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Mortality in Venezuelan beef cattle

D. Plasse, H. Fossi and R. Hoogesteijn

The authors can be contacted at the Universidad Central de Venezuela, Facultad de Ciencias Veterinarias, Apartado 2196, Maracay, Venezuela.
Acknowledgements. The authors wish to thank the owners, veterinarians, managers and staff of the following ranches for their collaboration in collecting data: Estación Experimental La Cumaca, Estación Experimental Calabozo, Cujicito, Guataparo, Jobito, La Herrereña, Los Caños, Los Gabanes, Mata de Agua, Matapalos, Merecure, San Pablo, Sta. Luisa and Turagua. They gratefully acknowledge the revision of the manuscript by Professor Lucia de Vaccaro.
The final processing of the data was supported by the Consejo de Desarrollo Científico y Humanístico of the Universidad Central de Venezuela through the Ayuda Institucional
No11-10-3720-96.

MORTALITÉ CHEZ LES BOVINS DE BOUCHERIE AU VENEZUELA

Afin d'évaluer les pertes de veaux entre le diagnostic de gravidité et l'âge de 18 mois, un jeu de données de base comprenant 71 654 années-vache provenant de 14 troupeaux participant à des programmes de recherche a été établi à partir de dossiers de production informatisés. Le taux de gestation s'élevait à 71 pour cent et celui de perte prénatale à 7,9 pour cent. Dans huit troupeaux, où toutes les pertes de veaux étaient motivées par la mortalité, 4,9 pour cent des 19 419 veaux nés vivants sont morts avant le sevrage et 7,5 pour cent avant 18 mois. Dans six autres troupeaux, où l'évaluation était moins précise, 6,6 pour cent des 18 585 veaux nés sont morts avant le sevrage et 12,3 pour cent avant 18 mois. Les pertes cumulées entre la palpation et l'âge de 18 mois s'élevaient à 17 pour cent. La mortalité et la perte de vaches constatées dans quatre troupeaux se situaient entre 1,2 et 4,1 pour cent. Dans six troupeaux, comptant 1 063 veaux morts, la fréquence relative la plus élevée de mortalité se produisait pendant les trois premiers jours de vie, mortalité imputable essentiellement à la malnutrition et à la faiblesse, mais également à d'autres raisons. Sur l'ensemble des animaux perdus, 71,3 pour cent sont morts avant le sevrage et le reste entre le sevrage et 18 mois. Sur une base annuelle, pour chaque 100 vaches faisant l'objet de l'étude, on a constaté 70 gestations, 64 veaux nés vivants, 61 veaux sevrés et 58 vivants à l'âge de 18 mois.

MORTALIDAD DEL GANADO VACUNO DE CARNE EN VENEZUELA

Con el fin de evaluar la pérdida de terneros entre el diagnóstico de preñez y la edad de 18 meses, se construyó, a partir de registros de producción computarizados, una base de datos de 71 654 vacas-años de 14 rebaños participantes en programas de investigación. El porcentaje de preñez fue del 71 por ciento y la pérdida prenatal del 7,9 por ciento. En ocho rebaños, en los cuales toda la pérdida fue explicada por mortalidad, el 4,9 por ciento de 19 419 terneros nacidos vivos murieron antes del destete y el 7,5 antes de los 18 meses de edad. En otros 6 rebaños con evaluación menos exacta, se perdió el 6,6 por ciento de los 18 585 terneros nacidos antes del destete y el 12,3 por ciento hasta la edad de 18 meses. La pérdida acumulada entre la palpación y 18 meses fue del 17 por ciento. La mortalidad y pérdida de vacas en cuatro rebaños fue entre el 1,2 y el 4,1 por ciento. En seis rebaños con 1 063 terneros, la mayor frecuencia relativa de mortalidad ocurrió durante los primeros tres días de vida y fue debida mayormente a desnutrición y debilidad pero también a otras razones. De todos los animales perdidos, el 71,3 por ciento murieron antes del destete y los restantes durante el período postdestete. Anualmente, cada 100 vacas en el estudio produjeron 70 preñeces, 64 terneros nacidos vivos, 61 destetados y 58 vivos a la edad de 18 meses.

High pregnancy percentages and low mortality rates are decisive factors determining the profitability of beef cattle production because they directly determine the number of animals available for sale and indirectly the genetic progress that may be achieved.

Low productivity of tropical beef cattle populations in Latin America is generally attributed to low reproductive efficiency, high mortality and low growth rates. However, data on death losses during different phases of life are scarce and future improvement programmes require better documentation of this trait.
The objective of this paper is therefore to summarize, as a series of case studies, the available data on mortality in tropical beef cattle derived from genetic research programmes in Venezuela.

MATERIALS AND METHODS

Computerized production data from 14 herds (A to N) in two experiment stations (A and B) and 12 private farms cooperating in genetic research programmes carried out over 27 years (1965-1991) were used. The data form a scientifically reliable subset of 276 484 records from 22 herds presented in a practical discussion of the theme by Plasse et al. (1993). Additionally, two commercial Zebu herds, 0 and P, were only used for cow loss evaluation.

