Frequent posthitis develops into fibrosis and loss of elasticity of the tissues and consequently impotentia coeundi of the bull. During the four years of the study, ...
Ms.received 9. 6. 1989
J. Anim. Breed. Genet. 106 (1989) 470-474 0 1989 Verlag Paul Parey, Hamburg und Berlin ISSN 0931-2668
Centro Internacional de Agricultura Tropical (CIAT), Colombia Institute for Animal Production, Technical University Berlin
Use of criollo bulls in a cow-calf zebu herd in the Eastern Plains of Colombia By B. RIVERA, R. R. VERAand J. H. WENIGER
Introduction The soil fertility conditions of the savanna region in the Eastern Plains of Colombia as well as water stress conditions during four succesive months of the year limit crop production (SANCHEZand COCHRANE 1985). Therefore extensive cow-calf grazing systems have developed which are limited by the low nutritive value of the native savanna and are characterized by very low productivity (VERAand S E R1985). ~ To increase animal production it is necessary to develop more efficient production systems with technologies that improve nutrition, management, health and genetic composition of the existing herds. The initial basis for the development of the cattle industry in the latinamerican tropics was constituted by the criollo cattle (Bos tuurus) that descend of the cattle introduced by the Spanish conquerors. The Sanmartinero breed, a criollo cattle type, was introduced into the Eastern Plains of Colombia by the Jesuits and is probably the result of a cross between Andaluzian “Retinto” and Asturian “Valle” (BRUNNSCHWEILER 1972). The breed characteristics are a result of the natural selection which took place in the course of at least 400 years. O n the other hand, the first zebu animals (Bos indzcus) were introduced to the Eastern Plains after 1930 (MORALES et al. 1986) in order to exploit the hybrid vigor of its crosses with the existing criollo cattle. The evident advantages of heterosis in animal productivity (PLASSE 1976; REYNOLDS et al. 1982; STONACKER et al. 1984; SYRSTAD 1985) have permitted the broad and quick diffusion of the zebu in the region. The grading-up to the zebu has progressed so much that in commercial herds no further benefits can be expected from heterosis. At the same time, the commercial exploitation of criollo cattle has in practice disappeared and at present, only the national research centers have preserved some specimens. The purpose of this paper is to describe the effects of the re-introduction of criollo bulls in commercial zebu herds on the productivity of weaned calves.
Materials and methods The experiment was carried out at the Centro Nacional de Investigaciones Agropecuarias, Carimagua in the Eastern Plains of Colombia. This research station has an altitude that ranges from 150 to 170 m.a.s.1. The mean annual precipitation during the four years of the experiment was 2415 mm (CV 6%), with a clearly defined dry period that extends from December to March. The mean average temperature was 26.2 “C. Eight groups constituted by 45 to 52 cows and two pure Brahman bulls each grazing native savanna supplemented with small areas of grass-legume pasture and/or a mineral lick were studied during four consecutive years. Detailed information regarding animal management and the experimental areas was provided by RIVERA et al. (1988). Throughout the second year of the experiment one of the zebu bulls was replaced in all herds by a purebred criollo bull of the Sanmartinero U.S. Copyright ClearanceCenter Code Statement:
0931-2668/89/0606-04705
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breed. In order to reduce the influence of the bulls on the fertility of the herds they were submitted to a yearly seminal evaluation by electroejaculation and were regularly rotated between herds. The breed of the cows was commercial zebu; the Brahman type predominated, but cows with different proportions of criollo blood were mixed indistinctly. For analysis the cows were grouped according to phenotypic characteristics. The characteristics of the criollo-type cows were as follows: absence of humps, small and usually hairy ears, long hair coat varying in color from very dark cherry red to yellow, thin horns and a very tranquil temperament. From the phenotypic classification of the cow and the calf, it was possible to infer the breed of the sire. Cow height was measured from the ground to the protuberance that forms the middle crest of the sacrum in the hindquarter of the animals. To reduce the error, the measurement was taken twice. The correlation coefficient between the two observations was 0.96. For the analysis of variance the cows were classified as either small (< 134 cm), medium (134-140 cm) or large (> 140 cm). The mean height of both breeds was similar (135.8 cm for criollo and 133.8 cm for zebu cows). Calf weaning weights were adjusted to the age of 270 days. The combined information of the calves born in the third and fourth years of the experiment was used. The distribution of offspring of one bull o r another was similar in all experimental groups. The least-squares and maximum-likelihood general program for fixed models was used for statistical analysis (HARVEY 1960). The sources of variation were sire breed, cow breed, sex of calf, cow height group and all the possible two-way interactions.
