Crossbreeding N'Dama and Jersey cattle in Ivory Coast

L. Letenneur

The low productivity of tropical cattle is one of the reasons for the imbalance in the worldwide meat market. The developing countries possess 70 percent of the world's cattle and buffaloes, yet produce only 34 percent of the beef; thus, the productivity per head of cattle is 4.5 times lower in the de­veloping countries.

The coastal countries of the Sudan-Guinean zone have only small national herds. It is estimated that the national herd of trypanotolerant cattle in Ivory Coast is 380 000 head; 320 000 of these belong to the so-called "Baoulé" breed, but in fact most of them are, to a greater or lesser extent, crossbred with either zebu or N'Dama. The remaining 60 000 are humpless N'Dama, which are located in the western part of the country and bred on the Aboukouamekro and Sipilou ranches. To this population should be added 100 000 zebu, most of which came north at the time of the great drought in the Sahel.

Jersey bull used in Jersey x N'Dama crossbreeding programme.

Almost 90 percent of the cattle spread out north at the eighth parallel in the Sudan-Guinean zone, grazing the natural savanna in a low produc­tivity system. However, as a result of the work of the Société pour le développement des productions animales and of the research on forage and fodder crops conducted by the CRZ,¹ the technical transformation of various stock farms is being acceler­ated through sound management of the savanna, livestock upgrading tech­niques, the intensive production of forage and fodder crops outside the scheme of crop rotation, and seed production. In each of these various fields there are definite and important possibilities, and it should also be noted that Ivory Coast has an abun­dance of agroindustrial by products useful for feed.

The major problem is one of ob­taining cattle breeds that are geneti­cally adapted to the climate, suffi­ciently trypanotolerant, and capable of converting these enormous feed re­sources into livestock products in a way that is economically feasible and suits the facilities of the stock farmer.

Selection among local breeds is done to increase the number and perfor­mance of cattle. This work is indis­pensable and must be pursued and intensified, but will not alone meet the need for rapid development of beef production.

Crossbreeding, however, does offer a great potential but it also involves great risks. This article examines its potential for increasing individual pro­duction and herd numbers, as well as for determining the limits of the resis­tance of cattle to the difficult Sudan Guinean climate and their tolerance to trypanosomiasis, by presenting a ten-year record of experimentation of Jersey X N'Dama crossbreeding.

Choice ¹ of animals.

Of the breeds available in Ivory Coast the N'Dama first caught the attention of breed­ers due to its larger size, its carcass quality and its trypanotolerance. The CRZ, which had started a selective breeding programme of the N'Dama in 1955, possessed by 1964 a rather homogeneous N'Dama herd with known individual perfor­mance that could be used as founda­tion stock for crossbreeding. That same year, in compliance with direc­tives from the Minister of Agriculture and in view of the encouraging re­sults obtained at the Centre d'élevage (Animal Breeding Centre) of Bingerville, the committee in charge of re­search programmes in animal hus­bandry and veterinary medicine in­vited the CRZ to undertake an exper­imental project for the upgrading of N'Dama cattle by introducing the Jersey breed. As previous trials had shown that it was possible to raise N'Dama cattle throughout Ivory Coast (including the coastal zone), it would be feasible to do extension work on crossbreeding if this exper­iment were also to give positive re­sults. The Jersey breed was chosen for reasons of physiology and hus­bandry and because of the goals of the first phase of the desired upgrading.

Owing to the poor results obtained in the past in trials with artificial insemination of trypanotolerant cattle, natural mating had to be employed and a bull selected that was compat­ible in size with the N'Dama cow. Moreover, physioclimatological work had shown that the larger size ob­tained by crossbreeding might upset the heat regulation process through alteration of weight/body size ratio.

The aims of the crossbreeding were: (i) to improve milk production in the vicinity of the large urban centres of Ivory Coast; and (ii) to test the extent to which the introduction of genes for milk production into the N'Dama genotype would make it pos­sible to obtain earlier maturing beef cattle through the better nutrition of calves during the suckling period.

