234- Lactation 1

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  • Created by: hope ball
  • Created on: 14-12-12 00:31

Lactation 1

  • One of the distinguishing features of mammals is that they possess mammary glands
  • Lactation is critical for neonatal survival and reproductive success
  • It is manipulated in animal husbandry and management

The National Dairy Herd

  • The Holstein is the predominant breed (>90%)
  • The Average yield is 7,800kg in 305 days
  • Target yield is 10,000-12,000 kg
  • The Average Milk composition is 4% fat and 3.2 % protein
  • One of the targets at this current time is to increae protein

Intensive Dairying

  • In post-war years when food was scarce farmers were encouraged to produce as much as possible
  • Yield has been increased progressively through

-Improved Genetics such as AI

-Improved Nutrition

-Improved technology (Biotechnology)

  • Historically emphasis was given to increase fat content
  • Latterly this has changed to decreased fat and increased protein
  • Yield has proven to be more plastic than composition

Overproduction and Quotas

  • Overproduction has led to introduction of Milk Quotas in the mid 1980s
  • The expansion of the EU exacerbates this problem
  • Nevertheless, most farmers still aim for increased yield by;

-Maximising peak yield

-Minimising calving interval

  • Quotas planned to be abolished in 2015

Dairy Cow Yield Curve

  • Milk yield increaes during Calving for the first 60 days
  • Milk yield peaks at 60 days 
  • As milk yield starts to decline thats when cows start to mate again
  • Milk yield continues to decline until 'Dry Off' at 300 days after calving until re-calvin at 360 days 

Conventional Lactation: 3 risk periods 

Extended Lactation: 2 risk periods therefore Less milk/cow/year

Persistent Lactation: 3x day milking, Lower peak? Genetics?

Problems associated with Lactation

  • Decreased fertility
  • Compromised immune function
  • Increased lameness, mastitis
  • 'Metabolic Stress'
  • Problems are concentrated in early lactation

Product Composition

  • Major components of all milks is protein, fat and lactose (carbohydrate)
  • Bovine: 4% fat , 3.2% protein, 4.5% lactose
  • Human: low protein, high lactose
  • Rodent: High Fat and Protein
  • Aquatic Mammals: Very high fat, little lactose


  • Major proteins are the Caseins (>80%) found in curd
  • Whey proteins include;

-B lactoglobulin

-a lactalbumin

-Immunoglobulins; remember colostrum (and mastitis)

  • Casein types include a-s1, B, k, a-s2 and Y
  • Protein A2 beta Casein-Wiseman marketing for "lactose intolerance"
  • Processing properties and yield of cheese dependent on casein types and amount

Casein Variation

  • Composition and yield of Casein varies through lactation
  • As the Lactation weeks progress, Casein concentration generally increase g/l (peaks at 23)
  • As the Lactation weeks progress, Milk yield graually decreases kg/d/gland (peaks at 2.25)
  • As Lactation progresses, Y casein % increases gradually (peaks at 23%) whereas a casein gradually decreases (lowest at 12%).


  • Vital for Neonatal nutrition and survival
  • Health-conscious consumers avoid dairy fats
  • Semi-skimmed milks have become increasingly popular, however so has cream!
  • Conjugated Linoleic Acid- and omega-3 enriched milks are available;

-by dietary manipulation of animal (M&S)

-by post-processing supplementation

Variation in composition

  • Holstein (3.9% Fat, 3.2 % Protein)
  • Jersey (5.4% Fat, 3.9 % Protein)
  • As well as across breeds Variation also occurs;

-Across lactation

-Across milking

-With season

-According to nutrition


  • Pre-partum milk secretion that…


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