I didn't guess the thermometer
at right that it would prove so useful - my only thought at the
time was to calibrate the more convenient dial thermometers, which,
just as I had heard, are often inaccurate. The key thing is that
it reads from 25 - 55 C. in tenths of degrees.
Skipping the tedious details, the problem animal was
a sensitivity to temperature shock. Exposing his semen to sudden
temperature changes in excess of roughly one half of one degree
Centigrade will cause surprisingly serious damage. There may be
nicer ways to approach the problem, but I needed an immediate solution,
and was not at all inclined to spend a fortune on it. Some types
of "environmental cabinets/chambers" might be help considerably,
but cost on one that would work for this purpose is, at least to
me, downright prohibitive. So, here is how it played out.
In my case, a one-man operation, the A-V stands by
perhaps as many as ten minutes after final prep, and the collection
bottle will cool considerably. The more convenient practice of using
one (pre-warmed) insulating sleeve was not working well enough for
the needs in this instance. I always set up to collect into a whirlpak
inside a bottle, which probably buffers a little, since only a smallish
area of the semen will directly contact the bottle, (through the
bag) but even so, this was a very likely problem area.
|I needed to provide much better
insulation. An afternoon spent with scissors, sewing machine,
a puffy warm blanket, and a ripped up old hood produced the
outer sleeve. There are maybe half a dozen layers of blanket
down toward the bottom end, progressively thinner toward the
top, to allow (reasonably) easy insertion of the original sleeve/bottle/A-V.
| It takes quite a while to warm
it up through and through, but it will hold a temperature for
quite a while. On the down side, it is far too unwieldy for
collecting, and has to be stripped off for action - it just
keeps the inner one warm until then.
This way, on a fairly chilly day, the semen will measure
around 36 point 2 to 36 point 5 centigrade upon removal from the
bottle. So, even with these precautions, some uncontrolled cooling
has already occurred. At that point, it seems questionable whether
it should be subjected to re-warming - a little dubious to make
it ride a thermal roller-coaster like that, and it would either
have to warm very gradually in the incubator, (too much time) or
suddenly in a waterbath (completely out of the question with this
Wracking my brain for other ways of tightening the
procedure it became apparent that there is no way to be certain
the cylinder the semen is first poured into is *exactly* the same
temperature as the semen. Air temperature in an incubator is one
thing, the actual temperature of glass in it is only an assumption,
then it is removed into open air and handled, where the original
temperature may change significantly. Also, it is impractical to
try adjusting its initial temperature to match that of the semen,
a possible variable, and when speed is essential. Eliminating that
pour from the bag eliminates the risk of temperature shock at that
point, and eliminates some excess "handling" too, but
presents a new problem - getting *only* the desired amount from
the bag. (Incidentally, using a non-spermicidal
syringe rather than a cylinder is marvelously convenient, but at
a price - some of those little guys are torn to pieces as they are
sucked in and plungered out.)
The "template" tacticians
argue the necessity of measuring collection volume largely to monitor
the stud - log it in, have statistics, etcetera. I did initially
accept those ideas, but now I wonder. What heroic intervention are
we going to perform, exactly, in case we *do* measure an average
decrease in his volume? Psychoanalysis? (I
am assuming the horse gets an occasional checkup anyway, maybe a
little bloodwork and a listen to his heart, stuff like that.)
Also, and more to the point, aren't we going to *notice* that there
is less in the bag than there used to be, and particularly, less
left over after what we need has been measured out? Retrospectively,
I begin to seriously question the benefit of that approach. Finally,
if we simply *must* know volume to the last cc, the amounts poured
into extender are known, and the leftover can be measured later
- add it up, and you have the total volume, without needing that
The semen being rather viscous, it is risky business to pour
directly from the somewhat floppy collection bag into a cylinder
of extender - more than wanted may come out in a big "gloop".
In this case the top of the bag is already folded over from
being in the bottle, and a little "spout" can be
formed neatly on the flat side. Then, pinching it into a narrow
"V", the intended amount can be added accurately
to the extender.
And no, the hand is *not*
filthy, just a shadowy evironment, and a lot of digital gain
to brighten the picture.
||But now, out of the
trenches and over the top. Getting both the extender, and especially
the glass above it to the exact temperature of
the semen, and quickly, is a real challenge. Considering that
the semen must run down the glass whatever distance before it
reaches the extender, clearly the *exact* temperature of the
glass is crucial with this animal.
Probably safer to get the extender to 98/99F for a while in
hopes that will dissolve completely - I have been told that
it can go as high as 105F without being ruined, although this
has to be weighed against some pretty firm instructions to *not*
overheat it, even a little. In any case, the extender will require
some temperature adjustments.
|Working with two waterbaths,
98F, 120F, and a large pan of icewater, the temperature of the
extender in a cylinder can be quickly adjusted to the same temperature
as the semen is at that moment. The
temperature will "creep" a bit after the cylinder
comes out - "quenching" in the relatively neutral
98F bath just prior to reaching target temp controls this to
a "degree" - no pun intended.
Every moment the glass is out of the incubator its temperature
is changing. Faster readings are possible with the thermometer
sitting in a short broad based cylinder in the 98F waterbath.
The mercury will be close to extender/semen temp, so there is
very little waiting.
If on target then, (maybe 1/2 - 3/4 a degree
over semen temp) one last flip for warm glass, the semen
can now be added, and the worries and cares are over for that mix.
(I prefer to mix each bag or vial individually,
as even when gently sloshing a large amount back and forth in a bigger
cylinder, the semen will not reliably distribute evenly, with risk
that one dose will be so rich as to starve them in storage, while
another may contain very few.)
||The glass will probably
be colder above the line of the extender, as it was out while
pouring and checking/adjusting temperature in it. Placing a
bit of Saran wrap over the top of the cylinder and turning it
upside down warms the glass to roughly the temperature of the
The cooler glass will take some warmth out of the extender,
so if it has stabilized at maybe one degree warmer than the
semen prior to flipping it over, it will usually check right
"in the zone" afterwards - hopefully a teensy bit
on the high side, anticipating one final flip.
While none of this has addressed the question of *why* this animal
would be so sensitive, it did make it possible to get him through
the season settling all but one mare, the majority with just one
shipment. Phew! I'll just let a professional stuntman handle that
in the future.
Mainly, it has made me a little bit better when dealing
with an "easy" animal - even if the non-viable percentage
is acceptably small, there will be those ones that
don't travel as they should. Tighter temperature control noticeably
reduces the numbers of "walking wounded" in the product.