Podcast on Elk Biology

[SAJ-99]

For those that geek out on this stuff, you might want to check out the Cutting The Distance podcast #42 with Jason Phelps and BYU bio-faculty Brock McMillan. Lots of good data from studies being conducted in the state.
Highlights
- Contra to a familiar belief, all data shows there is only one estrus cycle for elk and deer.
- % of cows that come into estrus each year can vary greatly (61% to 92%) leading to pregnancy variations (56% to 90%)
- 300+ elk births tracked, zero had twins
- No such thing as a "old, dry" cow, but often have calf every other year.
- 10% of antler size for a bull elk is determined by health of the mother while in utero. Another 10% determined by nutrition during antler growth cycle.
- Antler size of bull peaks at 7yrs and is 90% of max by age 6 (mentioned deer was 4-5).

I apologize in advance if I misstated anything, but it was very interesting. I'm not sure how it would differ by region, but it seems pretty general. There was discussion on managing bull/cow ratios and opportunity vs quality, showing how difficult the biologists' jobs are. I need to listen to #40 as it has some discussion on moon phases

 

[DFS]

For those that geek out on this stuff, you might want to check out the Cutting The Distance podcast #42 with Jason Phelps and BYU bio-faculty Brock McMillan. Lots of good data from studies being conducted in the state.
Highlights
- Contra to a familiar belief, all data shows there is only one estrus cycle for elk and deer.
- % of cows that come into estrus each year can vary greatly (61% to 92%) leading to pregnancy variations (56% to 90%)
- 300+ elk births tracked, zero had twins
- No such thing as a "old, dry" cow, but often have calf every other year.
- 10% of antler size for a bull elk is determined by health of the mother while in utero. Another 10% determined by nutrition during antler growth cycle.
- Antler size of bull peaks at 7yrs and is 90% of max by age 6 (mentioned deer was 4-5).

I apologize in advance if I misstated anything, but it was very interesting. I'm not sure how it would differ by region, but it seems pretty general. There was discussion on managing bull/cow ratios and opportunity vs quality, showing how difficult the biologists' jobs are. I need to listen to #40 as it has some discussion on moon phases

I did not listen to the podcast and probably won’t but that seems to be painting with a very broad brush. I have seen elk bugling in November. I have seen elk blow up after year 6 or 7 I have seen deer blow up after year 4-5. It’s funny how the studies and research always lead us to killing wildlife much like the medical field that I work in lead us to predetermined outcomes.

 

[BuzzH]

I'm always curious how the leading authorities on elk, deer, pronghorn, etc. determine when an animal has its best antler growth.

Pretty tough to say or determine when a vast majority of male pronghorn, elk, and deer are dead long before they reach their peak antler growth.

I heard the same thing about pronghorn from a "leading" Wyoming authority, that a pronghorn buck has about 90% of their potential by age 2. Well, that's awesome, so an 80" pronghorn at age 2 will be 10% bigger at age 3, which advanced math, moves that same buck well into a net B&C buck. The whole theory was to issue more pronghorn tags and kill them off at younger age. Not the best idea, IMO. I also don't believe that in pronghorn they peak at 2-3 years old, I think its much closer to 4 or 5. The trouble is most upper 70's to low 80's bucks get whacked when they're that size. No way to know, on a dead 2 or 3 year old buck how much better they would have been. You'll never know.

Case in point, this buck here, that I shot while hunting with @Oak in Wyoming:

Upper 70's at 2 years old, I can almost guarantee this buck would have been a no question B&C buck at age 3, 4, and 5 and likely in the mid-80's range if I wouldn't have killed him at 2.

Same with the quote about 6 year old bulls having 90% of their antler growth at age 6. Say a bull scores 350 at age 6, he's going to be a 385 inch bull at year 7. I also don't believe elk regress that much with age either.

Same with deer...yada yada.