The herds are located in seven states of Venezuela under a variety of environmental conditions and they are a fair representation of the main beef cattle production areas of the country. Only herds with complete and reliable records were taken into consideration. For each one, experimental genetic and non-genetic improvement programmes were designed at the beginning of the research programme. They were supervised by technical personnel and the authors. Each herd had veterinary assistance.
Herds A to N were composed of either registered Brahman, Nellore or Guzerat cows or non-registered élite cows of these breeds, Criollo and Bos taurus x Bos indicus cross-breeds, and produced bulls for use on the ranch or for sale.
The herds were subjected to one of two types of breeding season lasting four to five months: i) for calving at the end of the dry season and beginning of the rainy season in all ranches with higher non-flooded grassland; and ii) for starting to calve at the beginning of the dry season in areas with flooded savannahs. Pregnancy diagnosis was carried out by a veterinarian 45 to 60 days after the end of the breeding season. Calving took place in special pastures and calves were tattooed and weighed within 24 hours after birth. They were later branded with individual identification numbers. Calves stayed with their dams on pasture without supplemental feed except a mineral mixture, which was offered to all animals. Weaning took place at seven to eight months.
Herds A, C, D and G were maintained on cultivated pasture and herds J, K, M and N were kept on native savannah. In the others, weaners were maintained until 18 months on cultivated pasture and the rest of the time they spent on native grass, as did all other animals. The female calves of all herds were vaccinated against brucellosis and yearly follow-up tests were carried out. The first outbreak of leptospirosis was diagnosed in 1968 in herd A. As a result of the increase of abortions during the 1970s, most of the ranches introduced testing and vaccination for leptospirosis. Those with a high incidence of abortions also carried out vibriosis and IBR diagnostic tests with positive results. In more recent years, vaccination programmes against vibriosis were adopted by most of the ranches. No vaccinations were carried out against IBR because vaccines were not available. No trichomoniasis was diagnosed.
In this paper, mortality was determined for the following phases: (1) from pregnancy diagnosis to birth; (2) from birth to weaning; (3) from weaning to 18 months; and (4) for females in the breeding herd (yearly). In phase (1), abortions were observed by ranch personnel. Cows diagnosed pregnant, but which did not give birth to a live calf, were classified as having lost their conceptus. The sum of both incidents was defined as "prenatal loss". For phases (2) and (3) the material was subdivided into data sets I and II. The former corresponded to herds where all losses were proved to be caused by death, while data set II included those where extensive conditions made it impossible to determine the fate of every missing calf. Thus, losses were classified as death (proved) and "other losses". A calf in the latter classification might have died, but might also have been stolen, escaped to another herd, etc. However, in each case this represented an economic loss.
For six herds from data set I, age and cause of death were regularly recorded for the periods: < three days, four to 30 days and 31 days to weaning as being due to "undernutrition and/or weakness" or "other reasons"; and for the postweaning phase as "disease" or "other reasons". This classification was intended to separate the causes resulting from maternal effects (undernutrition of the calf) from the others.
Data on cow mortality were reported from herds A, H+O, J and P.

RESULTS AND DISCUSSION

Prenatal loss

Table 1 presents prenatal loss in the 14 herds recorded over an average of 8.7 years. The mean pregnancy rate of 71 654 cow-years was 71 percent, which is high for the Latin American tropics. The lowest value, 57.2 percent, was obtained in a herd on low savannah and the highest, 81.8 percent, on cultivated pasture in a more favourable area.

1
Prenatal losses in 14 Venezuelan herds
Pertes prénatales dans 14 troupeaux au Venezuela
Pérdidas prenatales en 14 rebaños de Venezuela

Herd

State

Years (No.)

Breed1

Cows palpated

Cows pregnant (No.)2

Observed abortions (%)3

Pregnant non-calving cows4 (%)3

Total prenatal loss (%)3

A

Yaracuy

10

RB

1 906

72.0

4.0

1.5

5

B

Guárico

17

RB, EB, CR, XX

6 398

70.4

2.7

3.0

5.7

C

Portuguesa

24

RB

7 501

72.8

2.9

5.0

7.9

D

Carabobo

10

RB, RN, RG

2 159

81.8

2.3

1.0

3.3

E

Guárico

9

RB, RN, RG

12 335

71.4

...5

5.5

5.5

F

Cojedes

5

RB

755

64.7

0.9

6.3

7.5

G

Cojedes

4

EB, XX

4 821

80.6

0.6

3.9

4.4

H

Apure

6

RB, EB, XX

6 160

80.4

2.0

5.7

7.7

I

Barinas

5

EB, XX

3 215

71.8

1.3

7.6

8.9

J

Apure

6

RB

2 549

74.6

1.8

6.9

8.8

K

Apure

5

ES

5 181

64.4

1.16

9.6

10.6

L

Apure

8

EN, EB, EG

12 919

65.3

0.6

12.6

13.1

M

Apure

8

EB

4 410

66.0

4.3

3.7

8.0

N

Apure

5

EG, EB

1 345

57.2

4.5

4.7

9.4

Total (14 herds)

   

71 654

71.0

1.6

6.3

7.9

 

1 RB = Registered Brahman; EG = Elite Guzerat; EB = Elite Brahman; RN = Registered Nellore; CR = Criollo; RG = Registered Guzerat; EN = Elite Nellore; XX = Bos taurus x Bos indicus.
2
In relation to palpated cows.
3
In relation to pregnant cows.
4
Non-observed losses.
5
Not recorded.
6
Observations made only during the last years.

