inyati13
Well-known member
Definitions: Genotype; The genetic constitution of an individual organism. Phenotype; The set of observable characteristics of an individual resulting from the interaction of its genotype with the environment.
Unless you can take a Bovine to a lab and do a total genetic makeup on it, the evidence of its genetic constitution is revealed by its pedigree and what you can see with your eye. EPDs are data collected on the animals performance. The performance reflected in the EPD data is influenced by the animals genotype and the environment. The best bull in the world could have poor WW data, if the cows he bred did not produce adequate milk to wean healthy calves.
These are fundamental concepts and I provide them because despite their simplicity, I see statements on CT that fail to acknowledge these concepts. For example, there was a thread that diminished the importance of looking at the bulls phenotype in favor of looking at the data. My question is this: where do you put the most emphasis as a breeder in your effort to evaluate the genetic quality of a Bovine?
I am not a breeder but from my understanding of genetics, I would think the order of importance unless you had a complete annotated genetic map of the animals DNA to study, would be: First, the Phenotype; Second the Pedigree: and third the data on the Bovines performance as reflected in the EPDs.
Here is why I would put Phenotype first. The Phenotype is the most direct insight into the animals genotype. Everyone is knowledgeable that in looking at a Bull that you see only those characteristics that are expressed and that defects my be hidden by the recessive genes. Conversely, there may be superior characteristics expressed if the bull was mated to a cow that would help uncover that characteristic. But when you look at a Bull you can only judge him as he is. Obviously if you know the cows you plan to mate him too you have more information to perform you evaluation. But in the science of genetics the dice have been rolled and what you see in the Phenotype is the result of all the genetic mechanisms having been played out. Mutations, meiosis, dominance, recessiveness, fertilization, crossing over of limbs of DNA strands, etc. Yet I talk to breeders around here who tell me they put more value on the EPDs. To the point that they exclude bulls or cows sight-unseen. I could see that if you needed a bull just for heifers and you were interested in CE only. Thanks. I hope this generates some entertaining debate. Let the fun begin.
PS. Can we agree to exclude the exceptions and focus on the fundamentals. I know you could justify using EPDs in exceptions like the CE point above. What is the general practice? That is what this is about. Thanks.
Unless you can take a Bovine to a lab and do a total genetic makeup on it, the evidence of its genetic constitution is revealed by its pedigree and what you can see with your eye. EPDs are data collected on the animals performance. The performance reflected in the EPD data is influenced by the animals genotype and the environment. The best bull in the world could have poor WW data, if the cows he bred did not produce adequate milk to wean healthy calves.
These are fundamental concepts and I provide them because despite their simplicity, I see statements on CT that fail to acknowledge these concepts. For example, there was a thread that diminished the importance of looking at the bulls phenotype in favor of looking at the data. My question is this: where do you put the most emphasis as a breeder in your effort to evaluate the genetic quality of a Bovine?
I am not a breeder but from my understanding of genetics, I would think the order of importance unless you had a complete annotated genetic map of the animals DNA to study, would be: First, the Phenotype; Second the Pedigree: and third the data on the Bovines performance as reflected in the EPDs.
Here is why I would put Phenotype first. The Phenotype is the most direct insight into the animals genotype. Everyone is knowledgeable that in looking at a Bull that you see only those characteristics that are expressed and that defects my be hidden by the recessive genes. Conversely, there may be superior characteristics expressed if the bull was mated to a cow that would help uncover that characteristic. But when you look at a Bull you can only judge him as he is. Obviously if you know the cows you plan to mate him too you have more information to perform you evaluation. But in the science of genetics the dice have been rolled and what you see in the Phenotype is the result of all the genetic mechanisms having been played out. Mutations, meiosis, dominance, recessiveness, fertilization, crossing over of limbs of DNA strands, etc. Yet I talk to breeders around here who tell me they put more value on the EPDs. To the point that they exclude bulls or cows sight-unseen. I could see that if you needed a bull just for heifers and you were interested in CE only. Thanks. I hope this generates some entertaining debate. Let the fun begin.
PS. Can we agree to exclude the exceptions and focus on the fundamentals. I know you could justify using EPDs in exceptions like the CE point above. What is the general practice? That is what this is about. Thanks.