Farm animal Gestation period (days) Typical litter size Cattle 283 1 Sheep 150 1 - 3 Goat 150 1 - 3 Pig 114 8 - 14 (a) Table 1.1 shows the gestation periods...

(a)(i) The animal with the longest gestation period is cattle, at 283 days. [1] This is read directly from the table; sheep and goats both have 150 days, and pigs have 114 days.

(a)(ii) The difference in gestation period between cattle and sheep:

\[ 283 - 150 = 133 \text{ days} \]

Cattle gestation = 283 days [1]; sheep gestation = 150 days; difference = 133 days. [1]

(a)(iii) Pigs produce larger litters than cattle because:

1. Pigs are polytocous (naturally adapted to produce multiple offspring per pregnancy), whereas cattle are monotocous (typically producing a single calf). The pig ovary releases many ova during each oestrous cycle, so multiple embryos implant and develop simultaneously. [1]
2. This is an evolutionary and selective breeding adaptation: larger litters compensate for the pig's shorter gestation period and allow rapid population growth, which is advantageous for commercial meat production where high output per sow is the economic goal. [1]

(b) A farmer should keep accurate breeding records for the following reasons:

1. To predict expected dates of parturition (calving, lambing, farrowing), so that the farmer can prepare housing, equipment, and veterinary support in advance. [1]
2. To monitor fertility by identifying animals that repeatedly fail to conceive or have long calving intervals, allowing the farmer to cull poor performers and improve overall herd reproductive efficiency. [1]
3. To track parentage for selective breeding purposes and to avoid inbreeding, which can lead to reduced vigour, lower productivity, and increased susceptibility to disease (inbreeding depression). [1]