Long post very short, my animal science anatomy/physiology teacher (who taught at a vet school for 20+ years, if it makes any difference) gave me an article recently (regarding a study he'd done) on the impact of nutrition to the dam in early pregnancy affecting muscle mass in the offspring and amount of fat at slaughter. The study was done on sheep, but the same thing applies to cattle. For those who aren't familiar with muscle development - muscle is laid down early in gestation and while muscle cells can increase in size after birth, the number of muscle cells cannot.
The study had two groups; a control group fed 100% of daily requirements, and a nutrient restricted group fed 50% of daily requirements until halfway through gestation, and then both groups were fed 100% of daily requirements. At birth, the lambs from nutrient-restricted dams had heavier birthweights than the lambs from control ewes. Size overall was similar. At 100 and 140 days of age the lambs were ultrasounded and the lambs from nutrient-restricted dams had more backfat than the controls. At slaughter the lambs from restricted dams were heavier, but had a higher fat to body weight ratio than the lambs from control dams.
I found it quite fascinating... it may not make much difference to some of you, but in the western part of the U.S. cows are often run on rough rangeland and may not see hay until December or later, even when all that's left to eat is sagebrush and snow. They're usually first-trimester to early-second at that point and most folks figure the fetus is small and the dam doesn't need much in the way of nutrition. But where nutrition during gestation influences the composition of the calf at slaughter.....
It may also explain differences in carcass quality even with calves that have had similar management from birth to weaning and are from similar genetics.
Just thought y'all might find that interesting.
The study had two groups; a control group fed 100% of daily requirements, and a nutrient restricted group fed 50% of daily requirements until halfway through gestation, and then both groups were fed 100% of daily requirements. At birth, the lambs from nutrient-restricted dams had heavier birthweights than the lambs from control ewes. Size overall was similar. At 100 and 140 days of age the lambs were ultrasounded and the lambs from nutrient-restricted dams had more backfat than the controls. At slaughter the lambs from restricted dams were heavier, but had a higher fat to body weight ratio than the lambs from control dams.
I found it quite fascinating... it may not make much difference to some of you, but in the western part of the U.S. cows are often run on rough rangeland and may not see hay until December or later, even when all that's left to eat is sagebrush and snow. They're usually first-trimester to early-second at that point and most folks figure the fetus is small and the dam doesn't need much in the way of nutrition. But where nutrition during gestation influences the composition of the calf at slaughter.....
It may also explain differences in carcass quality even with calves that have had similar management from birth to weaning and are from similar genetics.
Just thought y'all might find that interesting.