Karin
Well-known member
I was at a field day session down at one of the university's research ranches and got to listen to some of the talks going on there (more here: viewtopic.php?f=14&t=99523) but the highlight for me of that tour was the research going on with RFI on commercial cow-calf pairs grazing on native grassland.
It's the kind of study that brings out the question are low RFI cattle (high feed efficiency) are just as efficient in a drylot environment where feed choice is more restricted as they would be out in a continuous grazing or extensive managed grazing system (the same question could be applied in a more intensive grazing system like MIG or mob/rotational grazing)? With the search I did on this site on previous posts about RFI and FE$ EPD values of bulls and cows, that RFI only applying to animals tested in a drylot is quite obvious. So what about pasture or range, then? Is RFI selection for better, more feed efficient cows on range conditions also selecting for the same results in the drylot?
But the thing with this study is that there's limited spatial distribution that it can be done. It's the first study being done ever, really, as far as I know, that is performed in an extensive grazing system. I think one or two others are being done in a more intensive system on tame pasture, and I wouldn't doubt some experimenting with RFI, deliberate or not, with cows in yours or other herds on pasture have also been done to call into question if RFI or FE$ values in the drylot are reflected on pasture.
So with all that in mind there'd be testing on BCS, calving ease and calving interval, BW WW and season-long gains of calves, blood and fecal samples (fecals to assess microscopic dietary forage composition), behavioural attributes (movement and spatial distribution of a about a dozen cows on the extreme ends of low and high RFIs), and replacement heifer testing on pasture and drylot for what they eat and how much of it.
The herd the study is on is commercial Herefords. I'd be interested if something similar or different could be found in other breeds, like British vs. Continental, or European/British versus the Brahman-type cattle.
It's a lot to take in, and a lot of information, and even then there's still plenty of variables that had to be limited to make this study work. I'm certainly going to keep my ears open for what kind of results the graduate students working on this get when it's done.
It's the kind of study that brings out the question are low RFI cattle (high feed efficiency) are just as efficient in a drylot environment where feed choice is more restricted as they would be out in a continuous grazing or extensive managed grazing system (the same question could be applied in a more intensive grazing system like MIG or mob/rotational grazing)? With the search I did on this site on previous posts about RFI and FE$ EPD values of bulls and cows, that RFI only applying to animals tested in a drylot is quite obvious. So what about pasture or range, then? Is RFI selection for better, more feed efficient cows on range conditions also selecting for the same results in the drylot?
But the thing with this study is that there's limited spatial distribution that it can be done. It's the first study being done ever, really, as far as I know, that is performed in an extensive grazing system. I think one or two others are being done in a more intensive system on tame pasture, and I wouldn't doubt some experimenting with RFI, deliberate or not, with cows in yours or other herds on pasture have also been done to call into question if RFI or FE$ values in the drylot are reflected on pasture.
So with all that in mind there'd be testing on BCS, calving ease and calving interval, BW WW and season-long gains of calves, blood and fecal samples (fecals to assess microscopic dietary forage composition), behavioural attributes (movement and spatial distribution of a about a dozen cows on the extreme ends of low and high RFIs), and replacement heifer testing on pasture and drylot for what they eat and how much of it.
The herd the study is on is commercial Herefords. I'd be interested if something similar or different could be found in other breeds, like British vs. Continental, or European/British versus the Brahman-type cattle.
It's a lot to take in, and a lot of information, and even then there's still plenty of variables that had to be limited to make this study work. I'm certainly going to keep my ears open for what kind of results the graduate students working on this get when it's done.
