A case for using older stud dogs and improving semen quality.
Using an older stud dog wouldn't typically be the most desired thing to do because semen quality isn't generally at its best. The proportion of normal sperm is higher in young dogs than in older ones(1) and logically this is why breeders look to younger dogs to do the job. Older dogs have a higher proportion of midpiece defects, being afflicted by this defect means these guys don't swim as well or as efficiently so it's probably safe to say that they're not going to win the race. Unfortunately, these defective sperm can contribute to an increased risk of birth defects and issues with fetal health(2).
What happens if an older dog has proven itself in terms of temperament, health, breed type etc. and would technically be the better dog to use? This is the situation some breeders find themselves in, so shortly we're going to chat about how we can boost the boys and increase "normal" sperm. Let's continue... Researching the use of older stud dogs is a bit of a rabbit hole but let me invite you down a pretty cool one...The length of Telomere's and how an older stud dog can positively influence the longevity (life span) of their offspring. What is a Telomere you're probably thinking?
"Telomere (tel-uh-meer) are an essential part of our cells that affect how our cells age. Telomeres are the caps at the end of each strand of DNA that protect our chromosomes, like the plastic tips at the end of shoelaces. Without the coating, shoelaces become frayed until they can no longer do their job, just as without telomeres, DNA strands become damaged and our cells can’t do their job."(3) "Shorter telomeres have been associated with increased incidence of diseases and poor survival. The rate of telomere shortening can be either increased or decreased by specific lifestyle factors. Better choice of diet and activities has great potential to reduce the rate of telomere shortening or at least prevent excessive telomere attrition, leading to delayed onset of age-associated diseases and increased lifespan."(4) - The short of it means lifestyle helps you live longer, but you knew that right? :)
Ok, so what does this have to do with breeding older stud dogs? "Telomere length is largely inherited from parents. Because telomere length increases with age in sperm, and in both humans and other species, offspring conceived by older fathers have longer telomeres than those conceived by younger fathers. Breeding practices in dogs (specifically the age of the stud males used) may be used to affect the breed life span. For example, in humans, the average telomere length in children is 22 bp longer for each year older their father was at conception; therefore, telomeres in children conceived by 50-year-old fathers are ∼660 bp longer than those in children conceived by 20-year-old fathers. If this relationship holds true in dogs, as suggested by their similar telomere biology, it may be possible to increase the average healthy life span significantly, particularly in shorter-lived breeds, over a small number of generations, given the observed heritability of telomere length."(3)
Wow right!!! How cool is that!
Some of our breeds including my own being the Great Dane has such a heartbreakingly short life and it is likely we can increase this by simply using older stud dogs. But just imagine the life spans we could get on the average life spanned breed!
So, as well as using older dogs in breeding programs, using older HEALTHY dogs is also important because we don't want their lifestyle factors to have excessively shortened their telomeres that they're going to pass on. Many dog owners believe their dogs are healthy simply because the dog is alive, seemingly happy, has a wet nose and goes for a walk without an issue - as we know with our own health, there are far more factors than these that dictate a thriving being vs simply surviving. Let's explore some of the lifestyle factors that can shorten telomeres(4):
Smoking - this means exposing your dog to your or other peoples second hand smoke to
Exposure to pollution
Lack of dietary intake of fiber
Lack of dietary intake of polyunsaturated fatty acids, especially linoleic acid. Foods high in linoleic acid include the likes of vegetable oils, nuts, seeds, meats, and eggs.
Lack of antioxidant omega-3 fatty acids in the diet. Foods rich in omega-3 include the likes of oily fish, nuts, seeds and some oils.
Lack of healthy fats. Foods rich in healthy fats include the above mentioned but also the likes of Avocado.
Lack of antioxidants such as vitamin E, vitamin C, and beta-carotene in the diet
Lack of exercise
What is super interesting, is that so many of the lifestyle factors that can improve telomere length can also improve semen quality including semen defects - Let's kill 2 birds with 1 stone so to speak!
A 2018 study(5) set out to evaluate an association between dietary patterns (western vs healthy) and the risk of abnormal semen quality parameters in men - they concluded that the western diet i.e. not healthy may increase the risk of abnormal semen parameters.
It's not really that surprising though right? That old saying being "you are what you eat" and if you eat an unhealthy western junk food diet, your semen could very well be junk...is your dogs semen junk?
The problem we have in the canine community is that decades of conditioning by kibble manufacturers have lead the average dog caregiver to believe that kibble is healthy and has everything their dog needs yet you could very well compare it to the unhealthy western diet given its level of processing. It is so highly processed that the nutrients are degraded to a point that a vitamin and mineral mix has to be added in to account for the nutrient losses. These mixes are largely synthetic and the body just doesn't understand these in the same way they understand nutrients from whole foods. Another fact that dog caregivers do not understand about kibble is that they by large meet the MINIMUM nutrient guidelines set out by AAFCO - MINIMUM not OPTIMAL.