Thursday, November 12, 2015

Calving Journal - November 12

I'm responsible for caring for 160 first-calf heifers that are part of an experiment at the Sierra Foothill Research and Extension Center.  The goal of the experiment is to develop a vaccine for foothill abortion - a tick-borne disease that causes late-gestation abortions in unexposed cattle.  Some commercial producers can experience more than 50% loss rates.

These heifers were synchronized and Wagyu bulls were turned out on February 14, 2015.  The bulls were removed on March 9 - a 23-day breeding interval.  Theoretically, this means calves should start arriving in the third week of November.  Wagyu bulls were used because they typically "throw" low-birthweight calves, perfect for first-calf heifers.

Over the summer, we had a heifer die for unknown reasons, leaving 159 heifers to calve.  Beginning in August and continuing through the end of October, we started seeing a few abortions.  As part of the project, we try to recover aborted fetuses so that they can be evaluated by the California Animal Health and Food Safety lab at Davis to determine whether foothill abortion is the cause.  Sometimes we can find the fetuses before the coyotes, sometimes we can't.  All told, we had 15 heifers abort or deliver live calves that dies within a day or two of birth.

In October, we had two calves born (more than 4 weeks early) that have survived.  This week, we've started calving in earnest - 6 calves in the last couple of days.  Based on my visual inspection of the heifers this afternoon - and on the observation that stormy weather induces parturition, I expect that we'll have 15-20 calves on the ground by next Monday.  After so many abortions, I'm enjoying dealing with live, vigorous calves this week!

I intend to keep a daily journal of my experience calving these heifers.  I've lambed large groups of ewes, but this is my first opportunity to work with beef cattle.  We have the heifers in a large (120+ acre) annual pasture (consisting of mostly dry forage with some newly germinated grass coming up underneath).  We'll probably move to another similar pasture in several weeks.  We're providing supplemental protein and minerals.

Here are my observations/experiences for today:

  • Three new calves overnight - 2 bull calves and 1 heifer calf
  • The calves are weighing around 50 lbs - very light, but perfect for avoiding dystocias!
  • Most of the heifers are proving to be very good mothers.  Today, one heifer thought she'd like to come after me when I tried to tag her calf.  I went back up in the afternoon (to give the cow a chance to settle into motherhood - and to allow her to completely clean the calf.  I drove the truck between her and the calf and left my dogs in the cab (to help keep the cow calm).  I was able to quickly and safely tag the calf.
  • I'm recording birthweights and maternal scores for calving ease, maternal ability and calf vigor.  We've used these criteria with our sheep - I don't know if anyone uses a similar system with cattle.
  • The heifers have really been going after the trace minerals - they must be short of something in their diet at the moment.
  • The heifers, as you would expect with cooler temperatures, tend to follow the sun - they are on the east-facing hillside in the morning and the southwest slope in the afternoon.
  • Much like pasture lambing ewes, these heifers seem to stay on their "calving beds" (a 20-25' circle around where they delivered their calf) for 18-24 hours.  In that time period, I can easily catch the calf to tag and weigh it.  After 24 hours, the calves become more difficult to catch - just like lambs! 

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