Lamb growth data

[Sandpit Farm]

How do folks use their lamb growth data?

I am breeding some rams... Growth is the most important terminal trait for me but maternal data is most useful as I want 'ewe breeding' rams primarily but want their male progeny to finish off grass.

Most of my pedigree rams have done about 340g/day (300-380g with 340 median) from milk and grass alone to 16-18weeks. I am pleased with this as I have set stocked and haven't paddock grazed like GO would suggest. However!!!!!

The ram with the best growth rate of 496g/day was a single lamb reared by a teg and is crossbred (Roussin/mule). Is there any merit in keeping this guy on and running him with a bunch of Charollais mules to see how his progeny perform growth wise???? I guess there is no certainty that he will transmit this growth to his progeny. I should also mention that the teg (now a shearling) has grown like mad too - she will be about 68kgs.

Ram lamb is fit now at 43.2kgs.

How does that compare to other folks??

 

[Poorbuthappy]

Is the lamb roussin cross mule or the mother?
Don't forget he will have hybrid vigor, which will reduce with a further cross, and also his offspring would be quite varied including some throwbacks to the mule.

 

[Sandpit Farm]

Is the lamb roussin cross mule or the mother?
Don't forget he will have hybrid vigor, which will reduce with a further cross, and also his offspring would be quite varied including some throwbacks to the mule.

He is himself a throwback. He grew horns! He is a lamb from a Roussin/mule father and a Roussin/mule mother (a mistake). I've been thinking about it like Mendelian genetics and half the lambs will be like the mother and 25% will be BFL-like and 25% will be swale-like. I guess his horns make him Swale-like.

If a lamb is just a 'bag of genes' surely he would convey that to progeny equally?! I never thought about hybrid vigour. If he sired 50 lambs, would they all grow fast (in an ideal world)... If hybrid vigour didn't exist??

 

[Poorbuthappy]

I suspect you know more about genetics than my A level biology and general interest stand me in from what you've said in the past, but those 'throwbacks' will be different for different genes I take it. So you could get a lamb with swaley growth rates, bfl softness, and whatever a Roussin's poorest trait is in theory. In reality you'd just get a lot of variation I'm thinking.

 

[Poorbuthappy]

Also don't forget much of his growth rate to weaning will have been influenced by his dam's milkiness, which won't be transferred to his offspring if used as a terminal sire.

 

[Sandpit Farm]

I suspect you know more about genetics than my A level biology and general interest stand me in from what you've said in the past, but those 'throwbacks' will be different for different genes I take it. So you could get a lamb with swaley growth rates, bfl softness, and whatever a Roussin's poorest trait is in theory. In reality you'd just get a lot of variation I'm thinking.

Roussins poorest trait is wildness!!
Yes I think you are right. You end up with massive variation. Every gene can be thought of as a different variation. In peas it's easy but in sheep it also depends on what chromosome it sits on. I am venturing into the limits of my knowledge. Simple dominance and recessive or codominance is not sufficient to describe it (I guess). If you assume all good traits to be dominant, it works perfectly.... But I think you are right that you could end up with horned, small, wild sheep as well as fast growing bare headed sheep.

 

[Sandpit Farm]

Mind you if someone knows better or has any thoughts please say as this is all guesswork.

Thanks though PBH!

 

[Sawday]

Although the first cross hybrid vigour isnt heritable, you will still get hybrid vigour in the second cross by crossing it over a charollais?? Whether the progeny will still reach 496 grams/ day I dont know.

 

[Gulli]

I suspect you know more about genetics than my A level biology and general interest stand me in from what you've said in the past, but those 'throwbacks' will be different for different genes I take it. So you could get a lamb with swaley growth rates, bfl softness, and whatever a Roussin's poorest trait is in theory. In reality you'd just get a lot of variation I'm thinking.

I would agree, think you will end up with all sorts out of a ram with that breeding behind. Some with the best of everything some with the worst and the majority somewhere in between but I don't think he will throw a uniform set of progeny especially if you are adding another cross in there too.