Mean prenatal loss was 7.9 percent and varied between extreme herds from 3.3 to 13.1 percent. Annual variation within herds was as high as 2.3 to 16.2 percent in herd A. The mean of 7.9 percent for prenatal loss is composed of 1.6 percent observed abortions and 6.3 percent cows diagnosed pregnant but which did not calve. This means that only 20.3 percent of all losses were explained by a reported abortion. It is apparently impossible to draw conclusions about prenatal loss in beef cattle herds by only taking into consideration the observed abortions, since many foetuses are likely to be taken away by wild animals before they can be recorded. Also, early losses might result from absorption. This emphasizes the importance of pregnancy monitoring and strict recording of parturition.
The lowest prenatal loss was recorded in the herd with the highest pregnancy percentage (D) and the highest value corresponded to a herd with a relatively low reproductive efficiency (L). The correlation between the mean pregnancy percentages and prenatal losses of the 14 herds was -0.63 (P<0.05), which suggests that, to a certain extent, the same factors that produce high death losses between palpation and parturition also affect pregnancy percentages negatively. Cows which conceived at the beginning of the four to five months breeding season already had gestations of 5.5 to 6.5 months when they were palpated. This type of evaluation therefore underestimates the real loss, since open cows may have been pregnant and aborted before palpation. Thus, part of the real loss might reflect itself in a lowered pregnancy percentage. Also, cows diagnosed pregnant might have lost a foetus conceived earlier and then conceived again. In Venezuelan Bos indicus cows, Linares and Rodríguez (1983) found a 12.5 percent prenatal loss, most of which occurred in the fifth to seventh month of gestation. In the same area, Hoogesteijn et al. (1983a) found a 17 percent prenatal loss in four extensively managed Zebu herds. A survey study in Brazil, Colombia and Venezuela found prenatal death rates of 8, 14 and 16 percent (Vera and Seré, 1985). In the Beni, Bolivia, prenatal losses of 5.3 percent were found in a Criollo and a Zebu herd (Verde et al., 1993; Plasse, Fossi and Hoogesteijn, 1993). Our values do not seem excessively high since Australian workers reported 6 to 40 percent losses between palpation and the age of three to four months of the calf (Donaldson, Ritson and Copeman, 1967; Lamond, 1969; Young and Blair, 1974).
According to diagnostic results in most of the herds, the main causes of prenatal loss were leptospirosis and vibriosis. Although the majority of the herds followed vaccination programmes and some were successful in lowering the loss from over 20 to 5 percent or less, others did not have the desired results. We believe that, in some cases, problems in the refrigeration chain, owing to inappropriate transport and storage between laboratory and field, might have lowered the effectiveness of the vaccine; in other cases, that the vaccination programmes were not properly carried out.

 

W8600t23.JPG (47561 bytes)

Some herds were relatively small and were maintained on cultivated pasture under more intensive management ...
Certains troupeaux étaient maintenus sur des pâturages cultivés, de taille relativement faible et gérés de manière plus intensive...
Unos rebaños relativamente pequeños, manejados más intensivamente, fueron mantenidos en pasto cultivado...

 

W8600t24.JPG (44835 bytes)

... while others were large, less intensively managed and maintained on savannah
... tandis que d'autres étaient importants, avec une conduite moins intensive et maintenus sur la savane
... mientras que otros rebaños grandes, manejados menos intensivamente, fueron mantenidos en sabana
Photos/Fotos: D. Plasse

Preweaning loss

In eight intensively managed herds, evaluated during an average of 9.3 years, all calf losses were explained by mortality (Table 2). Of 19 419 calves born alive, 4.9 percent died before weaning, with a variation between herds from 2.4 to 11.5 percent. Annual within herd variation was as high as 1.5 to 22.1 percent in herd A and as low as 2.3 to 3.4 percent in herd G. In general, a low annual variation was characteristic of herds with a low mean mortality and a high yearly variation was usual for those with high averages.

2
Preweaning, postweaning and total calf mortality in eight Venezuelan herds (data set I)1
Mortalité des veaux avant sevrage, après sevrage et mortalité totale (jeu de données I)
Mortalidad predestete, postdestete y total de terneros en ocho rebaños de Venezuela (lote I)

       

Death loss

Herd

Years
(No.)

Calves born alive
(No.)

Calves weaned
(No.)

