I thought we needed something a little more light-hearted today …
Naked mums produce more milk, apparently.
Female mice that have their skin shaved produce more milk and wean heavier litters than their fully pelted peers.
The key question is why a hairy back should limit milk production. One theory is that it is a question of insulation. The researchers from Aberdeen University propose that by merely keeping cool, the female mice can raise chubbier babies.
Normally mice need their fur to keep warm. But when nursing, making more milk and digesting the extra food needed for this, generates so much waste heat that the mouse risks overheating. Once shaved, however, she can lose more heat through the skin and afford to eat and nurse more.
The team measured and subtracted the energy intake and expenditure of nursing mice mothers. What energy was left – a whopping 55% – was made into milk to nurse on average 11 babies each. But shaved mice mothers ate 12% more food, made 15% more milk and had litters that were 15% heavier than their fully coated counterparts.
If prevention of overheating is important for animals that need to keep a constant body temperature, like mammals and birds, then this could for example explain why litter and clutch sizes are bigger in cooler regions.
The researchers call for models of climate change to consider how heat loss needs may affect reproductive or feeding behaviours in mammals in response to global warming.
So should human mothers take off some clothes if they want to increase milk production? According to one scientist, our ability to sweat makes heat loss easier for humans. However some women mention feeling flustered when nursing. If that applies, and the woman worries about milk supply, then cooling down a little may be worth trying.
Journal Reference: The Journal of Experimental Biology (DOI: 10.1242/jeb.009779)
I’m not sure what to think of this one. When an experiment is first performed it’s unwise to draw deep conclusions before these are tested. Nowhere is this more true than in medical research where the media quickly forget caution and announce yet another “cure” for cancer or old age.
Where, for example, were the control groups? If they had taken at least two groups and kept one at a lower temperature, but otherwise in identical conditions, the results might have some significance but where we have a single group, results must be treated with extreme caution. What other variables might have affected the results?
Well, for one, shaving the mice. This could have all sorts of effects, not least emotional trauma. Mice, you see, don’t expect to be furless.
Note also that the mice were specially bred. Who knows how these specially bred mice might react, given that their genes will be skewed from those of normal mice, one way or another.
There are too many of these poorly planned one-off experiments where researchers snatch explanations out of the air or design experiments, as here, to support their foregone conclusions.
The sweat, therefore the moisture on our skin does act as a cooling effect on our body, so I can see the connection.
Perhaps, nursing mothers should try this.
However, most nursing women feel they need to be covered, as some may object if feeding in public. I know I felt this in my case of nursing a baby.
Whether further studies support this view would be interesting to know.
I think what is essential is that women need to feel comfortable in their environment when feeding, whether with or without clothes.
In reply to Silver tiger…
many thanks for your comments on our paper. I know from your comments that you didn’t bother to even read the title of the original article. If you had done then you would have noticed that this paper is in fact the TENTH paper in a series of papers that have addressed the issue of limits in milk production. This work stretchs back 10 years and includes an incredible array of test situations and control groups and very meticulous measurements of energy flux using state of the art isotope transfer methodologies. These studies include mice kept at lower temperatures as you suggest might be a good idea (and hotter temperatures as well). We took very special care to make sure the mice were not traumatised by the shaving. They were shaved under anaesthesia and their controls were anestherised but not shaved.
Your statement therefore that this is
…a poorly planned one-off experiment where researchers snatch explanations out of the air or design experiments, as here, to support their foregone conclusions.”
completely off the mark. This was in fact a meticulously designed experiment, peer reviewed and funded by the Uk research council (success rate at funding about 20% - so in the top echelon of funded research proposals) where an a priori hypothesis that milk production is limited by heat dissipation capacity based on years of prior experiments involving temperature manipulations was tested in a novel way and shown to be correct.
Thank you for taking the trouble to clarify aspects of your experiment and its history. In my comments, I was going by the information to hand including the “journal reference” which I assume that you or your team composed.
You will appreciate, perhaps, that the “journal reference” does not mention any prior research or control groups. I would have thought these pertinent points to include but perhaps I am mistaken about how such things are done.
Without wishing to be a bore, may I nevertheless make the following remarks (numbers refer to paragraphs in my original comment):
1. Nothing objectionable here, surely? The media are full of sensationalist reports about “cures for cancer”, “pills that slim”, etc on an almost daily basis. I do think it wrong to draw exaggerated claims from new experiments. A valid opinion, I would have thought.
2. I don’t see anything unreasonable here, in general terms. You may regard is as wrong in your case but, as I say, that was not clear from what I read.
3. Mice are hairy creatures and can be expected to react unfavourably to being shaved, no matter how gently. I still think so, even if you disagree. Being anesthetized (as I know from being a long-term cat owner) is not a trivial matter, either. Even if it lessens the fright of being shaved it nevertheless adds stress on its own account. I do believe there is a risk of upsetting the animals and causing anomalous reactions. You may disagree.
4. I think this is a valid point also. You may feel confident that the experiment nullifies any bias. You may be right. It is still legitimate for me to question it, however.
5. I admit this paragraph was loosely composed. Use of the word “these” does by implication bring your experiment into the general collection of “poorly planned one-off experiments”. It is my opinion that there are too many of these. You may disagree. Either way, I now accept from what you say, that yours should not be lumped together with them by my use of “these”.
To silver tiger..
So in reply to your comments for respective paragraphs..
1) Yes the media does often exaggerate scientific claims. But your critique is misplaced here. This study is not one of them. We are not claiming to have cured cancer. We have shown mice that are shaved produce more milk and larger offspring. This is not a sensationalist claim that exceeds our discovery.
2) The problem is you reached too quick a judgement based on inadequate information.
3) It is true mice are furry creatures that may react UNFAVOURABLY (your word) to being shaved. But in our experiment they did just the opposite. The shaved mice performed better than the unshaved ones. That is why we don’t think they are stressed by the procedure.
4) I don’t think it is legitimate for you to question it when you have not taken the time to ascertain the full facts. These mice are not specially bred - they are standard outbred stock mice.
5) Perhaps you feel this is the case because 99% of the time you make a snap judgement that something is a ‘poorly planned one off experiment’ without fully exploring the true situation, as you did with our work. Thanks for your apology.
John
Couldn’t help but notice the above discussion.
It is indeed good to have affirmed the opinion of oneself, as far as points two and five have stated.
It is too easy to assume when one is not fully acquainted with all the facts, both in relation to this particular study but also when passing other comments and judgements in relation to other blogs.
To pass judgement in this way highlights to me a shallowness of thought, with prejudice, and not taking into consideration the whole evidence, or the complexity of an individual situation. I call it narrow-minded blinkered vision.
To reflect on a debate and the part you have contributed/ written is both productive and useful; only if one then acts on what is learnt.I hope it is the case here and in the future.
Thank you John for taking the time to explain more about this study which was interesting to look at, and an even bigger thanks for showing us all how we need to think carefully before we jump to conclusions which may be false, offensive,misleading or highly contentious.