Vitamin E may enhance vigour
Cow condition crucial to lower concentrate inputs
Cows can achieve high
yields with moderate levels
of concentrate feeding.
Jessica Buss reports on an
MDC-funded study
IT is possible to feed high genetic merit cows enough forage to produce 8250 litres on just 1340kg of concentrate, on a sustainable system, an ADAS Bridgets study has discovered.
Dairy costings for the study herds show production of over 5000 litres from forage. The Hants research centres farm manager Robert Bull now believes it is possible to consistently produce 8000 litre yields with 6000 litres coming from forage with some minor alterations to herd management.
The MDC-funded MeDoC study, using 30 winter-calving cows with an average PIN of £56, is in its second year and yields of above 9000 litres a cow and 5000 litres from forage are predicted. But controlling cow condition and culling rate are crucial to the systems success.
Careful body condition monitoring is essential because it has proved difficult to increase cow condition, he says. "Cow body condition was lower than target at the start of the study and it was difficult to increase it. Condition has improved slightly but not enough.
"This shows it is important for cows to be in the correct condition before calving on a high forage system, giving cows their own buffer. When condition is too low it takes away flexibility," he says.
Cows still performed well with a margin over all feed costs of £1220 a cow or 14.89p a litre. But for a sustainable system on commercial units it may be best to expect less from the cows, with about 4500 litres acceptable from forage and a calving block of over nine weeks, suggests Mr Bull.
It is crucial to provide concentrate at the correct time and of the right type. "This year we tried feeding more concentrate in early lactation to improve body condition – but ended up with more milk. Cows are predicted to yield over 9000 litres this year, but we must find a way to increase body condition later in lactation."
Cow fertility and culling rate must also be within acceptable limits for a sustainable system.
In the trial, cow fertility was acceptable with a pregnancy rate of 70% and a 357 day calving interval, says Mr Bull. Cows held well to first and second service. But a high proportion of embryo losses and two abortions in this small group of 30 cows led to a high culling rate. Three further cows were elected as culls and not served.
To maintain a nine-week calving block, culling rate for the study group had to be 30% – 10% above the study target.
With so few cows in the study it is difficult to assess whether embryo losses were unlucky or linked with the study, says Mr Bull.
"A loss in body condition in the first nine weeks of pregnancy was recorded. Although we cant prove this was linked, if animals were culled because of it – at a cost of £2000 – we could have justified feeding 20t of wheat to prevent it. But this year we have fed higher levels of concentrate and have still suffered embryo losses."
Calving date may also be critical to maintain a sustainable high forage system. Mr Bull says calving later than the study group, which currently calves from mid-December to mid-February, may improve results.
"Calving later with a lower yield at grass may be a better way to achieve 5000 litres from forage." The study group went out in March last year producing 30 litres a cow.
High forage system is simple
PRODUCING over 5000 litres from high yielding cows relies on high forage intakes in winter and at grass, but need not be complicated.
ADAS Bridgets Robert Bull explains that after calving from December to February cows were fed a simple total mixed ration.
The daily ration offered included 11kg DM maize silage, 3kg DM grass silage and 9.3kg DM of concentrate. Intake measurements show that from December to February cows ate an average of 22kg DM of the ration a day.
Cows were producing 30kg a day at turnout on Mar 7, but continued to be buffer fed because of poor weather. They were out day and night from Apr 23 and no buffer was fed from mid-May to July 25.
"To maximise grass intakes cows were rotationally grazed and always had vast quantities of grass in front of them. They produced just under 3000 litres from grazed grass."
The theoretical maximum that could be achieved from grazed grass is 3500 litres. But Mr Bull says that it is very difficult to achieve that with high yields and maintaining health and fertility.
A buffer of 3kg DM maize silage and 1kg wheat was reintroduced in late July because cows had lost condition. The reasons for this remain unclear, but cows needed to gain condition before drying off and grass quality had begun to fall, he explains.
In mid-August grass supply had fallen, so the buffer was increased to 11kg DM maize and 1.8kg of rapemeal. A further increase in buffer was required in September and maize was fed ad-lib until drying off cows in autumn.
"This year, the maize area has been reduced from 6ha to 5ha to provide more autumn grazing for cows and increase flexibility," says Mr Bull. MeDoC cows were allocated a total area of 14ha (35 acres) for grazing and conservation of winter feed, with a stocking rate of 2.12 cows/ha (0.86 cows/acre).
"This high forage system is a simple way to manage cows," says Mr Bull. Cows had a long grazing season and came in just three weeks before calving in November.
after cleaning up grazing swards ready for spring. They calved over 10 weeks and soon went out again, he adds.
Grass shortage solution near?
MIMICKING drought conditions on winter-calving cows at grass shows that feeding concentrate at a fixed level may be a good way to buffer grazing shortages.
In an MDC-funded study at ADAS Bridgets, Hants, cows were allocated 10kg of grass dry matter a day to find the most economic way to cope with grass shortages, says farm manager Robert Bull.
The buffering options considered were fixed concentrate, variable concentrate level depending on yield, grass silage and maize silage.
Concentrates were fed in parlour and as a midday feed in the field for both fixed and variable treatments. Mixed forage rations were fed for an hour after each milking.
"The results show you can make a good case for all these options dep-ending on quota availability, milk contract, stocking rate and yield."
But the option many producers chose instinctively – feeding to yield in parlour – was of little benefit with block calved cows. Study cows with a yield range of 10kg a day didnt produce a good yield response when fed to yield, he adds.
