Post by buxombeefcowdairy on Sept 15, 2008 17:24:21 GMT -5
OK, first off, Jersey cattle do not collect birthweight or calving ease data. Beef breeds do, and use information from birthweight, and calves assisted (pulled, with leverage, etc) at birth so that bulls with small calves and few problems can be used on first-calf heifers. So there won't be a Birthweight EPD for Sweetie. Her own birthweight genetics will be very low, since all Jersey cattle are very low for birthweight compared to almost any beef breed (except Longhorn), in trials at the Meat Animal Research Center, but there won't be an actual figure.
The Holstein association does collect information on calving difficulty, and as a result there are Holstein bulls that are more appropriate for Holstein first-calf heifers.
You can generally find a birthweight EPD on your neighbors's bull by looking on his registration papers. Some breeds have their database searchable online, so for any Angus or Simmental bull, I could get the info and explain it to anyone who is considering using their neighbor's bull. A Beefmaster bull should have that info on his papers, I would think. If not, you could call the Beefmaster registry with his registration number, and ask them for his EPD data.
EPD stands for Expected Progeny Difference. It is expressed in pounds, but you cannot use it to accurately predict the weight of a calf. It is only for comparing one bull to another, of the same breed. (There are multi-breed adjustment figures to use, to come up with an approximation so you can compare one bull to another of a different breed.) For example, lets talk about the milk figures from dairy bulls. I believe they are called Breeding Values, rather than EPDs, but the concept is just the same. For milk, they are expressed in pounds of milk. They don't tell you how many gallons per day one particular daughter will produce, but in this case of three Select Sires Jersey AI bulls:
Geronimo Milk + 1842 Fat -.21%
Legal Milk +199 Fat +.07%
Maximus Milk - 18 Fat +.53%
These are not current figures, but they'll work for this example.
So, if we breed these bulls to cows that are pretty much equal for their own milk and fat genetics, Geronimo daughters on average will have lots and lots of milk, with the smallest cream line (negative percentage of fat). Legal daughters on average will have much more moderate milk production, and better cream lines. Maximus daughters will have the least milk, but with the widest cream line.
These figures represent the bull's genetics, and things can and do vary with offspring. It is entirely possible to get a Maximus daughter with more milk production and less cream than a Geronimo daughter, but not very likely. Most Geronimo daughters will have a lot more milk than most Maximus daughters.
Birth EPD works in a similar way. Calves from a -1.5 Birth EPD bull will almost always be smaller at birth than those from a +5 Birth EPD bull.
With different management systems, cow genetics, and environments, a herd sort of has to find out by experience what birth EPD will be right for his heifers. Some heifers have calving difficulty with a +2 Birth EPD bull, while another rancher might get by with +2 Birth EPD bulls just fine. And this is all talking about Angus Birth EPD, you have to use a conversion table to compare a bull of another breed. So if you have determined that you need an Angus of +1 or less, you can't just assume that you can use a Red Angus bull of +1. You have to convert the EPD, because the genetic database is different. The conversion for Red Angus Birth EPD to Angus is to add 2.8 pounds, so the Red Angus bull with +1 converts to Angus EPD of +3.8, which is a bit much for a lot of heifers. If you have a Beefmaster bull with a Birth EPD of +0, you would convert that to Angus by adding 9.2. Ouch! Nobody I know of would ever consider using a +9.2 Birth EPD bull on a heifer.
There aren't figures to convert dairy cow milk production numbers to beef cow milk numbers.
And regarding the size of the Beefmaster bull's calves from Beefmaster heifers: Beefmasters are part Brahma. Brahma cattle have a marvelous maternal effect: they will not make a calf larger than they can easily give birth to, except in the most extreme cases. It's like a pony mare, bred to a Thoroughbred or Quarter Horse stallion- they just don't make the baby bigger than they can deliver. So a Beefmaster or Brangus or Brahma heifer will not have nearly the kind of trouble that a non-eared heifer will when bred to a Beefmaster, Brangus, Santa Gertrudis, etc bull.
