Livestock Research for Rural Development 16 (10) 2004

Citation of this paper

Behavioural and morphological attributes of oestrus in West African dwarf does under different physiological states

S I Ola and G N Egbunike*

Department of Animal Science, Obafemi Awolowo University, Ile-Ife
*Department of Animal Science, University of Ibadan, Ibadan, Nigeria.
sola@oauife.edu.ng  or  id71ola@yahoo.com


Abstract

The behavioural and morphological changes associated with oestrus were studied in 28 West African Dwarf does grouped into 3 parity groups or under natural or synchronised cycle in the humid tropical climate of Ile-Ife, Nigeria. Behavioural changes which were diagnostic of oestrus in the WAD does include standing to be mounted by buck, Lordosis posture, tail wagging, keen interest in the male and slight swelling and reddening of the vulva lips.

These changes were not affected (P>0.05) by the animals' parity, time of the day that oestrus occurred or whether oestrus was hormonally synchronised or not. Other behaviours that were less frequently exhibited are increased vocalisation (bleating), homosexuality, vulva mucus discharge and aggression.

The scoring of these attributes indicated that the sexual desirability (Libido) of the does could be measured and selected for.

Keywords: Oestrus attributes, physiological status, West African Dwarf does.


Introduction

Several methods have been developed for oestrus detection for categories of livestock. These include video observation for mounting activity, pedometry, radiotelemetry, pressure activated heat-mount detectors, vasectomised males, hormone treated teasers, tail-paint or chalk, dummies, intravaginal/vulvular electrical impedance and even trained dogs that detect oestrus-specific odours (Stevenson 2001). Many of these methods employ oestrus-associated behaviour, which is specific for each livestock specie. Some of these behaviours have been reported (Tomkins and Bryant 1974; Hurniks et al 1975; Banumathi and Mukherjee 1981). Oestrus behaviour of the West African dwarf (WAD) doe has not been fully studied. Since oestrus detection is important for a successful artificial insemination and controlled breeding programme, the knowledge of oestrus behaviour particularly under different climatic and physiologic conditions is highly essential. Oestrus behaviour becomes even more important when it could be exhibited in the absence of the male, as is the case with cows (Hafez 1996).

Even though oestrus exhibition is under the direction of oestrogen hormone (Dieleman et al 1986) factors such as heat stress (Epperson and Zalesky 1995) and method of oestrus synchronisation (Selvaraju et al 1997) or detection (Oyediji et al 1992) have been reported to influence its exhibition. The objective of this study was to determine the oestrus-associated attributes in the WAD does with varying parity and under different periods of the day.


Materials and methods

Animals and management

The study was conducted in March/April, 2002 at the goat unit of the Teaching and Research Farm, Obafemi Awolowo University, Ile-Ife, Nigeria which is situated between 7o 28'N and 4o 33'E at an altitude of 240m. above sea level. The experimental animals were 28 normal cycling WAD does aged between 1.5 and 5 years and varied in parity from 0 to 6. During the experimental period, the animals were permanently confined to the pens and fed in groups of 3 per pen with Panicum maximum and Gliricidia sepium forage ad libitum supplemented with 150g/day/animal of ration. The ration contained 35% corn offal, 40% palm kernel cake, 23% wheat offal, 1% bone meal, 1% oyster shell, 0.25% common salt and 0.1% vitamin/mineral premix. Water was also supplied daily.

