Breed Composition and Forage Systems
All pastures were located on typical 'flatwoods' soils mostly Myakka
fine sand. Native range and improved pastures were used to develop three
forage systems each of which included enough land to carry approximately
System 1, Range. Forage available for grazing consisted of native grasses,
largely wiregrass and broomsedge. A total of 772 acres of native range was
used in this system. The area was divided in 5 pastures; one-half of each
was burned in alternate years. Stocking rate was 12.74 acres per cow. An
average of 555 pounds of hay, 52 pounds 41% cottonseed meal, and 52 pounds
of citrus meal were fed per cow annually. The feeding periods began in
December and continued for an average of 109 days.
System 2, Range plus pasture (combination). This included a combination
of 73 acres of improved pasture plus 315 acres of native grass. The improved
pastures included 40 acres of 'Pensacola' bahiagrass and 18 acres of 'Pangola'
digitgrass. Approximately 20 acres of the Pensacola was grown in conjunction
with Hairy indigo with the remaining 20 acres being in combination with non-
irrigated Hubam sweetclover and whiteclover. The cattle had access to the
native grasses continuously and grazed the various fields of improved pasture
on a rotational basis. The stocking rate on this system was 5.34 acres native
pasture and 1.24 acres improved pasture per cow.
* Associate Animal Husbandman, ARC,' Ona; Animal Geneticist, University of
Florida, Gainesville; and Agronomist and Animal Scientist, Emeritus
Agricultural Research Center,Ona *-*
Research Report RC-1977-6 March 19
BREED AND MANAGEMENT EFFECTS ON CALF PRODUCTION < ;
ON SOUTH FLORIDA RANGES
F. M. Peacock, M. Koger, E. M. Hodges, an W. G.i rk
\ ,' ''* e I "
Beef production is the result of a combination of\ge&etid and environ-
mental factors. Genetic factors may be masked by induced or natural
environmental influences which hinder expression of hereditary traits.
Environmental influences may either compliment or limit the genetic potential
of the animal. The objective of this report is to present research data
from two experiments: Part 1. A study of the relationship between breed
composition (Brahman-Shorthorn) and forage systems; and Part 2. Breed group
productivity under uniform treatment (Brahman, Angus, Charolais breeds and
The fertilizer program for Pangola was 400 pounds of 8-8-8 plus 150
pounds of ammonium nitrate per acre annually. Pensacola received a similar
amount of complete fertilizer plus 100 pounds/acre of ammonium nitrate.
The legume pastures received 250 pounds per acre of 0-8-24 fertilizer annu-
ally with extra applications of potassium on the whiteclover averaging 32
Cattle on this system received 43 pounds hay, 65 pounds cottonseed meal,
and 31 pounds citrus meal per cow annually. The feeding period lasted an.
average of 72 days from January to April.
System 3, Pasture. This system included only improved pastures, con-
sisting of 70 acres of Pangola, 27 acres of irrigated Pangola overseeded
with whiteclover, and 10 acres of Pensacola pasture. Fertilization followed
the same pattern as described for system 2. Stocking rate was 1.33 acres
improved grasses and 0.45 acre clover-grass pasture per cow.
Cattle on this system were fed an average of 280 pounds of hay per cow
annually. The feed period began in February and continued for an average
of 33 days for the 5 years.
Breed Groups. The herds on each of the forage systems included approxi-
mately 60 cows, which consisted of the following five breed groups: 10 Brahman
(B), 10 3/4 Brahman-1/4 Shorthorn (B3), 20 1/2 Shorthorn-1/2 Brahman (Fl),
10 3/4 Shorthorn-1/4 Brahman (B1), and 10 Shorthorn (S). The mating system
produced all crossbred calves. The B, B3, and one-half the F1 cows were bred
to Shorthorn (S) bulls while the S, B1, and one-half the F1cows were bred to
Brahman (B) bulls, resulting in six distinct breed groups of calves.