Birth -
weaning
(%)2

Weaning -
18 mths
(%)3

Total birth -
18 mths
(%)2

A

11

1 384

1 293

6.6

2.3

8.7

B

12

2 460

2 312

6.0

6.0

11.7

C

24

5 050

4 692

7.1

2.0

8.9

D

10

1 560

1 522

2.4

0.6

3.0

E

4

4 270

4 170

2.4

2.5

4.8

F

4

339

300

11.5

3.0

14.2

G

3

2 729

2 650

2.9

1.4

4.3

J

6

1 625

1 534

5.6

1.5

7.1

Total (8 herds)

9.3

19 419

18 473

4.9

2.4

7.5

1 For location and breeds see Table 1.
2
In relation to calves born alive.
3
In relation to weaned calves.

In six other herds evaluated during an average of 6.2 years (Table 3), not all calves born alive but absent at weaning were recorded as dead and losses were classified as either: i) calves reported dead; and ii) calves lost without a precise cause (dead, lost, stolen). Mean mortality was 5.3 percent and the average of other losses 1.3 percent, giving a total preweaning loss of 6.6 percent.

3
Preweaning, postweaning and total calf mortality and loss in six Venezuelan herds (data set II)1
Mortalité et perte de veaux avant sevrage, après sevrage et totalité dans six troupeaux vénézuéliens (jeu de données II)
Mortalidad y pérdida predestete, postdestete y total de terneros en seis rebaños venezolanos (lote II)

       

Birth - weaning

Weaning - 18 mths

 

Herd

Years
(No.)

Calves born alive
(No.)

Calves weaned
(No.)

Mortality2
(%)3

Other losses4
(%)3

Total preweaning loss
(%)3

Mortality2
(%)5

Other losses4
(%)5

Total postweaning loss
(%)5

Total loss birth -
18 mths
(%)3

H

6

3 932

3 645

5.3

2.0

7.3

0.5

3.6

4.2

11.2

I

4

1 544

1 416

3.1

5.2

8.3

2.0

7.3

9.4

16.9

K

5

2 815

2 590

5.9

2.1

8.0

4.5

5.8

10.3

17.5

L

8

6 882

6 508

5.3

0.4

5.7

2.2

3.4

5.6

10.8

M

8

2 633

2 472

6.1

0.0

6.1

2.1

2.8

4.9

10.7

N

6

779

726

7.3

0.0

7.3

1.1

1.4

2.5

9.1

Total (6 herds) 6.2

18 585

17 357

5.3

1.3

6.6

2.1

4.0

6.1

12.3

 

1 For location and breeds, see Table 1.
2 Diagnosed death.
3 In relation to calves born alive.
4 Missing but death not reported.
5 In relation to calves weaned.

Our values for preweaning mortality and total loss of 4.9 and 6.6 percent in data sets I and II, respectively, are lower than those reported in the literature from tropical Latin America where 21 herds with 58 079 live-born calves averaged 7.8 percent (Table 4) and also less than the 9 percent preweaning mortality reported by Cundiff, Gregory and Koch (1982) from 24 experiments in the United States.

4
Preweaning mortality in tropical Latin America
Mortalité après sevrage en Amérique latine tropicale
Mortalidad prenatal en América Latina tropical

Location

Breed

Calves born
(No.)

Mortality
(%)

Reference

Brazil, São Paulo

lndubrasil

13 760

7.0

Barros et al., 1972

Mexico, San Luis Potosi

Brahman

1 569

5.1

Rodríguez & Escribá, 1972

Venezuela, Anzoátegui

Crosses Bos taurus x Bos indicus

849

13.5

Montoni, González-Crespo & Verde, 1979

Venezuela

Brahman

 

5.3

Ordóñez, Bastardo & Plasse,1979

- Llanos Altos
- Occidentales

Brahman
- Santa Gertrudis

4 905

4.1
13.4

Ordóñez, Bastardo & Plasse,1979
Ordóñez, Bastardo & Plasse,1979

Venezuela, Apure

Brahman
F1 Simmental
F1 Marchigiana


1 242

8.0
6.0
3.0

Hoogesteijn et al., 1983b
Hoogesteijn et al., 1983b
Hoogesteijn et al., 1983b

Colombia, Meta

Brahman
Criollo San Martinero, crosses


785


7.4


Hernández in FAO, 1981

Colombia, Córdoba

Brahman, Criollo Romosinuano, crosses

1 561

7.4

Hernández in FAO, 1981

Colombia, Antioquía

Brahman, Criollo BON, crosses

676

4.0

Hernández in FAO, 1981

Venezuela, Monagas

Brahman and Charolais,
Sta. Gertrudis, Brown Swiss, crosses

1 441

11.7

Parés, González & Verde, 1983

Costa Rica, Pacifico Seco

Brahman

2 674

9.4

Chan et al., 1986

Brazil, Pará

Nellore

12 112

5.1

Hautle, 1987

Mexico, Tamaulipas

Brahman

771

7.0

González & Segura, 1989

Venezuela, Táchira

Brahman

918

9.0

Montoni, Rojas & Mago de Montoni, 1996

Venezuela, Portuguesa

1/2 Bos taurus1, 1/2 Brahman,
1/4 Bos taurus1, 3/4 Brahman


1 170

10.0
17.8

Martínez & Gabaldón, 1990
Martínez & Gabaldón, 1990

Bolivia, Beni

Zebu

6 312

3.3

Galdo et al., 1992

Bolivia, Beni

Criollo Yacumeno

7 334

5.1

Bauer et al., 1992

Unweighted mean of 21 values

 