 

[Fremont15]

For those that geek out on this stuff, you might want to check out the Cutting The Distance podcast #42 with Jason Phelps and BYU bio-faculty Brock McMillan. Lots of good data from studies being conducted in the state.
Highlights
- Contra to a familiar belief, all data shows there is only one estrus cycle for elk and deer.
- % of cows that come into estrus each year can vary greatly (61% to 92%) leading to pregnancy variations (56% to 90%)
- 300+ elk births tracked, zero had twins
- No such thing as a "old, dry" cow, but often have calf every other year.
- 10% of antler size for a bull elk is determined by health of the mother while in utero. Another 10% determined by nutrition during antler growth cycle.
- Antler size of bull peaks at 7yrs and is 90% of max by age 6 (mentioned deer was 4-5).

I apologize in advance if I misstated anything, but it was very interesting. I'm not sure how it would differ by region, but it seems pretty general. There was discussion on managing bull/cow ratios and opportunity vs quality, showing how difficult the biologists' jobs are. I need to listen to #40 as it has some discussion on moon phases

This was an excellent two part podcast.

 

[SAJ-99]

I'm always curious how the leading authorities on elk, deer, pronghorn, etc. determine when an animal has its best antler growth.

Pretty tough to say or determine when a vast majority of male pronghorn, elk, and deer are dead long before they reach their peak antler growth.

I heard the same thing about pronghorn from a "leading" Wyoming authority, that a pronghorn buck has about 90% of their potential by age 2. Well, that's awesome, so an 80" pronghorn at age 2 will be 10% bigger at age 3, which advanced math, moves that same buck well into a net B&C buck. The whole theory was to issue more pronghorn tags and kill them off at younger age. Not the best idea, IMO. I also don't believe that in pronghorn they peak at 2-3 years old, I think its much closer to 4 or 5. The trouble is most upper 70's to low 80's bucks get whacked when they're that size. No way to know, on a dead 2 or 3 year old buck how much better they would have been. You'll never know.

Case in point, this buck here, that I shot while hunting with @Oak in Wyoming:

Upper 70's at 2 years old, I can almost guarantee this buck would have been a no question B&C buck at age 3, 4, and 5 and likely in the mid-80's range if I wouldn't have killed him at 2.

Same with the quote about 6 year old bulls having 90% of their antler growth at age 6. Say a bull scores 350 at age 6, he's going to be a 385 inch bull at year 7. I also don't believe elk regress that much with age either.

Same with deer...yada yada.

Agree. He didn't get into the details and said "on average" which is pretty broad. Utah collects a lot of harvest data and I think with enough data we could make some broad generalizations that are accurate at the population level. None of that means there couldn't be single exceptions.

 

[TheJason]

- Contra to a familiar belief, all data shows there is only one estrus cycle for elk and deer.
- % of cows that come into estrus each year can vary greatly (61% to 92%) leading to pregnancy variations (56% to 90%)

This part was particularly interesting to me.

This also directly dovetails in with elk management in much of MT and a lot of other states with “non traditional” elk herds. Private land elk herds that are feeding on alfalfa circles in the summer will have much high calf recruitment than migratory public land herds during drought years.

 

[44hunter45]

This part was particularly interesting to me.

This also directly dovetails in with elk management in much of MT. Private land elk herds that are feeding on alfalfa circles in the summer will have much high calf recruitment than migratory public land herds during drought years.

Alfalfa fed cows are greatly undervalued in my opinion. Just sayin'...

It raises an interesting point. My love of farm fed cow elk meat causes me to select for those cows most likely to be bred.

 

[huntnpack]

Pretty tough to say or determine when a vast majority of male pronghorn, elk, and deer are dead long before they reach their peak antler growth.

I bet most of that data comes from captive animals. How transferable is that to wild populations? I'm not sure.

 

[SAJ-99]

I'm always curious how the leading authorities on elk, deer, pronghorn, etc. determine when an animal has its best antler growth.

