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 Nutrition Focus
Increasing Your Herd’s Profitability
Through Understanding Stressors
feeding, while overcrowding will limit lying time, which decreases rumination and blood flow. Overcrowding at the feed bunk lowers intake, decreases meal frequency while increasing meal size, which impairs rumen health. The rumen and the rumen microbes that can flourish in it, importantly, make the cow the truly sustainable animal that she is. The ideal rumen environment optimizes the microbial digestion of forages and grains, producing nutrients that fuel microbial multiplication. The resultant microbial populations become an ideal protein source, as well as a source of energy and vitamins, forming the foundation of the cow’s diet, helping her meet the nutrient demands to overcome metabolic stress.
Nutrition and Stress
To handle metabolic stress, your herd needs high levels of a well-mixed and balanced diet during those stress periods. Many specific nutrients have been identified which can enhance the cows’ ability to deal with metabolic stress, for example, trace minerals, amino acids and vitamins. More specifically, feeding these nutrients in a morebioavailableorrumen-protectedform will improve results. There is a reason that B vitamins are called the Stress or Energy vitamins. When fed to transition cows, B vitamins not only improve liver function, but they are also essential to glucose production and are well known for transforming by- products of metabolic stress.
Combining stressors often results in a Tipping Point
Take a pen of springing heifers, mixed with mature cows – normally, despite having lower dry matter intake and nutrient needs, the calvings go not too bad. Yet this month you have 30% more calvings – you planned it that way for incentives or perhaps it was the result of catching up a reproductive slump. Now the pre-fresh group is overcrowded.
Chris Gwyn, Ruminant Business Development Manager, North America Jefo Nutrition Inc.
Dairy cattle, during all stages of lactation and at all times of the year, are at risk of many potential stressors: physical, social and metabolic. Individually, and often the combination of which can result in health and performance losses. Research points to the economic losses associated with stress (IE- heat stress and social disruption). Lost milk, poor reproduction and impaired health are common negative effects. Stressors can be 1) acute – such as off-feed events from moving between groups, or 2) chronic – such as overcrowding or lameness.
Metabolic Stress
Since the early 1980’s dairy cows in BC have increased their annual butterfat production by 60%, significantly contributing to the industry’s sustainability. This heightened efficient production is a combination of improved cropping/forage quality, a clearer understanding of nutrition/ration balancing, improved housing, management and improved genetics for overall production and component yield. To achieve these improvements in efficiency, the cow’s rate of metabolism has dramatically increased.
The example of the Transition Cow and early lactation comes to mind:
Blood flow rate doubles from dry cow to early lactation from 24,000 litres of blood moved per day to over 52,000 litres! All this blood passes through the liver. The liver is a 11 kg organ central to many functions in the cow’s body. The liver manufactures the building blocks of reproductive hormones, detoxifies toxins, processes excess nitrogen
and is an immune function organ. A vital role of the liver is the production of glucose. More specifically, a large percentage of the forages and grains provided in her diet are fermented in the rumen, producing volatile fatty acids, such as propionate. Propionate is converted to glucose in the liver. Glucose is the primary source for lactose which is used in the mammary gland to produce milk. The cow needs to manufacture in excess of 3 kg of glucose per day!
It can’t be stressed enough how significant the liver’s function is, and the degree of metabolic stress it endures.
With every metabolic reaction in the liver, by-products are produced that need to be stabilized or removed. This is metabolic stress. Metabolic stress in early lactation can be a major factor contributing to health problems, production losses, impaired fertility, and premature culling. How you meet that challenge will influence the outcome. Your role as a dairy owner, advisor or influencer, is to put in place the environment to maximize feed intake of a well-balanced diet that supports the metabolic needs of the cow during intense production phases.
Social Stress
Social stressors impact how the cow will meet the additional nutrient needs of metabolic stress. A common result of stress in the cow’s environment is reduced dry matter intake and is often combined with a negative effect on rumen function. Negative social interactions take time away from
Modern dairy demands create multiple stressors on cattle, which can be eased through management and nutritional strategies.
The result? There is below adequate bunk and watering space, springers can’t get away to calve. It creates more calving issues, reduces early lactation milk, increases weight loss, increases early lactation culls and impairs reproduction for the cows that remain.Cowscancopewithsingleandoften double stressors, yet sometimes it is the slight additional stress that puts them over the edge.
What makes the difference in a herd’s ability to pass through stressful events is the overall management and plane of nutrition. Cow comfort, proper stocking density, air quality, heat abatement, barn hygiene, cow handling, mixing and delivering the best nutrients available are all necessary to ensure that the nutrition consumed by your herd during known periods of metabolic stress will help meet the individual cow’s nutrient needs. Beyond production, a cow’s health, fertility, and longevity are all improved when giving her the best conditions and inputs to mitigate metabolic stress.
for the New Year from all of us at Pacific Dairy Centre
The management, staff and families of Pacific Dairy Centre wish you peace, health and happiness throughout 2021!
May your cows be contented, and their butterfat high!

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