The milk production of the N'Dama cow is generally sufficient to feed the calf up to a certain stage of growth; animals crossed with large sized beef breeds would, if natural suckling were allowed, have to go through an initial stage of improvement of their milk production. Furthermore, it was also considered advisable to test not only the adaptation of the various cross­bred progeny to the environment, but also their disease resistance.

The crossbreeding plan.

Trials were designed for the breeding and testing of animals of the following grades:1/2, 3/4, 7/8 and 5/8 Jersey.

The decreased hardiness observed in 3/4 Jersey animals led, in 1971, to the proposal to abandon the upgrading process and to try to produce 3/8 Jersey-5/8 N'Dama animals instead. Thus a type of animal better adapted to the more usual stockraising conditions in Ivory Coast was sought, which would be used to breed early maturing beef cattle, particularly through the combined effects of heter­osis and better feeding of calves, while at the same time allowing a small amount of the milk to be marketed (provided that this did not adversely affect the growth of the calves).

Males and females with different proportions of Jersey and N'Dama breeding were obtained as follows: 192 halfbreds, obtained by mating Jersey bulls with N'Dama cows; 343 3/4-breds, obtained by mating Jersey bulls with F₁ cows (256), or by the interbreeding of the 3/4-breds them­selves (87); 236 3/8 Jerseys, obtained by mating N'Dama bulls with 3/4-bred cows (39), or by mating 3/4-bred bulls with N'Dama females (182), or by interbreeding the 3/8-breds (15); 112 5/8-breds, obtained by mating 3/4-bred bulls with F₁ cows.

Rearing conditions.

Parallel with the genetic improvement project, the CRZ conducted a programme for the intensive production of forage and fodder crops, thus providing a basis for the feeding system.

The conditions of calf rearing were closely linked to the genetic level of the dams. Lactating mothers were put out to graze either on the natural or improved savanna while calves of N'Dama cows or 3/8-bred cows were raised by natural suckling up to wean­ing at about 8 months of age. Calves from other crosses were separated from their dams at birth, fed colos­trum, and were then subjected to a standard feeding practice using whole milk, concentrates and hay; they were weaned at 4 months of age.

TABLE 1. Liveweight gains (kg) of N'Dama and Jersey x N'Dama crossbred males

The weaners were grazed rotationally on night and day pastures of Brachiaria ruziziensis, B. brizantha or Stylosanthes guianensis and, in addi­tion, were given a concentrate feed. This phase, the most critical one, lasted, on an average, 41/2 months. When the animals had reached 100-120 kg liveweight, they were included in the bull calf or heifer herds. Their feeding remained much the same at this stage, but the energy and protein supplement was restricted to 1 kg of rice bran or cottonseed and given dur­ing the dry season only. Once the animals had reached 210 to 230 kg liveweight, they were incorporated in the herds of adult males and breed­ing cows.

Jersey X N'Dama crossbred cow on Panicum maximum pasture.

TABLE 2. Liveweight gains (kg) of N'Dama and Jersey x N'Dama crossbred females

The males were then subjected to more intensive feeding on improved pastures, with supplementary feeding during the dry season (1.5 kg of cot­tonseed or rice bran). In fattening trials, however, some of the animals were raised on intensively grown for­age crops (irrigated Panicum maxi­mum) from June 1973 to July 1974.

The females were maintained on Stylosanthes pasture from 1968 to 1971; from then on they had Panicum maximum available to them. In view of the uses to which they were to be put and their performance, the 3/8-bred cows were kept on natural or improved savanna. During milking, they consumed on an average 2 kg of rice bran as a supplementary en­ergy source to the basic ration.

