UTILIZING BREED RESOURCES FOR DAIRY PRODUCTION IN THE TROPICS

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1 UTILIZING BREED RESOURCES FOR DAIRY PRODUCTION IN THE TROPICS F.E. Madalena Department of Animal Science, School of Veterinary Sciences, Federal University of Minas Gerais, Cx. P. 567, Belo Horizonte-MG, Brazil Key words: Bos taurus, Bos indicus, crossbreeding, dairy cattle, heterosis. Summary Brazilian results are reviewed indicating that medium input systems based on Bos taurus x Bos indicus cattle are more profitable than expensive systems based on B. taurus. Crossbreeding trials showed important heterosis in most traits, leading to profit superiority in F 1 crosses of Holstein-Friesian x Gyr or Guzerat. A simple scheme to exploit F 1 superiority in stratified crossbreeding was proposed, which is increasingly being used by farmers. However, numbers of Gyr and Guzerat cattle are too low for generalised use of the F 1 scheme. Breed numbers should grow due to increased demand, but there is also a risk of this not happening due to intense crossing, so monitoring of these processes should be undertaken. Introduction The management of animal genetic resources includes: 1) description, 2) evaluation, 3) utilization and 4) conservation. Full utilization of commercially more competitive breeds leads to the reduction of the numbers of other breeds, which may then require special conservation measures. Although development and conservation compete for limited resources in the developing world, a balance between them has to be established, because some conservation effort is needed to sustain development in the long run. However, it would not be logical to preserve genetic resources for the future when we do not properly use them now (Madalena, 1993a). There are some important special situations in which both development and conservation may be complementary, i.e., in the case of breeds that are commercially under-utilized, in spite of their potential to improve the economic efficiency of present production systems. Yet these valuable breeds may not be preferred by farmers or decision makers for a number of reasons, including: lack of research regarding their potential contribution, lack of investment/organization of the respective breeders and propaganda and vested interests of commercially more aggressive breeds. Germplasm from the promising breeds should be evaluated in the context of designing breeding strategies, including breed development, which would lead to commercial conservation. (Madalena, 1983). In this paper I would like to present the case of two Bos indicus Brazilian dairy breeds, the Gyr and the Guzerat, that exemplify the course of action proposed.

2 The need for crossbreeding Tropical production systems are characterized by restrictions in nutrients supplied to animals, due to both low quantity and quality of roughaghes and also to low levels of concentrates fed, challenges from diseases and parasites and climatic stress. Capital restrictions, and the lack of managerial skills, technical assistance and general education of farmers and employees are often the case. Under these circumstances, the crosses of specialised dairy Bos taurus breeds and local adapted breeds, such as those of Bos indicus, have shown advantages over the purebreds, due to the combination of production and adaptation (Madalena, 1990). In Brazil, crossing of Bos taurus x Bos indicus for dairying has been practised for more than 70 years in the tropical areas of the country, where a hybrid dairy herd completely replaced the 400-year long naturalised B. taurus Iberian cattle type Caracu. The gene fraction of each species varies widely, even within farms. Results of a recent survey involving 291 farms and 7195 cows in the State of Minas Gerais are in Fig. 1. The predominant breeds were Gyr (78% of the farms) and Holstein-Friesian (91%) % <1/32 1/32 to 1/4 1/4 to 3/4 3/4 to 31/32 >31/32 Bos Taurus fraction Figure 1. Percentage of cows in Bos taurus fraction classes (n=7195). Source: Madalena et al. (1997b). A description of dairy production in Brazil was given (Madalena, 1998a). In short, dairy farms in the tropical part of the Country are typically small, low input/low production systems based on hybrid cattle. In the above mentioned survey manual milking in the presence of the calf was practised in 95% of the farms and 78% of the cows were milked once a day. Nonetheless, a wide variation of practices exists, even within regions, associated not only to geographical differences but also to farm size and the socio-economic factors related to it. For example, once a day milking was practised in 95% of the farms selling <50 kg milk/day but in 33% of the farms selling >100 kg/day. Most (46%) farmers wished to keep the herd intermediate between Bos taurus and B. indicus, 13 and 1% wished to go pure breeding of either species and 40% had no definite goal in this respect. In the Southeast Region, which produces 45% of the Country s milk (some 7 million ton/yr.), average yield per cow is 885 kg/year.

