Artificial Insemination Basics and Estrus 10/12

Today we covered mostly things about AI. pretty basic for us show calf producers but you wouldn't believe the amount of farm kids who didn't have a clue about breeding a cow, heat detecting, semen freezing...

Semen standards for Rams

percent motility - 30% - 70%

percent normal morphology - 30%-50%

White blood cells >5

Brucella Ovis  - Negative

10-15 % of Rams fail a BSE

Male : Female ratio for breeding

18-1 for yearling bulls (1 bull for 18 cows)

30-1 for mature bulls

35to 50 - 1 mature rams

15-30 for ram lambs

Synchronized matings 1:5 or 1:10 (sheep)

Estrous Synchronization

Why synch cattle?

1. With AI, decrease time and expense of time & labor for detection of estrus

2. Success of Embryo Transfer , especially with fresh eggs. Recips have to be in the same exact level of estrus as the donor cow for fresh, non frozen implants.

3. Uniform groups of calves, calving in the same time frame. Groups of uniform animals bring higher prices at the sale and its a hell of a lot easier/less worrisome to calve in a 3 week window vs a 3 month window.

4. Labor Savings - calving can be strenuous and a pain in the ass, but its easier to make it last a shorter time vs. a longer drawn out time.

Methods of Synchronization 

1. Natural method - weaning will cause the estrous cycle to start (especially true in sows)

2. hormonal - induce or suppress estrus (Lutalyse(prostaglandin) and CIDR's)

CIDR - controlled internal drug release - suppresses estrus with progesterone, progesterone maintains a pregnancy, so if she thinks she's bred, she won't come into heat right? Once progesterone levels drop (after the CL is killed, estrogen levels come up and result in a standing heat)

Why is AI used?

1. Maximize genetic improvement. - we can use virtually any bull in the world today for a small cost and can dramatically improve the herd with ease. a $20 straw of semen cost less than a big money bull + feed + transportation + vet bills.

2. Control reproductive diseases. All bulls collected are tested for leptospirosis.

3. The use of dead or injured sires. We can use bulls from 50 years ago thanks to freezing semen. there is always semen to be had on an old bull who is still popular today (Meyer 734 for example)

Keys to Success with AI

The detection of estrus is essential to having a successful AI program. can be detected with behavioral changes and of course, standing to be bred.

2. Proper timing of insemination, having viable sperm at the time of ovulation so the sperm is alive and ready to make some babies. Breed towards the end of estrus (8-12 hours afar standing, or use the AM/PM rule)

3. Technician Skill - conception rates depend heavily on the guy putting the semen in. for instance, if he's breeding through the rectum.... he might not be the right guy for the job. the cervix is the hardest part and some techs are better at getting through it than others.

Estrus Detection

Primary Characteristic of Estrus - Standing heat. 

Secondary Characteristic of Estrus - Restlessness, chin resting, bellowing, red swollen vulva, discharge from the rear, flehman response  from bulls (lip curl) fighting, riding other cows, less feed intake. Theres quite a few ways to detect estrus even if no standing heat is observed.

most breeding mounts occur between 7pm and 7am, so check right at dark and first light.