| Livestock Research for Rural Development 30 (9) 2018 | Guide for preparation of papers | LRRD Newsletter | Citation of this paper |
All over the world it is difficult to determine the sex of Guinea keets at day one of hatching. The aim of this study was to determine the sex of Guinea fowls at day-old. A total of 1176 pearl, lavender, black and white eggs were set in an incubator at the poultry unit of the department of animal science education, Mampong Campus. Keets were reared from day-old to four months. Data obtained from both morphometric traits (head width, head, neck, body, shank, tail, thigh and wattle lengths, helmet thickness, pelvic inlet, wing span, and leg length) and biometric traits (egg shape, swollen leg, stretched leg, sound, wattle and phallus) were measured at day-old and at four months and analyzed using the General Linear Model Procedure of the Statistical Analysis System (SAS) and Chi square test. Males and females did not differ in all morphometric traits measured at day one of hatching, indicating that sexual dimorphism had not taken place at that age using morphometric techniques. However, at four months, neck, body, shank and wattles llengths in males were longer than in female counterparts. The helmet in males was also thicker than in females. However, females had wider pelvic inlet than males. At day-old, swollen leg technique indicated 52% and 48% expected males and females, and at four months there were 52.8% and 47.2% observed males and females, respectively. Results from stretched leg technique showed 56% and 44% expected males and females at day old, and 52.8% and 47.2% males and females, respectively, were observed at four months. In conclusion, the swollen and stretched leg techniques are effective in sexing Guinea fowls at day-old while at four months the use of sound, wattles and phallus techniques yielded good results.
Key words: biometric trait, morphometric trait, Guinea keets, sex determination, sexual dimorphism
Domestic Guinea fowl (Numida meleagris) is a common farm animal in Ghana and other African countries. The bird can also be found in Europe, specifically France, Hungary, Poland, Belgium and Russia as well as in Asia, Latin America, North America and Australia, large scale commercial production of the birds is common (Darre 2007). They are used as a source of income and protein. They have low cholesterol levels and the yield of edible meat is higher than that in chicken. Both the eggs and meat are delicacies, and the thicker shells of the eggs give them an advantage for longer storage and handling with less breakage (Dei et al 2007). In Ghana, the birds are used for cultural purposes, which include funeral celebrations, sacrifices and as a token for settling disputes (Annor et al 2013).
Sexing is a major problem militating against effective selection and breeding in Guinea fowls. Farmers and breeders have difficulty using the external features of Guinea fowls in distinguishing between males and females from day old to one month of age. In some birds such as the domestic chicken (Gallus domesticus), it is easier to differentiate between the sexes at the early ages using morphological characteristics. Morphological traits have been used successfully to predict the sex of Guinea fowls after one month of hatching.
Males show the phallus when they are four weeks old but females do not (Idahor and Akinola 2015; Teye and Gyawu 2001). Iddriss et al (2015) also observed that from four weeks old and beyond, males had bigger wattles than females while the opposite was true for the width of pelvic inlet. In spite of the various methods of sexing Guinea fowls developed by some researchers, none was able to sex Guinea fowls at day one. Evidence gathered from farmers in the Sekyere South District of the Ashanti Region indicates that Guinea fowls can be sexed at day-old using swollen leg and stretched led techniques. The justification of this research work is to help farmers in early separation of males from females to provide enough space for the growth of pullets to prevent precocious mating. The aim of this study was to determine the sex of Guinea fowls at day-old using biometric and morphometric traits
The study was conducted at the Poultry Unit of the Department of Animal Science Education, University of Education, Winneba, Mampong-Ashanti, Ghana. The experiment was carried out from April 2015 to March 2016.
