October 1, 1998
Forage Systems Update
Vol 7, No. 4
Weaning on Pasture for Low-stress Beef Production
Jim Gerrish
University of Missouri - Forage Systems Research Center
INTRODUCTION
Four types of stress commonly affect calves at weaning: 1) physical,
2) environmental, 3) nutritional, and 4) social. Severe physical
stress occurs if castration or dehorning coincide with weaning.
Lesser physical stresses may include long periods standing in
working facilities, physical abuse in the working chute, hauling to
weaning facility, among others. Environmental stresses fall into
two categories, man-made and climatic. The primary man-made
environmental stress is the weaning pen itself, whether it be drylot
or a mud lot. Other climatic factors such as rain, ice, snow, and
freezing temperatures are beyond our control but timing of weaning
must be considered based on these factors. Nutritional stress
occurs when calves are changed from a milk and green pasture diet to
dry ration of forage and grain. The social stress of removal of the
calf from its dam and herdmates is inevitable by the definition of
weaning. All of these stresses compound upon one another to weaken
the immune system and increase the risk of sickness. One goal of
our management should be to reduce stress to ensure healthy,
productive calves moving on to the next stage of beef production.
Pasture weaning offers a low-stress alternative to conventional
drylot weaning programs. Pasture weaning minimizes environmental
and nutritional stress by keeping calves in an environment and on a
diet that they are used to. The pasture is usually a clean, healthy
environment for cattle. Moving them from this environment to a
dusty drylot where they may walk steadily for several hours churning
up dust frequently leads to respiratory ailments. Weaning calves on
high quality spring or fall pasture keeps them on a similar plane of
nutrition as they have been receiving. Social stress of removal
from the dam and herd can be reduced with the use of cross-fence
weaning. With forward planning including castration at birth, use
of polled bulls, electric dehorning at spring roundup, and pre-
vaccination, physical stress on the calf at weaning can be all but
eliminated.
Pasture weaning has been used at the University of Missouri-Forage
Systems Research Center since 1985 as a routine herd management
practice with over 2400 calves being handled through this process.
At FSRC only spring born calves have been involved but pasture
weaning will work equally well for fall born calves weaned in the
spring. As with any good management practice, forward planning and
some preparation is required for pasture weaning to be successful.
This article provides information for pasture and herd preparation
for weaning and actual weaning period management.
PASTURE PREPARATION
It is critical to have good availability of high quality pasture at
weaning time in both spring or fall. This will ensure that the
calves have a diet which they will perform well on as well as a
clean environment. For fall weaned calves, hay regrowth or
stockpiled fescue provide excellent opportunities for pasture
weaning. The following guidelines will help ensure quality pasture.
Pastures to be used for fall weaning should be either grazed short
or clipped between mid-August and mid-September depending upon
specific objectives. Maximum stockpile yield is usually achieved in
about 75 days during the late summer-fall growing season. Managing
for maximum yield generally results in lower forage quality than
calves require. If the sward is top grazed with the calves only
harvesting 25 to 35% of the available forage, calf performance will
still be acceptable. If cows are expected to graze the residual
forage after calves have been moved off pastures, maximum yield
strategy can work. If only calves are expected to use the pasture,
shortening the stockpile growth period to 30 to 50 days will result
in much higher quality forage.
Applying 40 to 60 lbs N/acre will accelerate growth and provide
slightly higher quality forage for the calves. If at least 40% of
the annual production of the pasture is from legumes, adding N is
not likely to be cost effective. Grass-legume pastures can provide
very good quality fall and early winter pastures but should be
utilized earlier in the winter before stockpiled fescue pastures as
the legumes deteriorate in quality much more rapidly than does tall
fescue.
For spring weaned calves, early first-growth pasture will be of
excellent quality as long as vegetative conditions are maintained.
If the forage becomes too mature before weaning occurs, performance
and health during the weaning period may be reduced. If calves are
not weaned until June or July, clipping pastures early or using
regrowth on early cut hay fields can provide excellent quality early
summer weaning pastures.
CALF PREPARATION
A sound, ongoing herd health program will help ensure healthy calves
at weaning. Maintaining a regular vaccination schedule for both
cows and calves is usually much less expensive than doctoring sick
calves at weaning. Specific vaccination programs will vary
depending upon region and individual herd history. The following
health program is what has been used routinely for several years at
FSRC.
2-4 week prior to weaning: 7-way blackleg
IBR/PI3
BVD
BRSV
Haemophilus somnus
Pasturella haemolytica
Dewormer and pour-on
At weaning booster with: IBR/PI3
BVD
BRSV
Haemophilus somnus
Pasturella haemolytica
Castrating at birth or at spring roundup eliminates the risk of
compounding castration stress with weaning. Use of polled bulls
will reduce the need of dehorning. Electrical dehorning at spring
roundup can also be used to reduce the greater stress of dehorning
at a later age. If there are calves with horns present at weaning,
we prefer to delay dehorning until after the weaning period during
colder weather.