Results and discussion Calves born from criollo bulls were not significantly heavier at weaning than those from zebu bulls (166 Vs. 158 kg). But the probability of the interaction between sire breed and cow breed was < 6 % . The lowest weights at weaning occurred in calves born from zebu cows and bulls, the difference being 10.8% less than in other groups (Table I). PLASSE (1976) and STONAKER et al. (1984) reported heterosis as large as 10 O/O in weaning weight. An interesting significant interaction between sex of calf and cow breed was observed (P= 0.0421). Male calves were heavier at weaning than female calves only when the mother corresponded to the criollo type. Some studies indicate that due to their greater genetic capacity for growth, males can be at a disadvantage when poor nutrition is provided by the mother (KNAPPet al. 1980; SHARMA et al. 1982; AHUNUand MAKARECHIAN 1986). In the present experiment, males were able to express their potential for larger weight gains only under the improved nutritional status provided by the criollo cow. Calves of large cows were heavier at weaning than those of small cows. This effect of cow height was highly significant (P = 0.0017). It is very unlikely that the effect of height is Table 1. Weaning weights [kg] of calves (adjusted to 270 d) as related to breed type of the parents, sex of calf and cow height group
r Source Sire Breed
Cow Breed Criollo Zebu
Criollo 166 167 Zebu 167 149 Sex Male 179a 159b Female 154b 156b Cow Height Group Small 152 146 Medium 168 154 Large 179 172 Means within sources with different letters are significantly different (P < 0.05)
X
166 158 169 155 149c 161 b 176a
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confounded with that of cow age, since the coefficient of determination between both variables was only 2 %. Measurements of height were carried out when the younger cows were over 6 years old. HAYS and BRINKS (1980) found that at that age beef cows reach their maximum height at withers, thus completing their development. For both breeds the effect of height was similar, as indicated by the absence of a significant interaction (P = 0.72).The place of origin of the cows was the same research station, but differences in management and nutrition of heifers could have occurred affecting the size of adult cows. It is unknown to what extent different environmental growing conditions could account for the effect observed. Unfortunately this environmental factor cannot be separated from an eventual genetic factor that jointly could determine the appearance of a particular phenotype. STEENKAMP and HORST (1974) and HAYS and BRINKS(1980) state that in terms of net efficiency, large cows have advantages due to their lower requirements per unit of weight, greater fertility and larger growth rates of their offsprings. A small difference in the number of calves from zebu bulls (53 "/o) compared with those from criollo ones (47%) was observed. A similar difference had been obtained by STONAKER et a]. (1984). A preference effect of the sire with regard to the breed of the cow was not found: 51.6 O/O calves of zebu cows and 57.6 calves of criollo cows were recorded as offspring of zebu bulls. A breed characteristic of the Brahman sires is their large, pendulous prepuce which is very susceptible to injury by the harsh vegetation of the savanna causing acroposthitis (inflamation of the distal portion of the prepuce) generally aggravated by the invasion of Cocbliomya hominiworax larvae (Myiasis). Frequent posthitis develops into fibrosis and loss of elasticity of the tissues and consequently impotentia coeundi of the bull. During the four years of the study, out of a total stock of 30 zebu Brahman bulls, five had to be culled due to this disease. The high prices of purebred breeders that were lost for the above cause, the difficulties in treating the sick animals, the cost of surgery and the difficulties in management during the postsurgery period suggest that the economic losses can be large. Following surgical treatment the bulls almost always recover. However, this treatment should not be recommended due to the possibility of perpetuating a hereditary defect. It should be noted that none of the Sanmartinero bulls exhibited problems of acroposthitis. Calf mortality constitutes an additional argument against