Behavioural attributes

The 28 WAD does were randomised into 2 groups i.e. natural oestrus or synchronised oestrus. Oestrus was synchronised with a single 100mg progesterone injection (Egbunike and Ola 2003). Oestrus was checked in all the does at 0900, 1300 and 1700hr starting from the day of injection with intact bucks fitted with aprons. At the exhibition of first standing heat, oestrus was again checked during the next 3 consecutive checking periods. An average of 1.6 cycles per doe was monitored. At each oestrus the following attributes were observed: 1) frequent bleating or increased vocalisation (Be); 2) homosexuality i.e. mounting of other does or accepting mount from other does (Ho); 3) interest in male or male pen (Im); 4) vulva mucus discharge (Vd); 5) swollen/reddening of vulva lips (Sv); 6) aggression to pen mates (Ag); 7) tail wagging in the presence of the male (Tw); 8) lordosis posture i.e. arching of the back when the buck sniffs the vulva (Lp) and 10) standing to be mounted by buck to make copulatory thrust (Sh). The occurrence of any of the attributes was regarded as positive and given a numerical score of 1 while its absence was scored 0. The sum of the scores of all the attributes during the 3 consecutive tests make up the oestrus score (OS) while that of the attributes Im, Sv, Lp, Tw and Sh was regarded as libido score (LS) as recently proposed (Ola and Egbunike 2003).

Morphological attributes

In another trial involving the same 28 does divided into 2 equal groups, visual observation and linear/subjective measurement/scoring around the vulva lips (Labia majora) was performed. Group 1 was synchronised into oestrus with progesterone injection whereas in group 2 oestrus (and ovulation) was delayed for upward of 60days with intramuscular injection of 50mg Medroxyprogesterone acetate (Egbunike and Ola 2003). Observations and measurements were made at 3 to 5days before oestrus; day of standing heat and 5days after oestrus for does in group 1, whereas for group 2 observations and measurements were done at 10 days apart within 28days. Oestrus attributes that were either measured or scored subjectively included


Statistical analysis

Data obtained from the behavioural and morphological measurements were regarded as a randomised complete block design and thus analysed with the GLM procedure of the SAS 2000 software. Means were separated with the Duncan option. Linear correlation was also done between the behavioural attributes. The frequency of occurrence of the behavioural attributes was plotted with grouped vertical bar chart of the Microsoft Xcel software.


Results

Oestrus-related behaviours

The mean score of does for each attribute did not differ between the parity groupings of the does or types of oestrus (Table 1). A maximum score of 3 in any attribute would indicate that all the does exhibited the attribute at all of the 3 consecutive checking periods. This was not the case in any of the groups. A score of ≥1 indicates that all the does exhibited the attribute at least once out of the 3 consecutive checks. Attributes Im, Sv, Tw, Lp and Sh met this requirement and were thus used to calculate the libido score (LS). A maximum score of 15 and 27 was possible for libido and oestrus scores respectively. Oestrus score (OS) is the sum of all the attributes, which may not necessarily be exhibited by all the does. OS was significantly higher (P<0.05) than LS in all the groups of does. However both were not different between parity and oestrus type groupings.

Table 1: Mean score of oestrus attributes in different groups of WAD does

Attributes

Parity

Oestrus type

All does

Maiden

Primiparous

Multiparous

Natural

Synchronised

Increased Bleating

0.150.15

0.000.00

0.170.09

0.100.07

0.130.09

0.110.06

Homo-sexuality

0.620.29

0.210.21

0.280.14

0.240.15

0.460.18

0.360.12

Interest in male

1.620.27

1.790.28

1.440.28

1.710.24

1.500.22

1.600.16

Vulva discharge

0.080.08

0.140.10

0.220.15

0.290.14

0.040.04

0.160.07

Reddened vulva

1.080.21

1.000.23

1.280.23

1.190.21

1.080.15

1.130.13

Aggression

0.000.00

0.000.00

0.170.08

0.050.05

0.040.04

0.040.03

Tail wagging

2.390.21

2.500.14

2.610.14

2.620.11

2.420.15

2.510.09

Lordosis posture

2.230.20

2.290.22

2.000.28

2.140.24

2.270.17

2.160.14

Standing heat

2.390.21

2.500.14

2.670.14

2.620.11

2.460.15

2.530.09

Oestrus score

10.541.10

10.290.88

10.830.90

10.810.77

10.380.77

10.580.54

Libido score

9.770.91

9.930.72

10.000.68

10.140.59

9.710.63

9.910.43

P>0.05 within groups in each row

Correlation analysis between the attributes, OS and LS (Table2) showed that attributes Im, Sv, Tw and Sh were highly (P<0.01) and positively related to each other and to LS. Be and Ho were also positively and highly related while the correlations of Ag with Be, Vd and Sv as well as Vd with Be and Ho were negative but non-significant (P>0.05). OS was significantly related to all the behavioural attributes except Vd and Ag.

