"It's May the First, and if you haven't got grass by May 1 you're buggered," he says.
For many farmers in Hawke's Bay, drought has been a bigger imposition than the Covid-19 crisis, and its affects highlight the worsening shortages of feed in the region.
It's already the most severe of the three-yearly droughts in the past 15 years, says MacFarlane, third generation of a family who have been farming at Raukawa, west of Hastings, for 125 years.
But if there's no rain soon – and forecasters offer not much more than "cross your fingers" - then worse is still to come.
Like most parts of Hawke's Bay south of Napier, six months in a row have had below-average rainfall.
At MacFarlane's Waiterenui Angus, at the apex of Raukawa and Valley roads west of Hastings, just 52mm of rain has fallen since December.
Down the road at Bridge Pa, the Hawke's Bay Regional Council has recorded just 8mm in the past month (13 per cent of the April average).
February was a shocker too, with just 2.8mm compared with an average of 51mm, and 134mm since the start of November, less than half of about 320mm expected in that period.
There've been moments of relief. After the seed went in a couple of months ago, there was a show of green shoots. Since then, nothing, MacFarlane says.
He concedes he's not the worst off. The dams are dry, but there are good water sources on his 828ha, which peaks at 300 stud cows and 1830 ewes.
Winter feeding is now the problem, as highlighted midweek by the Hawke's Bay Rural Advisory Group.
At Waiterenui, MacFarlane had already dug into pit silage that hadn't seen air for years, but it called for more direct action in the shape of a Facebook plea for feed.
To his surprise the responses, despite wide areas of the North Island similarly troubled, flooded in.
StokmanAngus immediately gifted 40 round bales and put them on a truck and trailer in the Waikite Valley, near Rotorua, and had them ready to unload at Waiterenui the next morning.
By mid-morning some of it was being fed out, but still more was needed, and on the way.
Less than 48 hours after the Facebook post, it had had 50,000 views, 263 shares and 99 offers of hay and other feed. Trucks would be bringing a total of 720 bales, some from the South Island.
"People were ringing from all over the place," he said.
Stock movement - at Waiterenui the lambs are barely still lambs - have been upset, exacerbated by limit kills at the works with the onset of the pandemic restrictions.
"They were ready to go in January," MacFarlane said. "The last of them went on Wednesday."
Metservice said rain from the west forecast for Sunday and Monday is unlikely to bring much relief to farmers in Hawke's Bay.
For Sunday the forecast offered: "Cloud increasing. Rain developing about the ranges in the afternoon, with scattered falls spreading further east. Northerlies, strong in exposed places."
For Monday it said: "Rain near the ranges, heavy and possibly thundery, easing showers. Scattered falls further east, clearing later. Northerlies, strong in exposed places at first."
The duty meteorologist told Hawke's Bay Today: "After this system goes through we're going back into a more settled pattern, which might bring a few showers."
But it wasn't what Hawke's Bay was looking for, she said. "Cross your fingers."