The production characteristics of the indigenous Imroz and Kivircik sheep breeds in Turkey - A. Yilmaz^[24], M. Ozcan^[25], B. Ekiz^[26], A. Ceyhan^[27] & A. Altinel^[28]

Summary

This study was carried out to investigate the fertility, milk production and body weight of ewes and the survival and growth characteristics of lambs of the indigenous Imroz and Kivircik sheep breeds. The Imroz and Kivircik sheep breeds are included among the genetic resources in the project for the conservation of the indigenous breeds in Turkey.

Conception rates for Imroz and Kivircik ewes were 57.6% and 81.7% respectively, litter sizes were 1.2 and 1.2 respectively, milk yields were 89 kg and 62 kg respectively and average live weights (2-7 years of age) were 43 kg and 55 kg, respectively. Imroz and Kivircik lambs had survival rates at weaning (90^th day) of 98% and 96%, birth weights of 3.3 kg and 4.1 kg and weaning weights of 19.8 kg and 28.0 kg, respectively.

The results showed that the Kivircik sheep were heavier and the lambs had a better growth rate until weaning than the Imroz breed. However, the milk production of the Imroz ewes was higher than that of Kivircik. The lambs of both breeds had a satisfactory survival and growth rates until weaning and these results might be regarded as a desired adaptation of the Imroz and Kivircik lambs to the environmental conditions of the Marmara Region.

Resumen

Este estudio se llevó a cabo para averiguar la fertilidad, producción lechera y peso corporal de las ovejas y las características de supervivencia y crecimiento de los corderos de las razas indígenas Imroz y Kivircik. Las razas Imroz y Kivircik están incluidas entre los recursos genéticos del proyecto para la conservación de las razas indígenas en Turquía.

La tasa de ovejas grávidas en las razas Imroz y Kivircik fue de 57,6% y 81,7%, respectivamente. Los tamaños de camada fueron de 1,2 en ambas razas, el rendimiento leche de 89 y 62 kg, respectivamente. El peso medio vivo (2-7 años de edad) fue de 43 y 55kg. Los corderos Imroz y Kivircik presentaron una tasa de supervivencia a 90días del 98% alcanzando un peso de 19,8y 28,0 kg, respectivamente, mientras el peso al nacimiento fue de 3,3 y 4,1 kg.

Los resultados muestran que la oveja Kivircik es más pesada y que los corderos de esta raza tienen un mejor crecimiento respecto a la raza Imroz. Sin embargo, la producción de leche de las ovejas Imroz fue mayor. Los corderos de ambas razas presentaron una tasa de supervivencia satisfactoria y unos índices de crecimiento elevados. Estos resultados deben ser interpretados como una adaptación de los corderos de estas razas a las condiciones ambientales de la región de Marmara.

Keywords: Imroz sheep, Kivircik sheep, Genetic resources, Production performance.

Introduction

Turkey has a very young human population which is increasing rapidly, therefore the need for foods of animal origin is also increasing. The sheep population of 29.4million heads (FAO, 2002) in the country is an important resource for meeting this demand. This sheep population represents the first and seventh place in Europe and the world, respectively. The great majority (97%) of this sheep population is composed of indigenous breeds which have low production levels. However these breeds can continue to be productive under harsh climate and poor feeding and management conditions which they have adapted to over hundreds of years. In the arid, semi-arid and hilly areas of Turkey these breeds serve their breeders as food for life and as a source of economic income. The conservation of these indigenous sheep breeds as genetic resources might also assist the adaptation of farm animals to new environmental conditions which might occur in the future. It is important that the natural resources be preserved while simultaneously producing enough food to satisfy the demands of a growing human population (Boyazoglu,2002).

As a result of crossbreeding and shrinking breeding areas, the numbers of the purebred indigenous Imroz and Kivircik sheep breeds are decreasing. Because of this, these breeds have been included in a project for the conservation of indigenous breeds as genetic resources in Turkey.

This study was carried out to investigate the fertility, milk production and body weight of ewes and the survival and growth characteristics of lambs of the indigenous Imroz and Kivircik sheep breeds.