3 It has been claimed that such production systems should be substituted altogether by intensive systems based on high yielding Holsteins. However, economic results do not sustain such claims. Capital-intensive systems have not had higher net margins nor return on investment than the commonest extensive systems (Holanda Jr. and Madalena, 1998). An example is presented in Fig r, % Cost of de production, cents of real/kg milk Figura 2. Ratio of annual profit/capital invested (r) plotted against cost of production in 7 farms in Brazil. o: médium cost farms, x: high cost farms. Reproduced from Holanda and Madalena (1998). It is not meant to say that prevailing systems are efficient. To the contrary, there is ample opportunity to improve them, provided new practises are adopted on the basis of cost/benefit, rather than on mere imitation of those used in developed countries, where the economic conjuncture is completely different. Optimisation of use of local resources, such as solar energy, C 4 grasses and adapted cattle, may lead to very efficient systems, irrespective of milk yield per cow being much lower than in the intensive systems of temperate countries (Matos, 1997). In a recent study, Alvares et al. (2000) reported a 36% annual return over capital investment in a system based on irrigated pastures plus concentrates, in which F 1 Holstein x Guzerat cows produced 13,000 kg of milk per ha and 12.9 kg per per day of lactation. Crossbreeding strategies The results of an extensive trial to evaluate production, reproduction and survival of Holstein- Friesian (HF) x Guzerá crosses are condensed in Fig. 3. The trial was conducted in 67 farms to evaluate performance of 527 females during their first 12 years of age. Sixty farms were classed as low management, being representative of commercial farms milking twice a day and seven farms where classed as high management, mainly a reflection of one experimental station. Heterosis accumulating over traits of economic importance resulted in a marked profit superiority of the F 1, particularly in low management systems. As may be seen in Fig. 3, profit decreased as the genetic composition departed from the F 1, both at increasing and decreasing HF fractions. The presence of genetic x environment interaction was shown, its nature being that higher Bos taurus fractions responded to improved environment, while the higher Bos indicus fraction did not, so this became uneconomic under high concentrate feeding. On the other hand, impaired survival,

4 production and reproduction rendered uneconomical the use of high Bos taurus fractions in low management systems. High concentrate feeding levels rendered the high management systems uneconomic. Based on these results, the best strategy for a dairy farmer in either management system would be to continuously replace his herd with F 1 females. The second best strategy was rotational crossing, in the low management, resulting in 59% of the F 1 profit. In the high management system the second best strategies were grading up to HF and rotational crossing of two generations of HF and one of Guzerat, both yielding 75% of the F 1 profit in that management. The alternative of forming a new breed, represented by the inter se 5/8 HF group, had a very poor performance, suggesting that strong and continued selection effort would be needed to counteract the loss of heterosis under this strategy. In practical terms, the rotational crossing systems are feasible only for large farms that keep two bulls or for the minority of farms practicing artificial insemination. Instead, to maintain their herds intermediate between B. indicus and B. taurus, small farmers usually resort to the periodical switching of the species of the only bull on the farm, going back to B. indicus after some years of use of a B. taurus bull and vice versa. This practice generates too many extreme crosses of both species, away from the intermediate optimum. Alternatively, a hybrid bull is used, often home-bred. In the abovementioned survey of Madalena et al. (1997b), 40% of 387 bulls were hybrid. However, due to the breakdown of heterosis performance is very poor in inter se crosses (Fig. 3). Moreover, there are no sources of progeny tested hybrid bulls. The above considerations indicate that farmers do not have satisfactory means to keep the herd hybrid, as they would wish. Given the short comings of the other alternatives, a system of continuous replacement with F 1 females may be a convenient way to attain that aim.