General management. Cattle on all programs were bred in a restricted
season of 105 days, March 15 to July 1 and all calves were weaned in early
September. Replacement heifers were grown together from weaning until being
placed in their respective herds just prior to the breeding season. Cows were
culled on the basis of repeated reproduction failure or failure to raise a
Results and Discussion
Production in a cow-calf program is the product of weaning rate x weaning
weight, combined with quality of calf.
The average weaning age of all calves was 219 days, being 209 on native,
219 on native-improved and 229 days on all-improved.
Weaning weight. Weaning weight was influenced by forage system and
breeding as well as by their interaction (Table 1). The average weaning
weight of calves was 380, 457 and 504 pounds respectively, for the native,
combination, and all-improved systems. The calves from Shorthorn cows by
Brahman bulls had the lowest weaning weight on all rage systems while the
calves from F1 cows by Brahman bulls were the heaviest on all forage systems
(Table 1), except for the B3 cows producing the same on native range.
The forage system x bred interaction was principally due to differential
response by breed to the improved pasture systems. The calves from F1 cows
by Brahman bulls averaged 406 pounds on the native versus 549 pounds on the
all-improved system, for a difference of 143 pounds. Calves from B, cows
by Shorthorn bulls averaged 406 pounds and 486 pounds respectively, for the
same two systems for an increase of 80 pounds. Weaning weights of calves
produced by the Fl cows were highest of all breed groups irrespective of
breed of sire. Even though calves out of Shorthorn cows by Brahman bulls
increased in weight from 336 pounds for the native system to 470 pounds on
the all-improved system,134 pounds, they were lowest of all breed groups
on all forage systems.
Market grade. Market grade of calves is the result of nutrition and
breeding. Market grade was influenced by forage system, breeding, and
their interactions. Results are presented in Table 2. The average market
grade of calves was 8.7, 9.7 and 10.9, respectively, for the native, combin-
ation, and all-improved systems. The highest grading calves were from F1
cows by Shorthorn bulls (10.3) and lowest were from Shorthorn cows by
Brahman bulls (9.2). The exceptional mothering ability of the F1 cow plus
the fattening quality of the high percentage of Shorthorn resulted in the
highest market grade. The Shorthorn cow was not able to furnish the needed
nutrients to her calf, except on the highest nutritional level, resulting
in the lowest market grade of all breed groups.
The calves from Shorthorn cows by Brahman bulls graded lowest (7.4)
on the native but increased 48% on the all-improved system, whereas
calves from Brahman cows by Shorthorn bulls graded 9.3 on the native but
increased only 15% in grade on the all-improved system. These responses
indicated a lack of adaptability of the Shorthorn cow to the lowest
nutritional plane (native system) whereas the Brahman cow had a much wider
range of adaptability.
Calf Production per cow. Calf production per cow (Table 3), deter-
mined by multiplying weaning weight x weaning percent, is the summation of
breeding and forage system and their interactions. The average cow produc-
tion was 241, 340 and 406 pounds, respectively, for the native, combination,
and all-improved systems. The F cows were most responsive to improvements
in nutrition, averaging 229 pounds on native, 384 pounds on native + improved
and 456 pounds calf production/cow on the all-improved system. Their perfor-
mance was relative to associated improvements in forage systems. The B and
B cows responded to a supplementation of native range with improved pasture
but did not respond to the higher levels of nutrition from all improved
pasture. The S and B, cows required the highest level of nutrition to per-
form at their potential.
Brahman, Angus, Charolais and their crosses under uniform treatment
Herds were maintained on improved grass pastures, mostly Pangola
moderately fertilized, and the cows were supplemented with hay and approxi-
mately 5 pounds of cane molasses or 5 pounds of a mixture containing citrus
pulp and cottonseed meal (4:1 ratio) per head per day for 60 to 90 days
during late winter and early spring. The breeding season was restricted to
90 days, March 1 to June 1. All calves were weaned at the same time in late
August or early September. Data on condition score, weaning weight and
calf production per cow are presented in Table 4.
