Herd dynamics need more research
Producing milk for 40 plus weeks of the year is hard work for a cow – a point well made by Professor AJF Webster from Bristol University to the NZ Society of Animal Production conference in Hamilton in 2000.
He talked about the ‘‘fitness’’ and ‘‘welfare’’ of today’s highgenetic dairy cows in New Zealand grazing systems.
With brutal accuracy he described today’s cow, as being ‘‘permanently hungry, tired, full up and feeling sick’’.
He justified every word of this statement but it had zero impact on the audience of scientists and consultants, as nothing changed in New Zealand dairy husbandry as a result of his visit.
If anything, today’s cows are worse off with their genes for high production, driving up costs and needing massive reliance on nitrogen-fed pasture and PKE.
After calving, cows have a constant battle to meet what Webster called their ‘‘metabolic hunger’’, which drives them to keep on eating to meet the massive physiological demands of lactation and maintaining body reserves.
Our hard-working Kiwi cows have to graze for 9-12 hours during daylight, interspersed by regular periods of up 30-40 minutes to rest and ruminate.
Then there is time off pasture to walk to the shed and for milking taking a total of 3-4 hours.
They also need short periods of sleep during the night and if their daytime grazing is disrupted, they have to graze during the night.
Studies show that in the cow’s working day, she makes from 45,000-75,000 jaw movements, of which 36,000 are grazing bites, all of which takes energy.
A cow’s daily routine can also be disrupted by ‘‘social facilitation’’, where for example, if the herd is resting, then the first cow to get up and start grazing again will trigger them all to follow, so cows that need more rest may miss out, and the bigger the mob, the greater chance there is of such disruption.
All this ends up with stressed cows which then have impaired immune systems measured in high somatic cell counts, more mastitis, lower in-calf rates, lameness, higher vet bills and staff frustration.
The whole thing compounds and feeds off itself, quickly showing up in the bottom line where animal health costs per cow are well above $100/cow/year, when they should be about $20-$30.
High vet bills are not an indicator of good husbandry!
Future dairy herds will get bigger and will be grazed in larger groups, and already groups of more than 500 cows are common.
Cows graze with their heads down, and have almost 360-degree vision, but are always fearful of being attacked in the narrow blind spot at their rear.
So they need to constantly be on guard, checking that an approaching cow is friendly, and in mega herds this can be a major stressor.
This problem is especially bad for heifers when they first join the herd before calving, and until they work out a ‘‘pecking order’’ to avoid problems while grazing, at the water trough, when leaving the paddock to enter the farm race to come home for milking, and when entering the milking bail.
These are all high-stress areas that need management attention.
Farmers I have talked to reckon 240 cows is a good sized grazing mob – based on general observations of their cows’ wellbeing, and especially by the end of the season when they say their cows are clearly tired and reluctant to come for milking, especially if they have to face a long walk.
They get harder to move, so risk more stress from dogs and bikes.
We just don’t know what is going on in today’s big herds, and animal behaviourists should have been on to the problem from when it all started.
Old overseas research showed that herds of 100 were optimal for cows to work out their social rank and avoid stress. So what is happening in mobs of 500?
Ron Kilgour used to get us to stand among a group of cows in a paddock, yard or milking shed, with our eyes at the same level as a cow’s eyes, to note what we could see and feel (like the heat from cows’ bodies).
It is both revealing and scary – and I strongly recommend it when thinking of cow welfare.
Cow behaviour in today’s large herds needs urgent study, and it would be so easy with GPS to see where an individual cow is, and what she is doing in relation to her mates. If she is stressed, it will soon show up in her production, somatic cell count and vet bills.
But there are no animal behaviour scientists left or, I am told, no money to do work like this.
Dr Lindsay Matthews our bestqualified animal behaviourist who trained with Ron Kilgour, took redundancy from AgResearch when he saw no future there, and is now working in Italy on a European Union-sponsored project looking at ‘‘cow behaviour’’.
What does that tell you about New Zealand research?