1. What is the average milk solids production per cow in Eamonn Connaughton’s herd under the once-a-day (OAD) milking system?
The cows in Connaughton’s herd produce an average of 410kg of milk solids per cow annually under the OAD milking system.2. How has the six-week calving rate changed since the transition to OAD milking?
The six-week calving rate has reached nearly 90%, indicating improved herd fertility.3. What are the possible reasons why once-a-day milking has led to improved cow health and fertility?
Less physical stress: Cows are not required to walk to the milking parlour twice a day, reducing fatigue and hoof-related issues.Better body condition: Lower energy expenditure allows cows to maintain better body condition, which can lead to improved fertility.Reduced udder strain: Less frequent milking may lower the risk of mastitis and other udder health problems.More time for grazing and rest: Cows spend more time feeding and resting, contributing to overall well-being.4. Considering the reduction in milk yield, why might a farmer still choose OAD milking over the traditional twice-a-day system?
Lower labour costs: OAD milking requires fewer work hours, making it more manageable for farmers with limited labour availability.Improved work-life balance: Farmers can spend less time milking and more time on other farm activities or personal commitments.Reduced operational costs: Savings on electricity, feed, and veterinary costs help offset the lower milk production.Sustainability benefits: A less intensive system may reduce environmental impact and improve long-term farm sustainability.Leaving Cert Agricultural Science – Higher Level Dairy Sample Answers
Section A: Short Answer Questions (10 marks each)
1. List three factors that affect milk composition and explain how each one influences milk quality.
Breed: Holstein-Friesians produce high milk yield but lower butterfat, while Jerseys produce lower yield but higher milk solids.Diet: High-fiber diets increase butterfat content, while high-energy feeds boost protein levels.Stage of lactation: Milk fat is higher after calving, drops mid-lactation, and rises again before drying off.2. Describe two key differences between liquid milk production and manufacturing milk production.
Calving System: Liquid milk production requires year-round calving for continuous supply, whereas manufacturing milk production is seasonal (mostly spring calving) to align with grass growth.Milk Quality: Liquid milk production focuses on quantity, while manufacturing milk prioritizes high milk solids for better processing.3. Explain why colostrum is essential for a newborn calf and outline two of its key functions.
Colostrum provides antibodies that protect against infections, as calves are born without immunity.Key Functions:
Boosts immunity – Essential for disease resistance. Acts as a laxative – Clears the digestive system for nutrient absorption.4. What are the benefits of using a leader-follower grazing system for young calves?
Reduced parasite exposure – Young calves graze fresh grass first, lowering the risk of ingesting worm larvae.Improved grass quality – Young calves get better nutrition, as they graze the best parts first.5. Give two advantages and two disadvantages of using Artificial Insemination (AI) in dairy breeding.
Advantages:
Access to superior genetics – Farmers can use high-EBI bulls without keeping a bull on-farm. Safer than natural service – Reduces the risk of injury from bulls.Disadvantages:
Requires heat detection – Farmers must identify cows in heat. May have lower conception rates than natural service.6. Describe two common dairy cow diseases and suggest one method of prevention for each.
Mastitis: Udder infection that increases SCC. Prevention: Maintain strict milking hygiene.Milk Fever: Calcium deficiency post-calving. Prevention: Provide high-calcium supplements before calving.7. Explain why drying off cows before calving is important for milk production and udder health.
Allows udder tissue to recover, ensuring maximum milk yield in the next lactation.Reduces the risk of mastitis by allowing the use of dry cow therapy.8. How can a farmer reduce the risk of mastitis in a dairy herd? Provide two practical strategies.
Proper milking hygiene: Use teat disinfectants before and after milking.Reduce stress: Provide clean, dry bedding and avoid overcrowding.9. What is the Economic Breeding Index (EBI), and how does it help improve herd genetics?
EBI is a profitability index (€ per lactation) developed by Teagasc & ICBF.Helps farmers select cows with high fertility, milk solids, and longevity for breeding.10. Why is rotational grazing important in dairy farming? List two benefits.
Maintains high-quality grass: Cows always graze fresh regrowth.Prevents overgrazing: Helps maximize pasture production.Section B: Structured Questions (50 marks each)
Question 1: Milk Production & Dairy Systems
(a) Compare and contrast liquid milk and manufacturing milk production.
Milk production & dairy system table 2- Ag Science revision supplement
(b) Describe how the A + B – C milk pricing formula works and explain how it influences farmer decision-making. (10 marks)
A (Protein price) + B (Butterfat price) - C (Processing charge) = Price per liter.Encourages farmers to increase milk solids rather than just yield.(c) Outline the steps in the milking process to ensure milk hygiene and quality. (10 marks)