Pretty tough to say or determine when a vast majority of male pronghorn, elk, and deer are dead long before they reach their peak antler growth.

I heard the same thing about pronghorn from a "leading" Wyoming authority, that a pronghorn buck has about 90% of their potential by age 2. Well, that's awesome, so an 80" pronghorn at age 2 will be 10% bigger at age 3, which advanced math, moves that same buck well into a net B&C buck. The whole theory was to issue more pronghorn tags and kill them off at younger age. Not the best idea, IMO. I also don't believe that in pronghorn they peak at 2-3 years old, I think its much closer to 4 or 5. The trouble is most upper 70's to low 80's bucks get whacked when they're that size. No way to know, on a dead 2 or 3 year old buck how much better they would have been. You'll never know.

Case in point, this buck here, that I shot while hunting with @Oak in Wyoming:

Upper 70's at 2 years old, I can almost guarantee this buck would have been a no question B&C buck at age 3, 4, and 5 and likely in the mid-80's range if I wouldn't have killed him at 2.

Same with the quote about 6 year old bulls having 90% of their antler growth at age 6. Say a bull scores 350 at age 6, he's going to be a 385 inch bull at year 7. I also don't believe elk regress that much with age either.

Same with deer...yada yada.

Found some data in the elk plan. https://wildlife.utah.gov/pdf/bg/elk_plan.pdf The cited paper is here https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0058373
I may have misheard (or was misstated as the graph shows continued improvement in size with age, but the change is very small). Regardless, I respect the amount of data they collect on the subject and the use in making management decisions.


TLDR:

...that seems to be painting with a very broad brush. I have seen elk bugling in November. I have seen elk blow up after year 6 or 7 I have seen deer blow up after year 4-5.

Yes Doug, by definition, the word "average" paints with a broad brush. Some of the discussion is directly applicable to the situation on MT Mule deer. But you have to have an open mind...so a lot of folks will self-select out.

 

[stk]

Very interesting. I’ll have to listen to the podcast…sounds like a good one.

 

[ClearCreek]

Without a doubt there are regional differences in horn growth among pronghorn.

I have aged hundreds of pronghorn via incisor replacement that were killed in northcentral (east of the Bighorns) Wyoming. Many (most) 4 year old and older pronghorn bucks never had horns greater than 14 inches.

ClearCreek

 

[Flatbrimmer]

For those that geek out on this stuff, you might want to check out the Cutting The Distance podcast #42 with Jason Phelps and BYU bio-faculty Brock McMillan. Lots of good data from studies being conducted in the state.
Highlights
- Contra to a familiar belief, all data shows there is only one estrus cycle for elk and deer.
- % of cows that come into estrus each year can vary greatly (61% to 92%) leading to pregnancy variations (56% to 90%)
- 300+ elk births tracked, zero had twins
- No such thing as a "old, dry" cow, but often have calf every other year.
- 10% of antler size for a bull elk is determined by health of the mother while in utero. Another 10% determined by nutrition during antler growth cycle.
- Antler size of bull peaks at 7yrs and is 90% of max by age 6 (mentioned deer was 4-5).

I apologize in advance if I misstated anything, but it was very interesting. I'm not sure how it would differ by region, but it seems pretty general. There was discussion on managing bull/cow ratios and opportunity vs quality, showing how difficult the biologists' jobs are. I need to listen to #40 as it has some discussion on moon phases

Deer and elk don’t lose their antler vigor as they age. Believe me I got the shaft mentioning that!! Was it @antlerradar or @rogerthat or both or ya?

 

[antlerradar]

Agree. He didn't get into the details and said "on average" which is pretty broad. Utah collects a lot of harvest data and I think with enough data we could make some broad generalizations that are accurate at the population level. None of that means there couldn't be single exceptions.

I think that one has to be very careful when talking about peak antler/horn growth when using data compiled from a single point in an animals life. As Buzz points out, the bucks with the best head gear are often shot young. The data may be showing that hunters are selecting the best animals at a younger age and not peak growth. I have never seen a deer have peak antler growth at age five unless he died at age five.