58 079

7.8

 

1 Charolais and Simmental.

 

W8600t25.JPG (34462 bytes)

Registration at birth and daily supervision of the newly born calf are means to monitor abortion and early calf loss. In the photo: Criollo at Beni, Bolivia
L'enregistrement à la naissance et la surveillance journalière du veau nouveau-né sont des mesures qui permettent de surveiller les risques d'avortement et la perte précoce de veaux (Criollo à Beni, Bolivie)
El registro al nacimiento y la supervisión del recién nacido son medidas para monitorear abortos y pérdidas tempranas en los becerros (Criollo en Beni, Bolivia)

 

W8600t26.JPG (46427 bytes)

Good maternal ability is important for survival of the calf
Une bonne aptitude maternelle est importante pour la survie du veau
Una buena habilidad materna es importante para la sobrevivencia del becerro
Photos/Fotos: D. Plasse

Postweaning loss

Death loss between weaning and 18 months in data set I was 2.4 percent (Table 2) with extreme values between herds of 0.6 to 6.0 percent. The latter value corresponds to an experimental herd where the mean was influenced by high mortality in Criollo (Bos taurus) and 3/4 Bos taurus 1/4 Bos indicus cattle. In data set II (Table 3) postweaning mortality and other losses were on average 2.1 and 4.0 percent, respectively, for a total of 6.1 percent. Yearly within herd variation was as high as 1.8 to 21.2 (herd H) and as low as 0.7 to 3.9 percent (herd N). The range of values between herds was from 2.5 to 10.3 percent.

Accumulated loss to birth, weaning and 18 months

The accumulated loss up to birth, weaning and 18 months in 35 976 calves detected alive initially by palpation of the dams was 8.6, 13.6 and 17 percent, respectively, and prenatal loss was responsible for 51 percent of the total (Table 5). The majority of these values are higher than those reported in a Zebu herd in the savannah of the Beni, Bolivia, which were 5.3, 9.5 and 14.2 percent (Plasse, Fossi and Hoogesteijn, 1993) and in a Criollo herd at the same location, where corresponding losses were 5.3, 10 and 20.9 percent (Verde et al., 1993). However, Bellows and Short (1994) showed a 15 percent loss between pregnancy diagnosis and weaning in a large data set from the United States. Our data indicate that, for each 100 cows palpated, 70 were pregnant, 64 calved, 61 weaned a calf and 58 had offspring which were alive at 18 months of age. In the herd with best results (D) these values reached 81, 78, 76 and 76, respectively, while in the worst one (K) they were 62, 56, 52 and 47.

5
Accumulated loss at birth, weaning and eighteen months1
Pertes cumulées à la naissance, au sevrage et à 18 mois
Pérdida acumulada al nacimiento, destete y a los 18 meses

   

Cows

Accumulated calf loss (%)2
palpation to:

 

Herd

Years
(No.)

Palpated

Pregnant

Birth

Weaning

18 mths

Prenatal loss as
(%) of total

A

10

1 906

1 372

5.5

11.3

13.4

41

C

24

7 501

5 461

7.9

14.4

16.1

49

D

8

1 685

1 358

3.4

5.6

6.2

55

E

4

6 275

4 530

5.8

8.0

10.3

56

F

4

573

368

7.9

18.5

20.9

38

G

3

3 483

2 843

4.0

6.9

7.6

53

H

5

4 803

3 780

8.0

16.5

18.4

44

I

4

2 467

1 708

9.9

14.6

22.4

44

J

5

2 149

1 576

8.6

13.4

14.6

59

K

4

4 042

2 523

10.3

17.0

25.4

41

L

7

11 074

7 213

13.7

18.0

23.1

59

M

7

3 823

2 475

8.3

14.2

17.8

47

N

5

1 345

769

9.4

15.6

17.9

53

Total herds

136.9

51 126

35 976

8.6

13.6

17.0

51

1 For location and breed see Table 1.
2 In relation to potential calves palpated.

Causes of death loss in calves

The highest relative frequency of death occurred during the first three days of life (Table 6) and the number of deaths per unit of time decreased with increasing age of the calf. In early life, "undernutrition and weakness" of the calf was a more important cause than "other reasons", showing the influence of maternal ability at this age. After the first month, "other reasons" gained importance increasingly. While 71.3 percent of all deaths occurred in the preweaning phase, 28.7 percent of the dead calves were lost after weaning, when "diseases" and "other reasons" were of similar proportion.

6
Cause of death in six Venezuelan herds1
Causes de mortalité dans six troupeaux vénézuéliens
Causas de mortalidad en seis rebaños de Venezuela

     

Preweaning mortality

Postweaning mortality

Herd

Years
(No.)

Total dead calves
(No.)