1. Brush teats to remove dirt.
2. Forestrip (2-3 squirts) to detect mastitis.
3. Pre-dip with disinfectant.
4. Attach cluster to teats for milking.
5. Post-dip to kill bacteria.
6. Cool milk to 4°C within 30 minutes.
(d) Explain the role of grass-based feeding systems in dairy production and discuss two advantages of this system. (10 marks)
Advantages:
Low-cost feed source (cheaper than concentrates). Better milk solids compared to silage feeding.(e) Suggest two sustainable farming practices that can help reduce the environmental impact of dairy farming. (8 marks)
Use of multi-species swards – Improves soil health.Slurry management – Prevents water pollution.Question 2: Calving & Calf Rearing
(a) Describe three management practices that should be followed to prepare a cow for calving. (12 marks)
1. Use easy-calving bulls for heifers.
2. Monitor BCS (3.0 – 3.5) to avoid calving issues.
3. Provide clean calving pens with dry bedding.
(b) Explain the importance of colostrum and describe the best management practices for feeding it to newborn calves. (10 marks)
Provides immunity and nutrients.Best practice: Feed 3L within 2 hours of birth.(c) Outline the main steps involved in calf tagging and dehorning, and explain why these practices are necessary. (10 marks)
Tagging: Apply EID tags within 20 days.Dehorning: Use a disbudding iron (1-2 weeks old) to prevent injuries.(d) Discuss the nutritional needs of a calf from birth to weaning, including details on milk replacers, concentrates, and grass feeding. (10 marks)
Colostrum (Day 1-3) ? Milk or milk replacer (Weeks 1-6).Hay and concentrates introduced from Week 2.Weaning at 6-8 weeks onto grass and concentrates.(e) Explain how a farmer can prevent scours in young calves and describe two treatments if scours occur. (8 marks)
Prevention: Maintain hygiene in housing and avoid overfeeding milk.Treatment: Provide electrolytes, isolate sick calves, and call a vet if severe.Section C: Extended Response Question (50 marks)
Question 3: Dairy Sustainability & Breeding
(a) The role of the Economic Breeding Index (EBI) in improving dairy herd genetics. (10 marks)
Helps select cows for high fertility, milk yield, and health traits.Reduces reliance on low-performing cows.(b) The challenges of sustainable intensification in dairy farming and how farmers can address them. (10 marks)
More production = Higher environmental impact.Requires efficient nutrient and slurry management.(c) Two methods of reducing methane emissions from dairy cattle. (10 marks)
1. Feed additives (e.g., seaweed supplements) reduce methane production.
2. Breeding for low-emission cows using EBI.
(d) How dairy farmers can improve water and soil management to ensure long-term sustainability. (10 marks)
Rainwater collection for cleaning and irrigation.Reduced ploughing to maintain soil structure.(e) The advantages and disadvantages of robotic milking systems in modern dairy farming. (10 marks)
Advantages:
Reduces labor costs. Allows cows to be milked on demand.Disadvantages:
High installation costs. Requires technical knowledge.
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1. What is the average milk solids production per cow in Eamonn Connaughton’s herd under the once-a-day (OAD) milking system?
The cows in Connaughton’s herd produce an average of 410kg of milk solids per cow annually under the OAD milking system.2. How has the six-week calving rate changed since the transition to OAD milking?
The six-week calving rate has reached nearly 90%, indicating improved herd fertility.3. What are the possible reasons why once-a-day milking has led to improved cow health and fertility?
Less physical stress: Cows are not required to walk to the milking parlour twice a day, reducing fatigue and hoof-related issues.Better body condition: Lower energy expenditure allows cows to maintain better body condition, which can lead to improved fertility.Reduced udder strain: Less frequent milking may lower the risk of mastitis and other udder health problems.More time for grazing and rest: Cows spend more time feeding and resting, contributing to overall well-being.4. Considering the reduction in milk yield, why might a farmer still choose OAD milking over the traditional twice-a-day system?
Lower labour costs: OAD milking requires fewer work hours, making it more manageable for farmers with limited labour availability.Improved work-life balance: Farmers can spend less time milking and more time on other farm activities or personal commitments.Reduced operational costs: Savings on electricity, feed, and veterinary costs help offset the lower milk production.Sustainability benefits: A less intensive system may reduce environmental impact and improve long-term farm sustainability.Leaving Cert Agricultural Science – Higher Level Dairy Sample Answers
Section A: Short Answer Questions (10 marks each)
1. List three factors that affect milk composition and explain how each one influences milk quality.
Breed: Holstein-Friesians produce high milk yield but lower butterfat, while Jerseys produce lower yield but higher milk solids.Diet: High-fiber diets increase butterfat content, while high-energy feeds boost protein levels.Stage of lactation: Milk fat is higher after calving, drops mid-lactation, and rises again before drying off.2. Describe two key differences between liquid milk production and manufacturing milk production.
Calving System: Liquid milk production requires year-round calving for continuous supply, whereas manufacturing milk production is seasonal (mostly spring calving) to align with grass growth.Milk Quality: Liquid milk production focuses on quantity, while manufacturing milk prioritizes high milk solids for better processing.3. Explain why colostrum is essential for a newborn calf and outline two of its key functions.
Colostrum provides antibodies that protect against infections, as calves are born without immunity.Key Functions:
Boosts immunity – Essential for disease resistance. Acts as a laxative – Clears the digestive system for nutrient absorption.4. What are the benefits of using a leader-follower grazing system for young calves?