the use of purebred Brahman cows.The review of WILLIS(1976) shows that Brahman calves are weak and light at birth and present greater mortality rates than the others zebu-breeds. The udder of the Brahman cow shows frequently very large and deformed teats, which prevent the newborn from receiving colostrum, thus increasing calf mortality. In this experiment most calf losses were due to undetermined causes (59 Yo), but 3 % died due to difficulties in suckling. According to MOOREand ROCHA(1983), Bos indicus cattle are genetically capable of responding reproductively to improved nutrition and management. However, the present results suggest that the re-introduction of criollo bulls constitutes a relatively inexpensive and easy alternative in order to rapidly increase heterosis and productivity. From a practical standpoint the best breeding strategy for the utilization of the heterotic effects is open to discussion. The introduction of a third breed (exotic breed), often poorly adapted to the environment, is according to MOOREand ROCHA(1983) not necessary nor indicated at present. PLASSE (1976) recommended rotational crossing between zebu and criollo. O n the other hand, SYRSTAD (1985) suggests the formation of a composite (synthetic) breed keeping in mind that the slightly larger amount of heterozygosity in a rotational cross is probably not enough to outweigh the operational complexity of the scheme. The above author considers however that more research is needed on this point. Difficulties regarding the marketing of crossbred steers are frequently mentioned. The argument that the commercial handlers adduce is the lower dressing percentage of the crossbred animals in comparison with pure zebu. For the farmers that represents a lower price of the product. No scientific evidence exists to support this argument, but studies are
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required before suggesting the generalized use of criollo bulls in the herds of the Eastern Plains.
Summary A study was conducted in the Eastern Plains of Colombia to determine the effects of the re-introduction of criollo bulls (Sanmartinero breed) in commercial zebu cow-calf herds on the productivity of weaned calves. The lowest weights at weaning occurred in calves horn from zebu cows and hulls, the difference being 10.8%, less than in the groups zebu x crillo, criollo x zebu o r criollo x criollo. The interaction between sex of calf and cow breed was significant. It is likely that males were able to express their potential for larger weight gains only under improved nutritional conditions provided by the criollo cow. The relation between the presentation of acroposthitis and the use of Brahman sires in savanna paddocks which have very harsh vegetation is discussed. The results suggest that the re-introduction of criollo bulls constitutes a relatively inexpensive and easy alternative in order to rapidly increase heterosis and roductivity. From a practical standpoint the best breeding strategy for the utilization of the heterotic egects is open to discussion.
Resumen Introduction de toros Criollos en hato rebu comercial en 10s Llanos Orientales de Colombta En 10s Llanos Orientales de Colombia se realizci un estudio para determinar 10s efectos de la reintroducci6n de toros criollos (raza Sanmartinero)en un hato cebu comercial de cria sobre la productividad de 10s terneros al destetc. Los inis hajos pesos al destete se observaron en terneros nacidos de vacas y toros ceb6, 10.8'% mis hajos que en 10s grupos cehu x criollo, criollo x cehu o criollo x criollo. La interaccion entre el sexo del ternero y el tipo racial de la vaca result6 significativa. Es probable que 10s machos pudieron expresar su potencial para mayores ganancias de peso solamente hajo las mejores condiciones nutricionales ofrecidas por la vaca tipo criollo. Se discute la relacion entre la presentacion de acropostitis y el uso de reproductores Brahman en potreros de sabana 10s cuales tienen generalmente vegetacion muy tosca. Los resultados sugieren que la reintroduction de toros criollos constituye una alternativa relativamentr barata y ficil para incrementar la productividad de 10s animales en corto tiempo. Desde el punto de vista prictico, In inejor estrategia para la utilizacion de 10s efectos de la heterosis esti ahierta a discusion.
