calving ease question

[vanridge]

How much influence does the dam's side have on a calf's birthweight and shape? And is this where cross bred cows can give you some odd balls, that are either a lot lighter or a lot heavier than what is  happening in the rest of your herd? And, we have been having a really mild winter here in Manitoba Canada. Could this have an effect on our birthweights? We have been doing quite well with our calving but I was just curious if anyone  could give me some answers on this.

 

[kfacres]

How much influence does the dam's side have on a calf's birthweight and shape? 50%- isn't it funny how babies get one half of their chromosomes from their dam- and the other half from their sire?  The cow also puts 100% of the enviroment factor into the calves.

And is this where cross bred cows can give you some odd balls, that are either a lot lighter or a lot heavier than what is  happening in the rest of your herd?  Can happen in any breed or composite of a cow-  Big BW cows are more likely to make big BW calves b/c of the 50:50 ratio of inherited genetics.  Happens more frequently in crossed up cattle b/c of so many unknowns and how unpredictable they are.

And, we have been having a really mild winter here in Manitoba Canada. Could this have an effect on our birthweights? We have been doing quite well with our calving but I was just curious if anyone  could give me some answers on this. Yes, I would expect them to be slightly lighter than normal- although slightly lighter may only mean 5 pounds; which in the whole realm- doesn't mean diddly squat.

 

[vanridge]

with all the emphasis on calving ease bulls you would think that  the dam has nothing to do with birthweight etc.

A mild winter means lighter calves? I thought they would be heavier because the cow doesn't have to deal with -20C or colder weather constantly.

 

[vcsf]

with all the emphasis on calving ease bulls you would think that  the dam has nothing to do with birthweight etc.

A mild winter means lighter calves? I thought they would be heavier because the cow doesn't have to deal with -20C or colder weather constantly.

The theory is that the colder the weather the more the blood flow in the cow is increased in order to keep warm.  This increased blood flow throughout the body includes increased flow to the uterus resulting in more nutrients to the fetus thus causing bigger calves.  There is also an argument that the colder weather may cause the cows to get less exercise and that this also leads to larger calves.

 

[hamburgman]

Definitely seems to be a 50/50.  We have some cows who dont understand what small bw is.  One cow never calves a calf under 120, only one under 130 and that was when she was a heifer.  Another cow, smallest calf she ever had was a Warrant.  Bred her to Red Angus, Shorthorn and Simm/Angus and to date the smallest one was the Warrant.  Try explaining that one.  But for the most part when I look across the herd most cows seems to be the same year over year when bred to the same kinds of bulls.  I just don't expect to keep a 130 lb heifer back, breed her angus and complain he wasn't calving ease. IMO that is called reality, but some people seem to dismiss it.

 

[Gargan]

  The cow also puts 100% of the enviroment factor into the calves.




Jody, could you eplain this factor to me a little more? im a little unclear to what these factors add to or take from the calves genotype or phenotype (or both of these). thx

 

[kfacres]

  The cow also puts 100% of the enviroment factor into the calves.
Jody, could you eplain this factor to me a little more? im a little unclear to what these factors add to or take from the calves genotype or phenotype (or both of these). thx

Calving ease and birth weight are decided by two factors:  genetics and environment.  The genetics is obvious- calf gets 50% from each parent.  The environment has everything to do with the cow- and nothing with the sire- he's already 'injected' his part. 

By this i mean:  The way the cow is fed (nutrition), the climate the cow lives in (time of year, or location), and the makeup of the cow (pelvic size, age, exercise)-- all in many people's opinion are just as important as the actual genetics of the calf.

Mature cows, that are fed hard, in a cold Canada environment, calving in Feb, confined to a dry mud lot up by the barn-- could very well have a calf 20 pounds heavier at birth than that same cow who was a few years younger, out on grass, calving in August on pasture in Texas.

the actual phenotype, other than size- should not be effected: but could be effected by milking ability, creep feed, or somewhat by size at birth.  it seems that big boned, big headed, big shouldered bull calves- will always outperform the opposite: but more times than not: that's prob genetics causing it. 

 

[Gargan]

  The cow also puts 100% of the enviroment factor into the calves.
Jody, could you eplain this factor to me a little more? im a little unclear to what these factors add to or take from the calves genotype or phenotype (or both of these). thx

Calving ease and birth weight are decided by two factors:  genetics and environment.  The genetics is obvious- calf gets 50% from each parent.  The environment has everything to do with the cow- and nothing with the sire- he's already 'injected' his part. 

By this i mean:  The way the cow is fed (nutrition), the climate the cow lives in (time of year, or location), and the makeup of the cow (pelvic size, age, exercise)-- all in many people's opinion are just as important as the actual genetics of the calf.

Mature cows, that are fed hard, in a cold Canada environment, calving in Feb, confined to a dry mud lot up by the barn-- could very well have a calf 20 pounds heavier at birth than that same cow who was a few years younger, out on grass, calving in August on pasture in Texas.

the actual phenotype, other than size- should not be effected: but could be effected by milking ability, creep feed, or somewhat by size at birth.  it seems that big boned, big headed, big shouldered bull calves- will always outperform the opposite: but more times than not: that's prob genetics causing it. 

thanks!! makes sense now!!

 

[vanridge]

with all the emphasis on calving ease bulls you would think that  the dam has nothing to do with birthweight etc.

A mild winter means lighter calves? I thought they would be heavier because the cow doesn't have to deal with -20C or colder weather constantly.

The theory is that the colder the weather the more the blood flow in the cow is increased in order to keep warm.  This increased blood flow throughout the body includes increased flow to the uterus resulting in more nutrients to the fetus thus causing bigger calves.  There is also an argument that the colder weather may cause the cows to get less exercise and that this also leads to larger calves.

Thanks, I was looking for what the theory was behind the higher/lower birthweight in warmer/colder weather.