Table 2: Correlation matrix between the oestrus attributes

 

Attribute

Be

Ho

Im

Vd

Sv

Ag

Tw

Lp

Sh

OS

LS

 

Be

1.00

 

 

 

 

 

 

 

 

 

 

 

Ho

0.60c

1.00

 

 

 

 

 

 

 

 

 

 

Im

0.24

0.28

1.00

 

 

 

 

 

 

 

 

 

Vd

-0.10

-0.20

0.09

1.00

               

Sv

0.29

0.30

0.29

0.14

1.00

 

 

 

 

 

 

 

Ag

-0.05

0.10

0.24

-0.07

-0.03

1.00

 

 

 

 

 

 

Tw

0.18

0.08

0.55b

0.04

0.54b

-0.15

1.00

 

 

 

 

 

Lp

0.20

0.16

0.37

0.10

0.42a

0.14

0.65c

1.00

 

 

 

 

Sh

0.17

0.11

0.62c

0.02

0.54b

0.12

0.96c

0.69c

1.00

 

 

 

OS

0.47a

0.51b

0.74c

0.14

0.69c

0.19

0.77c

0.72c

0.84c

1.00

 

 

LS

0.28

0.29

0.63c

0.15

0.52b

0.11

0.74c

0.73c

0.77c

0.83c

1.00

 

aP<0.05; bP< 0.01; cP< 0.001
Be= Bleating,  Ho= Homosexuality,  Im= Interest in male, Vd= Vulva discharge, Sv= Swollen vulva, Ag= Aggression, Tw= Tail wagging,  Lp= Lordosis posture, Sh= Standing heat, OS= Oestrus score and LS= Libido score.

 

As depicted in Figure 1, attributes Im, Tw, Lp and Sh had consistent occurrence of more than 50% in all the oestrus groupings i.e. parity of does, synchronised or natural oestrus and time of day that oestrus occurred. Occurrence of between 30 and 49% were recorded for Sv. While Ho appeared to occur more in the maiden (20.5%) than the Primiparous (7.1%) and Multiparous (9.3%) does, the latter displayed more Ag behaviour during oestrus (0, 0, and 5.5% respectively). Be, Vd and Ag occurred at below 15% in all of the oestrus groups.

Figure 1.Frequency of occurrence of oestrus-associated behaviours in WAD does

Morphological changes

Table 3 shows the morphological changes in the external genitalia (Labia majora) of the experimental does during the oestrous cycle. In the cycling does the colour of vulva secretion tended toward whitish and the viscosity more slimy and sticky after the oestrus hours. The colour and the dimension of the Labia majora were however deeper and longer respectively during oestrus than outside oestrus hours. In the anoestrus does on the other hand, the viscosity of the vulva secretion decreased significantly along the consecutive measurements, whereas other parameters were not significantly affected by the interval of measurement.

Table 3. Morphometric changes in the external genitalia of cyclic and anoestrus WAD does

Traits

Cyclic does ( n=14)

Anoestrus does (n=14)

