Saturday, December 18, 2010


Galaxy at around 18 months of age
Genetics are interesting but bamboozling stuff when they throw up unexpected traits despite the best efforts with breeding programmes.   For instance, take the business of animals having horns, scurs or being polled.   All the research shows the polled gene being dominant but, to confuse the issue, every now and then an animal with a polled background of several generations suddenly sprouts real horns as in the case of the boy here.

The story of the bull we called “Galaxy” began when he was born in the corner of a paddock and managed to snuggle himself against the fence becoming almost invisible.   His mother went walkabout, forgot where her calf was and “calf-napped”  the newborn offspring of another cow.   Once we discovered what had happened we tried to reunite her with her own calf but she wasn't interested even when we put the two of them together in one of the races for a day.

Rather than cause more stress by trying to right a wrong we took the little bull home to rear and put the cow in a different herd to curb her obsession with the other calf.   We already had a number of hand feeders owing to several cases of twinning so Galaxy settled in well.   He was really laid back even as a youngster and thrived on the daily attention.

When Galaxy was around five weeks of age we noticed he was developing little horns, proper ones which really puzzled us knowing his background so we had a look back through his pedigree record.   Amazing reading.   With his dam we went back nine generations on the female side and six on the male before the indication came up “pedigree unknown” on the New Zealand Hereford Association database but ALL those animals were polled.   Then we looked at his sire's record and this is where the horny business started.   His sire had two paternal generations of polled animals then in came the horns with a great-grand-dam listed as “pure horned” and from this we traced back to1958 – all horned – before the pedigree records ran out.   The maternal side of Galaxy's sire showed one great-grand-dam which was horned but her parents, grandparents and as far back as we could go were polled!

In August of this year (2010) I took part in a webinar run by Southern Beef Technology in Australia
which was about a new DNA test for the polled gene.   The discussion covered a number of topics which has since been updated and I have permission to use some of this.

It has been found that the polled characteristic is dominant over horns, however, although you might buy a polled bull you won't know until he has progeny on the ground whether he is “true polled”.   An animal that is polled may still possess a copy of the recessive gene for horns and throw a proportion of horned calves.   The difficulty of distinguishing between homozygous polled animals and polled animals that are heterozygous carriers of the allele (an alternative form of a gene) responsible for horns is an impediment to breeding for polled stock.  

Research has shown that using bulls tested to be homozygous with the Beef CRC (Co-operative Research Centre) test will result in a reduction in the proportion of horned calves but in some breeds there will be an increase in the proportion of scurred calves and in all breeds there will be an increase in the proportion of polled calves.   Very basically homozygous means having two of the same alleles at the same location on a chromosome and heterozygous is having two different alleles at the same location on a chromosome.   All these terms and descriptions of them can be found on the internet.  

These factors need to be taken into account when breeding for polled Miniature Herefords.   They are relatively new on the scene when compared with the horned ones and all of them have been bred from polled animals among the larger Classic Herefords which in turn have evolved from polled Standard Herefords.    You can see this within a few generations in their pedigrees.   At least one of the bulls I have selected  for semen import is known to be homozygous and with around forty progeny so far is throwing 95% polled calves from horned cows.   Some others I have looked at have a heterozygous background with the resulting progeny being a mixture of polled, horned and scurred.   These animals would not be as suitable for using to breed polled offspring unless mated to a homozygous polled bull or cow when the chances could improve.   For this reason in breeding my own line of polled miniatures the heifers selected from among the standard Herefords have had their pedigrees scrutinised for any appearance of scurs or horns but that is still no guarantee that the polled factor will be dominant.

Galaxy as a 2 year old the day before his horns came off

We should have dehorned Galaxy in the autumn following his birth but by then the antlers were promising to be something spectacular (move over Donner and Blitzen) and we had hopes of selling him to one of the bullock teams which operate up here.   He would have been great as a stud bull for new team stock, although what guarantee could we give that his progeny would have horns?   At the very least he would have had to be mated with a horned cow.  

Unfortunately he wasn't wanted by the bullock teams nor as a ring-in for Santa's reindeer so reluctantly we had the deed done.   We couldn't keep him for breeding ourselves even though apart from the horns he would have been ideal as a stud bull so he was up for sale as a terminal sire to a dairy herd.   Parting with him was hard but we do know he has gone to a small dairy farm in a pleasant location where he should be able to live a peaceful and productive life. 

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