Land and Climate

Imroz (Gokceada) is the name of an island in the Aegean Sea, off north-western Anatolia. The Imroz sheep breed has been found on this island for more than one hundred years. The Imroz and Kivircik sheep breeds are raised in the Marmara Region. This region encompasses the transition between the Black Sea and Aegean Regions. The climate is predominantly Mediterranean; however, dry season aridity is not as great as along the Mediterranean coast. Temperature and rainfall vary markedly within relatively short distances. Average temperatures are 23-27°C in the warmest months and 1-8°C in the coldest months, with an annual precipitation of 590-810 mm. A relatively superior topography and denser population have contributed to make the region one of the most intensively cultivated in the country. Therefore sheep in this region have to compete with field crops (Figure 1). Success in this competition will largely depend on the intensification of sheep breeding and as such there is the need to determine the real production potential of the indigenous sheep breeds under intensified conditions (Yalcin,1986).

Figure 1. The ewe flock grazing in spring time.

Phenotypic Descriptions

Imroz

The breed is among the smallest sheep breeds in the country. Animals are predominantly white, with black marks around the mouth, nose and eyes, on the ears and rarely on the tip of the legs. The tail is thin and long, usually reaching below the hocks. Rams have strong spiral horns extending sideways; ewes are usually polled but up to 30% of the ewes may have small scurs. The head is narrow and its profile is straight. The wool is very coarse and long, and it covers the top of the head (Figures 2 and 3).

Kivircik

This is a medium-sized breed. Animals are white with long, thin tails, usually reaching the hocks. Rams have horizontal spiral horns extending sideways; ewes are usually polled. The ears are relatively short and extend horizontally. The fleece is of carpet-wool type, but the wool is of better quality than the wool of all other indigenous breeds in Turkey (Demir, 1997) (Figures 4 and 5).

Materials and Methods

This study was carried out in Marmara Animal Breeding Research Institute in the years 2000 and 2001. The purebred samples of the Imroz and Kivircik genotypes, which were gathered in the Institute for the conservation of these breeds as genetic resources, were used in the study. The sheep were collected from a number of villages, which still have pure-bred samples of these breeds, by an expert committee formed by the Institute for the Conservation of Genetic Resources Project in Marmara Region.

The two breeds were managed in the same flock at the Institute. The ewe flock was kept indoors during the winter months and then taken to pasture as the weather conditions improved. Before the mating season, 400-600 g/head of concentrated feed produced at the Institute was given daily to the ewes. A similar program was also used to prepare the ewes for parturition. Oestrus detection was performed daily by using teaser rams and ewes were mated with the selected rams. The lambs were kept together with their dams in individual boxes for the first three days after birth, then a flock composed of suckling lambs and their dams was formed. The suckling program of the lambs lasted for three months (90 days) on average. During this program, grass hay and lamb grower feed were given to the lambs to speed up rumen improvement.

To assess the fertility characteristics of the ewes, the conception rate, rate of infertility of ewes, birth rate, rate of single births, rate of prolific births, lamb production and litter size traits were determined for each genotype group. The body weights (after shearing) of ewes (2-7 years of age) were determined by weighing with a scale sensitive to 0.1 kg.

Milk yield in one lactation and lactation lengths were investigated. On milk control days, lambs were not allowed to suckle. The formulation below was used to calculate milk yield of any ewe in one lactation as;

where:

M = milk yield of any ewe in one lactation(kg);
A₁= the first control date;
D = date of birth;
k = milk yield in the first control (kg);
k and k’ = milk yields of consecutive controls (kg);
A and A’ = consecutive control dates (day) and
S = drying off date.

The survival rates of the lambs were evaluated up to the age of weaning (90days). To determine this characteristic all lambs that died and the reasons for death were recorded.

The statistical comparisons between genotype groups in respect of the milk production traits and live weight of ewes were made by t-test (Ozdamar, 1999).

The lambs were weighed monthly with a scale sensitive to 0.1 kg. The absolute 90^th day live weights of lambs were calculated by the interpolation method. The birth and weaning weights of lambs were given in Least-Squares Means. The effects of some environmental factors which affect the growth of the lambs were determined using the Least-Squares Means method and the significance of the differences between the groups was determined with a contrast test (Ozdamar, 1999).

Figure 2. Imroz ewe and ram.

Table 1. The fertility characteristics of the Imroz and Kivircik ewes.

The model below was used to determine the extent to which the factors affected birth weight and weight at weaning of lambs.

Y_ijkl = m + a_i + b_j + c_k + d_ijkl

where:

Y_ijkl = live weight of lamb at the age examined;
m = overall mean;
a_i = effect of genotype;
b_j = effect of birth type;
c_k = effect of sex and
d_ijkl = random error.

