# Gestation length on 1st calf--larger breed.



## greybeard (Jul 2, 2012)

I've always gone with the rule of thumb that a heifer or younger cow would "generally" calve a week earlier than an older cow, especially on the smaller breeds.  What about a young cow (1st calf) and larger breed? A heifer was bred at 19 months to a pretty big Beefmaster.


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## shawnfisher (Jul 3, 2012)

By your rule of thumb, my heifers all calve 2 weeks late then, and my old cows a week early...

I experience the opposite of you.  

I do tend to find that heifer calves have shorter gestation than bull calves-- and if a cow is running late on due date-- she's got a better chance of having a bull calf-- maybe only a 60% chance-- but it's still odds are it's a bull.

Most cattle need figured on a 280 day gestation.  ABS has a great chart to compare the different breeds gestation lengths-- which I think need to have a 7 day swing.


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## aggieterpkatie (Jul 3, 2012)

I've had the same experience with most species. First timers generally have birthed later than their due date, and pros usually go early.


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## greybeard (Jul 3, 2012)

That's odd. Maybe it's the difference in lattitudes. 

I've almost always had 1st timers drop calves a few days to a week early--older ones just seem to say "Ho-hum--I've done this before--gonna have something tugging at my udder every minute so I'm gonna wait as long as I can". 
I'm not sure where I saw it, but there is a disclaimer at the top o one of the online gestation charts as well, basically saying the same thing. The younger the momma--the shorter the gestation period.


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## Royd Wood (Jul 3, 2012)

greybeard said:
			
		

> That's odd. Maybe it's the difference in lattitudes.


No its all to do with breeds - I keep preachin from the pulpit on here about Galloways - my heifers and cows all calve at 9 months one wk 12 hours and 15 minutes


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## CochinBrahmaLover=) (Jul 4, 2012)

greybeard said:
			
		

> I've almost always had 1st timers drop calves a few days to a week early--older ones just seem to say "Ho-hum--I've done this before--gonna have something tugging at my udder every minute so I'm gonna wait as long as I can".


LOL!! From reading everything here, any momma, new or pro, likes to wait the SECOND you leave, to give birth. Whether shes been holding out for half a month or 3 weeks early, seems how it goes  lol


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## greybeard (Jul 4, 2012)

CochinBrahmaLover=) said:
			
		

> greybeard said:
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Or the kind of weather and conditions even a  duck would hate.  I can now set my calendar and alert the US Weather Service's long range forecast model.  The last week of Jan--first week of Feb gonna be cold as the artic, wind blowing like a banshee, and the river in full flood stage. And it will hit the ground (or be pulled) around 2:30 am on the darkest of dark nights. 

You can take that to the bank in Denver.


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## she-earl (Jul 4, 2012)

We have holsteins.  We bring our girls to the springing about three weeks before calving.  If because of the number in the pen prohibits putting them there at that point in time, the heifers will be brought first.  In general, there is a higher probability that they will calve early.  Generally if our older cows are calving a week or two early, we begin to suspect twins especially if the calf is small.


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