Preventive treatment was provided against contagious diseases such as rinderpest, bovine contagious pleuro­pneumonia and anthrax. Treatment for helminths and ticks was of the type that is standard in the Sudan-Guinean zone. No preventive or cura­tive treatment was used against trypa­nosomiasis, except for the herd of 3/4-breds; for the latter, two annual injec­tions of trypamidium were given until 1973, but thereafter a curative medica­tion with Berenyl (N.D.) was given as required, the risks of infestation having diminished.

Performance

Liveweight gain.

Owing to the na­ture of the experiment, animals of the various breeding groups could only be produced successively. Con­sequently it was not possible to make any contemporary comparisons of performance.

Comparisons were therefore limited to liveweight gains which are pre­sented in Tables 1 and 2. It may be concluded that the 1/2-, 3/4- and 3/8-breds have very good rates of weight gain.

When the herds were maintained on irrigated pastures of Panicum maxi­mum for one year, the 3/8-bred bull calves exhibited greater gains than did the 3/4-breds or the N'Dama.(439, 409 and 355 g/day respectively).

In some of the breeding groups distinct differences appeared to be linked with the manner in which they were produced. The weight gain of the 3/8-breds obtained by mating 3/4-bred males to N'Dama females was superior to that of 3/8-breds from reciprocal matings. As for 3/8-bred bull calves obtained by the inter se mating of 3/8-bred parents, too little data were available to make a com­parison possible.

The progeny of inter se matings of 3/4-bred parents gave poorer results than the F₁ . The maximum weights attained were 640 kg for 10-year-old F₁ draught oxen. F₁ cows are at present the heaviest of all crossbreds; the heterosis effect is particularly marked.

Productivity of females.

The aver­age age at first calving was 37 months for the N'Dama, 39 months for the F₁, 31 months in the 3/4-breds and 27 months in the 3/8-breds.

The 3/8-bred females appeared to be very precocious. Their age at first calving is on an average one year less than that of N'Dama females. This same aptitude did not appear in the F₁; however, the latter were bred at the age of 27 months on the basis of observations previously made among the N'Dama.

It may be noted that one 3/8-bred heifer that was accidentally mated at an early age did calve at 141/2 months. Her calf, which she suckled, weighed 110 kg at 9 months. The rather extraordinary sexual precocity ob­served among the 3/8-breds confirms similar observations made elsewhere on Jersey crossbreds. This charac­teristic would serve the goal of in­creasing herd size rapidly and could be a useful trait in the humid tropics. With adequate nutrition, it therefore seems perfectly feasible to obtain calving at the age of 24 months.

Average calving intervals were slightly less than one year for the various crossbred progeny. Compared with 410 days for the N'Dama, calving intervals among the F₁, 3/4-breds and 3/8-breds averaged 355, 363 and 352 days respectively.

The maximum number of concep­tions under natural mating conditions occurred at the end of the dry season for all animals, with the corresponding peak number of births in October, November and December.

Milk production.

Almost all F₁ and 3/4-bred cows let down their milk even when their calves were not present at milking time. They also showed good aptitude for complete hand milking. On the other hand, there was great dif­ficulty in hand milking the 3/8-breds; it is therefore concluded that these females should be kept as suckler cows, with the eventual possibility that some surplus milk may become available for sale.

Table 3 shows the milk yields of the F₁ and 3/4-breds in different lac­tations. Expressed as fatcorrected milk (fcm), the average milk yields (total and per day) of the F₁, increased progressively from the first to the sixth lactation (i.e., from 1 284 to 2 038 kg, which correspond to an average daily yield of 5 to 7.3 kg). The butterfat content was high; in the first lactation it was 5.76 percent, but declined there­after to 5.47 percent in the sixth lactation.

The milk production of the 3/4-breds was on average higher than that of the F₁. The yields increased substantially from the first to the fourth lactation (i.e., from 1 375 kg to 3 227 kg). The peak of the lactation curve was at the end of the first month. The persistency coefficient among the F₁ was 0.97 from the first to the second month and 0.92 from the second to the sixth month; there­after, there was a drop to 0.87 in the seventh month and to 0.82 in the eighth and ninth months. Among 3/4-breds the corresponding figures were 0.96 during the first three months and 0.87-0.94 from the third to the sixth month, depending on the length of the calving interval.

