KNERSIE":1iblijb2 said:
Give the long answer please
Sorry for the delayed response -- been a busy couple of days --
Before getting into the actual way we've decided to determine which old cows get to stick around and which ones don't, I feel like it's worthwhile for me to run you through our annual calendar ... once I've done that, I'll have a section at the very end that addresses your specific question.
As it relates to the calendar below, know that the start / end of the calendar may move up / back over time as I continue to feel out the best fit for my family's schedule in any given year. Also, in any year where we're dealing with a large embryo project (harvesting or implanting), it'll throw the calendar off a bit for some of the cows/bulls and so any female that's impacted by missing a date is given some reasonable leeway in order to catch back up.
The best way for me to explain this, I think, is to start with a calendar in a 'normal year' (i.e., no embryo projects are going on) with several to-do's and an explanation of the calendar's to-do's below that:
Feb 1st -- bulls (and sometimes any retained steers, too) are pulled from herd of bred cows and heifers and penned (until May 1st for some and June 1st for others (see below for details / logic)); all of the 2nd timers are moved up closer to the house until all have calved, then once they've calved, each pair goes back out with the bred cows
Feb 7th -- 2nd timers start calving (i.e., this is when cows who are going to have their 2nd calf start calving)
March 17th -- heifers are moved up to the house and are kicked out to pasture once they've calved
March 24th -- heifers and mature cows start calving
May 1st -- bulls go in with 1st timers (i.e., the young cows who just had their 1st calf) (see below for reasoning)
June 1st -- any cow or heifer (confirmed bred the prior fall) that hasn't calved by this date is getting shipped; there are a few different ways this goes for the female (see below for details) ... the later the calf comes, the more likely that she is gone the next year ... but, maybe she catches up ...
June 15th -- Mature cows (2nd calf and older) who calved before May 1st are candidates for AI, as are first time heifers (if any were retained the prior year), the bulls not currently in with the 2nd timers go in with cows, and heifers are added to the group with the 2nd timers
Oct 30th -- determine carrying capacity for the next year
Oct 31st (day) -- (i) preg check and grade the opens (see below), (ii) temperament test all calves and cows, (iii) cows weighed and hip heights taken, (iv) calves weighed and hip heights taken
Oct 31st (night) -- (i) calculate Maturity % (see below) of all calves and cows/heifers younger than 4yrs of age, (ii) calculate WW % for all females, and (iii) make all cull / keep decisions to be implemented the following day
Nov 1st -- (i) retag all cull cows/heifers/steers w/ different color tag, (ii) cut bull calves who will not be developed as bulls, (iii) wean calves, and (iv) ensure all bulls are removed from having access to weaned heifers and to-be-culled cows
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RE: Feb 7th -- not a big fan of starting to calve 2nd timers in the middle of the winter, but I'd rather do this for a smaller group of females than to deal with bulls going in in late July or August
RE: May 1st --- bulls go in with heifers calving their first calf so we can calculate calving interval between first and second calf --- we believe that while EPDs will tell us that fertility is only moderately heritable, that actually trying to press the issue by turning bulls in with the 1st timers (who hope to become 2nd timers) approximately 30 days after the first heifer to calve calves will allow us to know which heifers are most fertile and most adapted to our management and environment.
RE: June 15th -- if calving after this date, these cows / heifers just got bred too late for us; official start to the breeding season will give us calves that hit the ground around March 24th.
RE: Oct 30th -- once we determine what our carrying capacity is for the coming year, we know how strict to be on our keep / sell / cull decisions with all classes within the herd
RE: Oct 31st -- a big day, to be sure -- a day to write down lots of information, all of which will be analyzed that night so that the next day these decisions can be implemented -- we monitor cow size (weight and hip height) at this point mainly for tracking progress and their growth curve throughout their lives -- we track calf size (weight and hip height) in order to calculate the Maturity % referenced above. This calculation is described in Johann Zeitsman's book
Man, Cattle, Veld. Generally, the idea behind that single calculation is that it allows a producer to determine which of the cattle are arriving at their sexual maturity more quickly than another and it also allows a producer to determine which cattle are more adapted to their management and environment than another. This score (along with temperament and the dam's fertility score (calving interval between 1st and 2nd calf) are key parts of determining keep / sell / cull decisions for the calves. Essentially, the calculation described in JZ's book is extrapolating a calf's hip height using the standard UMissouri Frame Score Chart in order to determine how tall the calf should be as a mature adult, and then determine what percentage of that weight the calf is now, where the higher that percentage, the more adapted and more mature one animal is to another (heifers and bull calves are scored and ranked separately and only among their contemporary group; their scores don't transfer over very well to compare a bull born one year to a bull born another year, or to compare my calves to someone elses calves born somewhere else -- it's only for contemporary group scoring).
