ULTRASOUND ASSESSMENT OF FETAL DEVELOPMENT IN NELORE COWS (ESTUDO ULTRA-SONOGRÁFICO DO DESENVOLVIMENTO FETAL EM VACAS NELORE)

Bergamaschi M.A.C.M.

Description

Abstract
Real time B-mode ultrasound technology was applied to monitor gestation of Nelore cows which had been sired with semen from Nelore (G1), Canchim (G2), Angus (G3) and Simental (G4). Ultrasonographic examinations were taken to monitor the fetal growth. Ultrasonography allowed for a comprehensive study of gestation in Nelore cows until 122 days. Length, diameter and circumference of the head did not show differences (p>0.05) in fetal development, amongst genetic groups up to 122 days, even though represented reliable parameters for the estimation of age.
Resumo
A ultra-sonografia, em tempo real, em modo- B foi utilizada para monitorar a gestação de vacas nelore, inseminadas com sêmen de touros das raças Nelore (G1), Canchim (G2), Angus (G3) e Simental (G4). Os exames ultra-sonográficos foram feitos para monitorar o crescimento fetal. A ultra-sonografia permitiu o estudo da gestação das vacas Nelore até 122 dias da gestação. O comprimento, o diâmetro e a circunferência da cabeça fetal não diferiram entre os grupos genéticos até os 122 dias, embora representassem parâmetros confiáveis para a predição da idade gestacional.

Sujets

• Prenatal development
• Génotype
• Genotipo

Informations

• Publié par: erevistas
• Publié le: 01 janvier 2004
• Nombre de lectures: 7
• Langue: English

Extrait

NOTA BREVE
ULTRASOUND ASSESSMENT OF FETAL DEVELOPMENT IN
NELORE COWS
ESTUDO ULTRA-SONOGRÁFICO DO DESENVOLVIMENTO FETAL EM
VACAS NELORE
1 2 3 3 2Bergamaschi, M.A.C.M. , W.R.R. Vicente , R.T. Barbosa , R. Machado , J.A. Marques and
3A.R. Freitas
1Pos-graduate student in Veterinary Medicine. Universidade Estadual Paulista. UNESP. Campus de
Jaboticabal. Rua Sete de Setembro, 2875. São Carlos, SP. Brasil. 13560-181 055-16-2718066. E-mail:
[e-mail]
2Universidade Estadual Paulista. UNESP. Campus de Jaboticabal. Jaboticabal, SP. Brazil.
3Embrapa Pecuaria Sudeste. São Carlos, SP. Brasil.
ADDITIONAL KEYWORDS PALAVRAS CHAVE ADICIONAIS
Fetal growth. Genotype. Crescimento fetal. Genótipo.
SUMMARY
Real time B-mode ultrasound technology was ultra-sonografia permitiu o estudo da gestação
applied to monitor gestation of Nelore cows which das vacas Nelore até 122 dias da gestação. O
had been sired with semen from Nelore (G1), comprimento, o diâmetro e a circunferência da
Canchim (G2), Angus (G3) and Simental (G4). cabeça fetal não diferiram entre os grupos
Ultrasonographic examinations were taken to genéticos até os 122 dias, embora represen-
monitor the fetal growth. Ultrasonography allowed tassem parâmetros confiáveis para a predição da
idade gestacional.for a comprehensive study of gestation in Nelore
cows until 122 days. Length, diameter and
circumference of the head did not show differences
(p>0.05) in fetal development, amongst genetic INTRODUCTION
groups up to 122 days, even though represented
reliable parameters for the estimation of age. Genetic make up of the conceptus
and its relationship and interactions
with environmental factors play an
RESUMO important role on fetal development
and gestation in the cow (Gluckman,
A ultra-sonografia, em tempo real, em modo- 1986). Per rectum palpation and other
B foi utilizada para monitorar a gestação de vacas traditional methods are not suitable to
nelore, inseminadas com sêmen de touros das monitor early stages of embryonic
raças Nelore (G1), Canchim (G2), Angus (G3) e development and gestation. On the
Simental (G4). Os exames ultra-sonográficos other hand, ultrasonography can be
foram feitos para monitorar o crescimento fetal. A used to obtain fetal measurements
Arch. Zootec. 53: 371-374. 2004.BERGAMASCHI, VICENTE, BARBOSA, MACHADO, MARQUES AND FREITAS
allowing for effective and accurate RESULTS AND DISCUSSION
diagnostic of early pregnancy (Kähn,
The ultrasound examination at 311990), sex of the conceptus, gestational
days of gestation allowed to visualizestage, embryonic mortality and fetal
the conceptus and its heartbeats, indevelopment (Hansen & Delsaux,
agreement with the literature (Pierson1987). Kähn (1989) established the
& Ginther, 1984; Hansen & Delsaux,correlation coefficients between days
1987). The ultrasonography performedof pregnancy and several measures of
thon the 45 day of gestation permittedfetal size. The present trial aimed to
to visualize the fetus, allantois andstudy the fetal development and its
amnion. The initial differentiation ofeffects on the uterus of Bos taurus
the head and fetal limbs was observed,indicus cows carrying conceptuses of
as reported previously (Pierson &four different genetic composition.
Ginther, 1984).
In the examination at 59 days of
MATERIAL AND METHODS gestation, the fetus was totally
differentiated, which allowed to ob-
Cattle was handled under intensive serve the head, thorax, abdomen,
rotational management of pastures. A thoracic and hind limbs, organs of the
commercial TAI protocol was applied digestive system, urachus, umbilical
to 100 Nelore cows aged 3-5 years and cord and placentomes, similar to that
were inseminated with semen of bulls observed previously (Curran et al.,
of four different breeds: (G1) 12 1986).
animals gestating Nelore pure-breds The mean fetal length observed was
(F1); (G2), 13 animals gestating 1.07 ± 0.07, 2.35 ± 0.08 and 5.55 ±
crossbred fetuses (50 percent Canchim/ 0.08 cm, at 31, 45 and 59 days of
50 percent Nelore - F2); (G3), 14 gestation, respectively. Intermediate
animals gestating crossbred fetuses (50 results were confirmed, taking into
percent Angus/ 50 percent Nelore - account the difference of one day, since
F3); (G4), 14 animals gestating fetuses of Holstein cows were observed
crossbred fetuses (50 percent Simental/ to be 6.61 ± 0,17 cm at 60 days of
50 percent Nelore - F4). Ultraso- pregnancy (Curran et al., 1986) and
nographies were performed according 5.25 ± 0.7 cm for the same gestational
to standard procedures. B-mode real stage in Bos indicus fetuses (Totey et
time ultrasound was used coupled to a al., 1991). The fetuses exhibited a mean
5.0 MHz transducer and the exami- growth rate of 0.92 ± 0.08 and 2.3 ±
st thnations were done on the 31 , 45 , 0.07 mm/day for the periods between
th th nd th nd th59 , 94 , 122 , 150 , 192 , 220 and the first and second and between the
th255 days of pregnancy. Fetal measure- second and third determinations,
ments were taken (cm) throughout all respectively. The first interval was
examinations. The statistical analysis shown to be less than that reported for
was performed by using either the undefined cross breed cows, demons-
GLM or the REG procedures in SAS trating fetal development of 1.10 mm/
(SAS, 1993). day (Ferrell et al., 1976).
Archivos de zootecnia vol. 53, núm. 204, p. 372. ULTRASOUND ASSESSMENT OF FETAL DEVELOPMENT IN NELORE COWS