5 kg/day /4 1/2 5/8 3/4 1 Holstein-Friesian gene fraction Figure 3. Profit per day of herdlife in Holstein-Friesian x Guzerá crosses, expressed in kg milk (price of 1 kg = US$ 0.16). All crosses by Holstein-Friesian or Guzerá sires, except for the 5/8, which were by inter se matings of 5/8 parents. = high management, = low management Source: Madalena et al. (1990) The F 1 replacement scheme To capitalize on the superiority of the F 1 hybrid, a simple scheme for sustainable production of F 1 heifers in specialised nucleus was proposed, based on what some ranches were already doing (Madalena, 1993b). In that scheme, dairy farms only use F 1 cows, selling all male and female progeny and buying all replacements, which are produced in beef ranches on cheaper land, out of B. indicus dams. Given an observed herd life of F 1 of 7.1 yr (Lemos et al., 1996), an annual replacement rate of 0.14 is needed for the dairy herd. Thus, 1000 F 1 dairy cows could be sustained by 360 B. indicus females used for crossing, given an 80% weaning rate. In addition, 240 B. indicus females need to be mated to bulls of the same species to produce the purebred replacements. In other words, a B. indicus herd 600 strong would support itself and 1000 F 1 dairy cows by mating 40% of the females to B. indicus and 60% to B. taurus sires (Madalena, 1993b). The scheme proposed is an example of stratified crossbreeding, used in several species to make better use of available land or production resources (Lerner and Donald, 1966). A stratified scheme based on the reciprocal cross, of B. indicus sires x B. taurus dams operate in New Zealand, for export to tropical countries, and in the temperate savana of Bogotá, in Colombia, where the F 1 heifers are sold to farms in the hot lowlands.

6 Production and marketing of F 1 replacements In 1995, the extension agency of the State of Minas Gerais (EMATER-MG) identified 267 F 1 producers with more than 42,000 cows, which, under conservative assumptions, could supply some 1.5% of the replacement females needed for the 5 million milch cows in that State (Silvestre et al., 1996). A questionnaire was then mailed to those farmers, to which 68 of them replied. A range of farm types was apparent in this sample, from large ranches selling all the F 1 females and keeping most F 1 males for fattening, to smaller farms keeping most F 1 females for dairying and selling some females and a large proportion of males as weaners. Half of the F 1 producing farms were located in beef cattle regions and sold females to the dairy regions. Average length of time in this activity was 13 years, so this is an incipient technique. The 68 farms had a total of B. indicus cows, 62% of which were mated to produce F 1 and 38% to obtain B. indicus replacements; Gyr type cows predominated, totalling 62% and 43% of females used for crossbreeding and for pure-breeding, respectively. Sires used for crossing were mostly Holstein- Friesian (87%). Frequencies of farms using artificial insemination, natural service or both for crossing, were, respectively, 55, 28 and 17%, B. taurus bulls being unfit for natural mating in the hotter beef cattle areas. Prices of F 1 females were considerably higher than prices of other crosses, indicating that buyers expect a higher profit from the F 1, in agreement with research results. In fact, F 1 females sell for about 2.0 to 2.5 times the price per kg as fat steers. Therefore it was not surprising that almost all (99%) F 1 producers intended to continue this activity, indicating as the main reasons profitability, easy marketing, milk yield and satisfactory growth/fattening of males (Madalena, 1997a). Management of breed resources The advantages of F 1 crosses have been demonstrated in Brazil with Holstein-Friesian x Guzerat or Gyr, but results of crossing of other breeds have not been well documented. Farmers believe that the Nelore crosses have shorter lactations due to worse temperament. Most of the Brazilian cattle beef herd in the tropical part of the Country is of Nelore type, while Gyr and Guzerat type cattle are not common. These last two breeds register some 3 to 4 thousand females each per annum (Faria et al., 2000), so there are not enough animals of these breeds to support the generalised production of F 1. Although artificial insemination is currently the method of choice for F 1 production, embryo transfer might become economic, particularly with sexed semen (Teodoro et al., 1996). In fact, a prominent international company has announced its intention to sell in Brazil F 1 embryos out of Holstein ova obtained from US abattoirs and fertilised in vitro with semen of Gyr bulls progeny tested in Brazil (Ribeiro, 1998). It remains to be seen if and when (or rather when) these techniques become commonplace. Meanwhile, a large-scale increase of F 1 usage would require strengthening of the milking zebu base, likely by insemination of beef herds with dairy Gyr and Guzerat. Both breeds have dairy sections effecting improvement programs based on progeny testing and MOET nucleus, which

