Although I have never analized the affects of sex on sperm temp - ie conception result -- I do know that semen needs to be kept protected so as the temp is always at least stable OR on the incline. Any time you have a drop in semen temp after thawing there will be a negative affect.
As Jill mentioned, TIMING will be your number one thing that COU
affect calf sex. Assuming ALL bulls produce 51-49 semen ratios, the affect of timng will - to some degree -- help you in achieving a better ratio of desired calf sex.
Female sperm cells live LONGER to some degree, but do not swim as fast. Basicly they do not burn out so quickly, but are usually the last to arrive at the fertilization point.
Male sperm cells are kind of like the over eager cow dog - it's fast and furious, and then all of a sudden, bang -- the dog is n the water tank cooling off becasue he over did it!! hehehe Same thing here -- they will swim like crazy to get there first, but normally, they will have less vigor and be less able to survive any delay in ovulation.
It is risky to breed your cow TOO soon, however, if you get the timing perfect, you WILL have a slightly better chance of getting a hfr -- most of the time with normal bulls any way.
AAOK -- back when I started as a Tachnician for Midwest Breeders in the mid 70's, they were still using the old Majic Wand for semen storage and breeding. This involved a plastic pippete nut unlike todays infusion rods. We would take the wand out of the tank, and using a dog toe nail clipper -- clip off the sealed end. We would then place a rubber bulb onthere with slight vaccum pressure -- and go straight to the cow. The semen was still frozen or was stareting to thaw by the time we got there, and when we placed it in the cow -- she would finish the thaw process. It worked very well -- but you need to know this one fact!
Bach then, the semen was frozen SPECIFICALLY for that process, it was designed to be thawed slowy and was mized with cryoprotectant to get that done. Today's semen is different -- although the basics are the same, today smen is designed to be thawed FAST --in order to reduce sperm damage frm ice crystalization cutting the tails off. The media used has a slightly different Molality than it used to have (Meaning a different level of concentration and fluidity). Confusing I know.
To maximize todays semen and it's ability to fertilize, rapid thaw is universally reccommended, a standard 96 degree 25 second thaw works the best! If you leave the semen in too long, it iwll get to that same temp as the water -- and then you must worry about a decrease in temp as you go to the cow. Keep it simple as they say and it works very well.
The fella that rrained you most likely learned the old way - as did I! Small world for sure -- in your case -- if it is working use it.
I might say that a 5 minute wait time in the cow would be kind of hard to achieve when breeding 250 head in one afternoon!!
Any way -- that's my take on temp. One other thing you MAY run into is this -- if you are breeding a cow and she is standnig there shaking like crazy due to the cold -- you MAY not get the normal conception rate due to hormone release IE Adrenelin. Adrenelin has been shown to be the precurser for the release of Prostoglandins from the uterus, and will have a negative affect on the heat hormones (Estrogen, Leutinizing Hormone, Gnrh etc) If a cow is really agitated or scared or very cold -- conception will suffer!
Good luck all -- calving soon!!!!!!!