RE: Nov 1st -- cattle that will be culled get a new tag color so that it's easy to figure out who is going and who is staying when sorting later on as we typically process beeves 2-4 times a year -- bull calves out of cows with lower fertility scores are cut, bull calves with temperament issues are cut, bull calves with low Maturity % scores are cut -- heifers with low Maturity % scores are culled -- all bulls stay with confirmed bred cows until right before the first calves start coming in February. The cut-off point for each cull / keep decision can vary from year to year, depending on whether or not I want to increase the cow herd, make it younger, and whether or not I have orders for bred/open cows/heifers, bulls, etc.
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Late calving cows and heifers are classified in one of five ways, and depending on the quality and size of our heifer crop for that year, the stocking rate we think we can handle for the coming year, we may keep none / some / all of any of the cows in any of these four groups. Classification System for Opens at Preg Checking:
a -- not currently in calf & calved prior to June 15th -- these are the first to go, generally to the butcher for ourselves or our beef-buying clients (we have a waiting list for old Aubrac cow beef, believe it or not)
b -- not currently in calf & calved after June 15th -- these are the next ones to go; if they have a calf at their side (b/c they calved late), they're sold as a pair to someone who calves in the fall, or the calf is weaned and the cow is culled / eaten
c -- currently bred, but no calf to wean because the cow sloughed the calf at some point after being preg checked the previous year -- these are the next to go
d -- currently bred, but no calf to wean because the calf died within the first week of life -- these are the next group to go
e -- currently bred, but no calf to wean because it died some time after the first week but before weaning time -- these are the last to get culled (i.e., we kept a good recip another year even though her heifer calf died before weaning; hard to hold a lightening strike against mama when the calf was already almost 5 months old)
Once a cow falls into one of these five buckets, we will never again keep or sell any of her sons as bulls. Most years, all females in all five buckets are gone, however, we try to distinguish the nature of the open status in the event that (for example, we had only a very few heifers born the prior year, or we got a large new lease on some pasture and want to try to grow the herd, etc.).
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Keeping old cows vs. young cows
When calculating the Maturity % (above) as laid out in JZ's book, each cull / sell / keep decision is made based on how each calf ranks in the entire contemporary group of calves ... AND ... how each calf ranks in each contemporary group based on their dams' age.
So, for ease of analysis, say we have 100 bull calves and we're able to calculate the Maturity % for each. They're ranked 1-100 on a stand-alone basis ... and ... their maturity scores are normalized (to get a score of 0-100).
Then, say we have 10 bull calves out of first time heifers; these are ranked from 1-10 ... and ... their Maturity %'s are normalized (to get a score of 0-100).
And, maybe we have 10 bull calves out of 2nd timers; these too are ranked from 1-10 and their scores are normalized.
And, we have (say) 50 bull calves out of cows from 4 years of age to 8 years of age; these are ranked from 1-50 and their scores are normalized.
And, we have 20 bull calves out of cows from 9 - 12 years of age; these are ranked and normalized.
And, finally, we have 10 bull calves out of cows older than 12; these are ranked and normalized.
... then ... the normalized scores across all 100 bull calves are averaged with the normalized scores from within their dam's age group and then they are re-ranked based on the average of the normalized scores ... this allows (say) the #1 bull out of a cow older than 12 to have their Maturity % score to be more easily compared to the (potentially) higher scoring (on an absolute basis) bull calf out of a young 5yr old cow. It's a way to level the playing field for the bull calves a bit. Depending on the needs for retaining bulls for our own use, and for filling client demand, we'll start cutting bulls at the bottom of the list and work up until there aren't any more bulls needing cut.
... AND ... we will then take the normalized Maturity % for a cow's last 2, 3 and 5 calves and average them together to get a trend-line for each cow. If we're looking for additional reasons to cull a currently bred cow, they'd be as follows:
* Average of the normalized scores for her last two calves is in the bottom 10% of her then-current contemporary group, she's a candidate for culling
* Average of the normalized scores for her last three calves is in the bottom 25% of her then-current contemporary group, she's a candidate for culling
* Average of the normalized scores for her last five calves is in the bottom half of her then-current contemporary group, she's a candidate for culling
I think this allows truly excellent older cows to stick around as long as they're still carrying their weight within the herd and within their contemporary group -- normalizing the score in this way is a relatively easy way to compare the productivity of an old cow to a young cow. IMO.
ALSO --- Generally speaking, only the cows that had a great 1st-to-2nd-calf calving interval and who also are in the very top of their contemporary group for Maturity % are candidates for our donor program. These decisions are made on a case-by-case basis.
NOTE --- I'm really happy to consider improving what I'm doing here, should anyone really care to discuss this and/or offer actual suggestions for doing so. TIA.