TABLE 3. Recorded milk production in halfbred and 3/4-bred animals

The average lactation period was 255 days among the F₁. It was longer among 3/4-breds, in which group it varied from 263 to 464 days. The average length of the dry period was 100 days.

The highest milk yield recorded among the F₁ cows was 2 663 kg fcm in 276 days, corresponding to a daily average of 9.7 kg.

Behaviour of lactating cows.

Seven F₁ cows had to be withdrawn from the dairy herds because they could not be handmilked. They were placed in the N'Dama herd and used for selec­tive breeding. This herd was kept under the most primitive conditions of the station, namely on natural or im­proved savanna.

The 3/4 N'Dama-1/4 Jersey calves obtained from these F₁ females showed markedly superior growth during the first six months to their N'Dama halfsibs (30 kg more for males and 36 kg more for females). Despite the limited number of progeny (five males and eight females), the differ­ence is sufficiently great to be taken into account. The average daily milk yield during the first four months of lactation, estimated on the basis of the calf weight at four months of age, was 5.14 litres; this yield is close to that of the F₁ when milked by hand but kept under definitely better conditions.

F₁ and 3/4-bred cows thus had good milk yields and an aptitude for complete hand milking, whereas the 3/8-breds had to be kept as suckler cows. Their performance is similar to that observed in Ghana.

Meat production potential.

This was analysed almost exclusively on the F₁ males, since most of the 3/4-bred males had been used for repro­ductive purposes and the 3/8-bred males had been employed as draught cattle.

During intensive fattening trials the average daily gains observed on 37-month-old animals which grazed on Panicum maximum and received a concentrate ration (based on cotton­seed and rice bran) were 896 g in the first month, 604 g in the second and 263 g in the third.

The carcass weights averaged 211 kg, with a dressing percentage of 57.8; the highest carcass weight was 241 kg, representing 61.3 percent of the live-weight. The conformation of the car­casses was generally good and the fat quality index satisfactory. The tender, juicy and finely marbled meat from these carcasses has always been great­ly valued by consumers.

Health.

The health of the F₁ and 3/8-breds under conditions at the CRZ, which was comparable to that among the N'Dama, was excellent. In partic­ular, according to clinical observations they retained their trypanotolerance which is an essential quality of the N'Dama. Table 4 gives in summary form the percentage mortality recorded at the CRZ in each age class.

Jersey X N'Dama bullocks used for ploughing.

Among the 3/4-breds, however, mor­tality figures were particularly high, indicating that these animals are not very hardy. The main causes of death were rickettsiosis, pasteurellosis, try­panosomiasis, piroplasmosis and calf diarrhoea. The animals lost their trypanotolerance and after an initial ob­servation period a wholesale treatment with trypamidium was practised. This was however discontinued in 1973 when the glossina became rare as a result of various measures taken at the station.

This general lack of hardiness of the 3/4-breds in all age-classes was at­tested by a poorer adaptation to the climate than that of the F₁ and 3/8-breds and caused, in particular, a re­duction of their grazing period; the practice of not allowing the herds to go out except during the hotter hours of the day was catastrophic for the six 3/4-bred bulls loaned to local farmers. By contrast, in the same environment the F₁ and 3/8-bred steers gave complete satisfaction; the few deaths reported were attributable not to lack of hardiness among the animals but to accidents or to a lack of minimal care and to inadequate nutrition.

Conclusions

The overall balance is very favour­able for the F₁ and 3/8-bred Jersey X N'Dama crosses. The 3/4-breds, how­ever, lack hardiness, and this limits their potential future use in the humid tropics.