£3 days: Undernutriton ad weakness
(%)2

£3 days: Other reasons
(%)2

4-31 days: Undernutriton ad weakness
(%)2

4-31 days: Other reasons
(%)2

31 days to weaning: Undernutrition
(%)2

31 days weaning: Other reasons
(%)2

Disease
(%)2

Other reasons
(%)2

A

11

121

2.5

11.6

15.7

19.8

7.4

18.2

14.1

10.7

B

12

287

15.3

6.6

8.7

5.9

1.0

13.9

32.5

16.0

C

24

458

6.8

7.2

10.3

14.7

8.6

32.0

9.4

11.0

D

10

47

12.8

0.0

0.0

8.5

2.1

57.5

8.5

10.6

G

3

43

4.7

4.7

14.0

9.1

0.0

34.9

7.0

25.6

J

6

114

9.7

9.7

14.0

8.8

8.8

28.9

6.1

14.0

6 herds

11

1 070

9.1

7.4

10.5

11.9

5.8

26.6

15.5

13.2

1 See Table I for location and breeds.
2 In relation to total number of dead.

The high relative frequency of deaths during the first three days of life in tropical cattle seems to have two main reasons: very low birth weights and deficient maternal ability (including udder problems). In a study on the behaviour of cow-calf pairs, Beltrán (1976) found that 10 percent of the calves born required human help for suckling. All calves that died within the first three days after birth weighed less than 20 kg. This relation between low birth weight and early mortality was also shown by Koger et al. (1967), Parés, González and Verde (1983) and Montoni, Rojas and Mago de Montoni (1996).
Management and health programmes are of basic importance in improving calf survival. This was evident when Beltrán (1976) initiated a research project to detect causes of high preweaning mortality after a four-year average of 12.6 percent was found in herd A. During the five years of this study, death loss dropped to 3.9 percent and increased again to 5 percent in the two years afterwards. It can be concluded that the daily observations and the increased attention to cows and calves during the experiment had a positive influence on calf survival. A similar experience was published by Montoni, Rojas and Mago de Montini (1996), who found that an economic stimulus for the cowhands had a positive influence on preweaning survival. These workers estimated that 51 percent of their preweaning death rate (9 percent) could have been avoided.
The season of birth is important for calf survival. In the tropics, higher mortality is found in calves born in the rainy season compared with those born in the dry season (Rodríguez and Escrivá, 1972; Ordóñez, Bastardo and Plasse, 1979; Camacho et al., 1983; Montoni, Rojas and Mago de Montoni, 1996).
Breed composition also has an influence on mortality. In herd B, pure-bred Criollo had the highest death rate between birth and 18 months followed by 3/4 Bos taurus 1/4 Brahman calves while Brahman and 3/4 Brahman-1/4 Bos taurus had the lowest values (Ocanto et al., 1986; Plasse, et al., 1986).

 

W8600t27.JPG (44736 bytes)

On savannah, cows will walk long distances to graze. They leave their calves in a "nursery", where other dams take turns in caring for them
Dans la savane, les vaches parcourent de longues distances pour pâturer. Elles laissent leurs veaux dans une «garderie», où ils sont tour à tour surveillés par d'autres femelles reproductrices
En la sabana las vacas caminan largas distancias para pastorear, y dejan sus becerros en una «guardería infantil» donde otras madres se turnan para cuidarlos
Photo/Foto: D. Plasse

 

W8600t28.JPG (81972 bytes)

Abortion and death during the first months are the most important causes of low production per cow
L'avortement et la mortalité pendant les premiers mois sont les principales causes de la faible production par vache
Los abortos y la mortalidad durante los primeros meses son causas muy importantes de la baja producción por vaca
Photo/Foto: D. Plasse

 

W8600t29.JPG (103621 bytes)

A Zebu herd in the Venezuelan savannah
Un troupeau de zébus dans la savane vénézuélienne
Un rebaño cebú en la sabana venezolana
Photo/Foto: D. Plasse

Cow mortality and loss

In four herds with a total of 97 374 cow-years, the mean cow mortality and loss was 3 percent (Table 7). The values of herds A, H+O and J were due to mortality alone and comparable with the 1 to 2 percent reported by O'Rourke et al. (1995) from northern Australia. In herd P, loss from stealing contributed to the relatively high value. However, the higher mortality in this herd could also be explained by botulism (N. Márquez, personal communication) and by the high proportion of old cows. Culling of old cows, vaccination against botulism and better inventory control in this very large cattle ranch lowered the loss between 1990 and 1992 from 5.6 to 2.9 percent.

7
Mortality and other losses in cows in four Venezuelan herds
Mortalité et autres pertes de vaches dans quatre troupeaux vénézuéliens
Mortalidad y otras pérdidas de vacas en cuatro rebaños de Venezuela

Herd

State

Years
(No.)

Breed1

Cow-years
(No.)

