Farm animal Gestation period / days Average litter size Cow 283 1 Sow 114 10 Ewe 150 2 Doe (goat) 150 2 Table 1 shows the gestation periods and average litt...

(a) The animal with the shortest gestation period is the sow, at 114 days. [1] Gestation period is the time from fertilisation to birth. Among the four species listed, pigs carry their young for the least time, which is linked to the relatively small size of individual piglets at birth.

(b) The sow has a larger average litter size than the cow for two main reasons:

1. The sow has a large uterus with two long uterine horns, providing enough space for many embryos to implant and develop simultaneously. [1]
2. Pigs have evolved to produce large litters as a reproductive strategy to compensate for higher natural mortality rates among piglets. Because each piglet is small and vulnerable, producing many offspring increases the chance that enough survive to adulthood. [1]

In contrast, the cow invests heavily in a single large calf, which has a better chance of individual survival but limits litter size to one.

(c) Three signs that a ewe is approaching parturition (lambing):

1. Swelling of the vulva - the vulva becomes enlarged and reddened as hormonal changes prepare the birth canal. [1]
2. Udder development - the udder enlarges and fills with colostrum in the days before lambing, indicating that milk production is being initiated. [1]
3. Restlessness and separation from the flock - the ewe becomes agitated, paws at the ground, and moves away from other sheep to find a quiet place to give birth. [1]

Other acceptable signs include: a hollow appearing either side of the tail head as pelvic ligaments relax, and mucus discharge from the vulva.

(d) Colostrum is the first milk produced by the mother immediately after birth, and it is vital for two reasons:

1. It contains antibodies (immunoglobulins) that provide passive immunity to the newborn. [1] Young livestock are born with very little immune protection of their own; absorbing maternal antibodies through colostrum within the first 6-24 hours of life shields them against common diseases until their own immune system matures.
2. Colostrum is rich in energy, vitamins, and proteins that are essential for early growth and survival. [1] It has a higher concentration of nutrients than ordinary milk, giving the newborn the energy it needs to maintain body temperature and begin growing.

(e) Two management practices a farmer should carry out immediately after a calf is born:

1. Clear mucus from the nostrils and mouth to ensure the calf can breathe freely. [1] During birth the airways may be blocked by fluid, and failure to clear this can lead to suffocation.
2. Dip the navel cord in iodine solution to prevent infection. [1] The freshly cut umbilical cord is an open entry point for bacteria; applying iodine disinfects it and promotes drying, reducing the risk of navel ill (joint ill).