Island Guernseys


Breed description
The Guernsey is a medium sized dairy breed, generally coloured fawn and white but can vary from solid fawn to dark red and white. Brindled cattle were formerly quite numerous but are less common today. The skin has a deep yellow pigmentation. Females weigh circa 500-550kgs and Males 600-650kgs. Genotypic information from the International Bovine Haplotype Map Consortium shows that the Guernsey is genetically distant from other European breeds.

The Guernsey breed is noted for its robustness. Guernseys have strong feet and legs with good dairy strength and are tolerant of a wider range of temperature than most European dairy breeds.

The Guernsey is an excellent grazing animal that matures early and is an efficient converter of feed to product. Guernseys are extremely docile with very high calving ease even when crossed with larger beef breeds.

Guernseys produce high component milk of a deep yellow colour with distinctive mouth-feel and flavour. This colour is remarkable in other products such as butter, cream, cheese and yoghurt. Guernsey milk contains very high levels of the protein Beta Casein A2 as opposed to the predominance of the protein Beta Casein A1 that is present in the milk of other dairy breeds.

Guernsey beef is of a distinctive texture and flavour and has been praised as a superior product by leading international chefs.

No Milk kgs %Fat %Prot Fat kgs Prot kgs F+P kgs
300 5851 5.22 3.55 305 208 513
No Milk kgs %Fat %Prot Fat kgs Prot kgs F+P kgs
842 6140 5.16 3.56 322 222 544
No Milk kgs %Fat %Prot Fat kgs Prot kgs F+P kgs
1142 6140 5.17 3.55 318 218 536

LEADING HERD - Les Jaonnets Herd owned by Mr. M Bray
COWS Milk kgs %Fat %Prot Fat kgs Prot kgs F+P kgs
75 7414 5.13 3.51 380 260 641
HEIFERS Milk kgs %Fat %Prot Fat kgs Prot kgs F+P kgs
22 6337 5.36 3.58 339 226 566

LEADING ANIMAL - Les Jaonnets Shakas Princess
Milk kgs %Fat %Prot Fat kgs Prot kgs F+P kgs
10313 5.61 3.53 579 364 941

Breed History
It is thought that cattle were first brought to the Island of Guernsey from France in the latter part of the 10th century. They were then bred in relative isolation until the early 19th century and in complete isolation since that date. This isolation has meant that the island is free from many of the normally occurring cattle diseases. The island cattle are tested free from Tuberculosis, Brucellosis, EBL, IBR, BVD and Leptospira hardjo. Importation of semen from Guernsey bulls has been permitted since 1976 and the island is now at the heart of a Guernsey Global Breeding Programme, which has been developed to stimulate continued genetic improvement of the Guernsey breed.

Population Trend
In 1950 the Island population was circa 2,000 cows but as production per cow increased this fell to around 1,600 cows and has remained static for the past 8 years.

Breeding and conservation
The World Guernsey Cattle Federation is attempting to co-ordinate a Global breeding programme for Guernseys (GGBP) in order to preserve variation and avoid genetic drift and inbreeding while improving production, efficiency and health traits. A pilot programme using the Island and UK populations is proving very successful. All cattle are compared with the use of a breed specific index, the Guernsey Merit Index (GMI), which is weighted to achieve the agreed objectives of breeders. The Guernsey Global Breeding Programme uses teams of young bulls selected on merit index and used sparingly and at random in order to spread the genetics of the highest merit cows across the breed. The following graph compares the progress in Predicted Transmitting Ability (PTA) of the daughters of GGBP Bulls with those of all bulls, Non GGBP Proven and Farm bulls from 2005 - 2012

In 2012 the Royal Guernsey Agricultural & Horticultural Society's Herd Book Council decided to add female fertility to the Guernsey Merit Index. The new index GMIF will be used for mating selection to produce the next generation of Island GGBP bulls.

The Island population is the smallest amongst the WGCF Federated countries but has the largest Effective Population (Ne137). In 2013 it was decided to fine tune the Island's population management in order to avoid undue future increases in inbreeding. The adoption of EVA software to optimise the balance between genetic gain and inbreeding should increase the sustainability of the Island's contribution to the Guernsey Global Breeding Programme.


Please contact Bill Luff [email protected] for further information.
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