7 are described somewhere else in this volume (Penna, 2000, Teodoro, 2000). Albeit in small scale, the commercial success of these programs seems to guarantee the survival of the participating elite herds. Increased demand for Gyr and Guzerat F 1 s should likely strengthen the numbers of those breeds, but this should not be taken for granted, as herds placed below in the pyramid might conceivably choose to cross a higher proportion than required to sustain the purebred herd strength. Thus, monitoring of the crossbreeding process is required to prevent drift from placing the breeds at risk. Conclusions Well-designed tropical dairy production systems are profitable, in spite of some claims to the contrary. Recommendations should be based on research results in tropical countries. Continuous F 1 replacement schemes have sound economic basis and are implemented in small but increasing scale by farmers in Minas Gerais, favoured by the lack of feasible alternatives of crossbreeding. Government or NGO action is needed for further research on breed comparisons, to monitor breed usage/risks and to promote the rational use of F 1 dairy crosses. References Alvares, J.A.S., Holanda Jr., E.V., Melo, M.M. and Madalena, F. E. (2000) Cad. Téc. Esc. Vet. UFMG (in press) Faria, F.J.C., Vercessi Fo., A.E., Costa, M.D., Joshakian, L.A. and Madalena, F.E. (2000). Anais III Simp. Nal. Melhor. Anim Holanda Jr., E.V.; Madalena, F.E. (1998). Cad. Téc. Esc. Vet. UFMG, n 0 25:13-18 Lemos, A.M., Teodoro, R.L., Madalena, F.E. (1996). Brazil. J. Genet. 19: Lerner, I.M. and Donald, H.P. (1966). Modern Developments in Animal Breeding. J. Wiley & Sons. N. York Madalena, F.E. (1983). In FAO Anim. Hlth. Prod. Bull. 44/1:80-87 Madalena, F.E. (1990). Proc. 4th Wld. Congr. Genet. appl. Livest. Prod. 14: Madalena, F.E. (1993a). In FAO Anim. Hlth. Prod. Bull. 107:77-84 Madalena, F.E. (1993b). Wld. Anim. Rev. 74/75:17-25 Madalena, F. E. (1998a). In: Internat l Workshop on Animal Recording for Smallholders in Developing Countries. K.R. Trivedi (ed.). ICAR Tech. Series N o 1, p Madalena, F.E. (1998b). Proc. 6th Wld. Congr. Genet. appl. Livest. Prod. 27: Madalena, F.E., Teodoro, R. L., Lemos, A.M., Monteiro, J.B.N. and Barbosa, R.T. (1990). J. Dairy Sci. 73: Madalena, F.E., Madureira, A.P. and Silvestre, J. (1997a). Cad. Téc. Es. Vet. UFMG. 18:41-52 Madalena, F.E., Abreu,C.P, Sampaio, I.B. and Ferreira, F. (1997b). Rev. Bras. Zoot. 26: Matos, L.L In Anais. Symp. Tópicos Especiais Prod. Anim., 34 th Reunião SBZ, p Penna, V.M. (2000). Utilization of MOET selection nucleus in small breeds. The Guzerat experience. This volume Ribeiro, J.H Globo Rural, n 0 150, p Silvestre, J, Madalena, F.E. and Madureira, A.P. (1997). Cad. Téc. Esc. Vet. UFMG. 18:37-40 Teodoro, R.L. (2000). This volume Teodoro, R.L., Madalena, F.E. and Smith, C. (1996). J. Anim. Breed. Genet. 113: