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Composite Cattle: Rational and Development in Hawai'i

Brent Buckley

Rationale

Crossing Breeds of cattle has been shown to increase the efficiency of producing beef. This increase comes from two factors. One, combining breeds of cattle with traits to complement one another. Two, individuals arising from crosses exhibit hybrid vigor (heterosis) for many traits. Numerous crossbreeding systems have been developed to maximize these advantages and to achieve high levels of heterosis. Effective crossbreeding systems require recording of sire breed, maintaining separate breeding pastures and complicate replacement female selection.

Generally, conventional crossbreeding systems are difficult to manage in herds of less than 100 cows. In the United States 93% of farms and ranches have fewer than 100 cows. These herds represent about 55% of the total cows. Increasingly, beef production is a secondary enterprise which is not conducive to a complex breeding or management system. For the majority of beef producers, a typical crossbreeding system may not be suitable and producers may not utilize crossbreeding to improve production.

Composites

An alternative to conventional crossbreeding systems is use of composite breeds. Composite breeds are the result of multiple crosses of 2 or more breeds. Management of a composite breed system is simple. Composite breeds are managed like a straightbred, while allowing for nearly equal amounts of heterosis to conventional crossbreeding systems. Composites are routinely utilized in poultry and swine breeding programs. Composites are slowly being recognized by cattlemen as a viable alternative to traditional crossbreeding programs.

Composites may provide a mechanism for more adaptable cattle. Each breed has evolved in a single environment. Modern cattle are expected to perform under a variety of environments, from cool mountain climates to hot wet tropical conditions. In particular, cattle in Hawai`i are often exposed to environmental extremes over very short periods.

Objective

To develop a composite breed for use in Hawai`i and other tropical areas and compare performance to straightbred breeds.

Methods

Heterosis through a conventional crossbreeding system can increase pounds of calves weaned per cow exposed by 20-30% with careful management. A similar level of performance should be achieved by a composite created from 8 breeds.

For this experiment 8 breeds have been combined at the Mealani Experiment Station. The Mealani Experiment Station, located near Waimea, Hawai`i, represents a typical ranch environment for Hawai`i. The cow herd was comprise initially of Angus and Hereford. The other 6 breeds were introduced by using sires of Santa Gertrudis, Limousin, Tarentaise, Brahman, Maine Anjou, and Holstein.

These breeds represent a wide range of cattle types and have evolved in a variety of environments. During formation of the composite, 2-breed, 3-breed, and 4-breed combinations were created which allows for comparison to typical crossbreeding systems.

Straight bred Angus, Hereford, and Santa Gertrudis lines were maintained as a comparison. In addition, Limousin were maintained at the Waialee Experiment Station. The Limousin data were excluded form this analysis due to determination that environmental effects significantly increased their performance compared to the Mealani location.

Results

Calf birth weight is an important trait for two reasons. Heavier calves are an indication of faster growing and larger mature weight cattle. However, lighter calves are desired for easier birthing (calving ease). Results from this study (table 1.) indicate relatively moderate birth weighs between breeds and crosses with insignificant differences in calf birth weight among breed crosses. Nearly all cows regardless of breed calved without need of assistance (95% un-assisted births).

Table 1. Performance of Straightbred, Crossbreds, and Composites.
Cow Breed BirthWeight
(lb.)
Pre-Weaning
Daily Gain (lb./day)
Weaning Weight
(lb.)
Conformation
Score
Angus 78.8 ± 1.1 1.83 ± 0.02 453.2 ± 5.5 14.3 ± 0.1
Hereford 79.9 ± 1.5 1.69 ± 0.04 426.8 ± 7.3 14.2 ± 0.1
Santa Gertrudis 80.7 ± 2.0 1.83 ± 0.04 454.1 ± 10.1 13.8 ± 0.2
2-Breed 84.9 ± 1.1 1.94 ± 0.02 481.4 ± 5.1 14.6 ± 0.1
3-Breed 84.9 ± 1.1 1.96 ± 0.02 486.2 ± 5.3 14.5 ± 0.1
4-Breed 80.1 ± 1.5 1.94 ± 0.04 475.2 ± 8.1 14.3 ± 0.2
Composites 80.1 ± 1.5 1.89 ± 0.04 467.9 ± 8.1 14.3 ± 0.2


Average daily gain pre-weaning is economically important to the producer, since many cattlemen sell their calves shortly after they are weaned from the cow and faster growing calves will be heavier. This research indicates differences in pre-weaning average daily gain between breed crosses. The crossbred cows (2-, 3-, and 4-breed) and composites had higher average daily gain than straightbred cows (Angus, Hereford, Santa Gertrudis). This advantage can partially be explained by extra mild production associated with adding Holstein and Tarentaise breeds. Growth rate from Limousin, Maine Anjou, and Brahman additions also contribute to pre-weaning average daily gain.

Crossbred calves were heavier at weaning than calves from straightbred cows. These differences averaged about 40 pounds per calf when crossbreeds were compared to straightbreds. Composite line calves differed least from straightbreds, but were still nearly 14 pounds heavier than either the Angus or Santa Gertrudis breeds. This analysis did not include the effects of reproduction on weaning weight. Composite and crossbred cows, consistently demonstrate a 6-8% increase in calf crop weaned per cow exposed over straightbred cows. Inclusion of reproduction would result in average weaning weight differences between straightbred and crossbreds of 15-20%, similar to those reported elsewhere. Conformation score, based on a 17 point system was utilized as a visual appraisal of muscling, showed very little differences between breeds or crosses. Indication, addition of a variety of breeds did not affect the overall physical appearance or muscling of the cattle.

Table 2 shows the estimated percentage of heterosis demonstrated in the crosses and composites when compared to the straightbreds. As expected the 2-, 3-, and 4-breed crosses exhibited the highest amount of heterosis. However, this advantage is associated with the increased management of such a crossing system. Composites exhibited a lower amount of heterosis, but still yielded and advantage over straightbreds, while maintaining a comparable management system.

Table 2 Estimated Percent Heterosis

2-Breed 3-Breed 4-Breed Composite Line
Birth Weight 6.5 5.1 0.5 0.3
ADG Pre-Weaning 7.8 9.5 7.8 6.1
Weaning Weight 8.3 9.5 7.0 8.3

Implications

Creation of a composite line is a difficult and time consuming task for an individual breeder. However, a number of private breeders and university research stations, including the University of Hawai`i, have begun the process of "new" breed development. Composites, as the research conducted in Hawai`i indicates, will have performance advantages over traditional straightbred cattle while maintaining similar herd management. This should greatly benefit the majority of beef producers, whose herds are too small to readily take advantage of systematic crossbreeding systems which yield similar results to composites.



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