Interestingly, over the last several years, grullas have developed in the AQHA (American Quarter Horse Association) and elsewhere.  In the late 1990s and early 2000s, it seemed like everyone was jumping on the grulla "band wagon" with little care for quality of the breeding stock...or so everyone thought.  While there are plenty of those "breeders" that have tried to capitalize on the grulla coloring, show people (especially in the working cow/reining type events and limited halter) have also taken an interest to this rare and majestic color thanks to horses like Hollywood Dun It and Holidoc.  Good marketing on the part of some of the foundation breeders has brought up national as well as international interest in the grulla too.  Horse people in general, are more knowledgeable about the different colors too, so there are less grullas being registered black, brown, dun and red dun than before.

Homozygous This...Homozygous That...Another part of the color mix is the homozygousity tests that are available today for red factor (homozygous black), agouti, creme and more.  When these tests first came out several years ago, everything that was E/E (homozygous black) just HAD to be kept for breeding.  Even today, many breeding horses are advertised as E/E without mention of disposition, achievements or pedigree.  Although there are times that even Enloe Quarter Horses, as a small breeder, would love to be able to test for ever color gene possible, I am also grateful that some of the genes are still a mystery.  It reminds us to focus on the very important aspects of conformation and temperament first and foremost.  

And then there is the "shade" factor...Since grullas started gaining popularity, I can't tell you how many times I have been asked "How do you produce a white grulla?" and "What shade is my grulla?"  After you've had as many grullas born at your place as we have, it becomes easy for us to say by the time they are dried off that "Yep, it's a grulla" or "Nope, not this time".  Shade is another thing.  About 75% of the time we can tell if a colt is going to be lighter or darker, but not always.  Grullas are severely affected by age, time of year, feed, the amount of sunlight they receive, time of day, lineage and more.  We have light slate grullas that can look silver, we have dark slates that can look black.  We even have a "wannabe grulla" that is really a dun. She will look suspiciously grulla to the untrained eye at certain times of the year. 

One of my favorite photos that shows a white versus a silver grulla.  Note how dark the foliage is.  This photo has not been lightened or darkened.  For those wanting to purchase a particular shade of grulla, either take the time to look at it in person, or ask for multiple photos on different days.  Don't be disappointed if the "silver" baby you purchased turns out to be a little darker.  Don't be disappointed if your horse you bought in the late summer sheds off a little darker in the spring.  It happens.  No one can predict with 100% certainty what exact color shade you're going to get.
 

Color Chart Interpretation...Below is a color chart prepared specially for this article from the AQHA.  Although still very rare, grullas surpassed the 1% mark in 2006!  If people are breeding for grullas, then they are also breeding for anything non-bay, chestnut or sorrel.  Some of the trends may be attributed to popular stallions of the times, but no stallion or its colored offspring breeds enough mares to sway the chart by much.  All "rare" colors are on the rise as a percentage of the total foals registered.  Roans are especially trendy at this time.  Depending how you look at it, legend has it that the King Ranch can be thanked or blamed for so many sorrel horses.  Even though the color is homozygous recessive, it has grown to the most popular color in the quarter horse registry today.  A particular shade of sorrel was bred for down at the ranch.  Obviously color was only one of many factors that determined if a horse would meet the King Ranch's high standards for the breeding herd.  But logically, a sorrel should be rare if it hadn't been selected for.  Everything about a sorrel is recessive from leg color to roan effect to greying effect to dun factor and creme dilution. All these modifiers will change the color of a sorrel.  They can not hide behind the sorrel curtain.  If they aren't selectively bred out, they will show in phenotype (displayed color). While I believe a good horse can come in any color, to me, this is proof that you can breed for color without losing more important factors like working ability, conformation and disposition.  Proof that quality grullas, or any rare color for that matter, can be produced by responsible breeders willing to cull lesser quality individuals regardless of their pedigree or color.

Data compliments of the AQHA, 2007.

Common questions we have been asked about grullas...

Q: What is a silver grulla?
A:  To us, a silver grulla is a very light shade, almost the color of aluminum at it's darkest stage.  Silvers fade heavily in the summer months.  Silver grullas may or may not be homozygous dun.  Silver grulla is not associated with the silver or white genes.

Q: Do silver grullas carry a creme gene?
A: Some people say they carry a creme gene.  Ours do not.  We prefer none of our grullas to carry the creme gene and have selected breeding stock grullas that are not carriers.  Why do we do this?  For personal preference reasons, we eliminate the risk of producing a cremello of perlino.  Back in the day, you couldn't register these two colors, but AQHA now accepts them into the registry.  While it is true that you will increase the possibility of producing a diluted horse when it carries a creme gene, we don't like the fading effect it has on the purity of the color either. 

