Sow Number of litters per year Total piglets born alive Total piglets weaned A 2 24 22 B 2 20 18 C 2 22 14 D 1 11 10 (a) A pig farmer wants to improve the r...

(a)(i) The average gestation period of a sow is approximately 114 days, often remembered as "3 months, 3 weeks, and 3 days". [1]

(a)(ii) Calculating expected piglets over three years:

Farrowings per year = 2

Over 3 years: \( 2 \times 3 = 6 \) farrowings [1]

Total piglets = \( 6 \times 10 = \mathbf{60} \) piglets [1]

(b) Four management practices to ensure high piglet survival in the first week:

1. Provide a warm farrowing environment: Install a heat lamp or create a heated creep area for the piglets, as newborn piglets cannot regulate their body temperature effectively and are highly susceptible to hypothermia, which is a leading cause of neonatal death. [1]
2. Supervise farrowing and prevent overlaying: Ensure the sow is monitored during and after farrowing. Farrowing crates or rails can be used to prevent the sow from lying on (crushing) the piglets, which is one of the most common causes of piglet mortality. [1]
3. Ensure early colostrum intake: Make sure all piglets suckle colostrum within the first 6-12 hours of birth. Colostrum provides antibodies for passive immunity, and the piglet's gut can only absorb these immunoglobulins during this narrow window. [1]
4. Clip needle teeth and treat navels: Clip the sharp needle teeth of piglets shortly after birth to prevent injury to the sow's teats and to littermates during competition for teats. Apply iodine to each piglet's navel stump to prevent bacterial infection. Administer iron injections within the first few days to prevent iron-deficiency anaemia, as sow's milk is low in iron. [1]

(c) Pregnancy diagnosis determines whether a sow has conceived after mating. Two methods:

1. Non-return to oestrus: If the sow does not show signs of heat approximately 21 days after mating, she is likely pregnant. The farmer watches for behavioural signs of oestrus (restlessness, standing reflex, swollen vulva). This method is simple and cost-free but not completely reliable, as some sows may have a "silent heat" that goes undetected. [2]
2. Ultrasound scanning: A portable ultrasound scanner is applied to the flank of the sow from about 25-30 days after mating. It detects the presence of fluid-filled embryonic vesicles or foetal heartbeats. This method is more accurate, provides earlier confirmation, and can give an estimate of litter size. [2]

(d)(i) Sow A had the best overall reproductive performance. [1] She produced the highest number of piglets weaned (22 from 24 born alive across two litters), meaning 91.7% of her piglets survived to weaning. This combines both high prolificacy (24 born alive) and excellent mothering ability or management conditions (only 2 pre-weaning deaths). [1]

(d)(ii) Sow C had only 14 piglets weaned from 22 born alive (a loss of 8 piglets, or 36%), which is significantly worse than the other sows. Possible reasons include:

1. The sow may have overlaid (crushed) several piglets, particularly if the farrowing pen lacked adequate crate protection or the sow was restless. [1]
2. Piglets may have died from disease, infection, or insufficient milk supply. If the sow had mastitis or poor teat function, weaker piglets could not compete for milk and starved. Alternatively, a disease outbreak (such as scours) may have killed piglets in the early neonatal period. [1]