The Accidental Smallholder Forum
Livestock => Sheep => Topic started by: devonlad on May 08, 2013, 08:18:13 pm
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probably a daft question but here we go. We bought a lleyn ram to do the business for us this year and he generally seems to have done the business well. only one dead lamb and all the rest are fit and well. however of the 17 lambs there are 5 ewes and 12 rams. is this down to him or just the way it worked out ? done wonders for our freezer but less for our breeding stock
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Do you know his past history? , People are always too ready to blame the ram but genetics is a 50/50 business,
We have had the same with our goats this year , I'm blaming the weather.
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You may get more answers if you post this in 'Sheep'?
However it's been discussed several times recently - so maybe look up the other threads.
They do say that older males leave more male offspring - is he a youngster or an aged tup?
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You may get more answers if you post this in 'Sheep'?
However it's been discussed several times recently - so maybe look up the other threads.
They do say that older males leave more male offspring - is he a youngster or an aged tup?
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Ah that fits - we borrowed a 'last year' ram (5 I think) - had similar result (13 : 5). Will be a different ram for us next year so a new roll of the dice....
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Do you know his past history? , People are always too ready to blame the ram but genetics is a 50/50 business,
We have had the same with our goats this year , I'm blaming the weather.
The reason that people are ready to blame the ram is because all eggs released by the female (xx) are haploid and can therefore only carry an 'x' chromosome. The ram (xy) releases sperm, also haploid, but can be x or y - now technically because of the way that mitosis occurs an even number of x and y sperm are produced, but there can be a load of extraneous factors which affect the viability of said sperm. Therefore, the sex of the offspring is entireley down to the ram.
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We have nearly all ewe lambs from two different shetland rams, so it cam work the other way round - I'm talking 16 of 21 being female from this ram and 14 of 19 from the last ram :-))))
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Last year - 8 ram lambs and 1 ewe
This year- 2 ram lambs and 6 ewes
Different tups but both of a similar age.
Neighbouring farmer thinks it follows loosely to the age of the tup ??? What would the reason for that be?
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The reason that people are ready to blame the ram is because all eggs released by the female (xx) are haploid and can therefore only carry an 'x' chromosome. The ram (xy) releases sperm, also haploid, but can be x or y - now technically because of the way that mitosis occurs an even number of x and y sperm are produced, but there can be a load of extraneous factors which affect the viability of said sperm. Therefore, the sex of the offspring is entireley down to the ram.
I always think this could be too simplistic a view. For instance, the environment within the ewe, and even the egg itself, could be more or less receptive or hostile to X or Y sperm.
We get some cows always have bull calves... :thinking:
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Neighbouring farmer thinks it follows loosely to the age of the tup ??? What would the reason for that be?
They do say that older males leave more male offspring - is he a youngster or an aged tup?
As to reason... I've wondered about that, and I think the theory is that a young male in his prime wants lots of ladies in his flock to increase the receptacles for his genes; as he ages and becomes vulnerable to being deposed, he needs males carrying his own genes to be the ones most likely to depose him and take over his harem.
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SITN - Thanks. Didn't think of that. It does make sense.
Wonder if any actual research has been carried out ???
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I'm not sure the age thing works as our old ram threw ewe lambs and he was about 9 and the one we used this year is only 2 and the same thing happened. I wonder whether it is weather related, both were tough winters (year in between which was mild we didn't do any lambs so can't prove it)
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thanks all for lots of insight- we bought him as a three year old last october so assume he's now 4- the chap i bought him off is a customer of mine ( i work for mole valley farmers) so i know him quite well and i've asked him whether he usually sires more rams- he says not and i've no reason to doubt him. perhaps its him getting older ? or just bad luck this year
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Our 2 year old Shetland gave us lots more ram lambs than ewe lambs - the 2 year old moorit gave us more ewe lambs - results so far 14 ram lambs and 14 ewe lambs!! Same weather for both - not sure what to make of these results - 2 Moorits to lamb so will be interesting what happens with them.
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Sample size ( how many lambs you have) will also have an impact. There is a 50% chance of male butif you only have 2 lambs you might have 100% male. If you had 100 or 500 it's more likely to have reached 50%.
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This is an interesting point! I have a Pedigree Hampshire Down Flock, this year it was the ewes first time and I used a ram lamb (So plenty of inexperience!). From the 10 girls I got 13 ram lambs and 2 ewe lambs. 2 or 3 rams are looking like they have great potential to sell as breeders, but it looks like the freezer will be full for a while!
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I'm not going to claim to actually have a clue on this subject, but in my experience with chickens, all young males produce entirely male or almost entirely male offspring every time. I think it's a natural mechanism to provide a disposable generation to prevent a precocious/premature sire being inundated by his own sons by the time he comes to full maturity. Excessively young males don't seem to produce strong offspring; they're noticeably weakly, smaller, less prime in every way compared to the offspring he'll have later, and it's got nothing to do with the age of the females. I deliberately breed 'young teenage' males to get munchy-only crops, so to speak, as it's a reliable way for me to obtain about 99%-male crops.
It would make sense that a very young male would produce excessively weakly all-male offspring that are more likely to fail to become breeding males if they do make it to adulthood. I think it's a population and genetic strength control mechanism. If every adolescent male managed to sow his wild oats and the 'oats' were good enough to make it to breeding age in turn, the flocks would be overrun quickly with unproven genes, unlike those of males in their prime who have fought to obtain territory and thus been proven both strong and healthy enough to sire good stock.
But this is poultry I'm talking about, I've not bred sheep yet, only reared orphan lambs. Just a theory, since I notice many species including mammals seem to produce so-called disposable generations of weaker offspring (predominantly male) if the parents are too young, particularly the father.