A total of 1176 pearl, lavender, black and white eggs were collected in the morning in containers which were cushioned to avoid breaking or shaking according to Moreki and Mack (2013). Dirty eggs were discarded during egg collection. The shape of the egg was used to pre-determine the sex (Annor et al 2013). Each egg was individually marked with indelible ink before setting in an incubator (Humidaire Incubator Co., USA). Eggs were incubated at 37.5-37.8oC and 60% relative humidity for 28 days. Candling was done at 14 and 21 days after egg setting to determine fertile and infertile eggs. Hatchability of fertile eggs (728) was 44.6%. During egg transfer from the incubator setter to the hatcher (i.e., 3 days prior to hatching) hatching egg trays were partitioned using wire mesh to separate males from females that resulted from the use of egg shape to separate the sexes. Keets were identified by wing tagging soon after hatching, and were reared from day-old to four months.
Birds were brooded for 6 weeks (Teye and Gyawu 2001) in a brooder house, and then transferred to a deep litter floor house of size 49.9m x 8.17m x 2.48m. Males and females were housed in separate rooms. Birds were individually caged at the age of three to four months. Each cage measured 0.68m x 0.60m x0.44m. Feed and water were provided ad libitum.
In using egg shape to pre-determine the sex of Guinea fowls, eggs (Plate 1) with narrow and pointed end indicated males whereas those with the narrow end slightly rounded were females (Annor et al 2013). At day-old, swollen leg indicated males (Plate 2) whilst non swollen leg depicted females (Plate 3). When keets were raised above ground level by holding the wings, those with stretched leg showed males (Plate 4) but non-stretched legs (Plate 5) indicated females. At four months males produced monosyllabic sound like “kirkekekekeke” but their female counterparts gave disyllabic sound such as “chekwenchekwen” Annor et al (2013). In using wattles to determine the sex, males have wattles shortly attached to the jaws with a much bigger, coarse and thicker dangling lobe (Plate 6) whilst females (Plate 7) showed less pronounced and flatter wattles (Iddriss et al 2015).The birds were individually observed closely through the vent to finally confirm the sex. Vents were inspected at four months old for the appearance of a rudimentary phallus as a feature to differentiate between both sexes. Males (Plate 8) show the phallus when they are 4 weeks old but females (Plate 9) do not at that age (Teye and Gyawu 2001; Idahor and Akinola 2015). At four months the sound, wattles and phallus and other morphometric parameters (head width, head, neck, body, shank, tail, thigh and wattle lengths, helmet thickness, pelvic inlet, wing span, and leg length) were measured to distinguish between males from females.
|
|
|
| Plate 1. Female (left) egg oval at the end and Male (right) egg pointed at the end |
|
|
|
| Plate 2. Swollen leg |
Plate 3. Non-swollen leg |
|
|
|
| Plate 4. Stretched leg |
Plate 5. Non-Stretched leg |
|
|
| Plate 6. Male Guinea fowl (cupped wattles) |
Plate 7. Female Guinea fowl (flat wattles) |
|
|
|
| Plate 8. Presence of phallus | Plate 9. Absence of phallus |
Data on morphological traits were subjected to least squares analysis using Generalized Linear Models (GLM) Type III procedure of SAS (SAS, 2008) on the following fixed models:
yij = µ + Si + +eij
Where yij = the trait being measured; µ = the overall mean; Si = the effect of the ith sex of keet, i = 1...2 and eij is the random error term. Data obtained from biometric traits were analysed using the Chi square test (Steel and Torrie 1980) using the following formula:
Where χ2 = the Chi square
∑ = the sum of
O = the observed frequency (the observed counts in the cells) and
E = the expected frequency
There was no difference (p > 0.05) between expected males and females, and observed males and females using the egg shape, swollen leg and stretched leg techniques, sound, wattles and phallus to differentiate between the sexes using different techniques for sexing Guinea fowls (Table 1).
