Livestock seasons

I've been trying to get a picture of the livestock season looked like on the railroad late 50s through the end. From what I gather cattle was moved east to Alamosa for reload to markets east October through early November. An article in Classic Trains states that the 1964 season saw 156 carloads of cattle over Cumbres. I'd estimate that loadings were much higher in years previous.

I'm assuming most cattle moving east were heading for slaughter, but I've seen some mention that some were moved to winter grazing. Which brings me to my next question was their a spring rush to move cattle in for summer grazing and from where.

As for other livestock, I know sheep were also carried, and from what I gather this was for movement between summer and winter grazing. I've never seen much mention of pigs, so I'm guessing this wasn't a major commodity.