When we consider the bull is the ideal one, the other animal species (male and female) have the following characteristics:

1. camels: male: semen is highly viscous and difficult to manipulate in lab; Female: induced ovualtor and has no mid-cyclic CL, so control of estrous is too difficult.

2. small ruminants: male: not optimum protocol of buck semen; female: the cervix is narrow. so trans-cervical insemination is relatively difficult.

3. equines: male: spermatozoa are sensitive for freezing; female: the estrus phase is too long (5-7d) so frequent examinations are needed to determine the time of ovulation/insemination,  

many thanx Prof

Dear Hasan,

I agree with Ahmed ALI, Nevertheless I want to give my opinion about this issue.

I dont think Bull semen cryopreservation or freezing is successful compared to other ruminants. For example we have obtained good results in goat and ram semen cryopreservation and I can not see similar results in bull semen. I mean the progressive motility of frozen-thawed goat semen is  higher than 70% (looks like fresh semen). I think "freezability" of goat or ram semen is successful but the results of AI with frozen-thawed semen is not good. Because, we have to use laparoscopic AI in small ruminants to pass cervix. Or we can pass cervix with tenaculum forceps or other methods (it is a little invasive) and we can put the frozen-thawed semen to corpus uteri. However, we need special techniques for this aim and sedation or local anesthesia. And this applications cause stress in animals. Also some complications during these procedures may happen for example bleeding, aspiration pneumonia or wrong side or organ AI (?). You need a team for this applications. And it is expensive also. And it is difficult to predict the best time of AI in this techniques in small ruminants. Yes, alot of study point out the best time for AI but it sometimes is not suitable in field or for the some breed of sheep or goats. 

As for cattle, you can use a simple method to pass cervix and intra-uterine AI. The Recto-vaginal (transcervical intrauterine) AI technique is simple and non-invasive and it can not cause alot of stress in cattle. You dont need any anesthesia or other procedures. You can easily pass the cervix. Also you can easily predict the best time for AI. So frozen-thawed semen usage for AI is more successful in cattle compared to other ruminants (I mean small ruminants). However, freezablity can be discuss in ruminants if we look spermatologic parameters. 

In conclusion, If you use frozen-thawed semen, You have to inseminate corpus uteri or cornu uteri. Otherwise the pregnancy rates decrease. Intrauterine AI in cattle is simple compared to small ruminants. The main reason of success of AI with frozen-thawed semen in cattle is possibility of recto-vaginal intrauterine AI. 

My best wishes,

Success of artificial semen technology depends on two important factors; successful processing of semen  and ease of application in females. Though till date only 50% of cattle semen survive post-thaw, it is still better than many species. The most prominent reason being that this species is most widely used, hence much more work has been done on it. Second simplicity of application in cow as compared to other species has made AI industry in cattle much more successful than other species. 

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Dear colleague, initially all the sperm could be frozen. The truth is that the original trials in bulls were very successful and it was thought that the model would serve for all species, which is not. Basically, the quality of the membrane composition and the relationship with the cryoprotectants are the phenomena to consider when trying to preserve sperm. For example, the amount of cholesterol in membranes, which is related to resistance, and moreover, the amount of water bound in the cells, which can not be extracted by the action of cryoprotectants. Wish been helpful.

Dear Falah,

Two brief answers would be given for your question:

First, bull is most commonly studied species for optimising sperm handling steps (basically following Dr. Andersen's freezing method as published back in 1969 (please check the web); 4 cm above the LN2 for 7 min, followed by thawing at body temp, 37-38 degrees C for 30 sec.). Further, this routine freezing method has also been implemented in many other farm animal species.

Secondly, considering breed differences for sperm membranes structures, bull sperm plasma membrane has sufficiently high cholesterol level (providing elasticity or water conductivity of the sperm better) and low unsaturated to saturated fatty acid ratio, as compared to other species (e.g., stallion, dog, fox and boar, etc.).

These two basic advantages give superiority to bull semen freezing against other species concerned.

