285 (the black and white cow) is on heat. Video would have been far better because it would have picked up all the subtle movements still photography misses... but someone with a fast internet connection will have to stump up with video of a similar situation, I can't do it.
Rule of thumb, and I don't know why it's true but I've never seen an exception is that when one cow mounts another head on, the one on top is always the one on heat. The reason why there's no sequence of images for that movement is because it was all over in less than a couple of seconds... 175 moved aside looking alarmed.
175 earlier mounted 285 and played about for several seconds up there... you also see that she's drooling on 285's back. Saliva on a cow's back, flanks or tailhead is a good sign of heat.
Hillsdown, 175's condition is at calving target, 5 - 5.5. A lot of the herd are there at this point, calving starts 20 July and the farm will likely be struggling to provide enough grass through winter and spring again, so that's where I want them now.
She's been fat for a long while though and her production this year has been far less than I'd expect of her.
The open cows are the lightest. I suspect they're open because they're light and not vice versa.
175 - production is slightly above herd average, has done 368 kg at 1.55 kg MS/day but I expect more of her, she's a large cow and the F1 daughter of one of my high producers. She was exactly at the herd average on last herd test in mid March.
285 has done 355 kg at 1.77/day. I think that puts her at the lower end of the top 20% within the herd.
being a good operator simply increases the chances that the owner of your lease block will call it a good farm and sell it for way more than it's worth.