The average age of calves at weaning was 224 days. Little difference
in condition score was observed among straightbred calves, except the Brahman
being lowest of all breed groups, 8.8 compared to 9.2 for the Charolais and
Angus. The F1 A x B cow produced calves with the highest average condition
score among cow breeds and Angus bulls highest among sire breeds, with A x AB
calves, highest (10.7) of all breed groups. This shows the exceptional
mothering ability of the F1 A x B cow and the fattening quality of the Angus
sired calf. These traits (10.5) were also expressed in A x CB calves.
Weaning weight of the Charolais calf was highest of the straightbreds
and compared favorably with crossbreds, except for Charolais-sired calves
from F1 Charolais x Brahman and F Angus x Brahman cows which showed the
large additive growth effect of the Charolais.
The Charolais was highest of the straightbreds for weight of calf produc-
tion per cow. The Fl A x B cow produced the highest average weight per cow
with F C x B cow next in order. This study also shows that 3-breed crosses
(A x CB and C x AB) did not increase production over the C x CB backcross.
The advantage of crossbred over straightbred means were positive for
all traits. Percentage increases were highest for the F A x B cow, averaging
22.3% for weaning weight, 15.5% for condition score and 42.7% for calf pro-
duction per cow. Average percentage increases for the F, C x B cows were
13.9% for weaning weight; 10.3% for condition score; and 23.3% for production
per cow. Charolais sires on crossbred cows produced higher weaning weights
than either Angus or Brahman sires, whereas Angus sires on crossbred cows
increased condition score over Charolais and Brahman sires. These results
show the superior maternal performance of FI cows (Brahman x European), large
additive breed effects of the Charolais for growth, and fattening qualities
of the Angus.
Results from these studies show that production by design can be
accomplished by utilization of breed traits in the straightbreds and heter-
osis obtained by crossing complementary breeds.
Table 1. Adjusted Means for Weaning Weight in pounds of Calves
by Breeding and Forage System.
Breed of Dam B B3 F1 F. B1 S
Breed of Sire S S B S B B
Forage System Adjusted means
Native 381 406 406 372 383 336 380
Combination 470 455 480 477 436 420 457
All-improved 497 486 549 518 501 470 504
Adj. means 449 448 479 456 440 409
Table 2. Adjusted Means for Market Grade of Calves By
Breeding and Forage System.
Breed of Dam B B3 F1 FI B1 S
Breed of Sire S S B S B B
Forage System Adjusted means
Native 9.3 9.0 8.8 9.1 8.4 7.4 8.7
Combination 10.0 9.5 9.9 10.2 9.0 9.4 9.7
All-improved 10.7 11.0 11.0 11.5 10.5 11.0 10.9
Adj. means 10.0 9.9 9.9 10.3 9.3 9.2
~ 8, High Standard; 9, Low Good; 10,
Good; and 11, High Good.
Table 3. Calf Production Per Cow in
and Forage System.
Pounds, By Breed of Calf
Breed of Dam B B3 FI F1 B1 S
Breed of Sire S S B S B B
Forage system Adjusted Means
Native 240 276 251 207 271 192 241
Combination 348 419 386 381 311 218 340
All-improved 324 415 456 456 467 335 406
Adj. means 304 368 359 342 349 245
Table 4. Adjusted means for Production Traits of Brahman (B), Angus (A),
Charolais (C) and their crosses and crossbred advantage for
Calf Condition Score Weaning Weight Calf Production/Cow
score Ibs Ibs
AxA 9.2 404 271
B x B 8.8 399 326
C x C 9.2 492 372
A x AB 10.7 496 435
B x AB 10.4 488 444
C x AB 10.2 528 433
C x CB 9.6 540 449
B x CB 9.8 466 396
A x CB 10.5 501 412
Advantage of crossbreds over mean of straightbred, %.
A x AB 18.9 23.4 45.5
B x AB 15.6 21.4 48.5
C x AB 12.1 22.2 34.1
C x CB 6.7 21.1 28.7
B x CB 8.9 4.5 13.7
A x CB 15.4 16.0 27.6