 

[antlerradar]

Deer and elk don’t lose their antler vigor as they age. Believe me I got the shaft mentioning that!! Was it @antlerradar or @rogerthat or both or ya?

I thought I was on my best behavior, considering the old buck going down hill myth is one of my personal pet peeves.

 

[SAJ-99]

I think that one has to be very careful when talking about peak antler/horn growth when using data compiled from a single point in an animals life. As Buzz points out, the bucks with the best head gear are often shot young. The data may be showing that hunters are selecting the best animals at a younger age and not peak growth. I have never seen a deer have peak antler growth at age five unless he died at age five.

I think the word “peak” needs some clarification. The graph shows it isn’t a true peak or maximum until later years. But it also shows that by an age most would call maturity, an animal is 90-something percent of what it would ever be. If a bull is shot at 6.5yrs old and scored 320 (eliminating the nutrition variable- so saying it was good year) thinking that bull would have been 380-400 in two years is not supported by the data. Impossible for a bull to grow that much? No, but very rare. Same for deer. Really big animals are simply rare.

I’m not saying that there is no benefit to managing for age class and antler size, because older animals will be bigger and thereby increase the average. But it doesn’t mean there will be 180-200 inch bucks or 400in bulls in every section. In fact, the benefit may be temporary because more deer eventually degrades the habitat conditions and the females end up in less than ideal conditions which also impacts antler size. It is a tough balancing point.

I looked through the Freeman study and think it is pretty solid. A hunter could argue any single animal “would have been a monster” in two or three years, and we could never know because the animal is dead. If I had to bet money on it, I bet with what the data says.

Side note, I was listening to a podcast where the guide said the state’s (AZ I think) aging was wrong because he had a bull on trail camera for a certain number of years and the state said it was younger. Maybe there was a mistake in the lab, maybe it was a different bull, who knows. But it shows hunters have strong opinions on things that are hard to shift. Often wrong but never in doubt.

 

[Big Fin]

Interesting to read this on pregnancy rates and "dry cows" and second cycle. I didn't listen to the podcast. What has been recited here from the podcast contradicts a lot of studies that state how habitat quality and recovery from lactation is the largest driving factor in pregnancy rates, dry cows, and time/number of cycles. The notion of twins being rare agrees with just about every study on elk calving.

Summary of those cow elk studies I've read is that a cow elk that gets to 10% body fat, 40-45#, will have pregnancy rates over 90%. Thus, pregnancy rates/dates, which drive parturition dates, are a function of habitat quality and lack of disturbance to lactating cows, more than anything. Habitat that is capable of getting cows to 10% body fat by late September is getting less and less abundant for a variety of reasons.

Maybe the conversation extended to the important aspects of habitat quality needed for cow elk to have high pregnancy rates and the energy cost of disturbance during the important summer periods of "putting on the feed bag." I usually don't have time to listen to podcasts, but I might make time for that one.

 

[SAJ-99]

I thought I was on my best behavior, considering the old buck going down hill myth is one of my personal pet peeves.

Another side note. Here is a longitudinal study (same deer over years) on a recent mule deer antler growth in Texas. Average shows the same thing as mentioned previously, but the variability is crazy. You can see some deer that looked like they were on the path to being monsters at 3.5 and then they mean reverted, same with some that looked weak early. full read here https://issuu.com/texaswildlifeassociation/docs/2020-12-december_proof3_final/s/11364007

 

[SAJ-99]

Interesting to read this on pregnancy rates and "dry cows" and second cycle. I didn't listen to the podcast. What has been recited here from the podcast contradicts a lot of studies that state how habitat quality and recovery from lactation is the largest driving factor in pregnancy rates, dry cows, and time/number of cycles. The notion of twins being rare agrees with just about every study on elk calving.

