Newborn calves in Texas heat

Hello! Total newbie here, and just acquired a small herd of Black Angus cattle with the purchase of our new home/farm a couple of months ago; I tend to be an over-worrier, but my question/concern is for a 4-5 day old bull calf and whether he’s nursing enough in the TX summer heat within the first 24 hrs after birth, once we noticed his arrival, we watched closely and decided he was not attempting to nurse, became very weak and lethargic that evening and we brought him in to syringe feed colostrum mixture throughout the night; by the next morning he was up and moving and looking to nurse, yay! Then fast forward a couple days later, in the heat of the day, I noticed him stressing out trying to figure out how to go down and around this partial fence to get to mama, and by that point he was open mouth panting, looked weak and exhausted, and once with mom was not nursing; after some more observing I decided to give him some more formula mix for hydration and after some rest he was up and moving again, but now today, the day after, he’s been under a shady tree line all day and has not nursed for the past five hours and mom and herd are on other side of pasture again; question is should I intervene again? He’s cool to the touch, slightly panting but closed mouth, sleepy, doesn’t look to be in distress, but is this just normal activity or is he not nursing enough in this heat to stay hydrated and well?? Thanks for reading, and any advice appreciated. Thanks!  

Most mama cows are very protective of their babies.  Usually, they stick close to the babies so this maybe is the mama's first baby?

Do you have a place to put them together in a pen where you can observe how she is taking care of the baby?

If not you may need to take over for her by feeding the baby.  Set up a feeding schedule just like you would with a human baby.

Thanks for the reply! I don’t think she’s a first time mom, she’s about six years old we believe, and she’s been very attentive to him, staying close, and the first day when he wasn’t nursing we were more clued in on her behavior, being anxious and unsettled vs the calf’s, but she’s more relaxed the past couple days which makes me think he’s ok, I’m just not sure I don’t want intervene if all is well I’m just not as knowledgeable on their normal behavior...

Two issues here:  Hydration and energy.  Water is hydration.  Milk is energy and hydration.  Is he going to water?  Does he have good access to water?  How about minerals?  Break off a small chunk of the mineral block and put it on his tongue.  If he is low on salts, he will figure it out quickly.  (no salt/minerals means too much water loss.)

Second is energy.  Offer him a handful of grain or some alfalfa cubes.  He should be old enough to graze just don't over due.  If he acts like he is starving give him a few handfuls at a time through the day.  Have you seen him on teet?  Is she rejecting him?  Just things to observe as you keep an eye on him.  Don't overdue the grain on a young cow.  Grain does have a lot of energy, so a little goes a long way.  Whole oats from the feed store will get his energy level up quickly if that is the problem.

Thank you! Now that it’s cooled off again mom has returned and he’s up and following her to nurse; I guess in the heat of the day she and another cow have left their newbies among the shade trees so they’re not up and following them around and expending too much energy while it’s so hot. I will keep monitoring them, and tomorrow try offering water and some minerals during the heat of the day. Thanks again!

You can assess dehydration by skin tenting or checking gums:

Skin tenting is a quick way to evaluate hydration. Pinch a fold of skin on the neck and count the number of seconds it takes to flatten. If the skin flattens in less than 2 seconds, this indicates normal hydration. If the skin takes 2-6 seconds to flatten, the calf is about 8% dehydrated. Over 6 seconds would indicate severe dehydration over 10%. Gum color and moisture can also be evaluated. Normal gums will be pink and damp while white and dry gums indicate dehydration.

from: https://extension.iastate.edu/dairyteam/files/page/files/Recognizing%20the%20signs%20of%20calf%20dehydration.pdf

dehydration behavior:

From: https://www.amstewardship.ca/faast-reviews/veal-industry/evaluating-dehydration/

Calculating how much electrolytes and/or water to supplement:

It is nearly impossible to feed the calf too much electrolytes, but feeding too little is quite common. To determine the amount of electrolytes to feed, multiply weight of calf by the percent dehydration, and then divide by 2 to get quarts of liquid needed. For example, if a 100-lb calf is dehydrated 8% (100 x 0.08), 8 lbs of liquid divided by 2 equals 4 quarts needed per day in addition to normal feeding of milk.

These calculations are affected by the summer heat. When temperatures are over 90 degrees, increase the amount above by 50%. If temperatures are over 100 degrees, double the amount. Severely sick calves under heat stress can sometimes require up to 20 quarts of water daily to replace the total amount lost, so don’t be afraid to be generous with the fluids! Healthy calves under heat stress will drink between 6 and 12 quarts of water daily just to maintain normal hydration.

Also from: https://extension.iastate.edu/dairyteam/files/page/files/Recognizing%20the%20signs%20of%20calf%20dehydration.pdf

For example: Guidelines for Feeding Electrolytes to Dehydrated Calves
From: https://calfsessions.com/2012/02/feeding-electrolytes-how-much-does-a-calf-need/

Wow, so much good info, thank you, thank you!