Genetics and Predicting the Future

[EliAGrimmett]

How should one go about predicting which unit in Arizona (or somewhere else) will have the biggest buck(s) each year? We usually just base everything off the preceding year and sometimes even the year before that, but is there a way to make better predictions? Is there a way to determine when giants will again show up (like the photo below)...

The inserted photo in the photo below was taken in 2002. The main photo was taken in 2009. The photos were taken within a half mile of each other. Obviously, the genetics in that particular location are very strong considering both bucks were well over 90-inches. But, what's weird, is what happened in that area from 2004 to 2008....and that's to say nothing. We never saw a buck even close to those two bucks in the 5 intermittent years.

We see things similar to this in many of the better areas in Arizona and New Mexico. Watching the rise and fall of certain areas is part of the adventure of scouting, but I was wondering if any biologists or people smarter than me might have some insight into how these kinds of things work.

 

[MHMT]

Would it possibly be related to the rainfall and quality of food? What was the rainfall like leading up to 2002 and 2009 in that area? Maybe the genetics were there the whole time but just needed the right food and conditions to get the horn growth.

 

[sturge]

Just because your dad is 6'+ doesnt mean you will be. But your son might, or maybe your grandson. Traits can skip many generations before becoming expressed.

 

[Big Fin]

Wish I knew. The way I look at it is this:

If the genetics are there, good deal. The possibility exists for a great buck or bull.

After that, I better hope I drew a tag on a good year. A good year being an easy winter the year before, great moisture, and low harvest of adult bucks the year before.

Given the data you posted of the younger bucks actually being bigger in horn size, do you think it could have something to do with fawn survival? If too many fawns are taken by predators, can enough buck fawns survive to increase the odds that a lunker like those will pop up as a two or three year old?

Are the younger bucks predated on more, due to young age, lack of experience, smaller body size, lack of aggressiveness, etc., such that the bucks that do make it to four years old, just get older and older, regressing and regressing, with very few young bucks coming into the population?

Not sure, but it would be nice to figure it out.

If AZ gives me a tag this week, I will do my best to answer your questions by putting one on the ground and letting you take measurements.

 

[1_pointer]

My guess is that it's a comination of genetics (remember only 1/2 comes from dad) and conditions. You have to have the genetics, but you also have to have the conditions to express those as well. So, basically what Fin said...

If you can locate the nearest NRCS/NOAA weather station, it would be interesting to compare the amount and timing of precipitation the years starting from 2001 through 2009.

 

[EliAGrimmett]

All interesting thoughts. I've looked into the weather thing in the past, but not for this specific reason. I'll have to dig up some of that info again and check it out.

sturge: I was thinking along those lines, too, but some areas just don't make any sense in that regard. Take for instance Unit 4A where O'Haco killed the former World's Record with over 8" prongs. My Dad wasted a lot of his time scouting in there every year after that and never saw a big buck and never saw a buck with prongs over 6". O'Haco's was killed in 1985. We haven't located a single buck in there that exhibits his buck's genetics since then. So, it seems that in some areas it's possible that "fluke" genetics can occur and in others the DNA is perhaps more uniform? I'm just throwing darts now. But why? To be able to differentiate the "fluke" giant bucks from the herds that can routinely produce giant bucks would be a huge boon to us, given the time constraints we're faced with every year.

1_pointer: Very good observation about the does carrying half the genetics. That could definitely have something to do with it.

Fin: The fawn survival could definitely be on the right track. For instance take Unit 5A in Arizona. In 2007, 2008, and 2009 it was a GREAT unit and probably one of the best in the state, but the weird thing to us was that every year we scouted it we saw only the same bucks that we had seen the year before. That's to say that we never saw any NEW big bucks show up which, I guess, would mean that the fawns weren't surviving from the 2004-2005-2006-2007-2008 seasons. I haven't looked at the surveyed data from those dates in that area, but that's what we've personally witnessed. As such 5A turned out to be a very tough hunt last year because there were still no new bucks to be seen, and the ones that were big were "over the hill" so to speak.

I'll dig up some stats on 5A and Unit 10 and see what I can make of it.

 

[EliAGrimmett]

Wow! Just a quick glance at the precipitation data has revealed a lot more than I thought - at least so far. It might turn out to all be rubbish after further investigation.

Time now to dig into the fawn survival and herd data.

 

[tarheel]

Saw some research results on this very thing not too long ago; seems that it might be more weather and food related, because some of the bucks they were studying reached their best growth in their second year, some in their third, etc. Going by that, age doesn't mean big. Wish I could remember where I saw it.
Did notice that the AZ bucks in the pics don't have that high Roman nose that is so prevalent in WYO goats.

 

[Brisco]

What does Eastmans and huntinfool base their info from? Book entries? Do they use more than that to make their pics. Surely a biologist or someone has done a study similar to this. The question would be if they have made the information avalible or not. If you found deciding factors in this would you make it availible to everyone else (not a specific question to you but more of a though as to why you may not find certain info). Topic is interesting

 

[EliAGrimmett]

There have been several horn growth studies done. I've volunteered over 100 teeth from antelope we've taken to one of the studies. The problem with these studies is that they do very little in regards to helping hunters figure out where to apply if they wanted to find another GIANT buck.

Me knowing that a pronghorn has the biggest horns when it's 3 1/2 years old means nothing when I'm filling out an application. Or for scouting purposes, should my Dad and I go scout in Unit 1 this year to look for an auction tag caliber buck? I have no idea and none of the studies done so far offer any advice in this regard.

Also, the study was showing that better precipitation during the year resulted in increased horn growth, but this doesn't explain the fact that in 2002, one of the worst droughts in a long time down here, we found no less than 4 bucks that would have broken the B&C World's Record (one of which we killed - and it scored 95.) We see this happen on seemingly poor precipitation years quite often.

