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Computers play a critical role in the management of my flock. I have
spent years developing an assortment of spreadsheets to not only keep
records, but use those records to make management decisions.
Selection:
I firmly believe that the cornerstone of any herd enterprise is its female base.
Assembling a winning team of ewes is every bit as challenging as putting
together a winning sports team. The key is to identify those
individuals who are "pulling the wagon" and those who are weighing it down.
There are numerous flock management programs available to manage flocks,
including Ewebyte, NSIP and others. None of these meet my need to
maximize the only parameter that I'm concerned with - profitability.
Starting in the fall of 2007, I have been developing software that
combines virtually every profit controlling parameter into single number -
what I call the Profitability Index (PI). Simply, the PI is the
amount of profit that the ewe is generating under given market conditions (I
currently use a 4 year average).
The index includes all variable costs (including labor), fixed costs, finish weight,
feed efficiency, prolificacy, heterosis and longevity.
The method not only helps me find those ewes that are making me the most
money, but also attempts to project future performance based on to-date
performance and historical data for sheep of that type (breed / cross).
Further, the software decouples each characteristic so that complimentary matings can be identified.
Finally, the software models the price
of lamb, corn and other feedstuffs to assist in marketing and
culling/retention decisions.
The software is not commercially available, in part, because it is not
fully automated.
Rations:
I use the NRC 2007 "Nutrient Requirements of Small Ruminants" to
compute
rations for highly productive sheep for
gestation and lactation periods. The
goal is to provide high performance rations at the least cost. In
current market conditions (everything is expensive), I find that means
meeting the nutritional requirements with extremely low feed waste.
Marketing:
I monitor and project lamb and feed prices to find the marketing date
that produces the maximum profit. That may mean selling the lambs as
feeder lambs all the way up to the upper end of Yield Grade 3.
Data:
I measure the following data:
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Prolificacy is measured by the number of lambs weaned per ewe
dry-lotted after breeding.
-
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
animal 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.
-
Ewe feed cost is computed from the ewe's mature weight
and production. 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. In 2010, the
average predicted feed efficiency for a group of about 40 lambs was
within 2% of the actual feed efficiency I measured. In 2011, the
predicted value was within 1% of the actual value.
Results - Mature Ewes:
I began using the software in Spring 2008 to select
replacement ewe lambs, rams and culls. For the first two years, I did
not have a scale, so the growth data was estimated. In 2010 and
2011, precise growth data was added. Results for ewes born on my
farm are presented below.
In 2011, I was able to hold the earlier gains in
production, but no progress was made over 2010. This is due, in part,
to a couple open ewes in 2011 (there weren't any open mature ewes in 2010).
Another negative factor for 2011 was reduced finish weights of the lambs,
due to three main sources:
- Very hot summer. In Eastern Iowa, the
summer of 2011 the heat killed a great deal of livestock. I was
fortunate in that none of my lambs died, but nearly 2 weeks of 110-115
degree heat indexes definitely impacted gains.
- Cold winter. About half of my lambs were
born in February 2011, which was very windy and cold. While the sheep
were housed in open-faced sheds, the very low temperatures probably
retarded neo-natal gains. I don't think the cold was as much of a
factor as the heat though.
- The rams I used for the 2011 were physically
smaller than those used for the 2010 crop. However, the 2011 sires
were from more prolific lines, which should start to show up as more
prolific ewes in the coming years.
In summary, I believe there is more upside
potential in the mature ewes. Even though lambing rates have been
stagnating, weaning rates are still on the rise. The upcoming ewe
lambs appear to be more prolific than any I've had before. I also
think there is upside for the finish weights, as the data collected from
the scale works its way through the system. Results
- Ewe Lambs:
As mentioned above, I did not start weighing lambs until 2010, so
only 2 years of "lbs of finished lamb" is available.
The ewe lambs that lambed in 2011 caught me by
surprise. With a 207% drop rate, nutrition became very critical.
I was not prepared. Although the rations I offered them met the NRC
requirements, they did not consume as much as the NRC predicted. The
result was that some of the ewe lambs that were carrying triplets developed
ketosis, and those litters were lost (one set of triplets was weaned by Pink
2). A couple ewe lambs carrying twins also became mildly ketotic, but
their lambs survived. In addition, because the ewe lambs had a low
body condition score, they did not milk as well as other years.
For the coming 2012 crop, I have moved toward custom
pelleted feed with limited hay. This new feeding program was started
well before breeding. The pre-breeding ration was not as energy rich
as last year's, which may lower the drop rate some. However, the
post-breeding ration is more energy-rich and TDN consumption is up nearly
20% over last year (so far - fingers crossed!). My hope is that the
potentially lowered drop rates will be more than compensated for by
increased survival and growth rates.
Note
It is important to remember that the software selects for total profitability.
Since the last couple years have been pretty good for the sheep industry
profits, the software has 'relaxed' the selection pressure to capture higher
total profit in lieu of maximum per unit profits. The result is
somewhat stagnate production progress. |
