I was intrigued by this observation and so did a little research.
According to the ASPCA website:
"While on assignment in Russia as an American diplomat, a New Yorker named Henry Bergh stopped a carriage driver from beating his fallen horse. The year was 1863, and it was then and there that Bergh realized the effect he could have on the world. He soon resigned his post and returned to New York to devote his energy to the prevention of cruelty to animals. In 1866, he founded the American Society for the Prevention of Cruelty to Animals.
Henry Bergh, Founder of the ASPCA
The ASPCA’s official seal, drawn by Frank Leslie and unveiled in 1867."
https://www.aspca.org/about-us/history-of-the-aspca
The article points out that it should be of no surprise that the seal is of an angel protecting a fallen carthorse given why the organization was founded.
The History website adds that:
"On April 10, 1866, the American Society for the Prevention of Cruelty to Animals (ASPCA) is founded in New York City by philanthropist and diplomat Henry Bergh, 54.
In 1863, Bergh had been appointed by President Abraham Lincoln to a diplomatic post at the Russian court of Czar Alexander II. It was there that he was horrified to witness work horses beaten by their peasant drivers. En route back to America, a June 1865 visit to the Royal Society for the Prevention of Cruelty to Animals in London awakened his determination to secure a charter not only to incorporate the ASPCA but to exercise the power to arrest and prosecute violators of the law.
Back in New York, Bergh pleaded on behalf of 'these mute servants of mankind' at a February 8, 1866, meeting at Clinton Hall. He argued that protecting animals was an issue that crossed party lines and class boundaries. 'This is a matter purely of conscience; it has no perplexing side issues,' he said. 'It is a moral question in all its aspects.' The speech prompted a number of dignitaries to sign his “Declaration of the Rights of Animals.”
Bergh’s impassioned accounts of the horrors inflicted on animals convinced the New York State legislature to pass the charter incorporating the ASPCA on April 10, 1866. Nine days later, the first effective anti-cruelty law in the United States was passed, allowing the ASPCA to investigate complaints of animal cruelty and to make arrests."
Anyways, it looks like the man who founded the organization was in Russia when he came up with the idea. It then solidified in England. His visit to the Royal Society for the Prevention of Cruelty to Animals in London occurred in June 1865, meaning he was abroad from some time in 1863 (per Lincoln's appointment) - Summer 1865 (after the conclusion of the war). So a direct connection between Bergh and his personal motivations and the American Civil War seems unlikely (beyond that he was in London on appointment from Lincoln).
That said, it is possible that a general social attitude linked to abolitionist sentiment, temperance movements, the second and third great awakenings, etc. inspired Bergh and other early members to join the organization. My history teacher encouraged us to always think not just about
when an event occurred but
why it did not occur earlier or later. Perhaps the Civil War era was just so full of these kinds of ideas that it makes sense an individual would have the idea to create a humane society and enough social support to see its success. Perhaps the New York State legislature was swayed by the recent conflict and therefore more susceptible to pleas of the heart (although an equally strong case could be made that the conflict did nothing but harden their hearts, especially with the vast number of animals sacrificed "necessarily" for the war effort. Or perhaps that they would think, "why at a time of such immense
human suffering should we stop to think about
animal suffering?" That said, they did vote for it). Regardless, I would say that anti-animal cruelty sentiments came from the same soup of the 19th Century as many other movements, rather than that one was necessarily an extension of the other.
What an interesting question @majorbill. I'm interested to hear what other people think. You've got me thinking about all sorts of stuff now. My poor school work is just NEVER gonna get done at this rate ; )