3 Fig. 3.1 shows a zero-grazing unit used for keeping dairy cattle on a small-scale farm. (a) State two advantages of keeping dairy cattle in a zero-grazing...

Labelled answer diagram:

(a) Two advantages of a zero-grazing unit over free-range grazing:

1. Feed intake can be controlled and measured accurately, allowing the farmer to optimise nutrition for each animal and maximise milk production. [1]
2. Animals use less energy because they do not walk long distances to find pasture, so more energy is directed towards growth and milk yield. [1]

Other acceptable answers: easier to monitor individual animal health; land use is more efficient as less grazing area is needed; milk yield can be higher due to better feeding management.

(b) Structure X is the feeding trough (manger). [1] Its function is to hold cut fodder (such as Napier grass) or concentrate feed so the cattle can eat without wasting food on the ground. [1]

(c) Two materials for the floor of a zero-grazing unit:

1. Concrete (durable, easy to clean, allows drainage when sloped). [1]
2. Compacted earth (cheaper to construct but requires more maintenance). [1]

Other acceptable materials: stone slabs, brick.

(d) How housing design reduces internal parasite spread:

1. A sloped concrete floor with a drainage channel allows urine and wash water to flow away quickly, keeping the floor dry. [1]
2. Dry conditions prevent the survival and development of parasite eggs and larvae (e.g. roundworm larvae), which require moisture to complete their life cycle. This breaks the transmission pathway. [1]

(e) Two features for keeping animals comfortable in hot weather:

1. Open sides or large ventilation openings that allow free air circulation to dissipate body heat. [1]
2. A high roof that lets hot air rise and escape, or a wide roof overhang that provides shade and reduces direct solar heating of the interior. [1]

Other acceptable: trees planted nearby for additional shade.

(f) Two problems with a zero-grazing system compared to free-range:

1. The farmer must cut and carry all fodder to the animals every day, which requires substantially more labour and time. [1]
2. The cost of building and maintaining the housing structure is high compared to simply allowing animals to graze on open pasture. [1]

Other acceptable answers: animals may develop foot problems or sores from standing on hard floors for long periods; if the fodder supply fails, the animals have no alternative food source.