Move to smaller tags likely

16 April 1999

Two more names join in quest for sexed semen

By Jessica Buss

CATTLE and pig breeding companies Genus and Ridley have invested £0.9m in semen sexing, joining cattle breeding company Cogent in the race for commercial development.

Announcing the move this week, both Genus and Ridley – Canadian parent company of Cotswold Pig Development – are investing to supply UK producers with sexed semen which will produce male or female offspring as desired.

Genus has invested £0.5m and Ridley has invested £0.4m in Gensel Biotechnologies, a company of the University of Guelph, Canada. It has developed a technique of sperm sexing, but needs to develop it for commercial sale – expected in two to three years.

Steve Amies, managing director of Genus Breeding believes it is an investment its farmer customers and shareholders will benefit from.

"When farmers are asked what they want its always semen sexing and its what they would choose to spend R and D money on.

"Look at the difference between the price of male and female beef calves, never mind being able to breed the best cows to top bulls for a guaranteed female calf."

Cotswolds director of science and genetics John Webb says that there will be financial benefits for pig producers.

"Breeding only boars will mean half the pigs will be 15% more efficient." It would also save the need for split-sex feeding and there would be less variation in meat produced, improving uniformity.

Breeding companies will also benefit, he says. Multipliers currently discard about 50% of their output, but breeding litters of only gilts will reduce overhead costs.

The technology developed by Gensel is based on sperm having sex specific proteins on the cell surface, explains Mr Amies. It has identified an antibody specific to each of these proteins.

Adding male antibody to the sperm sample means it binds with those sperm, making them bigger. This means the female sperm can be filtered out. However, the technology to filter out male sperm after adding female antibody has not yet been developed.

Only the sperm not treated with antibody are used. These have not been touched so there is no reason why they cant be frozen and incorporated in standard AI procedures, says Mr Amies.

He expects the technique to be more than 90% accurate, but so far sperm has only been sorted on a small scale. Larger scale sorting and farm trials are now needed.

According to Mr Amies, the technique currently used by Cogent looks at each sperm, requiring an expensive machine and skilled operators. Then sperm must be inseminated deeper into the cow because they cannot swim.

But Cogents Tim Heywood welcomes Genus move into semen sexing. "Gensel has interesting technology which was developed in the early 1980s. There are no pregnancies yet, but we congratulate Genus for its commitment.

"After evaluating various research projects we had the choice of both and elected to choose XY, and this year we have large scale field trials of its technology in the UK." However, Mr Heywood was not prepared to say when sexed semen would be available commercially.

Set in a box


Genus, Ridley and Cogent.

Less than three years away?

Benefits for producers.

GRASS is growing above cattle requirements in all dairy regions, so magic day has arrived, writes Paul Bird.

If growth rates continue at or above these levels over the next six weeks, at least half of the grass growing is surplus and must be silaged.

Producers with low stocking rates may not need to apply any more nitrogen until late summer when building grass for autumn grazing.

All stock should be out day and night, maximising the grass eaten/ha and minimising silage requirements. Herds feeding little or no concentrates are achieving yields of 25 to 27 litres/cow a day from grazed grass.

Skip grazing areas over 3000kg DM/ha (12-13cm) because if good growth rates continue these areas can be made into silage. If growth rates fall away due to cold weather, be flexible enough to graze parts of these fields in a few weeks time.

When reducing concentrate fed, ensure cows are receiving adequate magnesium by increasing concentration in concentrates or water, or though magnesium pasture dusting.

Where moving to a grazing based system, re-assess breeding decisions. Dont choose bulls producing daughters which are not interested in getting back in calf every 365 days. Each cow should average at least 4.5 lactations. The current UK average is only three lactations.

&#8226 Profitable milk production around the World and breeding cows for grass-based dairying will feature at an international dairy conference later this month.

Speakers from the US, UK and Ireland will address the Midland Bank, MDC, BGS and FARMERS WEEKLY-sponsored conference at Harper Adams college, Newport, Shropshire, on Thur Apr 29. Attendance costs £30 including coffee and lunch. For further details contact the British Grassland Society (0118-931 8189).

Daily growth rates

Cumbria 70kg DM/ha

Anglesey 83kg DM/ha

Dorset 65kg DM/ha

Pembrokeshire 71kg DM/ha

Sussex 48kg DM/ha

Staffs 73kg DM/ha

Move to smaller tags likely

SMALLER approved primary tags are available other than those being used by most producers. This may reduce loss rates and time spent re-tagging cattle.

As reported in farmers weekly (April 2) producers are suffering unacceptable levels of tag loss, up to 50% in some herds. Tag design and quality is being questioned by some producers.

Primary tags have to be 45mm x 55mm (2in x 2.5in) in size to comply with EU legislation. However, it appears that standard tags sold by many manufacturers are larger than this.

But primary tags made to the minimum EU size, designed for smaller breeds of cattle such as the Dexter and Jersey, are available from certain manufacturers.

MAFF states: "While it is improper for us to recommend one tag over another, producers should be aware of the availability of these tags on welfare grounds.

"Other manufacturers are expected to start producing similar designs and if other smaller and lighter tags become approved we will advise accordingly."

Many producers have blamed tag losses on their size. According to the MLCs Archie Sains, these bigger tags are more likely to get caught on barbed wire, fences and gates. "Whether they then break is down to the quality of their manufacture."

Losses are being monitored by the Electronic Tag Allocation System (ETAS), with some manufacturers achieving loss rates as low as 1-2%. However, MAFF is currently unwilling to divulge which tags perform best.

But there appears to be reasonable evidence to suggest that some tags are not up to the job. "The number of approved tags will reduce over time with some poor designs being withdrawn from the market," says Mr Sains.

But he says producers persist on putting tags in wrongly and this is a major cause of primary tag loss, despite there being precise instructions on insertion issued with tags.

MAFF spokesman told farmers weekly that Cooper Marketing is no longer approved to supply primary or secondary eartags. "This is for supplying inappropriate primary tags."

Small approved primary tags.

Feering International, MAFF 0.

Cox Surgical, medium male and female.

Allflex, small leaf.

Ritchey Tag, HT2

Dalton Suppplies, new supertag, size 3.

See more