From 1985 through 1997, over 2400 calves from the FSRC herd have
been weaned on pasture at FSRC. During this time period, no calf in
the 2400 has become sick during the weaning period, which is
typically 15 to 25 days depending upon forage and weather
conditions. In 1992 fifty-two cows and calves were transported to
FSRC from another University of Missouri facility in May. Three of
these calves were treated for respiratory ailments during the
weaning period. We believe that these calves were never fully
recovered from the shipping stress which occurred in spring. In
1995 and 1996, approximately 150 to 200 head of newly weaned calves
were purchased either through a sale barn or by private treaty.
These calves were received onto stockpiled pastures and handled
similar to FSRC calves during the same time period. Each year
approximately 3% of these purchased calves were treated for
respiratory disorders.
FENCES AND WEANING
The idea that weaning fences need to be five feet high and chicken
tight is an artifact of drylot weaning programs where calves are
looking for a way out to escape the multiple stresses that have been
applied to them. While a single wire electric fence probably won't
serve as a weaning fence, three-strand electrified hi-tensile fences
have been used very successfully. How much previous exposure cows
and calves have had to electric fence has a great deal of influence
on what type of fence will be appropriate for a particular herd.
For cattle with limited exposure to electric fence, a pasture with
either woven wire perimeter or at least five electrified wires will
probably be required for weaning. If cattle have had constant
exposure to high power electric fences, then three wires will
probably be adequate to keep weaned calves in place. Adding a
single hot wire on an offset insulator to existing 4 or 5 strand
barb wire fences may also serve to keep calves in place.
One variation of pasture weaning is what is known as ‘across-fence
weaning'. In this system the cows are placed on one side of the
fence and the weaned calves on the other. This method is thought to
reduce the social stress of weaning by allowing the dam and calf to
still have visual and scent contact, but prevents nursing. If
calves and cows are allowed visual and scent contact for several
days following actual separation, when the cows are removed from the
adjacent pasture, both cows and calves seem to be well adjusted.
This system works well with cattle who are well trained to electric
fence. A multi-strand fence will be required for at least the first
week to two weeks that the calves are separated from their dams.
Producer experience suggests that the two herds will remain
separated by a single-wire fence in as little as one weeks time. An
approach that is often used on stockpiled pasture is to allow the
calves to top graze one paddock while the cows follow behind and
clean up the residual in the previous paddock. If the calves are
transported away from the cows, keeping the cows where they belong
may actually be more challenging than keeping calves confined.
GRAZING MANAGEMENT DURING WEANING
Calves have the ability to be very selective grazers and also have a
high nutritional demand if they are to maintain growth during the
weaning period. These are two key considerations in pasture
weaning. Providing high quality pasture and allowing selective
grazing to take place will generally ensure favorable calf
performance during the weaning period.
At FSRC weaned calves are placed on stockpiled tall fescue-red
clover pastures that have been managed for maximum stockpile yield.
Calves are typically stocked at a stock density of 10 to 15 calves
per acre and are shifted to new pasture every 3 or 4 days. This
results in the calves grazing approximately 25% of the available
forage. The remaining stockpiled forage is grazed by dry cows later
in the winter. If calves are forced to utilize more of the forage,
performance during the weaning period will decline.
Calf performance, while being positive in every year, has been
variable. Several factors affect performance during the weaning
period including calf body condition, pasture conditions, and
weather. In years when weaning weight is above average and calves
come off of the cows in very fleshy condition, weaning period
performance is usually lower. The years included in Table 1
represent a variety of summer growing conditions and illustrate the
range in weaning period performance that we have experienced.
Calves in 1989 gained very well during the weaning period. That
year was characterized by severe drought until late August-September
when significant rain fell. Cows came off of summer pastures on the
thin side but calves went to excellent fall regrowth pastures. Fall
weaning weights in 1992 were the highest ever achieved at FSRC
following one of the best overall grazing years we have ever
experienced. Weaning period ADG's were among the lowest we have
recorded.
Table 1. Weaning performance of steer and heifer calves weaned on
stockpiled tall fescue pastures at FSRC.
Year Heifers Steers Weaning
(lb/hd/day) (lb/hd/day) Period
1987 1.32 .87 31 days
1989 1.70 1.87 14 days
1992 .72 .70 16 days
1993 .25 1.24 20 days
4-yr mean 1.00 1.17 20 days
SUMMARY
Weaning beef calves on pasture offers cow-calf producers a cost
effective method to enhance health and performance during the
weaning period. Preparing pastures and cattle for the weaning
process well in advance of the actual weaning process is critical to
success. An ample supply of good quality forage on firm ground is
very important. This keeps calf nutrition high and their
environment clean. A consistent health care program including
appropriate vaccinations administered in advance of weaning is very
cheap insurance against sickness at weaning. Try to minimize
handling stress on weaning day to keep calves healthy and growing
through the weaning period.
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