Cow mortality
(%)2

A

Yaracuy

12

RB

 2 320

1.4

H+O

Apure

 7

RB, CB, XX

31 900

1.2

J

Apure

 6

EB

 3 099

2.0

P

Apure

 7

CB

60 055

4.1

Total (4 herds)

 

8.0

 

97 374

3.0

1 RB = Registered Brahman; EB = Elite Brahman; CB = Commercial Brahman; XX = Bos taurus x Bos indicus.
2 In relation to cows palpated the previous year.

CONCLUSIONS

High mortality between pregnancy diagnosis and the age of 18 months was clearly demonstrated by this study and can be considered to be one of the primary reasons for low productivity of beef cattle herds in Venezuela, as well as in the Latin American tropics in general. It must be emphasized that the herds evaluated were all managed under technical supervision and it must be assumed that their production level is above that of average herds in the country, which are estimated to have a pregnancy percentage of around 50 percent and a higher mortality rate than found here (Plasse, 1992). High prenatal losses of 7.9 percent were responsible for 51 percent of the total. Although some herds had good results from their leptospirosis and vibriosis vaccination programmes, in most cases the results have been rather disappointing. Probable reasons may include the reluctance of the cattle breeders to carry out intensive vaccination programmes persistently, the difficulty of acquiring good-quality vaccines and the involvement of other non-controlled virus diseases. On a national level, lack of sufficient information and education on reproductive diseases, combined with the near collapse of the official sanitary sector have hindered progress in the solution of the problem. On the other hand, the large variation between herds in this study indicates that considerable improvement is possible on most of the ranches. However, our values still underestimate the loss during gestation for reasons discussed above. A large proportion of prenatal death is not expressed in our figures but occurs before palpation and influences pregnancy rate rather than loss as defined in this paper. According to Bellows and Short (1994), early embryonic death is quite high in beef cattle, including tropical breeds (Plasse, Warnick and Koger, 1970).

Our values of preweaning and postweaning mortality are lower than those given in the literature, but the large variation between herds indicates that it can still be improved by better management, stricter inventory control and more intensive management and health programmes as well as by culling cows with low maternal ability.
The mean total loss between pregnancy diagnosis and the age of 18 months was 17 percent, which is very high. Variation between herds ranged from 6.2 to 25.4 percent and indicates that there is ample opportunity for improvement.
In our opinion, it is essential to inform the cattle industry about the magnitude of these problems and offer available technology for their solution. Government agencies, universities, veterinary associations and private technical assistance groups must cooperate with cattle breeders to lower the heavy losses from death and other causes.

