Veterinary control of fertility in cattle Flashcards
History for individual infertile cow or heifer
Age and parity
Time since calving
History of dystocia, retained foetal membranes, or other puerperal problems
Previous heats or services
whether the animal is running with the bull
Results of previous examination or treatments
What should the vagina be assessed for?
Abnormalities, such as scar tissue or tears and an assessment can be made of vaginal tone, and whether pneumovagina is present
What sould the cervix be examined for?
lesions and to check its patency
How often shoud a farm have a routine fertility visit?
at least twice a year
What is the calving interval?
the interval in days for an individual cow between one calving and the next
What is the calving index?
the average (usually the mean) of the calving intervals of all cows within a herd at any given time
What is the calving to conception interval?
the average (usually the mean) of the calving intervals of all cows within a herd at any given time
an up-to-date and more relevant version of the calving index
Meaning of days open
The interval in days from calving to conception of cows that conceive, and from calving to culling or death of cows that do not conceive is described as days open
Calving to first service interval
The interval from calving to when a cow receives her first service
Non-return rate
a crude estimation of pregnancy rate (and often called the assumed pregnancy rate), and is useful if no pregnancy diagnosis is performed
measured as a percentage of cows that have been inseminated and have not been presented for a repeat insemination within a specific period of time (usually 30 to 60 days)
often more than 20% higher than the actual conception rate
Conception rate
The number of services given to a group of cows, over a given period of time which results in a diagnosed pregnancy.
(The reciprocal of this is often used and described as the number of services per conception).
What two measurements give an indication of oestrus detection accuracy?
the first service submission rate
the distribution of Inter-oestrus Intervals (period between services)
First service submission rate
measured as the percentage of cows that receive a first service in the 24-day period (the upper end of a normal oestrus cycle) following the voluntary waiting period (The 24-day Submission Rate)
gives an indication of the heat detection accuracy in the first part of the service period
The distribution of inter-oestrus intervals
indicator of heat detection accuracy in the subsequent service period
expressed as the percentage of normal oestrus interval at 16 to 24 days and 36 to 48 days, and may be presented as Percentage Normal Oestrus Cycles.
Oestrus detection rate
21 divided by the mean interservice interval
Target: >70%
Oestrus detection efficiency
Warren equation; (B+D)/(A+B+C+2[D+E])x100*
Target: >50%
First service submission rate
Number of eligible cows served within 21 or 24 days of the end of the voluntary waiting period divided by the number of eligible cows
Target: >70%
Mean or median calving to first service interval
Mean or median days from calving to first service interval for all cows served
Target: 65 to 75 days