Summary of those cow elk studies I've read is that a cow elk that gets to 10% body fat, 40-45#, will have pregnancy rates over 90%. Thus, pregnancy rates/dates, which drive parturition dates, are a function of habitat quality and lack of disturbance to lactating cows, more than anything. Habitat that is capable of getting cows to 10% body fat by late September is getting less and less abundant for a variety of reasons.

Maybe the conversation extended to the important aspects of habitat quality needed for cow elk to have high pregnancy rates and the energy cost of disturbance during the important summer periods of "putting on the feed bag." I usually don't have time to listen to podcasts, but I might make time for that one.

Yes, he seemed to confirm that reproductive capability is highly dependent on health. Getting old sucks for them too so they start skipping a year. He summarized as something like "there is a cost to reproduction". He admittedly didn't have an explanation for why pregnancy rates would vary greatly from one unit to another in the same year. I can picture @JLS point on alfalfa. How can you move elk off a private pivot or private wintering range in a drought year? Seems impossible. Any improvement in public land habitat has to be tied to restricting cattle grazing leases on that land, rotating at the very least. That might get to a messy negotiation between stakeholders.

 

[BuzzH]

I think the word “peak” needs some clarification. The graph shows it isn’t a true peak or maximum until later years. But it also shows that by an age most would call maturity, an animal is 90-something percent of what it would ever be. If a bull is shot at 6.5yrs old and scored 320 (eliminating the nutrition variable- so saying it was good year) thinking that bull would have been 380-400 in two years is not supported by the data. Impossible for a bull to grow that much? No, but very rare. Same for deer. Really big animals are simply rare.

I’m not saying that there is no benefit to managing for age class and antler size, because older animals will be bigger and thereby increase the average. But it doesn’t mean there will be 180-200 inch bucks or 400in bulls in every section. In fact, the benefit may be temporary because more deer eventually degrades the habitat conditions and the females end up in less than ideal conditions which also impacts antler size. It is a tough balancing point.

I looked through the Freeman study and think it is pretty solid. A hunter could argue any single animal “would have been a monster” in two or three years, and we could never know because the animal is dead. If I had to bet money on it, I bet with what the data says.

Side note, I was listening to a podcast where the guide said the state’s (AZ I think) aging was wrong because he had a bull on trail camera for a certain number of years and the state said it was younger. Maybe there was a mistake in the lab, maybe it was a different bull, who knows. But it shows hunters have strong opinions on things that are hard to shift. Often wrong but never in doubt.

With deer and pronghorn in the shit in Wyoming and Montana, having degraded habitat and too many animals on the landscape is about 10,342 on the scale of things to worry about.

 

[TheJason]

Interesting to read this on pregnancy rates and "dry cows" and second cycle. I didn't listen to the podcast. What has been recited here from the podcast contradicts a lot of studies that state how habitat quality and recovery from lactation is the largest driving factor in pregnancy rates, dry cows, and time/number of cycles. The notion of twins being rare agrees with just about every study on elk calving.

Summary of those cow elk studies I've read is that a cow elk that gets to 10% body fat, 40-45#, will have pregnancy rates over 90%. Thus, pregnancy rates/dates, which drive parturition dates, are a function of habitat quality and lack of disturbance to lactating cows, more than anything. Habitat that is capable of getting cows to 10% body fat by late September is getting less and less abundant for a variety of reasons.

Maybe the conversation extended to the important aspects of habitat quality needed for cow elk to have high pregnancy rates and the energy cost of disturbance during the important summer periods of "putting on the feed bag." I usually don't have time to listen to podcasts, but I might make time for that one.

In domestic livestock (I think it’s fair to assume there is high crossover to wild ungulates) if an animal is on the marginal edge of body fat percentage, there is a “flushing” affect from having access to high quality feed for several weeks prior to estrus.

This alternating year is likely due to the fact the cows are on the lower edge of the nutritional scale and don’t necessarily have the reserves going into lactation to recover from it prior to the next breeding season.