The 3/8-breds would do perfectly well under the care of trained stock­men. Their hardiness, their suitabil­ity as draught animals, their high growth rate — definitely superior to that of the N'Dama — along with their sexual precocity (making calving pos­sible at slightly over two years of age), the eventual possibility of partial milk­ing (a difficult habit to change, be­cause it is the regular source of in­come from most local herds and would result in catastrophic consequences for the calves) should make 3/8-breds the choice animals in a general programme for rapid development of meat production. Moreover, consid­ering its ease of calving, this type of animal could be used as the stock for a more ambitious genetic upgrading programme. Nevertheless care has to be taken not to reach the 3/4-bred level.

TABLE 4. Percentage of mortality in different breed groups

In making a summary report on overall performance the F₁ could be readily ranked as the best; it com­bines hardiness and high liveweight, good carcass quality, excellent apti­tude for use as a draught animal, and a good milk yield, with the possibility for complete hand milking. This type of animal should be popularized among middlesize farms that prac­tise a minimum of intensive produc­tion of forage and fodder crops, and also among surburban improved stock farms which have trained manpower at their disposal and which market their milk. F₁ females are, in fact, capable of giving a gross monetary value seven times greater than N'Dama cows and have much better fitness characteristics; the males are choice beef or draught animals. In any case, extreme prudence in selecting a breed­ing programme is essential. The re­sults obtained for the 5/8-breds are still too incomplete to recommend production of this type of animal, and the risk of segregating genetic traits by crossbreeding of the F₁ has not been assessed, so further experimen­tation is needed. Other genetic ave­nues that permit maximum benefits from heterosis, such as two-stage crossing and rotational crossing, remain to be explored, but it would be worth while seeking out parent stock adapted to the tropics.

Under present conditions, the pro­duction of 3/4-breds is not recom­mended; indeed, it is to be avoided. Commercial crossbreeding, involving the slaughter of F₁ females, is also not advised, because this would be con­trary to the important policy of in­creasing herd size. The use of F₁ animals for breeding should be looked at in relation to the end use of the progeny. If they are to remain in the farm sector, backcrossing to the N'Dama may be recommended; the resultant animals exhibit excellent hardiness and are superior in perfor­mance to the N'Dama.

The mating of 5/8-bred bulls with F₁ females probably presents the min­imum risks for medium-sized enter­prises or dairy farms on the outskirts of towns with trained manpower and improved pastures. A return to a policy of two-stage crossing might also be considered, provided that the greatest caution is exercised in the choice of the third breed which would, in any case, be of minimum hardiness. The 3/4-breds are not to be recom­mended in the various production settings.

The question that remains is: what policy should be adopted for a large-scale crossbreeding programme in the humid tropics in the light of these ten years of experience with Jersey X N'Dama crossbreeding in Ivory Coast?

Apart from the necessity of care­fully identifying the best stock farm­ing areas, ascertaining the level of technical knowledge of stock farmers, and investigating possibilities for in­tensive production of forage and fod­der crops and for using agroindus­trial by-products as feed, it is impor­tant to adopt an appropriate method for reproduction, whether it be nat­ural mating or artificial insemination. Widespread natural mating is only feasible with 3/4-bred bulls on N'Dama cows or 5/8-bred bulls on F₁ cows, while the production of 3/4-bred bulls should be organized in specialized centres prior to their use in a few stud farms, where the sires would be under close surveillance. This could be facilitated by a well-controlled lending scheme to herds run by trained stockmen in favourable regions, in particular, in natural savanna regions with heavy soils where draught ani­mals are used, or in stock farming re­gions where trained stockmen are implementing a forage improvement programme. The use of 5/8-bred bulls in mediumsized enterprises or in suburban stock farms with trained manpower and improved pastures presents much less difficulty.

Recourse to artificial insemination does not seem a Utopian dream and is favoured by the current practice of community raising of large herds. In any case, two prerequisites, at present the subject of research, should be mentioned: a good knowledge of the sexual physiology of local humpless cattle, and the development of ar­tificial insemination techniques through oestrus synchronization.