Cows fed a fixed level of 8kg of concentrate produced more milk at 21.4kg a day with a higher output of fat and protein, but with a lower protein %, than cows fed to yield – producing 19.2kg a day.
Overall margins
Margins over all feeds were £94/cow or 15.65p a litre for a fixed feeding level and £82/cow or 15.21p a litre for cows fed to yield over the four weeks of the study.
"This makes feeding a fixed level of concentrate a solution for block calving herds without a mixer wagon and selling milk on a liquid contract. However, if quota is limiting you must include that in your calculations," advises Mr Bull.
Both mixed ration diets aimed to support production of 27 litres of milk with grass intakes of 11kg of dry matter. Rations included 5kg DM of either maize or grass silage and 3kg of concentrate.
Feeding a maize silage mixed ration resulted in a yield of 19.6kg a cow compared with 17.3kg from cows fed the grass silage ration.
Cows fed a maize ration produced milk of lower protein % than the grass silage ration. But maize maintained cow liveweight better than other treatments.
Margins over all feed were 15.67p a litre for grass silage fed cows and 16.87p a litre for maize silage fed cows. However, feeding out costs, estimated at 0.2p a litre, and additional quota needed for higher production are not included in these margin figures.
and producers must consider these costs for individual units, suggests Mr Bull.
Listing lamb losses offers a wide range of possible answers
By John Burns
DETAILED recording of lamb losses and their causes has highlighted possible ways to cut them on one Devon farm.
The Holland family, of Slade Farm, West Anstey, are in the second year of a collaborative project with ADAS to assess lambing percentage improvements under commercial conditions.
The list of losses, meticulously compiled by Andrew Holland with helpful nagging at times from brother Richard and parents, Norman and Christine, gives no fewer than 29 different causes – if unknown, missing, and unexplained count as causes.
On the list of 54 lambs born dead, there were nine different causes. For the 61 lambs which died between birth and July 14 there were 20 different explanations.
The percentage losses overall are similar to those experienced last year, but a determined effort this year to record causes has helped identify possible areas for further investigation and improvement.
At first sight, considering loss level is similar to last years and there is such a wide range of causes, it is tempting to conclude that they are inevitable, says local ADAS consultant Charles Stone.
But laboratory tests on aborted material suggested toxoplasmosis might be involved, and more than half the lambs born dead were either mummified or aborted, has led to the decision to investigate the flock thoroughly by blood sampling. If toxoplasmosis is confirmed, a vaccination programme will probably be started.
The Hollands run 150 Exmoor Horns, 300 Mules, and 200 Scotch Blackface ewes. Their farm includes an area of true moorland on which the Blackface ewes run all year round except at lambing when they are brought home but remain outdoors. The other flocks are shorn and housed.
This years lambing percentages – lambs alive to date (mid-July) divided by ewes put to ram, with figures in brackets being scan predictions – are Exmoor Horns 127% (153%), Mules 176% (197%), Blackface 125% (142%).
High price for excessive cull rates
A EWES optimum breeding life is five crops of lambs, after which problems increase and ewe and lamb losses are more likely.
Graham Webster of Intervet told a farmers meeting at the Holland familys farm that with increasing age there were more sudden deaths, more barreners, more metabolic problems, difficulty maintaining body condition, and poorer lamb viability.
But to cull by age without incurring exceptionally high replacement costs, the number of ewes culled for other reasons had to be kept to a minimum he said.
It was not uncommon to find 10% or more of a flock were over the optimum six years old, because too many had to be culled for other reasons such as abortion or mastitis. Ewes which gave problems during the year which warranted culling must be marked effectively, not for example by a paint mark on wool which disappeared at shearing.
Excessive cull rates could be avoided by checking for diseases and taking appropriate action.
such as vaccination, and making sure trace element nutrition was correct. Any sheep bought in should be sourced from flocks with a good health record, quarantined on arrival, and introduced to the vaccination programme if necessary, he said.
Vitamin E may enhance vigour
SUPPLEMENTING ewes with vitamin E before lambing can produce lambs with greater vigour, which are quicker on their feet to sucking, and heavier at weaning.
In ADAS trials, lambs from housed Scottish Blackface ewes were offered diets supplemented with at least 100iu a day of vitamin E for the last 70 days of pregnancy. They were compared with lambs from ewes fed 0, 50, 75, 150, or 300iu of extra vitamin E over their diet naturally.
The experiment, conducted last year at ADAS Redesdale, Northumberland, showed that feeding at least 100iu a day of vitamin E resulted in significant increases in vitamin E in the blood plasma of both ewes and lambs. But it had no significant effect on ewe liveweight or condition. Lamb growth rates were significantly higher, giving weaning weights up to 1kg heavier where ewes were fed any of the levels of extra vitamin E, except 300iu.
Lamb vigour was assessed by the length of time it took both lambs of each set of twins to stand and successfully suck the ewe. Lambs from ewes given at least 100iu vitamin E a day achieved the target 25 minutes faster on average than those from ewes given no extra vitamin E.
All lambs were twins, sired by Blue Faced Leicesters. Feeding extra vitamin E had no effect on lamb mortality, though it should be noted that average mortality from scanning to weaning at Redesdale is only 6%, and last year was only 3%.
Presenting the results to a farmers meeting at the Holland familys Slade Farm, West Anstey, ADAS sheep specialist Kate Phillips said work on vitamin E supplementation was concentrated on finding a suitable bolus to enable it to be given to hill ewes kept where hand feeding was not practical.
That work would continue and all aspects extended to testing experimental results under truly commercial farm conditions.
The meeting was part of the MAFF-funded project aiming to improve lamb survival in the hills and uplands.