In the model used, it was assumed that there were no significant interactions between the factors investigated and the sum of the effects of the subgroups of factors were assumed to be zero.

Results and Discussion

Fertility

The fertility results of Imroz and Kivircik ewes are presented in Table 1.

In this study the conception rate of the Imroz ewes was lower than that of the Kivircik ewes. This might be because of the adaptation problems of the Imroz ewes to the breeding system of the Institute. However, the prolific birth and litter size of Imroz ewes were similar to Kivircik ewes and Imroz ewes in different studies (Yalcin et al., 1980; Corekci and Evrim, 2001).

Milk yield and lactation length

The results of milk yield and lactation length of Imroz and Kivircik ewes are given in Table2.

Table 2.The milk production and lactation length of the Imroz and Kivircik ewes. (: Means, : Standard error).

*P<0.05

Table 3. The live body weight of the Imroz and Kivircik ewes (kg). (: Mean body weights, : Standard error).

* P<0.05

Table 4. The birth and weaning weights of the Imroz and Kivircik lambs and the effect ratios (ER) of investigated factors (kg). (: Mean weights, : Standard error).

^a,b The differences among the means of groups carrying various letters in the same column are significant (P<0.05).

Table 5. The number and survival rates of the Imroz and Kivircik lambs at the age of weaning.

Figure 3. Imroz lamb.

Figure 4. Kivircik sheep breed.

Figure 5. Kivircik lamb.

Imroz ewes had significantly (P<0.05) higher milk yields and longer lactation than Kivircik. Milk yields of the Imroz ewes in this study was also higher than Kivircik ewes in different studies (Demir and Baspinar, 1992; Altinel et al., 2000). These results support the idea that the milk production characteristics of the Imroz ewes is comparatively good when, measured against the indigenous sheep breeds of Turkey.

Body weight of ewes

Live weights after shearing of Imroz and Kivircik ewes are presented in Table 3.

The Kivircik ewes were significantly (P<0.05) heavier than Imroz. The Kivircik ewes were also heavier than Kivircik and Imroz ewes in other studies (Demir and Baspinar, 1992; Corekci and Evrim, 2000) but were similar to the results reported by Altinel et al. (2000) for Kivircik ewes. The body weights of the Imroz ewes in this study were similar to the results of Imroz ewes in different studies (Ozcan et al., 1980; Corekci and Evrim, 2000).

Growth of lambs

Live weights of lambs at birth and 90^th day of age are presented in Table 4.

The birth and weaning weights of Kivircik lambs were significantly (P<0.05) higher than those of Imroz lambs. However, the growth of both breeds was satisfying. The growth until weaning of the Imroz and Kivircik lambs in this study were generally higher than the results previously reported for these breeds (Yilmaz, 1998; Ekiz, 2000; Corekci and Evrim, 2001). These growth results could be regarded as representing the improvement in growth performance of the indigenous Imroz and Kivircik lambs when introduced to more intensified breeding conditions.

The effects of genotype, sex and birth type were also found to be statistically significant (P<0.05) in birth weight and weaning weight of the lambs and these results were in accordance with the references (Corekci and Evrim, 2001; Ozcan et al., 2001).

Survival of lambs

Survival rates of lambs until 90^th day of age are given in Table 5.

The survival rates until weaning of the Imroz and Kivircik lambs were high and similar. This result could be taken as a sign of the effective adaptation of these breeds to the environmental conditions of the Marmara Region and the Institute.

Conclusions

As a biological consequence of uncontrolled crossbreeding may ultimately be the disappearance of the indigenous Imroz and Kivircik sheep breeds, pure-breeding and conservation studies on these breeds should be continued and supported.

In this study, it was shown that Kivircik breed was heavier and Kivircik lambs had a better growth rate until weaning than the Imroz. However, the milk yields of Imroz ewes were higher than those of Kivircik. The breeding system of Imroz ewes in the Institute should be designed in a more suitable way to improve the conception and birth rates. The lambs of both breeds had satisfactory survival and growth rates until weaning and these results might be regarded as the effective adaptation of the Imroz and Kivircik lambs to the more intensified conditions at the Institute.

Acknowledgements

This study was supported by the Research Fund of the Istanbul University, Turkey, Project No: 1528/16012001.

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