Advantages Of Crossbreeding For Philippine Cattle
Our country imports more than 99% of our dairy consumption, and almost 30% of our beef consumption. To increase our own local dairy and beef production, one essential factor is missing – dairy-beef capable cattle that have the genetic potential to efficiently produce milk and meat under Philippine environmental conditions. To produce our own dairy-beef cattle, we need the productivity of exotic dairy-beef or dual purpose breeds to combine with the hardiness and fertility of the indigenous Philippine breed through crossbreeding using Artificial Insemination or AI.
We can produce the needed dairy-beef dual purpose cattle at much lesser price than imported cattle through the use of Rengab Genetics AI semen. At the same time, we will create business and job opportunities in the rural areas.
Our local cattle population is characterized by fertility, docility and hardiness, but low growth rate, muscularity and milk production. By crossbreeding the indigenous population with the selected crossing breed, we aim to introduce the genes for higher growth rate, more muscularity and higher milk production; while maintaining fertility, docility and hardiness.
In ‘Crossbreeding systems and appropriate levels of exotic blood: examples from Kilifi Plantations’ by Alexander K. Kahi (2002), Department of Animal Science, Egerton University, P.O. Box 536, Njoro 20107, Kenya
Crossbreeding between highly productive and adapted breeds can improve overall performance. …. In the starting phases of a crossbreeding programme, performance is always improved due to the heterotic superiority of the first cross. … Cunningham and Syrstad (1987) reported a linear improvement in almost all performance traits up to the 50% B. taurus inheritance. Beyond 50%, there was a slight increase in calving interval, but no clear trend in the other traits. Madalena et al. (1990a; 1990b) found increases in performance for all milk, reproductive and calf traits up to 62.5% B. taurus inheritance, after which performance began to decline. In a comprehensive review of 80 reports from Africa, Asia and Latin America, Rege (1998) reported an improvement in milk yield when the proportion of exotic blood increased from 0 to 50% and a constant level between 50 and 100% exotic inheritance. A similar trend was observed for age at first calving. Lactation length increased over the entire range of exotic grades, although with 'up-and-down swings'. For calving intervals, the shortest were observed for animals with 50% exotic genes and were longer both for animals with lower or higher exotic inheritance.
The advantages of crossbreeding are:
1. Breed Complementarity
Breed complementarity refers to the crossing of breeds together so that they complement each other to produce the desired offspring. Therefore, complementarity is achieved by choosing combinations of breeds that not only maximize productivity but also profitability. Certain crossbreeding systems, such as a terminal sire system, can achieve complementarity by mating a relatively small, low cost, easy calving and fertile female to a large, fast growing, good carcase quality sire. Composite breed development can use complementarity when choosing the foundation breeds that when married together will complement each other for a wide range of traits. (Composite Breeding by David Johnston, Animal Genetics and Breeding Unit, University of New England, Armidale, NSW, Australia)
We will be using the selected crossing breeds to introduce the characteristics that are lacking or weak in the local cattle population in order to enhance the productivity of the resulting crossbred progenies. These characteristics are higher milk production, more muscularity and higher growth rate. From the local cattle, it will contribute its fertility, docility, and specially its hardiness to the local environment that the exotic breeds lack. We will be combining the strengths of the local cattle with that of the exotic cattle to offset or complement weaknesses of the other. In this manner we aim to develop the optimum dual purpose dairy beef cattle for the smallhold farmer.
2. Hybrid Vigor or Heterosis
Heterosis or hybrid vigour is defined as the increased performance of the resulting crossbreds relative to the average of the straightbred parents. In genetic terminology, it is the result of increased heterozygosity in the crossbred, commonly a result of recovery from inbreeding in the foundation straightbreds. Simply the crossbred animal has genes sampled from more than one breed and this allows the individual to perform better, particularly under stressful conditions. To maximise the retention of heterosis in a stabilised composite more than four breeds are recommended in equal proportions. A composite with equal proportions of four foundation breeds would theoretically retain 75 % of the heterosis expressed in the mean F1. More than four breeds will theoretically retain higher levels of heterosis but the complexity of the initial mating systems usually precludes such designs in practice. (Composite Breeding by David Johnston, Animal Genetics and Breeding Unit, University of New England, Armidale, NSW, Australia)
Heterosis normally is greatest in the traits that are low in heritability like reproductive traits, conception rate, calving interval, fitness traits, longevity and lifetime productivity, among others. (Crossbreeding Systems for Beef Cattle by Peter T. Anderson, Extension Animal Scientist-Beef Cattle, Department of Animal Science, University of Minnesota)
If no inbreeding is practiced, the heterosis is retained in composites for several generations as shown in research results from the US Meat Animal Research Center data (Composite Beef Breeds by Brett Barham, Ph.D. Extension Livestock Specialist University of Arkansas Division of Agriculture, Cooperative Extension Service, Little Rock, Arkansas).
The hybrid vigor expressed by crossbred cattle means that our Philippine Cattle breed has an important role to play in crossbreeding programs now and in the future. It is the source breed for fertility, docility and hardiness, and must be conserved and developed to play this important function. This can be done by identifying superior Philippine bulls and reserving the first and second calvings of Philippine cows for matings with Philippine bulls.