Reduced parasite exposure – Young calves graze fresh grass first, lowering the risk of ingesting worm larvae.Improved grass quality – Young calves get better nutrition, as they graze the best parts first.5. Give two advantages and two disadvantages of using Artificial Insemination (AI) in dairy breeding.
Advantages:
Access to superior genetics – Farmers can use high-EBI bulls without keeping a bull on-farm. Safer than natural service – Reduces the risk of injury from bulls.Disadvantages:
Requires heat detection – Farmers must identify cows in heat. May have lower conception rates than natural service.6. Describe two common dairy cow diseases and suggest one method of prevention for each.
Mastitis: Udder infection that increases SCC. Prevention: Maintain strict milking hygiene.Milk Fever: Calcium deficiency post-calving. Prevention: Provide high-calcium supplements before calving.7. Explain why drying off cows before calving is important for milk production and udder health.
Allows udder tissue to recover, ensuring maximum milk yield in the next lactation.Reduces the risk of mastitis by allowing the use of dry cow therapy.8. How can a farmer reduce the risk of mastitis in a dairy herd? Provide two practical strategies.
Proper milking hygiene: Use teat disinfectants before and after milking.Reduce stress: Provide clean, dry bedding and avoid overcrowding.9. What is the Economic Breeding Index (EBI), and how does it help improve herd genetics?
EBI is a profitability index (€ per lactation) developed by Teagasc & ICBF.Helps farmers select cows with high fertility, milk solids, and longevity for breeding.10. Why is rotational grazing important in dairy farming? List two benefits.
Maintains high-quality grass: Cows always graze fresh regrowth.Prevents overgrazing: Helps maximize pasture production.Section B: Structured Questions (50 marks each)
Question 1: Milk Production & Dairy Systems
(a) Compare and contrast liquid milk and manufacturing milk production.
Milk production & dairy system table 2- Ag Science revision supplement
(b) Describe how the A + B – C milk pricing formula works and explain how it influences farmer decision-making. (10 marks)
A (Protein price) + B (Butterfat price) - C (Processing charge) = Price per liter.Encourages farmers to increase milk solids rather than just yield.(c) Outline the steps in the milking process to ensure milk hygiene and quality. (10 marks)
1. Brush teats to remove dirt.
2. Forestrip (2-3 squirts) to detect mastitis.
3. Pre-dip with disinfectant.
4. Attach cluster to teats for milking.
5. Post-dip to kill bacteria.
6. Cool milk to 4°C within 30 minutes.
(d) Explain the role of grass-based feeding systems in dairy production and discuss two advantages of this system. (10 marks)
Advantages:
Low-cost feed source (cheaper than concentrates). Better milk solids compared to silage feeding.(e) Suggest two sustainable farming practices that can help reduce the environmental impact of dairy farming. (8 marks)
Use of multi-species swards – Improves soil health.Slurry management – Prevents water pollution.Question 2: Calving & Calf Rearing
(a) Describe three management practices that should be followed to prepare a cow for calving. (12 marks)
1. Use easy-calving bulls for heifers.
2. Monitor BCS (3.0 – 3.5) to avoid calving issues.
3. Provide clean calving pens with dry bedding.
(b) Explain the importance of colostrum and describe the best management practices for feeding it to newborn calves. (10 marks)
Provides immunity and nutrients.Best practice: Feed 3L within 2 hours of birth.(c) Outline the main steps involved in calf tagging and dehorning, and explain why these practices are necessary. (10 marks)
Tagging: Apply EID tags within 20 days.Dehorning: Use a disbudding iron (1-2 weeks old) to prevent injuries.(d) Discuss the nutritional needs of a calf from birth to weaning, including details on milk replacers, concentrates, and grass feeding. (10 marks)
Colostrum (Day 1-3) ? Milk or milk replacer (Weeks 1-6).Hay and concentrates introduced from Week 2.Weaning at 6-8 weeks onto grass and concentrates.(e) Explain how a farmer can prevent scours in young calves and describe two treatments if scours occur. (8 marks)
Prevention: Maintain hygiene in housing and avoid overfeeding milk.Treatment: Provide electrolytes, isolate sick calves, and call a vet if severe.Section C: Extended Response Question (50 marks)
Question 3: Dairy Sustainability & Breeding
(a) The role of the Economic Breeding Index (EBI) in improving dairy herd genetics. (10 marks)
Helps select cows for high fertility, milk yield, and health traits.Reduces reliance on low-performing cows.(b) The challenges of sustainable intensification in dairy farming and how farmers can address them. (10 marks)
More production = Higher environmental impact.Requires efficient nutrient and slurry management.(c) Two methods of reducing methane emissions from dairy cattle. (10 marks)
1. Feed additives (e.g., seaweed supplements) reduce methane production.
2. Breeding for low-emission cows using EBI.
(d) How dairy farmers can improve water and soil management to ensure long-term sustainability. (10 marks)
Rainwater collection for cleaning and irrigation.Reduced ploughing to maintain soil structure.(e) The advantages and disadvantages of robotic milking systems in modern dairy farming. (10 marks)
Advantages:
Reduces labor costs. Allows cows to be milked on demand.Disadvantages:
High installation costs. Requires technical knowledge.
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