Animal Breeding and Genetics

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What proportion of differences between individuals is attributed to variations in their genetic makeup?

Half

Almost all

A quarter (correct)

Three-quarters

What is the average milk production of Holstein cows per season?

3500 kg

2500 kg

6000 kg

5000 kg (correct)

What happens to the milk yield of an animal if it is calved for the first time at an age younger than appropriate for its species?

It increases in the first season and subsequent seasons

It remains the same

It decreases in the first season and subsequent seasons (correct)

It increases only in the first season

Why does the nutrition of an animal at a young age not allow for the accumulation of effort and energy for milk production?

It is limited and insufficient to meet growth and fetal nutrition needs Signup and view all the answers

What is the primary reason for the focus on specific environmental factors in the study of milk yield?

Comprehensive knowledge of all environmental components is impractical Signup and view all the answers

What is the approximate milk production of local cows per season?

1200 kg Signup and view all the answers

What is the typical duration of the lactation season when milk secretion reaches its peak?

4-6 weeks Signup and view all the answers

What trait influences milk production by maintaining the highest daily milk yield for the longest duration?

Perseverance Signup and view all the answers

What is the benefit of cows being able to feed on forage materials without concentrated feed?

Reduced production costs Signup and view all the answers

What is the effect of increasing the calving interval on milk yield per season?

It increases Signup and view all the answers

What is the result of reducing the calving interval in European cattle?

A significant decrease in milk yield Signup and view all the answers

What is correlated with the duration of lactation?

Milk production Signup and view all the answers

What is the main reason why milking multiple times a day is not always adopted?

It is largely dependent on labor costs and the potential increase in milk yield Signup and view all the answers

What is the effect of increasing the frequency of milking on blood vessels and secretory cells in the udder?

It reduces pressure on blood vessels and secretory cells Signup and view all the answers

A cow is currently being milked 4 times a day. If the milking frequency is reduced to 3 times a day, what is the expected effect on milk yield?

It will decrease by 13% Signup and view all the answers

What is the effect of a longer interval between morning and evening milkings on milk yield?

It results in a significantly higher quantity of milk in the morning Signup and view all the answers

What is secreted by cows immediately after birth, and how long does it last?

Colostrum, lasts for 3-4 days Signup and view all the answers

If a cow is currently being milked 3 times a day and the milking frequency is increased to 4 times a day, what is the expected effect on milk yield?

It will increase by 13% Signup and view all the answers

What is the primary reason for the decrease in milk production during pregnancy?

Increase in the fetus's needs Signup and view all the answers

What is the average range of the service and gestation period in native dairy cattle?

2 to 3 months Signup and view all the answers

What is the calving interval in Egyptian cattle?

420 days Signup and view all the answers

What is the effect of reducing the service and gestation period by 85 days?

Decrease in milk yield Signup and view all the answers

What percentage decrease in milk production do cows with 8-month-old fetuses experience?

20% Signup and view all the answers

What is the relationship between the insemination period and milk yield in Egyptian cattle and buffalo?

Milk yield increases with an increase in the insemination period Signup and view all the answers

What is the insemination period in Egyptian buffalo?

177 days Signup and view all the answers

What is the primary factor affecting milk production in dairy cattle?

Nutrition Signup and view all the answers

What percentage of milk yield is obtained when dairy cattle are fed solely on roughage?

75-87% Signup and view all the answers

What is the ideal ratio of concentrated feeds to roughage in the diet?

40-60% Signup and view all the answers

What is the minimum proportion of concentrated feeds in the diet required for optimal milk production?

30% Signup and view all the answers

What is the result of feeding Friesian and Jersey cows on concentrates along with roughage?

Increase in milk production Signup and view all the answers