Field Notes: Eat, [don’t] sleep, watch calves, repeat

Research teaches you way more than you’d expect:

  • Which trendy caffeinated drinks do and don’t work to keep you awake (stick to coffee.)
  • What exercise you can do during observations to stay active without distracting your subjects (squats.)
  • Which podcasts are best for keeping you alert without making you panic when you’re outside alone in the middle of the night (family annihilator crime stories are less threatening since they never happen to people that are alone at a barn; hypothetically, non-murder podcasts would work too.)
  • How many layers you need to stay warm during summer Californian nights (the limit does not exist.)
  • How to live on 30 minutes of sleep a day (you don’t.)

Oh, I study feeding behavior in dairy calves—was that not clear? 

I’m interested in how early feed experience can influence the development of oral behaviors in dairy calves, which requires endless time spent staring at calves. Ideally, my research will help improve the lives of the 9 million dairy cows we have in the United States, and countless others worldwide. At the very least, it’s already improved my life thanks to the countless hours I’ve spent listening to political podcasts, which came in handy during family dinners over the holidays (though this gain may be cancelled out by the total lack of REM sleep during this same period). 

Dairy cattle have been domesticated for human use: we use them for milk, cheese, yogurt, butter, and meat. To do this effectively, we’ve had to alter many aspects of their natural life, and many of these changes have hit calves the hardest. Calves in natural settings are born on pasture and spend their time hanging out with mom, sucking milk from her udder, learning how to be a cow from watching herd mates, and eating grass all day. 

Cows in Point Reyes, CA enjoy prime oceanfront real-estate. This farm setting is not typical of dairy cows in most countries.

In typical farm settings calves are raised in individual housing by humans and as such have limited time to suckle (from a bottle) throughout the day, have restricted milk quantities, and aren’t given any grass or hay to eat. Calves also have the disadvantage of basically going through puberty at this time: their stomach is growing and developing to allow them to eat more varied types of feed and they have screaming tantrums when they’re hungry in a similar way that a preteen wanting to go out with her friends would. This all combines to create a potentially stressful early life for calves. In these same farm settings, we tend to see some weird behaviors: 

Do any of these behaviors look familiar? Calves sucking on bars and seemingly trying to grab something with their tongue would be “normal” if they were in natural conditions: swap the bar for mom’s teat and air for grass, and you have normal drinking and eating behaviors. While we seem to know that the change in environment causes these abnormal behaviors and know that they indicate something is frustrating about the environment (such as how I endlessly twist my rings on my fingers when I’m nervous about giving a talk), we’re still trying to figure out the best way to address these behaviors. Big changes, like returning to pasture-based living, aren’t feasible given the required scale of dairy production while solutions related solely to milk intake or bottle-feeding behavior still seem to lead to abnormal behaviors. I wondered if adding another aspect of “natural” settings that is currently missing on farms – hay or grass – could help with these abnormal behaviors. 

It might seem weird that adding hay could help with apparently misplaced sucking behaviors, but the feedback it provides is what’s important. Eating hay requires a lot of tongue manipulation, chewing, and stimulates rumination, which is the process of “chewing cud,” a.k.a. regurgitating, re-chewing, and re-swallowing already ingested food. Increasing the feedback to the mouth and stomach in this way could help calves reach a point of satisfaction that is currently missing, which may be what is driving abnormal behaviors. Imagine that you were given either carrot juice or a full carrot to eat, and nothing else for the rest of the day. You would most likely get hungry faster if you were only given the juice, because consuming the juice didn’t require any chewing or extensive stomach processing. You would feel like something was missing. Calves likely have this same feeling. Something is missing, but instead of turning to biting their nails or chewing gum, they’re turning to sucking on bars and extra tongue use. 

To test this theory, I’m apparently a masochist because I decided 24-hour live observations, with behaviors recorded by a human observer every minute, were the best way to evaluate the effect of hay on behavioral development in calves. To be fair to me and my poor mental state, it wasn’t without reason: 

  1. Preliminary results showed that subsampling calf behavior (i.e. daylight hours only, or only around feeding times), common to feeding studies, gives vastly different results and interpretations.
  2. Calves will eat/suck everything they can, so putting a camera in their hutches would completely skew the results (and probably lead to some soggy, destroyed cameras).
  3. Calves change behaviors rapidly—like “8 behaviors a minute” rapidly. Common sampling strategies, like 5-minute scans, miss a lot of behavioral diversity. 

This meant that there was a total of 88 days of live observations – 4 per calf throughout early life – or 126,720 minutes of staring at [sometimes soundly sleeping, motionless] calves. As I mentioned above, this gives you a lot of time to learn non-research skills, like how to identify the murderer before they announce him on podcasts, but you gain some cool research-related skills and calf knowledge too, such as:

  1. How to deal with unforeseen challenges, like when your feed intake data is messed up by surprise rain in the dry season or calves that learn they like the feeling of food between their toes.

2. How to light calf hutches in the middle of the night without disrupting their behavior.

3. Calves yawning is the cutest thing you never realized you needed in your life.

Ultimately, understanding why calves develop abnormal behaviors and how we can mediate them is important because we know that adult cattle perform these same behaviors, suggesting they may be experiencing long-term frustration. We also know that the early environment is critical for behavioral development in other species. Sacrificing 5 months of sleep to investigate whether simply adding hay could encourage calves to find better outlets for oral feedback could help cattle be more satisfied as adults, and helping us ensure that that Happy California Cows™ stays an accurate marketing strategy.

All images were taken by Blair Downey.

Blair Downey is a 3rd year PhD student in the Animal Behavior Graduate Group at UC Davis. She is a member of the Center for Animal Welfare in Dr. Cassandra Tucker’s lab and studies how early life feed experience can influence the behavioral development and welfare of dairy cattle.

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