Regards and good luck,

Omer

Dear Falah HB

 Artificial insemination by and large has been most successful in bovines. The reason includes both good freezability of bull semen as well as easy placement of cryopreserved semen in deep cervix or uterine body. It is a fact that there is 50% decrease in quality particularly progressive motility from pre freeze to post thaw in bull semen. This percentage is slightly higher in ram, buck , stallion etc. The reason is the difference in sensitivity of the sperm from different species towards extreme low temperature. Even in case of bull, the sensitivity varies between different individual animals. Also the area of bull semen preservation has been thoroughly studied while as in others it is still going on to standardise the freezing protocols. The female side also plays an important role so for as conception rate is concerned. For example, even if the post thaw motility is 40%, still we are able to deposit it in the uterus in the cow. This enables the oviductal sperm reservoir to become established, which ensures fertilisation, where as in ewe, the sperm can not be deposited beyond vagina due to non penetration of pipette through cervix because of tortuous nature of ovine cervix and its cervical hud. Therefore the sperm are deposited in vagina which is a harsh environment for sperm and also due to freezing the sperm velocity decreases,   can gain excess in large numbers. With the result conception rate are too low. There are other options to inseminate like laproscopic AI but too costly and requires expertise. Stallion semen is also sensitive to freezing but research is going on and some promising results have been obtained. Boar semen highly sensitive to cold temperature. Buck semen needs to be washed by centrifugation to remove seminal plasma before dilution as it contains enzyme coagulase which coagulates egg yolk present in extender. This step may not be required if plant based extenders are used. 

Read can not gain acess instead of can gain

 many thanx all of u

In general, I think it all boils down to selection. Bulls with unfreazable semen are just not kept around. The proof is that for instance stallions from countries where horses are also selected based on their semen quality parameters, their sperm also fair better when frozen, than those from stallions only selected based upon performance. Certainly the boar case is apart because of the membrane composition which makes it more sensitive to freezing. 

Hello I agree with all responders.

Just want to add: except of strict selection of bulls there is (or should be if you want to do good management of reproduction) also strict selection of cows for reproduction. 

I worked in the field of equine reproduction and even though I dissuade owners from AI (based on historical and actual data) they still insisted on AI. So in the Czech Republic we sometimes have to perform difficult preparation (e.g. hormonal treatments) of mares (sometimes longer than one breeding season) to get the mare pregnant.

Hi Falah. In fact, the success of frozen bull semen is due to membrane conditions , which are suitably adapted to the processes of freezing and thawing. The phospholipid / cholesterol ratio and the amount of free water make the bull sperm more apt to withstand the stress of the process . It is true that some bulls are "bad freezers" but if we look at it in a global perspective, sperm from bovines are the easiest to keep (between slaughter animals) . This is clear if we compare the bull sperm membrane with boar, species which is much more difficult to have good success. Still, the mistake is to think that the freezing process should be the same for all species. Each one has a protocol which will make the process more efficient. Specifically should consider issues such as the adequacy of the diluents, cooling curves, stabilization, type of packaging, the rate of freezing and thawing, an issue often forgotten, in which the phenomena of crystallization and modification of membrane fluidity are equally or more important. It is true that the selection applied in bulls for AI centers makes that many "bad freezers" are discarded, but that also can be done with other species. For example, in boars  they are selecting the "good freezers" to incorporate into conservation programs semen.

Thanks so much all of you

Dear Falah,

ALL THE PREVIOUS COMMENTS ARE PERFECTLY RIGHT.

BOVINE... SIMPLY IT IS ONE OF THE MOST STUDIED SPECIES..

Further,

FOR BULLS, CONSIDERABLY MORE CRYO-RESISTANT MEMBRANE STRACTURE OF BULL SPERM PLASMA MEMBRANE.. ALSO, OVER 1500 BULL SIRE CANDIDATES ARE TESTED EVERY YEAR ACROSS THE GLOBE AND ONLY LESS THAN 10% (AROUND 8.5 %) ARE CHOSEN FOR FURTHER USE AS AI BULL. AS PREVIOUSLY COMMENTED UPON, GOOD FREEZERS ARE CHOSEN FOR FREEZING AND STORAGE FOR THE FUTURE USE. BRIEFLY, THE *BEST GUYS* ARE CHOSEN AS SEMEN DONORS.

For Female, cows, it is VERY easy to inseminate effectively (intrauterine route). Its milk and meat yield is EVONOMICALLY VERY IMPORTANT (valuable in price) for years. As with the bull selection for semen source, cow sires are also strictly chosen for their high yield (milk and calf). AGAIN, as with the selection of best bulls, the BEST MOTHER CANDIDATES ARE CHOSEN FOR FUTHER USE AS *BEST GIVER*.. namely MILK, CALF AND BEEF.

Briefly, in other words, we actually talk about MONEY especially for this *Bovine* species, as being more common, more needed and more rewarding all over the world.

Regards,

Omer