Zusammenfassung Der Einsatz von Criollo-Bullen in Zebu-Herden im ostlichen Llanos eon Uolumbien In den osthchen Llanos von Kolumhien wurde ein Zuchtprograrnm durchgefuhrt, um die Auswirkung einer Wiedereinfuhrung der Criollo-Rasse (Sanmartinero) in kommerzielle Zebu-Mutterkuhherden durch Anpaarungen mit Criollo-Bullen im Vergleich mit Anpaarungen von Brahmann-Bullen im Hinblick auf die I'roduktivitat der ahgesetzten Kalher zu untersuchen. Das geringste Absatzgewicht fand man hei reinrassigen Zebu-Kalbern. Diese hatten ein um durchschnittlich 11 "A geringeres Absatzgewicht als dieTiere der Grup en Zebu x Criollo, Criollo x Zebu oder Criollo x Criollo. Die Interaktion zwischen dem Geschlecht Kalhes und der Rasse des Muttertieres war signifikant. Es scheint, daR mannliche Kilber ihr Potential f i r hiihere Gewichtszunahinen nur unter verbesserten Ernahrungshedingungen realisieren konnen. Eine solche gunstige Ernahrungssituation ergab sich jedoch nur fur Criollo-Kiihe. Die Ergebnisse hahen gezeigt, daR die Wiedereinfuhrung von Criollo-Bullen eine relativ kostengiinstige und einfache Alternative darstellt, um uher Heterosis-Effekte schneller Produktivitatssteigerungen 7.u erzielen. Im Hinblick auf die Zuchtungspraxis bleibt die Diskussion um die beste Kreuzungsstrategie zur Nutzung dieser Heterosis-Effekte weiterhin offen.
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MOORE,C . P.; DA ROCHA,C . M., 1983: Reproductive performance of gyr cows: the effect of weaning age of calves and postpartum energy intake. J. Anim. Sci. 57 (4): 807-814. MORALES,G.; AYCARDI,E.; GUZMAN,V. H.; URIBE,A,, 1986: Principales enfermedades carenciales, infecciosas y parasitarias de 10s animales domesticos en 10s Llanos Orientales Colombianos. Supl. ganadero 6 (2): 7-42. PLASSE,D., 1976: The possibility of genetic improvement of beef cattle in developing countries with particular reference to Latin America. In: Beef cattle in developing countries. Ed. by A. J. Smith. Edinburgh: Univ. of Edinburgh, pp 308-331. REYNOLDS, W. L.; BELLOWS,R. A.; URICK,J. J.; KNAPP,B. W.; PAHNISH, 0.F., 1982: Rate of pregnancy, calf survival rate to weaning and net calf crop of Angus, Hereford, Charolais and Brown Swiss dams mated to Angus, Hereford and Charolais sires. Proc. West. Sec. Amer. SOC.Anim. Sci. 33: 336.
RIVERA, B.; VERA, R. R.; WENIGER,J. H., 1988: Moglichkeiten fur eine verbesserte Nutzung der Savanne in den kolumbianischen Llanos zur Rinderproduktion. Giefiener Beitrage zur Entwicklungsforschung 1 (17): 243-248. SANCHEZ,L. F.; COCHRANE, C., 1985: Colombia. Estudio biol6gico y tecnico. Descripci6n general del ecosistema. In: Sistemas de Produccion Pecuaria Extensiva. Ed. by R. R. Vera and C . Sere. Brasil, Colombia, Venezuela: CIAT, Cali, Colombia. p. 216-225. SHARMA, A. K.; WILLMs, L.; HARDIN, R. T.; BERG,R. T., 1982: Sex of calf and age of dam adjustments for some performance traits in two populations of beef cattle. Can. J. Anim. Sci. 62: 699-708. STEENKAMP, J. D. G.; HORST, C . V., 1974: The relationship between size and efficiency in the beef cow. S . Afr. J. Anim. Sci. 4: 81-89. STONAKER, H . H.; RAuN, N. S., GOMEZ,J., 1984: Beef sowcalf production experiments on the savannas of eastern Colombia. Winrock International. SYRSTAD, O., 1985: Heterosis in Bos taurus x Bos indicus crosses. Livest. Prod. Sci. 12: 299-307. VERA,R. R.; SERB, C. (Eds)., 1985: Sistemas de Produccion Pecuaria Extensiva; B r a d , Colombia, Venezuela. CIAT, Cali, Colombia. WILLIS, M. B., 1976: The use of Bos taurus in beef breeding programms in tropical areas. In: Beef cattle in developing countries. Ed. by A. J. Smith. Edinburgh: Univ. of Edinburgh, pp 332-346. Atrthors’ Addresses: B. RIVERA,CIID, AA 53016 Bogota, Colombia; R. R. VERA,CIAT, AA 6713 Cali, Colombia; J. H . WENIGER, Institute for Animal Production, TU-Berlin, Lentzeallee 75,1000 Berlin 33, Bundesrepublik Deutschland
