Sex ratio in AI of elephants

dragon(ele)nerd

dragon(ele)nerd

Well-Known Member
Hey everyone,

A topic that has been covered before of the high number of males produced by AI in elephants. Well, I finally decided to ask my Biology teacher about it, in which he asked another biology teacher who asked Veternairy faculties of Monash and Melbourne Universities, who both do not have an answer.

Anyone like to share their theories?
 
One interesting theory is that it is stress related.

The more stressed the female at conception the more likely a male will be produced.

I would imagine that for most elephants AI is a very stressful situation.

Does anyone know at what point in the period from conception, is the sex of an elephant determined by mother nature?

I am still surprised that this information is still unknown until birth.
 
I've wonder if the skew towards males in captive elephants is something to do with females having it too good. In studies on red dear the more dominant females tend to have male calves and in lean years there is less food about the number of male births drop.
The general explanation for this is that males take more energy to produce and raise and so females in better condition are more likely to have male calves. This would explain both the higher rate of males born to high ranking females and the generally higher rate born in food abundant years.
Maybe inflicting some nutritional stress on gestating females would lead to more female births? It would be interesting to know if studies on other mammals species have similar results.
 
zooman said:
One interesting theory is that it is stress related.

The more stressed the female at conception the more likely a male will be produced.

I would imagine that for most elephants AI is a very stressful situation.

Does anyone know at what point in the period from conception, is the sex of an elephant determined by mother nature?

I am still surprised that this information is still unknown until birth.
Click to expand...

I think I am correct in stating that it has been suggested that if the cow elephant is given food to eat during the insemination, this takes her mind off it, does not make her stressed and thus a cow calf is born, that is the theory anyway, if this is true in practice I do not know.
 
zooman said:
One interesting theory is that it is stress related.

The more stressed the female at conception the more likely a male will be produced.

I would imagine that for most elephants AI is a very stressful situation.

Does anyone know at what point in the period from conception, is the sex of an elephant determined by mother nature?

I am still surprised that this information is still unknown until birth.
Click to expand...

That theory works accordingly to other herds animals such as antelope ( I remember them sayings this off Zoo Days)


However when I asked a zookeeper about the topic, he said it was actually that a calm cow produces a male calf. Further more that the female has to be calm and relaxed for the process is why more males are born.
 
Ned said:
I've wonder if the skew towards males in captive elephants is something to do with females having it too good. In studies on red dear the more dominant females tend to have male calves and in lean years there is less food about the number of male births drop.
The general explanation for this is that males take more energy to produce and raise and so females in better condition are more likely to have male calves. This would explain both the higher rate of males born to high ranking females and the generally higher rate born in food abundant years.
Maybe inflicting some nutritional stress on gestating females would lead to more female births? It would be interesting to know if studies on other mammals species have similar results.
Click to expand...

Are there more male calves born to elephants in captivity that were conceived by natural mating or is it just the case with animals conceived by A.I.?
 
According to the elephant database in general there is around a 50/50 to both genders. Very very slightly to females.

Take a look at Zoo Emmen in Holland though, 25 elephant births, all natural mating, 3 females, 22 males.
 
dragon(ele)nerd said:
According to the elephant database in general there is around a 50/50 to both genders. Very very slightly to females.

Take a look at Zoo Emmen in Holland though, 25 elephant births, all natural mating, 3 females, 22 males.
Click to expand...

So it approximately 50/ 50 for calves conceived by natural mating, do you know what the figure is for calves conceived by A.I.?, that is an astounding number of calves to be born male at Emmen conceived by natural mating, have they just been "unlucky"?, if unlucky is the correct word!
 
Ned said:
I've wonder if the skew towards males in captive elephants is something to do with females having it too good. In studies on red dear the more dominant females tend to have male calves and in lean years there is less food about the number of male births drop.
The general explanation for this is that males take more energy to produce and raise and so females in better condition are more likely to have male calves. This would explain both the higher rate of males born to high ranking females and the generally higher rate born in food abundant years.
Maybe inflicting some nutritional stress on gestating females would lead to more female births? It would be interesting to know if studies on other mammals species have similar results.
Click to expand...