Cows like Holsteins, Jerseys, Angus,...anything that doesn't have Brahman blood, do NOT have that mitigating effect on birthweight. So first-time heifers have to be mated with concern for the size of the calf at birth.
The Holstein association does collect information on calving difficulty, and as a result there are Holstein bulls that are more appropriate for Holstein first-calf heifers.
You can generally find a birthweight EPD on your neighbors's bull by looking on his registration papers. Some breeds have their database searchable online, so for any Angus or Simmental bull, I could get the info and explain it to anyone who is considering using their neighbor's bull. A Beefmaster bull should have that info on his papers, I would think. If not, you could call the Beefmaster registry with his registration number, and ask them for his EPD data.
EPD stands for Expected Progeny Difference. It is expressed in pounds, but you cannot use it to accurately predict the weight of a calf. It is only for comparing one bull to another, of the same breed. (There are multi-breed adjustment figures to use, to come up with an approximation so you can compare one bull to another of a different breed.) For example, lets talk about the milk figures from dairy bulls. I believe they are called Breeding Values, rather than EPDs, but the concept is just the same. For milk, they are expressed in pounds of milk. They don't tell you how many gallons per day one particular daughter will produce, but in this case of three Select Sires Jersey AI bulls:
Geronimo Milk + 1842 Fat -.21%
Legal Milk +199 Fat +.07%
Maximus Milk - 18 Fat +.53%
These are not current figures, but they'll work for this example.
So, if we breed these bulls to cows that are pretty much equal for their own milk and fat genetics, Geronimo daughters on average will have lots and lots of milk, with the smallest cream line (negative percentage of fat). Legal daughters on average will have much more moderate milk production, and better cream lines. Maximus daughters will have the least milk, but with the widest cream line.
These figures represent the bull's genetics, and things can and do vary with offspring. It is entirely possible to get a Maximus daughter with more milk production and less cream than a Geronimo daughter, but not very likely. Most Geronimo daughters will have a lot more milk than most Maximus daughters.
Birth EPD works in a similar way. Calves from a -1.5 Birth EPD bull will almost always be smaller at birth than those from a +5 Birth EPD bull.
With different management systems, cow genetics, and environments, a herd sort of has to find out by experience what birth EPD will be right for his heifers. Some heifers have calving difficulty with a +2 Birth EPD bull, while another rancher might get by with +2 Birth EPD bulls just fine. And this is all talking about Angus Birth EPD, you have to use a conversion table to compare a bull of another breed. So if you have determined that you need an Angus of +1 or less, you can't just assume that you can use a Red Angus bull of +1. You have to convert the EPD, because the genetic database is different. The conversion for Red Angus Birth EPD to Angus is to add 2.8 pounds, so the Red Angus bull with +1 converts to Angus EPD of +3.8, which is a bit much for a lot of heifers. If you have a Beefmaster bull with a Birth EPD of +0, you would convert that to Angus by adding 9.2. Ouch! Nobody I know of would ever consider using a +9.2 Birth EPD bull on a heifer.
There aren't figures to convert dairy cow milk production numbers to beef cow milk numbers.
And regarding the size of the Beefmaster bull's calves from Beefmaster heifers: Beefmasters are part Brahma. Brahma cattle have a marvelous maternal effect: they will not make a calf larger than they can easily give birth to, except in the most extreme cases. It's like a pony mare, bred to a Thoroughbred or Quarter Horse stallion- they just don't make the baby bigger than they can deliver. So a Beefmaster or Brangus or Brahma heifer will not have nearly the kind of trouble that a non-eared heifer will when bred to a Beefmaster, Brangus, Santa Gertrudis, etc bull.
Cows like Holsteins, Jerseys, Angus,...anything that doesn't have Brahman blood, do NOT have that mitigating effect on birthweight. So first-time heifers have to be mated with concern for the size of the calf at birth.