 b Brachycephalic (1) or non‑brachycephalic (0), cSize categories: Large (L), medium (M), small (S) Figures in brackets reflect confidence intervals = statistical term , when probability is indicated as 0.38 means 38% probability.
These results indicate that the average CS rate (probability of CS) in a bitches lifetime is high and largely agrees with the CS probability surveyed in UK across very many breeds. It also indicates that lots of work needs to be done in order to effectively select against this high incidence of CS.
Effective selection methods against need for CS is needed in many breeds. In order to reduce the high proportion of bitches in many breeds requiring CS, some kennel clubs only allow two CSs in a bitch and do not allow registration of puppies thereafter from these bitches (The Kennel Club UK, 2012). Some breeders have similar self-imposed selection protocols by not breeding a bitch again if she has required one prior CS. It is doubtful if such selection protocols would work. This is because selection against the occurrence of a CS may not be as effective as selection against the underlying anatomic- and physiologic traits within the breed that are the true causes of the need for a CS in the first place. It is suggested that one such anatomic trait is the cephalic index of a breed. Selecting against CS without selecting against brachycephaly and (or) other anatomical traits (and also adopting a change in breed standards) may be futile as such selection may in any event change the morphology of the breed away from the preferred morphology as embedded in the existing breed standards. Such selection may therefore threaten the existence of some affected breeds in their currently preferred morphological standards—something breeders may be unwilling to accept. Study 2 Prevalence of CS in German Shepherd Dogs in South Africa The probability of CS in the German shepherd breed varied around 13-15% depending on age and number of litters produced. It appeared that province of the breeder also influenced results with Gauteng having a higher CS prevalence than the western cape. The reason for this may be twofold. Breeders in the cape may have under-reported litters born partly or in full by CS. Veterinary surgeons in the cape as well as breeders may be less prone to perform a CS than breeders and veterinary surgeons in Gauteng. The problem is also self-perpetuating. This is because once the first CS has been performed on a bitch the likelihood of another CS in that bitch is much higher. (see study 4 below). Study 3 Odds of stillbirth in Boerboel bitches allowed to whelp normally On average the probability of a still birth in a Boerboel puppy is 22%. Stillbirth was however correlated to litter size. Litters smaller than eight puppies had an average probability of 27% of stillborn puppies whereas, for litters larger than 11 puppies, it was 32%. Singletons had a 50% mortality or higher. This phenomena where litter size seems to influence puppy survival at birth following natural birth is also reported in other large breeds. Poor puppy survival when attempting natural labour has been the major drive towards planned CS in this breed. Although I did not prove this, it is my opinion that the incidence of CS has risen parallel to the breed become larger and bulkier. Anecdotally, breeders of non-show type Boerboels that are more athletic, lighter, slender and long-faced (doligocephalic) have less whelping issues and higher puppy survival associated with natural whelp. Study 4 Likelihood of CS following a prior CS Our study showed that 62% of bitches that had undergone a prior CS required a repeat CS to deliver part or all of the litter. This was also true for the GSD where a bitch had a 11 times higher chance to undergo another CS if her prior litter was delivered by CS than if it was not. Therefore, avoiding unnecessary first time CS (in most breeds but not all) should be any breeders priority and selection in breeds to preclude excessive caesarean statistics should always be advocated. Further research is however required to identify effective selection criteria in this respect. Study 5 Probability of stillbirth when delivery method is by elective caesarean section as opposed to emergency caesarean section Our study showed that stillbirths following emergency CS was much higher than was the case for elective CS. What this tells us is that if it is known that a CS will be very likely because of breeds, prior history of whelping problem, prior history of CS, very small or very large litters, then it might be better to plan an elective CS. Newsletters to follow Newsletter 2 (later in January 2018) Planning a caesarean section in bitches on a fixed date and time (as they do in women) for those bitches in which the only choice of delivery is caesarean section Newsletter 3
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