The Fertility Question

 Ron Parker

The Fertility Question originally appeared in The Horsemen’s Journal, December 1982

I don’t know about you, but technical articles in magazines about the physiological aspects of Thoroughbred reproduction are somewhat outside of my attention span.

It’s not that I don’t want to learn more about the vagaries of breeding, it’s just that most of these articles are written by some guy who’s spent too much time alone in a room swabbing glass slides with colored dye.  By the time he gets to a typewriter to explain what he’s found, he thinks he’s Carolus Linnaeus writing a letter to Charles Darwin.

Alex Harthill might know what the guy is writing about, but I get lost after the first “dilution of spermatozoa.”  And I even got an A in high school biology.

I mean, can’t they tell me the mare is barren and the stallion is a loser in plain English?

This was brought home to me the other evening when I was sitting at home scientifically marking pertinent factual data in the Daily Racing Form relative to the next day’s equine contests, while my wife was reviewing the weekly accumulation of racing magazines.

“Here’s an unusual article in The Washington Horse,” she said.

“Oh?” I replied, underlining a :35-2/5 workout.

“It’s about a doctor who teamed up with the head of obstetrics and gynecology from the University of Washington to work on something called ‘The Sperm Penetration Assay’.”

“What does a gynecologist have to do with horses?” I asked absently, while wondering if the horse I was contemplating in my Form could get a distance.

“It seems that this assay, which they call SPA, has been an effective method of predicting fertility in humans, and now they want to adapt it to horses.”

“That’s nice, dear,” I muttered, turning the page to the consensus selections.

“It points out,” she continued, “the truism that a stallion’s fertility is measured in the number of percentage of mares the horse has gotten into foal.”

“I’ll certainly go along with that,” I said.  “Which reminds me, did you notice that Mrs. Simone is pregnant?”


“Yeah, I think that’ll be number nine.  No wonder her husband looks so thin.”

“Anyway,” she went on, “it says here that current semen analysis of stallions consists of collecting an ejaculate from the horse using an acceptable collection device.”

“Acceptable to whom?” I asked, looking up from my Form.  “The scientist or the horse?”

“It doesn’t say, dear.  But at any rate, the semen is then evaluated as to its motility, morphology, volume, concentration and other variables.”

“It’s mo-who?”

“I think those are technical terms,” she said.

“Are you sure you’re not reading Biology Today or Scientific American?” I asked.

“No.  In any event, that data is compared with other horses of known fertility.  If the semen under evaluation has characteristics comparable to the semen of other known fertile individuals, then we can say that, to the best of our knowledge, this horse should be capable of performing as well as those to whom he has been compared.”

That makes sense,” I replied.  “But wouldn’t it be easier to simply turn the horse loose in a field and let nature take its course?  You’d sure find out in a hurry if he was fertile or not.”

“You certainly don’t understand the science of breeding very well,” she sniffed.

“Oh, I know a little about breeding, or,” I added as an afterthought, “I used to.  I just don’t understand what horses did before biologists were invented.  Seems to me they did pretty well without them.”

“Now here’s something interesting I’ll bet you didn’t know,” she went on, ignoring my crack about breeding.  “For conception to take place the sperm cell must be able to penetrate the female egg, not merely be present in the same environment.  Exposure of sperm and egg does not necessitate conception unless certain biochemical events between these two cells occur, enabling subsequent fertilization to take place.”

“I’ll agree with that logic, but what do they mean in that part about certain biochemical events?  Was that written for the horsemen or the undergraduates at Harvard Medical School?”

“I don’t know, dear.”

“Well, anyway, what’s so special about this SPA thing?” I encouraged her.

“According to the article, its basis is the ability of the zone-free golden hamster egg to be fertilized by sperm from other species, including man.  And…”

“Wait a minute,” I interrupted.  “What’s this zone-free jazz, sounds like something out of the Boston Celtics press guide.  And that bit about the hamster, are you trying to tell me they’re going to cross it with a man?”

“It’s merely a scientific study, dear, to see if the sperm penetrate.”

“And what does the poor hamster think about all of this?”

“It’s only an egg,” she replied quietly.

“Then what about the guy in some laboratory donating his sperm to science.  Does he know his hereditary sacrifice is going to end up in a hamster egg?  I think we better send a copy of that article to the Birthright Foundation.”

“Just as you say,” she said condescendingly.  “But it’s only a test that might be helpful in gauging horse fertility.”

“Oh my God, now they’ll probably want to cross the hamsters with a horse.  I’m calling the SPCA.”

“Why don’t you let me finish?  Once they collected and prepared the hamster eggs, semen samples were obtained, placed in appropriate media, and allowed to incubate with the hamster eggs for several hours.  Then the eggs are microscopically examined for the presence of a swelling sperm head and accompanying tail in the egg cytoplasm.”

“That sounds obscene.  Still,” I reflected, “I certainly wouldn’t have found that out in the Form.  But will all this fooling around with hamsters help with the horses?”

“That’s what they want to find out.  As the article concludes, ‘continued refinement of the testing procedures by identifying the optimal incubation time for sperm and egg, and by determining the appropriate dilution of stallion sperm to be utilized in the assay, are several of the next steps which lie ahead.  As soon as these problems are resolved, we will then be able to determine the penetration rates for stallions which we know as fertile.  It is only through the elucidation of these normal values can we then utilize the SPA as a clinical tool to identify the infertile or subfertile individual.’

“Well,” she asked, looking up from the magazine.  “What do you think?”

“I think the guy has one helluva dictionary, that’s what I think.”

“No, no,” she said, handing me the copy.  “I mean about the scientific aspects.  Look at the photomicrographs which show the need for determining the appropriate dilution of stallion sperm needed for exposure to the hamster eggs in order to determine penetration without obscuring the egg surface.”

“God forbid,” I said, “that we should obscure the egg surface.

“But if you really want an opinion, why don’t you take the article out to your friend in the Valley who has the horse farm?  Maybe she can make some sense out of things like ‘appropriate media’, ‘appropriate dilution’ and ‘egg cytoplasm’.  Might even explain why that eight-year-old mare can’t get in foal.”

She looked thoughtful for a moment.  “Well, I’m not sure she’d understand the article, not having finished school and all.”

I suddenly felt a sense of victory.  “Then you tacitly admit that such scientifically written articles are obscure to the majority of readers and more properly belong in The Veterinarian’s Digest?”

“I didn’t say that,” she said defensively.

“Well,” I allowed, “as complicated as it sounded, I still think I might have gotten something out of it.”

“You did?” she asked hopefully.

“Well, actually, all that vague terminology gave me an idea.

“Why don’t we make a couple of drinks, take them to the bedroom and get comfortable, and conduct our own assay.  We can snuggle up and discuss things like motility, morphology and optimal incubation time.  We could even,” I winked, “talk about refining our testing procedures.”

“Not tonight,” she said, picking up another magazine.  “I’m rapidly undergoing an intracranial pathological transition.”

“Does that mean that you have a headache?”

“Something like that.”

“That’s the trouble with science,” I muttered, picking up my Racing Form.  “It’s too damn scientific.”