understanding EBI, PTA's

djmc

Getting AI Catalogues in the post this week again and I am a bit confused with some of the indexs on bulls
The EBI I thought the higher number the better but some top american bulls I have used eg.(rdz) have a very low EBI
There seems to be different indexs for different breeds and all the + and - %has me a bit confused.
I think I should look for + in milk and protein and - in scc.
Has anyone a simple way to explain this jargon thanks.

browned

the ebi system is designed mainly for spring calving herds so thats why some of the top american bulls mightn't be so high up on the list. rdz for example has very low solids so has a low ebi figure for milk. his fertility is also very low as he's only predicted to last 3 lactations in a herd.

i think all the breeds have ebi calculated for them and will prob feature on the icbf website.

when ever i select a bull i look for combined % fat and protein, his fertility figure and his calving difficulty.

irishh_bob

djmc wrote: »

Getting AI Catalogues in the post this week again and I am a bit confused with some of the indexs on bulls
The EBI I thought the higher number the better but some top american bulls I have used eg.(rdz) have a very low EBI
There seems to be different indexs for different breeds and all the + and - %has me a bit confused.
I think I should look for + in milk and protein and - in scc.
Has anyone a simple way to explain this jargon thanks.

fertility is the biggest indicator of EBI score along with production of solids , generally speaking american bulls have a poor score for both fertility and solids , EBI is less important for those involved in year round production although it should not be completley ignored either IMO

djmc

Thanks lads that explains things a bit.

Indubitable

The best way to know how good a bull is, is by looking at his calves

whelan1

i would normally look at the reliability - how many daughters he has too

browned

the genomic bulls have very low reliability, but u can spread the risk by usin a team of bulls.

djmc

By team of bulls do you mean different bulls in different straws or mixed bull seman in one straw.

browned

if u were to use just one low reliability bull accross ur herd his ebi could go down as well as up. by using say 5 bull u reduce this risk. its extremely unlikely that all 5 bulls would all drop in ebi, some could drop but others could gain.

last jan the bull byj had rel of 53% and an ebi of 189 this jan his rel is 70 but his ebi has gone up to 217

irishh_bob

kingofthe3rdyrs wrote: »

The best way to know how good a bull is, is by looking at his calves

that only applys with beef bulls

Indubitable

irishh_bob wrote: »

that only applys with beef bulls

Unless you have the time to see how good the cows are at milk production and how many lactations they produce. Which is a long long time.

browned

kingofthe3rdyrs wrote: »

Unless you have the time to see how good the cows are at milk production and how many lactations they produce. Which is a long long time.

you'd be talking about the older a.i bull in that case and could be missing out on the new bulls coming through as a result. you can check how the dams of new zealand bulls preformed in each of their lactations.

irishh_bob

kingofthe3rdyrs wrote: »

Unless you have the time to see how good the cows are at milk production and how many lactations they produce. Which is a long long time.

are you telling me that you can know by looking at a fresian heifer calf , whether or not she will be a good milker

Indubitable

irishh_bob wrote: »

are you telling me that you can know by looking at a fresian heifer calf , whether or not she will be a good milker

No but when they are older and are producing milk. Which isnt a great idea

irishh_bob

kingofthe3rdyrs wrote: »

No but when they are older and are producing milk. Which isnt a great idea

you,ve lost me now , you said in an earlier post that the best way to tell if a bull was good was to look at the calves out of him

John_F

@irishh_bob: era :rolleyes:

@djmc: the ebi figures are based on a 'base cow', this cow is taken from the figures of thousands of cows around the country, then for example the base cow does x amount kg's of protein, and a bull with + of this is above the base cow, calving interval however is good to get a - figure

understanding EBI here