Q: What does the creme gene do to the grulla color?
A: It really depends.  Most of the time, you can't look at a grulla and say, yep, it carries the creme gene.  That said, the creme gene narrows the pigment that is allowed to flow through the hair shaft.  The more narrowing, the lighter color the hair.  Creme carriers generally fade a lot worse then non-carriers.  So why can't you tell they are carriers if they are lighter?  A silver grulla will turn very light, almost white grulla where a dark slate that carries a creme gene may turn to a common slate color and look perfectly normal and no one would ever suspect its a creme gene carrier.  Carriers also tend to have a lighter eyelid, especially when they are born.  This may darken as it gets older.

Q: What's a white grulla?
A: To us, a white grulla is a homozygous silver grulla that is the color of dirty snow.  It is a distinctive shade, not to be mistaken with silver.  White grullas are often mistakenly identified as a silver grulla with a creme gene.  We have had several white grullas and none has carried the creme gene.  White grulla is not associated with the silver or white genes.

Q: Can you tell if a grulla is homozygous dun by looking at it?
A: Most researchers will tell you no.  We question this some cases.  There is a particular lineage of horses that produce white grullas that are always 100% dun factor producers.  That said, we also have another line of homozygous dun horses that are a pretty blue color, not even silver.  Yet every foal they produce is dun factored.

Q: What color should my horse be bred to if I want a grulla?
A: Most of the time, I say buy a grulla.  If you want to try to produce a grulla, have your horse tested for red factor and agouti at UC Davis or one of the other genetics labs in the country.  I can't tell you by looking at a picture if your horse is going to produce a grulla.  I can't tell you your horse is homozygous black.  Grullas, blacks and true blue roans never carry agoutis, so if you have one of those colors, you don't have to worry about Agouti.  If you have a red dun, palomino, perlino, sorrel or chestnut that is out of two grullas, blacks, blue roans or a combination of those colors, you also won't have to worry about agouti.  Everything else should be tested.

Q: What color should I breed to produce grulla?
A: Grulla of course!  There are some horses that are not able to produce a grulla no matter what you breed them to.  These include horses that are homozygous grey or roan, and those that carry two Agoutis (can be found in any horse that is not black, grulla or true blue roan).

Q: Greys produce a lot of grullas, right?
A: Wrong.  Greys produce 50-100% grey offspring, and most of the time, you don't know the base color of a grey (the color the foal was born before it greyed out) so there is even a bigger risk to no producing the color.  

Q: Duns produce a lot of grullas, right?
A:  Some think duns are a good color to use.  They can be, but they are known Agouti carriers.  Agouti genes (A) are usually the hang-up to producing a grulla.  All Duns can have one or two Agouti alleles.  If there are two, bye bye to producing a grulla, it will never happen.  If they have one copy (Aa), you are still in business as long as you breed it to another horse that has at least (Aa).  Of course, you just decreased your possiblity of producing a grulla by 50% when using a Aa dun versus a grulla which is always aa.

Q: What lines produce the "best" grullas?
A:  That is all a personal preference.  We chose the lines we wanted and figured out how to get those lines in the grulla color.  Not an easy thing.  It has taken years. 

1) One of the first things you should concentrate on are your interests (all-around, roping, reining, pleasure, trail, etc.)  Quarter horses are specialized, so the first question to ask is what do I want to do with my horse?  It's not a good idea to breed a hunter/jumper to a reining stallion because the stallion is grulla.  Know what you want to do with your horse.   We also don't believe it is a good idea to breed to a cutting stallion because you have seen it on TV and thought it looked cool.  You have to be a pretty good rider to stay on top of these types of horses.  They have been selectively bred to be quick and super sensitive to follow a cow.  Although some horses can do both, if you are looking for a dupity-do horse that trail rides, they might be a little jumpy for your style.

2)  Look at conformation.  Do you want a bulldoggie type horse or a streamlined horse?  Do you want a horse that is 14.2 and easy to get up on, or do you want a 16.1 hand sky-scraper.  All a personal preference.

3)  Look at temperament.  Are the lines known for your interests?  Does the line produce a lot of using horses, show horses, trail riders, etc...

4) Lastly, can the line produce the color I want?  If there are a lot of grullas in the background, chances are pretty good it can.