--- On Thu, 10/14/10, Richard Hendrickson <rhendrickson@...> wrote:

I think during the steam era, all livestock had to be
quarantined at the border...So, this would cause any
cross border livestock shipments to change cars.

This has been my understanding as well.  However,
there is a surviving conductor's train sheet from
the Santa Fe in Texas in the early 1950s showing an
empty CN stock car.  How it got there is an open question,
but it was there, apparently en route to being loaded.
I have several photos of CN & CP freight reefers at
locations far below the border, such as southbound
towards Los Angeles on a UP train at Ogden and at
San Diego.  It's my impression that these cars 
were carrying Canadian fish and meat products, though
I can't document that.
Richard Hendrickson

This is a good question, since I'd like to have a CN stock car or two on my layout as well.

Breezing through the web finds all sorts of interesting things on historical trans-country stock trade (including the 1952 Mexican hoof & mouth breakout killing the US/Mexican LIVE cattle trade), and a couple of things are leading me to believe that, a) we don't know as much as we think we do about US/Canadian livestock traffic, and b) there's a whole lot of mystery Canadian finished, processed meat that's going SOMEWHERE besides the Dominion of Canada, and we modelers don't know where!

A couple of links worth looking at:

http://onlinelibrary.wiley.com/doi/10.1111/j.1744-7976.1952.tb02277.x/abstract

I'm not about to buy this book, but "THE TRANSPORTATION FACTOR IN THE MARKETING OF CANADIAN LIVESTOCK" written in 1952 has GOT to be of interest to someone here, and definitely relates to rail movements.

http://www.geog.uvic.ca/dept/wcag/mclachlan.pdf

This is a fascinating article on the growth of Canadian stockyards, and it states that the large yard in Lethbridge was specifically built as a trans-shipment point for US and Canadian LIVE cattle. The article also has some good introductory information on Canadian packing companies. The same site also has several other intersting-looking, rail-related articles:
http://www.geog.uvic.ca/dept/wcag/publications.htm

Next, several sites found quickly referred to breeder herds being developed in twinned facilities in the US and Canada, and stock moving between the two sites. As a quick overview, here's links to articles from 1950 and 2009:
https://kb.osu.edu/dspace/bitstream/1811/44782/3/SPECULUM_v04_i01_1950_low.pdf
http://www.txfb.org/newsmanager/templates/TXFBTemplate.aspx?articleid=5319&zoneid=109

Finally, I haven't had the chance to dig through this site (yet), but it might be the best of all for our purposes:
http://www.statcan.gc.ca/pub/11-516-x/sectiont/4147444-eng.htm


So at a cursory glance, although it might logically be assumed that Can-Am livestock traffic would be halted & quarrantined at the border for a trade-killing long time, that doesn't seem to be the case (necessarily; a quarrantine might have just been part of the nature of doing business). There are plenty of references to Can-Am livestock trade out there; someone just needs to dig through them all to figure out what was really going on!

Regards,
Ray Breyer
Elgin, IL