Clawdd Offa Farm

Project Aim:

Investigate the potential in increasing total cheese yield through selecting for the Kappa Casein BB gene.

Introduction:

Past laboratory studies have shown that cheese yield and formation can be greatly influenced by the amount and profile of Casein in the milk. It is believed that every litre of milk with higher levels of the desirable BB Kappa Casein produces 10% more cheese yield and forms up to 25% faster than AA Kappa Casein at the same fat and protein percentages.

Up until recently identifying cows that carry the BB gene was expensive and time consuming and was only done for research purposes. However it is now commercially possible to profile a herd for the Kappa Casein gene which could greatly influence cheese making efficiencies at factories. The potential is there to produce more cheese more quickly, increasing the turnover and total yield of cheese vats.

How the BB gene for Kappa Casein influences cheese yield:

The BB gene is responsible not only for higher total casein content but also higher Kappa Casein content. Kappa Casein also has smaller casein micelles which improves the rennet coagulation, the curd is firmer and is able to retain a greater amount of substances like fat and minerals rather than being lost in the whey portion, leading to increased yields.

Most Jerseys carry the BB gene along with having higher fat and protein %. Water Buffalo are 100% carriers of BB hence the quality and quantity of Mozzarella cheese produced from their milk. Around 15-23% of Black and white Dairy cattle in Europe carry the Homozygous BB gene whilst the remainder are made up of either Homozygous AA or Heterozygous BA

What will be done:

100 cows from one spring calving unit supplying Arla Llandyrnog cheese factory will be hair sampled for their Kappa Casein profile and split into three possible groups. Kappa Casein BB (desirable for cheese making) – Kappa Casein BA and Kappa Casein AA.

Most animals will be either NZ Friesian or a Jersey crossbred type cow.

From the returned samples, cows with a similar age, stage of lactation and fat & protein % will be allocated into each group and milked separately in order to be turned into soft cheese at the Food Technology Centre in Llangefni. Here a series of small scale experiment will be undertaken by Lab Dairy Specialist Julia Skinner, who will run small scale experiments on rennet coagulation time, firmness and conduct texture experiments. Also a 40 Litre specialist vat will measure accurately the amount of soft cheese produced per litre of milk. As it will be soft cheese these experiments can be done over a time period of 24 hours.