AI in cattle

Question 1

what are the advantages of AI

Answer 1

Genetic progress and increases production 
Disease control 
wider choice  of sires 
safety 
improved record keeping

Question 2

Disadvantages of AI

Answer 2

Cost
Required good management
Requires skill and training
increased frequency undesirable traits within the population
can reduce reproduction performance in some circumstances

Question 3

Conception rate is

Answer 3

(no. of inseminations that resulted in pregnancy/no. of insemination)/100
% of oocytes during oestrous that are fertilised and develop into a zygote after insemination

Question 4

Pregnancy rate

Answer 4

(no. of cows within a herd or group selected for analysis that are diagnosed pregnant/total no. of cows in herd or those selected for analysis) x 100
- Total no of cows that are diagnosed as pregnant for the group being analysed

Question 5

in Calf rate

Answer 5

refers to the % of animals within a herd or group being analysed that are diagnosed pregnant after a certain time period

Question 6

100-day in calf rate

Answer 6

% cows that diagnosed pregnant 100d after calving (esp in yr round calving)

Question 7

Non-return rate

Answer 7

% of cow that are not detected in oestrous following insemination

Question 8

Explain AI Technique

Answer 8

Rectovaginal technique

1. Insert AI gun through cervix
2. stop when the tip of the gun just penetrates the cervix, use tip of your finger to judge the distance
3. deposit all semen in body of the uetrous (the uterine body is hsort, if you penetrate to far you will go into one forn and therefore only deposit sperm into 1horn - lower chance for preg

Question 9

what are the two methods used for semen collection

Answer 9

Artificial vagina or electrojaculatory

Mounts - artificial breeding mounts

Question 10

what is the frequency of collection allowed

Answer 10

3wl, up to 2x daily 3 days wk

Question 11

what are the 4 preservation techniques for semen

Answer 11

Frozen - most common - maintain at a temp
Liquid
Caprogen liquid extendor
semen packaging

Question 12

what are some of the factors that affect pregnancy rates through AI

Answer 12

Dose of semen 
Sire 
Timing of AI
semen storage 
semen handling and thawing 
insemination technique 
poor record 
Fertility cows

Question 13

What is the min amount of sperm required for opt fertility

Answer 13

(5 X 10) X 10^6 live sperm 
In general (15 X 20)X 10^6 live sperm are loaded into a semen straw within the assumption that 50% may die after freezing and thawing

Question 14

When is the opt time for AI

Answer 14

4-14 hours post onset oestrous

AM-PM rule - cow in heat in the morning - inseminate in the afternoon