Length, bi-parietal diameters and
F 6
E circumference of the head of the fetusT
A
L did not appear to be significantly
L
4E distinct among the groups. However,N
G 2H the correlation coefficients (R ) of the
2 regression equations that related these
variables with fetal age, indicated that
(cm)
these parameters are good predictors
40 50 60
DAYS OF GESTATION of fetal age, corroborating the results
of other workers (Ferrell et al., 1976;
Figure 1. Cubic regression for fetal length Hansen & Delsaux, 1987; Kähn, 1989).
during early gestation (y), of experimental The gestations examined were
groups, as a function of day of gestation localized in the abdominal cavity at
2(y=12.4 – 0.818DAY + 0.0174DAY – 9.3 * 150 and 192 days of pregnancy, in
-5 3 210 * DAY , R = 0.98). São Carlos, SP. which none of the parameters were
(Regressão cúbica do comprimento fetal, dos evaluated, since the fetuses exhibited
grupos experimentais, em função do dia de a posterior longitudinal presentation,
2gestação (y=12,4 – 0,818DIA + 0,0174DIA – 9,3 thereby not having access to the head.
-5 3 2* 10 * DIA , R = 0,98). São Carlos, SP.). These results disagreed with others
(Kähn, 1989; Rajamahendran et al.,
1994), who accomplished measure-
Figure 1 shows fetal growth at the ments during this gestational stage. At
beginning of gestation. The length was the end of this period, fetuses became
not affected (p>0.05) by genotype and
sex of the fetus.
At 122 days of pregnancy, the
volume of the uterus, and its projection
O 4into the abdominal cavity, making the FD
I
Tultrasonographic examination difficult A
M H
3EEand impossible to perform in some
T
E Hanimals, concording with other studies
R E
2A(Kähn, 1989; Rajamahendran et al., D
(cm)1994).
60 80 100 120
There was no difference (p>0.05)
DAYS OF GESTATION
for bi-parietal diameters (figure 2) and
circumference of the head during fetal Figure 2. Cubic regression for fetal head
life and at birth within the principal diameter, of the experimental groups, as a
effects of genetic group and sex of the function of day of gestation (y = 1.47 +
2 -6 3fetus. 0.0123DAY + 0.0013DAY – 5.2 * 10 DAY ,
2Figure 2 shows patterns of growth R =0.95). São Carlos, SP. (Regressão cúbica
less pronounced than that observed for do diâmetro da cabeça fetal, dos grupos
the fetal length. The genotypes behaved experimentais, em função do dia de gestação (y
2 -6 3similarly for the development of the = 1,47 + 0,0123DIA + 0,0013DIA – 5,2 * 10 DIA ,
2diameter and circumference of the head. R =0,95). São Carlos, SP.).
Archivos de zootecnia vol. 53, núm. 204, p. 373.BERGAMASCHI, VICENTE, BARBOSA, MACHADO, MARQUES AND FREITAS
more accessible, due the initiation of to be effective in the determination of
the ascent process. fetal age. There is a lack of highly
No difference (p>0.05) among accurate methods for the evaluation of
genotypes of conceptuses have been bovine fetal growth in the last trimester
found in the circumference of the ocu- of gestation, for the correct determi-
thlar orbit of the conceptuses (220 and nation of eventual differences in these
th255 day of gestation). evaluated parameters.
The data gathered in this study with
Zebu Cattle as subject have shown that
CONCLUSION pregnancy events and fetal development
occurred in a similar fashion as
The ultra-sonographic evaluation compared to european breeds of Cattle.
of the fetus was shown to be an efficient
method up to 122 days of gestation,
al