Before oestrus

During oestrus

After oestrus

Day 1

Day 10

Day 20

Quantity of Vulva secretion

0.21 0.11

0.50 0.25

0.71 0.16

0.29 0.13

0.14 0.10

0.07 0.07

Colour of Vulva secretion

0.21 0.11b

0.36 0.17b

1.29 0.27a

0.36 0.17

0.21 0.16

0.07 0.07

Viscousity of secretion

0.21 0.11c

0.29  0.13b

0.57  0.14a

0.29 0.13a

0.140.10b

0.070.07c

Colour of Labia majora

1.43 0.17b

1.86 0.21a

1.21 0.11c

1.29 0.13

1.36 0.13

1.43 0.14

Texture of Labia majora

1.57 0.20

1.71 0.22

1.50 0.17

1.71 0.19

1.79 0.19

1.64 0.13

Labial length, mm

22.21 0.92b

24.14 0.83a 

21.07 0.85b

20.21 0.51

20.64 0.67

20.14 0.62

Labial diameter, mm

11.57 0.71b

13.64 0.63a

10.86 0.57

10.36 0.54

11.43 0.45b

10.79 0.40

a,b,c Values (meanSEM) with different superscripts within a  row for  each group differ significantly (P<0.05)


Discussion

Behavioural changes during oestrus have been reported for many goat breeds (Rajkonwa, and Borgohain 1978, Banumathi and Mukherjee 1981) including the WAD goats (Akusu 1987). Many of these oestrus-associated behaviours are also buck-dependent and are thus poor indicators of oestrus in the absence of the buck. In agreement with these previous findings those attributes (Im, Sv, Tw, Lp and Sh) that were scored above 1 in our scoring system, which qualified them to be used for measuring sexual desirability (Libido) of the doe, were all buck-dependent. In the presence of a active teaser buck attributes Sh, Lp and Tw with an overall mean score of 2.53, 2.16 and 2.51 could be taken as been diagnostic of oestrus in the WAD doe. The variation observed in these 3 attributes between the different periods of the day is an indication of the variation in the duration of oestrus. Of the 45 oestri monitored in this study, 55.6% started in the 0900h period some of which did not last beyond 1300h period. In some cases Tw preceded the first Sh or was still displayed after the last Sh behaviour. This explained why Tw occurred more frequently than Sh at all the periods of checking. Highly correlated to Sh and Tw attributes but also buck dependent was the Im behaviour. Does in oestrus actively seeked for buck in their surrounding and in the absence of response from the buck attempted to mount the buck (Ho) or become aggressive to other does around (Ag). Rajkonwar and Borgohain (1978) classified these behaviours as salient features of oestrus in the doe. Thus attribute Im may be useful in identifying oestrus does when only inactive bucks are available as teasers. In agreement with the findings of Smith (1980) and Akusu (1987) attributes Be, Vd, Ho, Ag were not dependable as oestrus signs in the doe as they had very low scores (<1) and occurrences (< 15%).

Of significant importance also is the reddening/swelling of the vulva lips (Sv). This attributes occurred in 37.8% of the 125 oestrus checking periods with a mean score of 1.13±0.13. However the measurement of this attribute was subjective and thus its reliability and applicability will depend on the intuitiveness of the person taken the measurements. This deficiency could be overcome with the use of a standardised colour chart. Our own observation with the colour chart method indicated that there was a slight reddening of the vulva lips during oestrus. Again these changes are rather small and may be of little practical use. The scoring of attributes as used in this study demonstrated that sexual desirability of the does could be measured and selected for in order to improve the reproductivity of the female. Both the LS and OS could be used to select against silent oestrus, nymphomania and split oestrus. A record of OS could also be helpful in AI schedules.


Conclusion

When teased by the buck Standing heat (Sh), Tail wagging (Tw) and Lordosis posture (Lp) are common behavioural stances during oestrus in WAD does and could be taken as confirmatory of oestrus in the presence of the buck. However in the event of inadequate or lack of capable bucks to tease does in oestrus behavioural signs such as keen interest in the male or adjascent male pen by the female (Im) could be taken as the confirmatory sign of oestrus. In other words the audiovisual contact rather than the individual physical contact could reveal a large proportion of does in oestrus. Painstaking observation of the external genitalia could also reveal the oestrus does.


References

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Received 23 May 2004; Accepted 9 August 2004

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