Scheduled Births? Does feeding time really affect when cows calve?
for Tri-State Livestock News
The Science and the Questions Behind Evening Feeding and Daytime Calving
Anyone up at all hours checking calving heifers and cows this time of year is ready for a break and a little bit more sleep. What if you could schedule 80 or even 90% of your cows to give birth during the daytime hours? Research says it is possible.
Marshall Ruble, Superintendent of the Ag Research Station at Iowa State University, has spent several decades calving out cows on the Iowa State teaching farm at Ames and swears by evening feeding to encourage daytime calving. Ruble participated in studies done some thirty-five years ago that proved the effectiveness of evening feeding.
“We heard reports from Manitoba that a cattle breeder named Gus Konefal had experienced this,” Ruble said, “And we decided to give it a try. We fed the cows at 4 pm and they had feed available to 6-6:30 am the next morning. We kept track of what time of day they calved; close to ninety percent calved between 6 am and 9:59 pm. This is a pattern we have been able to repeat for a long time, in fact we still use it as a management tool.
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“The professor at the time of the original study decided to reverse the feeding times and see what happened. We put feed in front of the cows from 6 am to 4 pm, and 50-60% of them calved at night. We repeated this for two years, with both spring and fall calving herds, and it held true that the cows fed at nighttime calved during the day and the cows fed during the day calved at night.”
The cows spend their days on a three acre bluegrass pasture that has tough sod so it doesn’t get chewed up too badly from all the hoof action, but it doesn’t afford much daytime grazing for them. They are fed a ration of corn silage and haylage with a feed wagon along a fenceline bunk at 4 pm.
“This is about 60% of what I expect them to eat daily,” Ruble explained. “It’s pretty well gone by 9:30 when I’m doing my last check of the evening. I let them in to a pen next to the calving shed with a large round bale in it and they have access to that all night. At six o’clock the next morning I kick them back out into that little pasture. Once they’re on the schedule they’re waiting for you and moving them is pretty easy. They all follow in.”
Ken Olson, SDSU Beef Specialist in Rapid City, SD, said he knows many beef producers who swear by evening feeding to encourage daytime calving in their herds.
“I personally think it’s a good way to go,” Olson said. “We have plenty of anecdotal evidence that evening feeding causes more cows to calve during the day. There are producers who calve on the range and producers who calve in a more controlled environment and it works in both situations. Even with cows on pasture evening feeding still means the cows eat their major meal in the evening and less during the day. Most people who feed in the evening are convinced it works.”
Olson has also seen other interesting calving patterns documented in Kansas and Idaho that support the data from Iowa State.
“Early in my career I worked at a research station in Kansas,” he recalled. “Our herdsman fed in the evening for the same reason, to encourage the cows to calve during the day. When they calved he recorded the time of day the calf was born. Over several years he picked up on a pattern: the time of day a heifer gave birth to her first calf recurred with subsequent offspring! Whether she calved in the morning, or in the afternoon, or in the evening, she would calve close to the same time of day for the rest of her life! This was not officially part of a research project but it was well documented.
“Later the herdsman met a group from the University of Idaho who said they had observed the same thing. The cows in Idaho were in more of a controlled/small lot environment where they didn’t have access to grazing; the cattle in western Kansas were out on range and just had hay delivered to them in the evening. Both groups were fed in the evening, both calved predominately during the daytime hours, and both noticed that if they could get a cow into a pattern she would stay in that pattern for her lifetime. This was documented by two different universities in very different climates.”
Evening feeding to promote daytime calving was also tested by the USDA Agricultural Research Station at Miles City, Montana. While they did see an increase in daytime versus nighttime births, their percentages were not quite as high as those at Iowa State. The percentage of cows calving during the day increased from 66.9% to 78.1%. This was not as drastic of a change as Konefal’s increase from 38% daytime births when cows were fed earlier in the day to 80% daytime births when cows were fed later in the day, nor as significant as Iowa State’s daytime birth rate increase from 50% to 85% when evening feeding was implemented.
What makes evening feeding work? That is a theory that is still a theory and may always be somewhat of a theory due to the delicate nature of near-parturient mothers.
What we do know is that fetal stress and rising cortisol levels trigger the onset of labor. Fetal hormone levels, however, are impossible to test without causing greater stress to the unborn calf and the expectant mother; attempts to do a research project to document what hormones are changing and what is causing the levels to rise would probably cause more problems than they would give answers. Brent Bunderson, a retired Utah State extension agent speculates that the stress levels in the fetus are triggered by pressure of the near-term calf on the uterine artery when a cow is lying down to rest.
“This is a theory,” Ken Olson said. “When you’re close to calving you can’t mess with the cows so we can’t test it in a controlled fashion. However, there are other things that we know do cause restricted blood flow to the unborn calf, thus triggering labor, so I think it is a valid theory.
“Anyone running cows in Ponderosa Pine is aware that the Isocupressic acid present in pine needles can cause cattle to abort. This chemical causes restriction of blood flow to the uterus, thus triggering labor, and a birth way too early to get a live calf.
“Another thing we know is that the Brahman breed, known for calving ease and low birthweight, has genetics that dictate that when the calf gets to a certain size there is something in the cow’s physiology that restricts blood flow to the uterus, thereby triggering labor.
“We know that the stress hormones that trigger labor can come from genetics and they can come from certain poisons; it is entirely possible that something related to the rumen getting full could also be a trigger. Bunderson’s theory is just a theory but I think it is a good theory. I’m not sure we need to prove it; from the standpoint of research we’re curious, but from the producer’s standpoint if it works we don’t necessarily need to know why.”
For the producer wanting to try evening feeding, and those who may have tried and felt their results were not what they had hoped, here are a few things to consider.
Keep feeding time and time away from feed as consistent as possible.
“Time to feed initial ration was 3:59 pm-4:01 pm,” Ruble said. “If I was not around for the 4 o’clock feeding and the employee on the weekend changed the time by one hour my cows would calve early or late by 3 hours. They didn’t have to tell me their feeding time, the cows did!”
What are your expectations? Data suggests that 80% daytime calving using evening feedings is reasonable to expect, but things such as how much additional grazing or extra hay is available during the day or variations in the time feed is delivered can cause this to vary. Look at the whole picture and see what you might be able to tweak to make night feeding more effective.
Weather and other factors can definitely influence calving time so be aware that before and after major storms calving times may be less consistent than when the weather is stable.
“My working hours are best when I feed at night,” Ruble laughed! “Only ten percent of our calves are born when I’m not there. Night feeding is part of our calving protocol and has been for the last thirty-five years. We twin 3% of the time and we are averaging live calf numbers at 102%. That’s a pretty big deal.”
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