Question

the following information was obtained from a farmers record book
number of ewes mated = 800
number of ewes pregnant = 775
» of ewes lambed down = 760
» of lamb born = 1090
» of lamb hooped = 1020
calculate:
conception rate
lambing percentage
weaning rate
mortality rate
survival rate
twinning rate

Explanation:

Conception rate

Step1: Formula

Conception rate = (Number of ewes pregnant / Number of ewes mated) × 100

Step2: Substitute values

Number of ewes mated = 800, number of ewes pregnant = 775
Conception rate = ($\frac{775}{800}$) × 100 = 96.875%

Lambing percentage

Step1: Formula

Lambing percentage = (Number of ewes lambed down / Number of ewes mated) × 100

Step2: Substitute values

Number of ewes mated = 800, number of ewes lambed down = 760
Lambing percentage = ($\frac{760}{800}$) × 100 = 95%

Weaning rate

Step1: Formula

Weaning rate = (Number of lambs weaned / Number of lambs born) × 100

Step2: Substitute values

Number of lambs born = 1090, number of lambs weaned = 1020
Weaning rate = ($\frac{1020}{1090}$) × 100 ≈ 93.58%

Mortality rate

Step1: Formula

Mortality rate = [(Number of lambs born - Number of lambs weaned)/Number of lambs born] × 100

Step2: Substitute values

Number of lambs born = 1090, number of lambs weaned = 1020
Mortality rate = [$\frac{1090 - 1020}{1090}$] × 100 = ($\frac{70}{1090}$) × 100 ≈ 6.42%

Survival rate

Step1: Formula

Survival rate = (Number of lambs weaned / Number of lambs born) × 100 (same as weaning rate in this context as we assume no pre - weaning losses other than those accounted for in the formula)

Step2: Substitute values

Number of lambs born = 1090, number of lambs weaned = 1020
Survival rate = ($\frac{1020}{1090}$) × 100 ≈ 93.58%

Twinning rate

Step1: Formula

Assume average number of lambs per birth. First, find total number of births. Since number of ewes lambed down = 760 (assuming single - birth per ewe for simplicity, if we consider twinning as multiple lambs per birth). Number of lambs born = 1090.
Twinning rate = [(Number of lambs born - Number of ewes lambed down)/Number of ewes lambed down] × 100

Step2: Substitute values

Number of ewes lambed down = 760, number of lambs born = 1090
Twinning rate = [$\frac{1090 - 760}{760}$] × 100 = ($\frac{330}{760}$) × 100 ≈ 43.42%

Answer:

• Conception rate: 96.875%
• Lambing percentage: 95%
• Weaning rate: ≈ 93.58%
• Mortality rate: ≈ 6.42%
• Survival rate: ≈ 93.58%
• Twinning rate: ≈ 43.42%