I've also heard about this, where females in the wild tend to produce more females when less food is available. I also remember reading that this is the case with gorillas, which is why there is a high number of males in zoos. Unfortunately I can't find the article where I read it.
 
The story about sex ratio regulation suggests that the proportion of males could increase:
- with obesity of females (which can be estimated from the photographs taken about the time of pregnancy):
- with smaller exhibit size,
- with dominance status of female in the herd.
- with age of female.
It would be interesting to check it! Emmen exhibit is small and elephants are very plump.

BTW, direct comparisons with logging camps or wild may be wrongly interpreted. Some cows in zoos have stillbriths or young die early, but one can argue that these cows in the wild would die or not breed, not counting into the breeding statistics. So good health and good breeding in the wild may be result of elimination of all but strongest animals from the population, not especially good conditions.

Second idea is that elephant caught in the wild or sold from Asia to a Western zoo is weaker and sicker than average, not a random representative of the population.
 
In North America there are 6.4 living African elephant calves resulting from AI.

Considering there have only been 10 births resulting in living calves to date; it seems more like a matter of luck.
Maybe the technology or methods have become more effective but all the living female AI calves have been born in the last five years (Although Amali was the first female AI calf ever back in 2000).
 
The Australasian region has had 10 Asian elephant calves to date:

1.0 born 2009 (Natural)
1.0 born 2010 (AI)
0.1 born 2010 (AI)
0.1 born 2010 (Natural)
1.0 born 2013 (AI)
1.0 born 2013 (AI)
1.0 born 2016 (Natural)
0.1 born 2016 (AI)
1.0 born 2017 (Natural)
0.1 born 2018 (AI)

So 75% male calves through natural conception and 50% male calves through AI.

10 years on, I’d be interested to hear what theories exist around this and whether a higher incidence of male calves has been a trend over the last decade in other regions.

In humans, the timing of conception is theorised to influence gender with a close proximity to ovulation favouring boys. Given that AI in elephants is an involved (and potentially expensive) process, it’s historically been carried out at peak ovulation time (to increase chances of it working). Therefore this could have previously tipped the balance in favour of male calves.

Poor nutrition in wild female Southern white rhinoceros is linked to higher birth rates of female calves, though I acknowledge there would be little opportunity to test this in captive elephants given it wouldn’t be ethical to deprive them of food.
 
You wouldn't necessarily have to deprive the females of food, you could simply increase the percentage of straw and decrease the percentage of hay in the diet, and eliminate unnecessary treats such as fruits and some vegetables, leaving the cows on a diet of primarily browse and straw, along with enough heat to sustain a reduced caloric need. For training fruits and veggies can be replaced with a lower nutrient herbivore pellet.
 
Last edited:
Hyak_II said:
You wouldn't necessarily have to deprive the females of food, you could simply increase the percentage of straw and decrease the percentage of heat in the diet, and eliminate unnecessary treats such as fruits and some vegetables, leaving the cows on a diet of primarily browse and straw, along with enough heat to sustain a reduced caloric need. For training fruits and veggies can be replaced with a lower nutrient herbivore pellet.
Click to expand...
I agree the more nutrition of female has the higher probability that she would produce a male calf
 
Mr.Ivory said:
I agree the more nutrition of female has the higher probability that she would produce a male calf
Click to expand...
I am just wondering if it would be worth looking into the zoos that have bred the most female calfs and find out what type of diet they are being fed by the those zoos?
 
Zorro said:
I am just wondering if it would be worth looking into the zoos that have bred the most female calfs and find out what type of diet they are being fed by the those zoos?
Click to expand...

I’m thinking Taronga trialled the AI ahead of ovulation method to get Porntip to conceive a female calf. It has a lower success rate of conception and we know there had already been at least one failed AI attempt with her prior to conceiving Kanlaya.

I’d imagine Melbourne Zoo are also trialling this with natural conception given there’s no expense associated to do so.
 
You must log in or register to reply here.
Back
Top