There was no significant difference (p > 0.05) between males from females at day one of hatch using the external features to differentiate Guinea fowls (Table 2) but at four months, neck, body, shank and wattles lengths in males were longer (P>0.01) than their female counterparts (Table 3).
|
Table 1. Different methods of sexing Guinea fowl |
|||||
|
Technique |
Sex |
% Expected |
% Observed |
X2 |
p |
|
Egg shape |
Male |
53.6 |
52.8 |
0.03 |
3.84 |
|
Female |
46.4 |
47.2 |
|||
|
Total |
100 |
100 |
|||
|
Swollen leg |
Male |
52 |
52.8 |
0.03 |
3.73 |
|
Female |
48 |
47.2 |
|||
|
Total |
100 |
100 |
|||
|
Stretched leg |
Male |
56 |
52.8 |
0.03 |
2.85 |
|
Female |
44 |
47.2 |
|||
|
Total |
100 |
100 |
|||
|
Sound |
Male |
52.8 |
52.8 |
0.00 |
1.84 |
|
Female |
47.2 |
47.2 |
|||
|
Total |
100 |
100 |
|||
|
Wattles |
Male |
52.8 |
52.8 |
0.00 |
2.61 |
|
Female |
47.2 |
47.2 |
|||
|
Total |
100 |
100 |
|||
|
Phallus |
Male |
52.8 |
52.8 |
0.00 |
3.66 |
|
Female |
47.2 |
47.2 |
|||
|
Total |
100 |
100 |
|||
Results obtained from morphometric traits measured at day one of hatching indicated that males did not differ significantly (P>0.05) from females in head width, head, body, neck, shank, leg and wing lengths, and pelvic inlet (Table 2).
|
Table 2. Means and standard errors for day-old body measurement |
|||
|
Parameter (cm) |
Male |
Female |
p |
|
Head width |
1.80 ±0.02 |
1.74 ±0.01 |
0.090 |
|
Head length |
3.1 ±0.04 |
3.0 ±0.03 |
0.074 |
|
Body length |
11.1 ±0.04 |
11.01 ±0.02 |
0.21 |
|
Neck length |
3.1 ±0.02 |
3.1 ±0.02 |
1.00 |
|
Shank length |
1.2 ±0.03 |
1.16 ±0.02 |
0.30 |
|
Leg length |
6.12 ±0.03 |
6.07 ±0.03 |
0.33 |
|
Pelvic inlet |
2.08 ±0.03 |
2.04 ±0.02 |
0.32 |
|
Wing length |
3.05 ±0.03 |
3.05 ±0.02 |
0.92 |
|
Means with different letters in the same row are significantly different (P<0.05) |
|||
At 4 months old males did not differ significantly (P >0.05) from females when head width, head, tail, thigh, leg and wing lengths were considered but neck, body, shank and wattles lengths in males were longer (P>0.01) than their female counterparts (Table 3).
|
Table 3. Means and standard errors for 4-month old body measurement |
|||
|
Parameter (cm) |
Female |
Male |
p |
|
Head width |
2.49 ±0.03 |
2.54 ±0.03 |
0.28 |
|
Head length |
6.91 ±0.04 |
6.97 ±0.04 |
0.36 |
|
Neck length |
12.60 ±0.14b |
13.4 ±0.14 a |
0.0001 |
|
Body length |
52.90 ±0.28b |
53.9 ±0.26a |
0.0055 |
|
Tail length |
16.07 ±0.13 |
15.90 ±0.12 |
0.21 |
|
Shank length |
5.34 ±0.03b |
5.42 ±0.03a |
0.039 |
|
Thigh length |
12.90 ±0.08 |
12.80 ±0.07 |
0.23 |
|
Wattle length |
2.30 ±0.06b |
3.21 ±0.06 a |
0.0001 |
|
Helmet thickness |
0.84±0.02b |
1.06±0.02a |
0.0001 |
|
Pelvic inlet |
6.03 ±0.08a |
3.49 ±0.08 b |
0.0001 |
|
Leg length |
24.40 ±0.15 |
24.40 ±0.14 |
0.75 |
|
Wing length |
19.2 ±0.13 |
18.90 ±0.13 |
0.087 |
|
ab Means with different letters in the same row are significantly different (P<0.05) |
|||
The present study revealed that egg shape had a relationship with the probability of determining the sex of the hatched chick. Using the egg shape to differentiate between the sexes, the expected proportion of males and females were similar (p>0.05) to the observed proportions (Table 1). Pointed eggs were more likely to produce male chicks and rounded eggs were more likely to produce female chicks. Similarly, Mao et al (2006) reported that rounded (oval) shaped eggs were most likely to produce pullets (female) and pointed end (pointy) shaped eggs were most likely to produce cockerels (male). Again, Idahor and Akinola (2015) conducted a research using egg colour, weight and shape to predict the sex of Guinea keets. The results showed that both conical and oval eggs yielded both males and females, indicating that the use of egg shape in pre-determining sex yielded good results in that study. Furthermore, Yilmaz-Dikmen and Dikmen (2013) conducted a study on the use of egg shape index, width, length, weight, volume and concluded that only shape index was the most prominent factor for determining the sex of the egg in white layers.
