I use a lot of data to manage my
flock. The following data is collected and analyzed:
Prolificacy is measured by the number of lambs weaned per ewe
dry-lotted after scanning.
Ewe longevity is measured by the ewe's age.
Growth is measured by taking 3 weights of the lambs.
Generally, these are at weaning, around 100 days and right before
slaughter. The weights are then standardized to 60, 120 and 180
day values by curve fitting the 3 measurements to the Gompertz growth
function. The Gompertz growth function is a mathematical model for
growth. It accounts for the fact that a lamb's growth rate
continuously varies with time. This is particularly important
because growth starts to decline as they 'finish' or put on fat. This method is more accurate and far less optimistic than the linear
methods used by virtually everyone else.
Ewe feed cost is computed from the ewe's mature weight
and weaning rate. Ewes
are weighed once a year and adjusted to Body Condition Score 3.
Feed efficiency is computed from the 60, 120 and 180 day weights
using a relationship between body weight and feed intake.
Labor. Prior to 2012,
labor costs were distributed evenly across the ewe flock. Starting in 2012, an
estimate of individual annual labor requirements is assigned to each
principle differentiator is the number of assisted births. The goal of the labor tracking
is to make sure that production levels are optimized with labor
requirements. Labor requirements have been used in
determining ewe lamb selections starting with the 2013 crop.
This data is used to rank ewes by
their financial performance, using a 4-year average. This ranking,
along with constraints to limit prolificacy and lambing problems is used to
select breeding stock and identify culls.
I began using this data-driven approach in Spring 2008. For the first two years, I did
not have a scale, so the growth data was estimated. Starting In 2010, precise growth data was added.
In 2014, I began limiting prolificacy in
order to reduce labor requirements. Specifically, ewes were no longer allowed to wean
quads, very problematic ewes were culled and lambing ease became a
Production results for mature ewes born on my
farm are presented below. Results are tracked starting from 2013
due to a copper poisoning issue in 2012. Finish weights are standardized to
Production has generally remained constant. This is despite
removing the ultra-prolific ewes from my flock and reducing assisted
births. The goal is profitability - not production at all
Results for ewe lambs are shown below. Trendline production is decreasing from 2013 levels, which is
a result of intentional prolificacy reduction. Since 2016,
there has been a steady increase of about 4 lbs of finished lamb per