Bibliography

Barros, H.B.M., Kuchembuck, M.R.G. & Rodrígues de Oliveira, M. 1972. Mortalidad de bezerros Zebus. Raça o sexo. Arq. Esc. Sup. Vet. Belo Horizonte., 24: 45-48.
Bauer, B., Plasse, D., Galdo, E. & Verde, O. 1992. Producción en un rebaño de bovinos de carne Criollo Yacumeño en el Beni, Bolivia. I. Peso y mortalidad. Rev. Fac. Agron. (Maracay), 18: 159-179.
Bellows, R.A. & Short, R.E. 1994. Reproductive losses in the beef industry. In M.J. Fields & R.S. Sand, eds. Factors affecting calf crop, p. 109-133. London, CRC Press.
Beltrán, J. 1976. Genetic and phenotypic aspects of early growth in Brahman cattle. University of Florida, Gainesville, FL, USA. 80 pp. (thesis)
Camacho, J., Bolaños, H., Arroyo, R. & Ortiz, F. 1983. Reproducción y longevidad de un hato Brahman registrado. ALPA Mem., 18: 165-166 (Abstr.).
Chan, T., Camacho, J., Arroyo R. & Blanco, F. 1986. Peso al nacimiento y mortalidad de terneros cebú. ALPA Mem., 21: 15 (Abstr.).
Cundiff, C.V., Gregory, K.E. & Koch, R.M. 1982. Selection for increased survival from birth to weaning. Proc. Second World Congr. on Genet. Appl. to Livestock Prod., Madrid, Spain, 5: 310.
Donaldson, L.E., Ritson, J.B. & Copeman, D.B. 1967. The reproductive efficiency of several North Queensland beef herds. Australian Vet., J. 43: 1-6.
FAO. 1981. Las razas criollas colombianas para la producción de carne. By B.G. Hernández. In Recursos genéticos animales en América Latina. FAO Animal Production and Health Paper No. 22. Rome.
Galdo, E., Plasse, D., Bauer, B. & Verde, O. 1992. Producción de un rebaño de bovinos de carne cebú en el Beni, Bolivia. I. Pesos y mortalidad. Rev. Fac. Agron. (Maracay), 18: 181-200.
González, G. & Segura, J.C. 1989. Factores que afectan la mortalidad al nacimiento, destete y año de edad en ganado Brahman. Vet. México, 20: 259-563.
Hautle, M. 1987. Reproduktionsleistung and Gewichtsent-wicklung in einer Nelore Herde in den semihumiden Tropen Brasiliens. Diss. ETH Nº 8358. Zurich, Switzerland, Eidgenössische Technische Hochschule. 154 pp.
Hoogesteijn, R., Rodríguez, R., Verde, O. & Plasse, D. 1983a. Porcentaje de preñez en cebú comercial en el Estado Apure. III Congr. Venezolano Zoot. F32.
Hoogesteijn, R., Verde, O., Plasse, D., Bastidas, P. & Rodríguez, R. 1983b. Peso al destete y mortalidad predestete de becerros de vacas Brahman comercial y toros Brahman, Simmental y Marchigiana en Apure. III Congr. Venezolano Zoot. F29 (Abstr.).
Koger, M., Mitchell, J.S., Kidder, R.W., Burns, W.C., Hentges, J.F. & Warnick, A.C. 1967. Factors influencing survival in beef calves. J. Anim. Sci., 26: 205 (Abstr.).
Lamond, D.R. 1969. Sources of variation in reproductive performance in selected herds of beef cattle in northeastern Australia. Australian Vet. J., 45: 50-58.
Linares, T. & Rodríguez, R. 1983. Mortalidad prenatal en vacas cebú después de la temporada de servicios. III Cong. Venezolano Zoot. F33 (Abstr.).
Martínez, A. & Gabaldón, L. 1990. Evaluación de la mortalidad en un rebaño mestizo de bovinos para carne (Bos indicus x Bos taurus) en los llanos occidentales. VI Congr. Venezolano Zoot. GR 17 (Abstr.).
Montoni, D., González-Crespo, J. & Verde, O. 1979. Mortalidad de becerros en un rebaño de carne. ALPA Mem., 14: 121 (Abstr.).
Montoni, D., Rojas, G. & Mago de Montoni, M. 1996. Mortalidad pre y postdestete en un rebaño Brahman registrado en el Estado Táchira. Rev. Fac. Agron. (LUZ), 13: 211-227.
Ocanto, D., Plasse, D., González, M., Aguirre, L., Linares, T. & Verde, O. 1986. Mortalidad pre y postdestete de doce grupos raciales de bovinos de carne en el Llano Venezolano. ALPA Mem., 21: 43 (Abstr.).
Ordóñez, J., Bastardo, J.R. & Plasse, D. 1979. Supervivencia predestete en rebaños bovinos de carne. Acta Científica Venezolana, 30 (Supl. 1): 35 (Abstr.).
O'Rourke, P.K., Fordyce, G., Holroyd, R.G. & Loxton, J.D. 1995. Mortality, wastage, and lifetime productivity of Bos indicus cows under extensive grazing in northern Australia. I. Seasonal mating in the speargrass region. Australian. J. Exp. Agric., 35: 285-295.
Parés, E., González, J. & Verde, O. 1983. Mortalidad de becerros en una finca de ganado de carne en el estado Monagas. III Congr. Venezolano Zoot. Resumenes. F34 (Abstr.).
Plasse, D. 1992. Presente y futuro de la producción bovina en Venezuela. In C. González-Stagnaro, ed. Ganadería mestiza de doble propósito. Maracaibo, Venezuela, Universidad de Zulia, Facultad de Agronomía y Ciencias Veterinarias, FUSAGRI, GIRARZ.
Plasse, D., Bauer, B., Galdo, E. & Verde, O. 1993. Producción de un rebaño de bovinos de carne Cebú en el Beni, Bolivia. II Porcentaje de preñez y destete, pérdidas y producción por vaca. Rev. Fac. Agron. (Maracay), 19: 367-389.
Plasse, D., Fossi, H. & Hoogesteijn, R. 1993. Mortalidad y pérdida en ganado de carne. In D. Plasse, N. Peña de Borsotti & J. Arango, eds. IX Cursillo sobre Bovinos de Carne. Maracay, Venezuela, Universidad Central de Venezuela, Facultad de Ciencias Veterinarias.
Plasse, D., González, M., Verde, O., Linares, T. & Burguera, M. 1986. Comportamiento productivo de Bos taurus y Bos indicus y sus cruces. VIII Mortalidad pre y postdestete. ALPA Mem., 21: 42 (Abstr.).
Plasse, D., Warnick, A.C. & Koger, M. 1970. Reproductive behavior of Bos indicus females in a subtropical environment. IV. Length of estrous cycle, duration of estrous, time of ovulation, fertilization and embryo survival in grade Brahman heifers. J. Anim. Sci., 30(1): 63-72.
Rodríguez, O.L.R. & Escrivá, J.L.S. 1972. Factores que afectan el porcentaje de destete en ganado Brahman; mortalidad entre nacimiento y destete. Tec. Pec. México, 22: 22-27.
Vera, R.R. & Seré, C., eds. 1985. Sistemas de producción pecuaria extensiva. Cali, Colombia, CIAT. 530 pp.
Verde, O., Plasse, D., Bauer, B. & Galdo, E. 1993. Producción de un rebaño de bovinos de carne Criollo Yacumeño en el Beni, Bolivia. II. Porcentaje de preñez y destete, pérdidas y producción por vaca. Rev. Fac. Agron. (Maracay), 19: 391-411.
Young, J.S. & Blair, J.M. 1974. Perinatal calf losses in a beef herd. Australian Vet. J., 50: 338-344.

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