Whichever method of reproduction is chosen, extension work to popu­larize a policy of crossing requires the establishment of specific breeding fa­cilities, such as a centre for multipli­cation of sires with a high percentage of Jersey blood (over 50 percent), a stud farm, and an artificial insemina­tion centre.

The establishment of such facilities is largely a prerequisite for the popu­larization of the Jersey X N'Dama cross, which offers the potential of a 50 percent increase in meat produc­tion as compared with the local N'Dama cattle. Taking also milk yield into account, the gross production value of each halfbred cow could be increased fivefold and the enormous forage potential of the countries in the humid tropics could be utilized profitably. Moreover, the maternal qualities of F₁ and 3/8-breds open the way to more ambitious genetic programmes. ■

References

Charray, J. 1975. Bilan des abattages de bæufs N'Dama réaliséts au C.R.Z. de Minankro de mars 1974 à mars 1975. Etude des carcasses. C.R.Z. de Bouaké-Minankro. 4 p. (Mimeo­graphed)

Coulomb, J. 1967. Selection des taurins de race N'Dama au C.R.Z. de Mi­nankro 1956-1966. I.E.M.V.T. 65 p. (Mimeographed)

Coulomb, J., Riviere, Pagot, J. & Ca­bot. 1971. Métissage Jersiais-N'Dama. Résultats obtenus au Centre de recherches zootechniques de Bouaké-Mi­nankro. l^ére note. I.E.M.V.T. 68 p. (Mimeographed)

Glattleider, L. 1974. Note sur la valeur alimentaire des fourrages tropicaux. Premiers résultats sur Panicum maximum K 187 B. C.R.Z. de Bouaké-Minankro. 18 p. (Mimeo­graphed)

Gombaud, B. 1973. Engraissement de bœufs N'Dama de 4 ans en stabulation et sur pâturage permanent complé-mente. C.R.Z. de Bouaké-Minankro. 53 p. (Mimeographed)

Ivory Coast. Centre de recherches zootechniques. Annual reports, 1965 to 1974.

Jouve, J.L., Letenneur, L. & Catala, P.E. 1971. Mise en place d'un élevage d'embouche en secteur paysan. Résultats après 1 an d'expérience. C.R.Z. de Minankro-Bouaké. 47 p. (Mimeographed)

Jouve, J.L. & Letenneur, L. 1972. Essai d'embouche intensive de taurins Jersey-N'Dama en Cote d'lvoire. Rev. Elev. Méd. vét., Pays trop., 25(2): 309,316.

Letenneur, L. 1973. Production four-ragere en Cote d'lvoire et possibilités dintensification. 58 p., 42 tables.

Messager, J.L. & Letenneur, L. 1972. Un exemple de production fourragére intensive. Observation sur l'exploita­tion au pâturage du Panicum maxi­mum. 45 p.

Pagot, J., Coulomb, J. & Petit, J.P. 1972. Revue et situation actuelle de I'emploi des races trypanotolerantes. Rapport au séminaire interrégional FAO/OMS sur la trypanosomiase africaine, Kinshasa, 23 octobre-3 novembre 1972.

Ralambofiringa, A. 1975. Contribution à I'étude de la physiologie de la repro­duction, la méthodologie de la détec­tion de l'æstrus et la technologie de I'insémination artificielle de la vache N'Dama en République de Côte d'lvoire. Toulouse. (Thesis)

L. Letenneur is with the Institut d'élevage et de médecine vétérinaire des pays tropicaux, 10 rue Pierre-Curie, 94700 Maisons-Alfort, France.

¹ The project for crossing of Jersey X N'Dama cattle conducted at the Center de recherches zootechniques (CRZ, Animal Husbandry Research Center) of Bouaké-Minankro was launched in 1965. It was executed by J. Coulomb and R. Cadot from 1965 to 1970; and by L. Letenneur, J.C. Mathon, J. Charray, G. Roberge, J.L. Messanger, L. Glattleider, B. Carino and L. Hermitteau from 1970 to 1976.