It was observed that males did not differ significantly (p > 0.05) from their female counterparts at day-old using swollen leg (Plate 2) and non-swollen leg (Plate 3) technique (Table 1). It was also observed that in both stretched legs (Plate 4) non-stretched leg technique (Plate 5), males did not differ significantly (p > 0.05) from their female counterparts. The observations from both swollen/non-swollen and stretched/non-stretched legs techniques indicated higher males than their females counterparts. Scientists have concluded that it is difficult to determine the sex of Guinea keets at day one of age, unless they are about 8 weeks old (Iddriss et al 2015; Teye and Gyawu 2001).
It was observed that males gave monosyllabic sound like “kir ke ke ke ke ke” but their female counterparts produced disyllabic sound when they were four months old such as “chekwen chekwen” as reported by Annor et al (2013). Similar observations were made by Iddriss et al (2015) and Teye and Gyawu (2001). The present study therefore agrees with the works of the aforementioned scientists.
It was observed that at 4 months old the wattles of a male Guinea fowl was cupped and inclined at an angle of 90o to the side of the upper jaw (plate 6) whereas their female counterparts had a flat wattle attached to upper jaw (Plate 7). Umosen et al (2008) concluded that birds with their wattles cupped were confirmed positive for males after slaughter while those with their wattles tucked were also confirmed positive for females. This observation agrees with the report of Umosen et al (2008). Moreover, it was observed that males had phallus present (Plate 8) while females exhibited a labia like structure (Plate 9). This confirms the work of Teye and Gyawu (2001), who distinguished between males and female birds earlier at four weeks of age by observing vestigial phalli in the cloaca of males while females had none or at best possessed a labia-like structure at four weeks of age. Similar observation was made by Iddriss et al (2015) in 8 weeks old Guinea fowls.
Results obtained from morphometric traits measured at day one of hatching indicated that males did not differ significantly (p > 0.05) from females in head width, head, body, neck, shank, leg and wing lengths, and pelvic inlet (Table 2). These indicate that sexual dimorphism had not taken place at that age using morphometric techniques. In consonance with Moreki and Mack (2013), it was very difficult to sex Guinea fowls at day-old since males and females all look exactly the same morphologically. Similarly, Ikani and Dafwang (2004) reported that it is difficult to differentiate between the sexes at day-old since there is no difference in their appearance.
At 4 months old, males did not differ (p > 0.05) from females in head width, head, tail, thigh, leg and wing lengths, but neck, body, shank and wattle lengths in males were longer (P < 0.01) than in their female counterparts (Table 3). Nsoso et al (2006) reported that body length, neck length for males were higher than females. In another study by Nsoso et al (2008), Guinea fowl body length and shank length were higher in males than in females. The helmet in males was also thicker than in females. However, females had wider (p< 0.01) pelvic inlet than males. These observations give an indication that it is possible to differentiate between the sexes in four months old Guinea fowls using neck, body, shank and wattles lengths, and helmet thickness. Iddriss et al (2015) concluded that males from 4 weeks old and beyond had bigger wattles than females while the opposite was true for the width of pelvic inlet. The present study indicates that at four months, neck, body, shank and wattle lengths in males were longer (p< 0.01) than in female counterparts. The helmet in males was also thicker than in females. However, females had wider (p< 0.01) pelvic inlet than males (Table 7). This is in consonance with Annor et al (2013) who reported that between four to twelve weeks, male Guinea fowls had longer necks, bigger body frame, pronounced and more concave wattles and much bigger helmets.
