What if cows had smaller bladders

Nitrogen leaching is a serious problem for NZ waterways. The main contributor is cow urine.

There are lots of best practise management techniques partially employed around the country to manage the problem. Everything from fencing and effluent storage/reapplication to using nitrogen inhibitors. However its clearly hard work & expensive which is why the Govt recently threw $130M at the problem.

The ‘patch’ does not have the capacity to process all the nitrogen in the urine. However a paddock could have the capacity if the urine was:

A). Spread over an even area. Note in this storage/ mechanical re-application trial although they achieved a 50% leaching reduction the application intensity had a negative impact on pasture production. Reducing intensity increases mechanical re-application costs.

B). Regularly in small amounts.

If cows had smaller bladders they would spread the load more evenly and the pasture system could process more urine/nitrogen. (To a lesser extent walking whilst urinating would also help).

A).This may increase nitrogen oxide levels, a serious greenhouse gas.

B). The health of the cow (cystitis).

Start selectively breeding or genetically engineering cows with a small bladder. (Takes too long but is the best long-term solution)

Surgically reduce the size cows bladders. (Too expensive) But what about fitting a catheter? Bypassing the sphincter muscles.

If you fill the cows bladder with something to reduce its size the bladder might just expand, the muscle we want to control is the sphincter. So how do you make the cow want to pee all the time? Farmers might have ideas but apparently you can do it by rubbing! Maybe a solar powered gadget that emitts an electric impulse to stimulate the cow?

A disperser, is doubling the size of the patch enough?

UPDATE: Just listened to Keith Betteridge & Des Costall on Radio NZ.

They are gathering data on the volume and concentration (nitrogen) of events. Facts from the show:

  • Event volumes range from .5L to 12L! With an average of 2L
  • Nitrogen concentrations vary a lot, even in an individual animal. However there are patterns emerging which we could use to change cow behaviour and divert the N.
  • Frequency is 10-12 times a day. Over the course of a year only 25% of a paddock is covered in patches. Quote “If only we could get the urine on the other 75%”. Awesome, my assumption above was correct!

Check the cows out wearing hi-tech gear here.

An interesting idea mentioned on the show. Adding salt to the cows diet would increase water consumption and dilute the N. Most water on farms is used for irrigation so in theory this would just be a small divergence in delivery. I guess the effects soil and milk salinisation need to be tested.

After reading a lot of awesome research by Keith Betteridge on the subject, there is one major factor I had not considered. Cows pee in the night! Also the early morning urinations are particularly high in N. Keith refers to the cow campsites as Critical Source Areas (CSAs).

If I was reprogramming cows I would tell them “If walking then pee a little bit”. That would move events away from CSAs. However it would involve them having to get up in the night for a stroll quite a bit. The cow could be fitted with a dielectric elastomer so when the cow walked a small current was sent to a medically inserted stent which would force its urinary sphincter open so it leaked. However the cow would still be able to control its bladder the rest of the time, this is important so that it does not rupture its bladder in the night. The alternative means the cow leaks in its sleep which will not dilute the CSAs.