The limitations of these studies are numerous and some of the largest considerations are that:

1. The studies have been confined to very specific locations which may or may not be very good and...
2. The studies base the results off of bucks that the hunters actually harvest, which has little to do with what kinds of bucks are actually there and...
3. There's no way of knowing how big any of these particular bucks were during their previous seasons.

Unfortunately, these limitations are always going to exist in studies of this type if the researchers are going to come up with credible R values, and such.

I, however, am willing to fudge a lot of the evidence and variables to come up with a better way of determining something useful to say about any particular unit on a given year. For instance, I could say that in 2002 I saw a buck that I estimated to score 85 and then in 2003 I killed the buck and it scored 88. I can then pretend that both measurements are concrete evidence and use that information in the research. This is something that no biologist would ever do because one of the numbers is a guess.

Brisco: I don't have a clue what those services base their information on. The Huntin Fool actually used to call my dad to ask about Arizona information, but that hasn't happened in years.

tarheel:
"because some of the bucks they were studying reached their best growth in their second year, some in their third, etc."

This is sort of what I'm referring to in the above considerations. How do they know the buck taken in it's third year wasn't bigger the year before? They don't and unless they're raising the pronghorn on a farm and collecting their sheds or darting them or something to that effect, the studies like this are never going to know.

 

[tarheel]

All valid points. Doing sketchy and poorly controlled research is kinda like postulating on ancient history; there's a lot of speculation involved, and speculation is hardly quantifiable.

 

[1_pointer]

Also, the study was showing that better precipitation during the year resulted in increased horn growth, but this doesn't explain the fact that in 2002, one of the worst droughts in a long time down here, we found no less than 4 bucks that would have broken the B&C World's Record (one of which we killed - and it scored 95.) We see this happen on seemingly poor precipitation years quite often.

Just a couple of questions regarding this. What was the precip the previous year? I'm almost wondering if timing of precip is more important than actual amount...?

 

[EliAGrimmett]

Well, that's kinda what all my armchair research is indicating. In fact, the precipitation for the year the buck is taken has almost no bearing on horn size according to what I see. Even the year before has no bearing.

The only year that matters is....wait for it....the year the buck was BORN.

It all makes perfect sense when I hear it said out loud. And this could very well be one of the key indicators for predicting future giant bucks.

For instance let's take the current B&C World's Record that we took in 2002 in Unit 13B.

Annual precipitation for the nearest weather station to 13B:

1995 18.6
1996 10.7
1997 14.6
1998 26.4
1999 16.0
2000 14.2
2001 16.1
2002 9.1

For this buck, though, the weather in 13B is almost irrelevant according to my theory because the buck was transplanted into the unit from 19A.

Annual precipitation in 19A:

1995 16.2
1996 10.8
1997 16.2
1998 22.7
1999 16.5
2000 15.8
2001 12.8
2002 7.2

In looking at this the years before 2002 are all wetter, but which year actually means larger horns? Well, according to my theory, it all depends on which year each individual buck was born.

Using my theory you could guess which year the world record was born...and the tooth aging verifies that the 95" world record was 4 1/2 years old.

Take it for what it's worth for now, but I'll look into it more and see if the pattern holds true. The problem, of course, is now I'm having to guess how old most bucks are, but if the majority of research that's been done is right about bucks being the biggest when they're 2-4 years old, then I'm speculating that 2-4 years before each buck was taken there will be a spike in precipitation.

At least that's the theory.

 

[EliAGrimmett]

Here's some more weather data to play with:

1973 7.6
1974 7.8
1975 7.7
1976 6.8
1977 9.2
1978 8.4
1979 6.2
1980 8.1
1981 8.8
1982 12.1
1983 8.7
1984 10.4
1985 9.6
1986 8.4
1987 9.8
1988 7.3
1989 5.6
1990 5.8
1991 7.3

Just looking at it and using my theory I'm betting you can guess which year the largest bucks were born. If you said 1982, then you get an extra bonus point! Ha! I wish. O'Haco's former world record was taken right near this weather station in 1985 and was aged at 3 1/2 years old.

Kinda cool, huh? I'm sure this research would crumble under the pressure of credibility, but I think it's fun.

 

[1_pointer]

Since, I'm delegating the work to you , it would also be interesting to compare the montly rainfall amounts for the year prior and the year of harvest.

 

[EliAGrimmett]

Are you speculating that rainfall in certain months produce larger horns?

I think this was already covered in most other research and what was found is that winter precipitation is bad and summer precipitation is good. The current research has shown that it increases the average horn size by maybe 1 inch (I forgot the actual number) which isn't even worth knowing.

What I'm trying to figure out is when and where the next 90-incher is going to show up.

I'll see if I can look into some of the monthly stuff, but I'm thinking it won't pass my eyeball test.

 

[Deleted member 16014]

I did a literature review a couple of years ago on antler formation and morphology for cervids. Some info could be extrapolated to goats, some surely cannot. I found that the timing of the green forage "release" appeared to be of importance--not the same as timing of precip. The health of a fawn had a large impact on reaching its antlerogenic potential. Big study in TX with whitetails on that topic. Obviously the body condition of the dam determines fawn health to a great degree. Anyway, just some food for thought.

 

[Dinkshooter]

Eli must have got this for x-mas!! Pretty cool stuff indeed.

 

[fowladdict]

Screw 90-inches. I want to see 100 inches Eli. Think we will live long enough to see that happen??

 

[EliAGrimmett]

Me too and yes. It's already happened at least once (1878, Antelope Valley, AZ). I expect it will happen again. Just don't know when or where.