Ostrea® Seashell and Oyster Shell Flours are a source of chalk derived from natural shell banks in the North Sea. The shells are washed, dried and heated and then ground into a powder. Ostrea® is not just a rich source of calcium carbonate, but also contains a wealth of other minerals. Ostrea® is held in high regard by dairy farmers in Holland, Belgium, France and the UK who have used the product as a rumen buffer for many years.

• Sustained buffering capacity stabilises rumen pH in the optimum range between 6 & 7
• Reduced risk of rumen acidosis, leading to improved performance & feed efficiency
• Improved general health of high yielding dairy cows
• Healthier hooves and reduced lameness
• Improved Calcium : Phosphorous balance in feeding stuffs
• Natural source of essential minerals & trace elements
• Rich in Calcium
• Good absorption

Why is there a need to feed rumen buffers?

Typically 80% of the cow’s energy needs and 70% of her protein requirements are supplied by the rumen microbes from the feed that she consumes. This complex eco-system transforms the energy sources in the feed into organic acids, predominantly acetic, proprionic and butyric acids. The acids are absorbed through the rumen wall to be metabolised in the liver to meet the cows energy needs.

The rumen micro-organisms function most effi ciently at a pH between 6 and 7. The cow has evolved an elegant mechanism to buffer the acids they produce. The cow is capable of producing up to 2.5 kg of sodium bicarbonate per day in the saliva, produced during cudding. How much she actually produces will vary depending on the fibrous nature of her diet and how long she spends resting, ideally half of her day.

To meet the huge energy requirements of the modern dairy cow, especially in the early weeks of lactation, diets require high levels of starches and sugars. The populations of microbes that digest these soluble carbohydrates can multiply very quickly and produce large amounts of lactic acid. Other microbes that utilise the lactic acid are unable to respond quickly enough to metabolise these high levels, leading to the rumen buffering mechanisms being over-whelmed and the rumen pH falling below 6. This depresses the function of the microbes needed to digest the forage component in the diet.

Once the rumen pH falls below 6, Sub Acute Ruminal Acidosis (SARA) can trigger serious consequences for milk production and animal health.

Good diet formulation can go a long way to reducing the risk of SARA depressing herd performance and animal health. However many other factors can infl uence rumen function including forage quality, diet processing, feed allocation and feeding facilities. For just a few pence per day, Ostrea® can balance the rumen environment to help keep the microbes working, thus maintaining the high energy and protein supply.

Risk Factors for Sub Acute Ruminal Acidosis (SARA)

• High concentrate diets
• Feeding more than 3kg of concentrates per feed
• Rapidly degradable sources of starch
• Sudden changes in diet
• Increasing concentrate levels by more than 0.75 kg/day
• Lack of physically effective dietary fibre
• Feed sorting
• Wet acidic silages
• Heat stress
• Grazing grass rich in soluble carbohydrates and low in fibre

How Ostrea® works as a rumen buffer

Ostrea® is rich in calcium carbonate. One molecule of calcium carbonate is capable of binding with two molecules of a volatile fatty acid, twice the capacity of sodium bicarbonate. Because the molecular weight of calcium carbonate is higher than that of sodium bicarbonate, in practice this means Ostrea® is able to buffer 150% more acid than the same weight of sodium bicarbonate.

Ostrea® flour also has unique physical characteristics which make it an ideal rumen buffer. It has a large
surface area and complex honeycomb structure and combines high availability in the rumen with a sustained action.

Other rumen buffers can cause a rapid rise in rumen pH taking the pH above the 6-7 range in which the microbes work most effectively. Ostrea® has a natural ability to minimise wide fluctuations in rumen pH but cannot over-buffer the rumen, making it very safe to use across the whole herd at all stages of lactation, whilst also contributing to the cows’ calcium and trace element requirements.

Benefits of Ostrea® compared to other rumen buffers

In recent laboratory trials separate model rumens were loaded with organic acids to mimic pH conditions in a real life rumen. They were than buffered with four commercially available products; sodium bicarbonate, product A, Ostrea Seashell Flour and Ostrea Oyster Shell Flour, at the equivalent of commercial doses. The pH was monitored over a period of up to four hours . The model rumens were subjected to acid loading to simulate post feeding rumen conditions in cows fed TMR diets and then higher levels of acid as experienced after twice daily parlour fed concentrates. Each time the pH was then monitored for up to 90 minutes.

The results shown above demonstrate Ostrea’s® superior buffering ability to sustain the pH within the optimum range of 6-7 for good rumen function, without causing an initial “alkali” shock.

Signs of Sub Acute Ruminal Acidosis (SARA)

SARA is a common metabolic disorder which can have a signifi cant impact on feed conversion efficiency, milk production and animal health in the modern high yielding dairy herd. Diagnosing SARA in the field can be a challenge.

The following signs can be useful, but can vary and be caused by other factors:

• Lower than expected dry matter intakes
• Poor rumen fill
• Lower than predicted milk yield
• Loose dung
• Variable dung consistency across the herd
• Tail swishing and dirty backs
• Less than 80% of cows lying in the cubicles cudding
• Dropped cuds
• Individual cows butterfat % one full point below herd average
• Individual cows milk protein % more than 0.4 higher than butterfat %
• Butterfat % returns to normal when a rumen buffer is added to the ration
• Cows experiencing laminitis and foot problems especially first lactation and fresh cows
• Haemorrhages in soles or horizontal ridges in walls of claws

Ostrea® Product Information

Ostrea® Seashell and Oyster Shell Flours are complementary feeding supplements, intended to improve cattle rations as an aid in the reduction of the risk of acidosis. They have a pearly off-white colour and have been ground to a fine powder.

Both available in 1000 kg tote bags. Seashell also available in 25 kg bags.

Oyster Flour Analysis:

Ash	%	99.44
Calcium Carbonate	%	97.64
Calcium	%	39
Phosphorus	mg/kg	10
Magnesium	mg/kg	3,900
Potassium	mg/kg	240
Sodium	mg/kg	4,600
Chloride	mg/kg	2,000
Sulphur	mg/kg	288
Iron	mg/kg	2,800
Manganese	mg/kg	180
Zinc	mg/kg	32
Copper	mg/kg	1.6
Cobalt	mg/kg	20
Selenium	mg/kg	<0.1

Seashell Flour Analysis:

Ash	%	99.44
Calcium Carbonate	%	96.1
Calcium	%	44
Phosphorus	mg/kg	12
Magnesium	mg/kg	450
Potassium	mg/kg	150
Sodium	mg/kg	5,000
Chloride	mg/kg	1,130
Sulphur	mg/kg	470
Iron	mg/kg	4,400
Manganese	mg/kg	55
Zinc	mg/kg	18
Copper	mg/kg	12
Cobalt	mg/kg	16
Selenium	mg/kg	<0.1

What do farmers say about Ostrea®?

We have noticed an improvement in our milk quality and dung consistency since swapping from bicarb to Ostrea®.

Devon Farmer

The cows seem more content and milk quality has definitely improved since we introduced Ostrea® to the diet. We know that only the acidic cows are being targeted by the Ostrea’s® unique way of working.

Cornish Farmer

After trying many other more expensive products we fi nally found the solution, Ostrea® and it was only fed at 100g/cow/day.

Devon Farmer

Butterfats jumped up by 0.3 in only 72 hours. It is far more cost effective than using a fat product and it also contains organic minerals. Our overall farm mineral input reduced, resulting in great cost savings.

Devon Farmer

Ostrea® is very well priced and we have used it to great success on our farm for the past 6 months.

Cornish Farmer