Effects of Cow Rearing on Milk Quality

Questions and Answers

What is the effect of underfeeding cows on milk production?

Has no significant impact on milk quality

Increases volume of output and lowers fat content

Decreases both volume and fat content of output

Increases fat content while reducing volume of output (correct)

Which characteristic describes colostrum produced within the first 7 days after calving?

Saltier in taste and thicker in viscosity (correct)

Thinner viscosity, less yellow in color

Lower in nutrients and antibodies than regular milk

High lactose and low fat content

What happens to fat globules in fresh, unprocessed milk when the milk stands?

They rise to the surface and form cream due to density differences (correct)

They increase in size and form a stable emulsion

They become smaller and aggregate into larger clusters

They dissolve completely into the watery portion of the milk

How does severe mastitis in cows affect their milk?

Increases fat and salt content while decreasing lactose Signup and view all the answers

What is the primary role of casein in milk?

To precipitate and form curd in cheese production Signup and view all the answers

What is a consequence of prolonged heating of milk in terms of whey proteins?

They denature and may lead to scum formation on the surface. Signup and view all the answers

What is the purpose of fortifying milk with Vitamin D?

To improve absorption of calcium and phosphorus. Signup and view all the answers

What effect does homogenisation have on milk?

It reduces the size of fat globules to prevent separation. Signup and view all the answers

Which mineral is particularly valued for its presence in milk?

Calcium Signup and view all the answers

What occurs if too much non-fat dry milk is added to ice cream?

It imparts a sandy texture due to lactose crystallization. Signup and view all the answers

Study Notes

Rearing of Cows and Milk Quality

Cows fed grains produce milk with higher fat content compared to those on grass.
Nutrient deficiencies in cows lead to them delivering essential nutrients to milk at the expense of their health.
Underfeeding results in increased fat content and reduced milk volume.

Stages of Lactation

Colostrum, produced within the first 7 days post-calving, is nutrient-rich, containing antibodies and growth factors.
Colostrum is saltier, thicker, and more yellow than regular milk.
Acceptance of colostrum decreases after the first 6 days.

Illness Impact on Milk

Severe mastitis reduces milk production and alters milk composition, increasing fat and salt while decreasing lactose content.

Composition and Properties of Milk

Fat: Known as milkfat or butterfat, contains short-chain saturated fatty acids like butyric and caproic acids.
Fat globules cluster into larger groups when standing, resulting in cream rising due to fat's lower density.
Homogenization reduces globule size preventing creaming.
Protein: Milk is a complete protein source with casein and whey as the primary proteins.
- Casein: Precipitates during cheese-making and forms a soft curd at pH 4.6, causing milk to become opaque.
- Whey: Heat-sensitive, denatures with prolonged heating, contributing to scum formation on heated milk.
Lactose: Known as milk sugar, less sweet and less soluble; excess can lead to a sandy texture in frozen products.
Minerals: Contains essential minerals like calcium, phosphorus, magnesium, and sodium, with notable calcium value.

Milk Production Processing Steps

Centrifugation & Separation: Skim milk has most fat removed, achieving a lower fat content.
Fortification: Nutrient addition enhances milk's nutritional value; Vitamin D supports calcium and phosphorus absorption, while Vitamin A is added to low-fat and skim milk.
Homogenization: Prevents cream separation by breaking fat globules into smaller units under high pressure, ensuring uniformity.
Heat Treatment: Involves pasteurization to eliminate pathogens and extend shelf life.
Filling & Packaging: Ensures proper storage for freshness and hygiene.
Cooling: Rapidly cools milk post-processing to inhibit microbial growth.
Distribution: Transport of milk to retailers while maintaining quality and safety.

Description

This quiz explores how different rearing practices of cows impact the nutritional and physical quality of milk. It delves into factors such as diet, stages of lactation, and the consequences of nutrient deficiencies on milk production. Test your knowledge on the relationship between cow nutrition and milk characteristics.