I wish to express my sincere appreciation to the Almighty God for His protection and guidance throughout the course. I am also grateful to Prof. Annor, S.Y. and Prof. Kagya-Agyemang, J. K. who resourcefully and untiringly superviced this work by giving their priceless guidance and constructive criticisms.
Annor S Y, Ahiaba J and Apiiga S Y 2013 Guinea fowl Production: A Handbook. Qualitype Limited, Accra, Ghana, pp.1-2.
Darre M J 2007 Guinea Fowl Management Extension Poultry Specialist. Department of Animal Science, University of Connecticut. Storrs CT 06269-4040.
Dei H K, Tetteh E and Otchere E O 2007 Nutritive Value of a Processed Product from Cassava and Blood in the Diets of Layer Chickens. Ghana Journal of Animal Science, 2, 3(1): 45- 51.
Idahor K O and Akinola L A F 2015 Keets Sex Predetermination Using Egg Colour, Weight and Shape. Journal of Recent Advances in Agriculture, 3(1): 345-350.
Iddriss I A, Bawa A, Ian A J, Robinson J E and Obese F Y 2015 Sexing in Guinea fowls (Numida meleagris). Poultry Science, 94:311-318.
Ikani E L and Dafwang I I 2004 National Agricultural Extension and Research Liaison Services, Poultry Series No. 8, Extension Bulletin No. 207, Zaria, Nigeria.
Mao K M, Sultana F, Howlider M A, Iwasawa A and Yoshizaki N 2006 The magnum-isthmus junction of the fowl oviduct participates in the formation of the avian-type shell membrane. Zoological Sciences, 23: 41-47.
Moreki J C and Mack N 2013 Effect of storage time and egg position on hatchability of Guinea fowl eggs. Journal of Animal Science Advances, 2(5):259-261.
Nsoso S J, Mareko M H D and Molelekwa C 2006 Comparison of growth and morphological parameters of Guinea fowl (Numida meleagris) raised on concrete and earth floor finishes in Botswana. Livestock Research for Rural Development. Volume 18, Article #178. http://www.lrrd.org/lrrd18/12/nsos18178.htm
Nsoso S J, Mareko M H D, Manyanda S and Legodimo P P 2008 The effect of housing type on body parameters, feed intake and feed conversion ratio of Guinea fowl (Numida meleagris) keets and chemical composition of their meat during growth and development in Botswana. Reproductive Journal of Animal Science, 2(2), 36-40.
Statistical Analysis System 2008 Version 08 Series Statistical Analysis System Software. SAS Institute, Inc. Anatomical record, 294(2): 322-334. North Carolina, USA.
Steel R G D and Torrie J H 1980 Principles and Procedures of Statistics: A Biometrical Approach. 2 nd Edition, McGraw-Hill International Book Company, Singapore, pp. 633.
Teye G A and Gyawu P 2001 The benefits of intensive indigenous Guinea fowl production in Ghana. World Poultry- Elsevier, 17 (9): 53-54.
Umosen A D, Onyeanusi B I, Salami S O, Nzalak J O, Imam J and Ibe C S 2008 Observations on the Wattles of Adult Helmeted Guinea Fowls ( Numida meleagris galeata)International Journal of Poultry Science, 7 (12): 1204-1206.
Yilmaz-Dikmen B and Dikmen S 2013 A Morphometric Method of Sexing White Layer Eggs. Brazilian Journal of Poultry Science. ISSN 1516-635X v.15 / n.3 / 169-286.
Received 18 June 2018; Accepted 2 August 2018; Published 3 September 2018