Selection to improve birth and weaning weight of Javanese Fat Tailed Sheep

In Indonesia, the Javanese Fat Tailed Sheep is a very populär domestic animal for its meat production However selection to increase body weight has never been done by local farmers. As a result the variability of body weight is high, and expected that application ofa selection program can improve this trait Two Steps of selection were done in order to improve birth and body weight. In the first selection, the elite group was established by selecting the best 40 females and 3 males from 12500 sheep reared by local farmers based on their mature body weight and tail length. The control group was established by randomly selecting 40 females and 4 males In the second step of selection, the best 50% females and 5% males of the progeny of the elite group was selected based on their weaning weight and tail size. The first selection results indicate that there was a positive genetic progress in both birth and weaning weight. Selection had increased 7.17% and 5.48% of male and female birth weight respectively and 9.48% and 9.78% of male and female weaning weight, respectively. Positive genetic progresses of birth and body weight were also found after the second selection. Birth weights of males and females were 6.75% and 7.20% higher than those in the control group. Male and female weaning weights were 5.60 % and 8.19% higher than those in the control group, however, selection for weaning weight did not affect reproduetive traits.


Introduction
The sheep population in Indonesia is the largest when compared to that in other South East Asian countries.In 1992, the number of sheep in Indonesia was 5,750,000 with 49.97% of them concentrated in West Java.There are two types of sheep, i.e. thin tailed sheep and fat tailed sheep.Thin tailed sheep can be found in the wet areas, e.g.West Java.On the other hand fat tailed sheep can mostly be found in dry areas, e.g.East Java and the eastern parts of Indonesia (SUTAMA, 1992).The sheep are relatively small, with mean mature ewe weight of 20 to 39 kg under traditional management.However, they are well adapted to the warm, humid climate of the country.They breed all year around and can have a mean lambing intervals of as low as 200 days (BRADFORD and INOUNU, 1996).DEVENDRA and McLEROY (1982) suggested that the javanese fat tailed sheep originated from West Asia and/or East Asia and were introduced by Arab traders hundred years ago.EDEY (1983) stated that after the introduction, the Indonesian fat tailed sheep were concentrated at Madura Island and then spread out to different parts of East Java and Nusa Tenggara Islands.The original fat tailed sheep have been crossed with some local sheep resulting in the fat tailed sheep that are found at present.MASON (1980), DEVENDRA and McLEROY (1982), SUTAMA and INIGUEZ (1990), SAKUL et al. (1994), and BRADFORD and INOUNU (1996) described the characteristics of fat tailed sheep as follows: hornless, white coat colour, medium size ear, sigmoid shaped tail with 15-18 vertebra!bones, birth weight of 1.6 kg, weaning weight of 8.6 kg; mature weight is 43 and 40 kg for male and female respectively, and prolific ewes with high frequency of litters of three, four or more than can be expected for populations with mean litter size of generally between 1.3 and 1.9.SABRANI et al. (1993) found that lamb survival of this type of sheep is low (51.4%),coefficient of Variation of weaning weight is high (26.60%)and coefficient of Variation of mature weight is even higher (45.45%).With these high phenotypic variabilities, the breeder can select them in order to get significant improvements in birth and weaning weight.Selection on birth and weaning weight of javanese fat tailed sheep has not been done (Noor et al., 1998).Therefore, the main objective of this experiment was to evaluate birth and weaning weight through selection.

Material and Methods
An intensive survey was conducted to collect important data from 12500 sheep reared by local farmers in areas of East Java (in six districts, i.e.Situbondo, Sumenep, Bondowoso, Pasuruan, Pamekasan, and Probolinggo).The data collected were sex, age, birth type, number of sheep at weaning (3 months old), mature body weight (the age estimated based on the formation of permanent teeth), body length, body height, heart girth, tail length, tail width, coat colour.Units of measurement were (i) body weight (kg): animal weight before eating in the morning, (ii) body length (cm): distance between Tuber ischii to Tuberositas humeri, (iii) body height (cm): vertical distance between the highest point of scapula to the ground, (iv) heart girth (cm): heart girth behind scapula (also known as ehest circumference behind scapula), (v) tail length (cm): distance between the top ofthe tail to the end of the tail, (vi) tail width (cm): the widest tail width, (vii) coat colour: categorised into two classes, white and non-white.

Correlation among traits
In order to study the relationship among the body measurements and the relationship between body weight and linear body measurements, coefficients of correlation were estimated.

First Step of Selection
The elite group was established by selecting the best of 40 females and 3 males based on their mature weight from the 12,500 sheep that were measured independent from age, birth type and lactation (Fig. 1).Besides the mature weight, the selected sheep should have white colour coat, free from any exterior abnormalities, have large and sigmoid shaped tail.The size and shape of tail are the second selection criteria, because the traits are highly correlated to the ability of animals survive in dry areas.The selection method used in this experiment was independent culling level.The control group was established by randomly selecting 40 females and 4 males.It should be noted that in the elite group only three males have mated the selection criteria.Both groups then were maintained at Garahan Research Centre, at Jember, East Java .Both groups were given the same type and quality of feed.Second Step of Selection.The progenies of both groups were maintained until they were weaned.The best 50% females and 5% males of the progeny of the elite I group were selected based on their weaning weight and used for the parent for the next generation.There was no selection in the control group.

Heritability Estimation
The heritability of birth and weaning weight was estimated using 'Animal Model' of DFREML (MEYER, 1993).The heritability values were estimated from lambs which were born from the elite and control groups.Both sex and birth types were treated as fixed effects.Differential Selection (DS) was calculated using the following formula (NOOR, 1996)

Means of Body Measurement Traits
In general, the javanese fat tailed sheep originating from Pasuruan, Situbondo and Probolinggo were significantly larger than those of other districts (Fig. 2).The variations in mean body measurement traits among district were high.Coefficient of correlation among body measurement traits in the six different districts at the base population is presented in Table 1.Body weight was highly correlated with body height, heart girth, tail length and tail width (r = 0.45 to 0.85) (Table 1).Animals that had high body weight tended to have larger tail.Some negative correlation was observed between traits other than body weight (body length, body height and heart girth) and tail length or tail width, especially in female sheep.Fig. 2: The body weight, body length, body height, heart girth, tail length and tail width of male and female javanese fat tailed sheep in six districts in East Java (Note: 1. Situbondo, 2. Sumenep, 3. Bondowoso, 4. Pasuruan, 5, Pamekasan and 6.Probolinggo) (Körpergewicht, Körperlänge, Körperhöhe, Herzumfang, Schwanzlänge, Schwanzbreite von männlichen und weiblichen Javanesischen Fettschwanzschafen in 6 Regionen von Ostjava (Region I. Situbondo, 2. Sumenep, 3. Bondowoso, 4. Pasuruan, 5. Pamekasan und 6. Probolinggo)) Table 1 Coefficients of correlation among body measurement traits of male (lower diagonal) and female (upper diagonal) javanese fat tailed sheep in Situbondo, Sumenep, Bondowoso, Pasuruan, Pamekasan, and Probolinggo (Korrelationskoeffizienten zwischen den Merkmalen der Körperkonformation in männlichen (unter der Diagonalen) und weiblichen (über der Diagonalen) Javanischen Fettschwanzschafen in 6 Regionen)

Selection Experiment Results
Birth and body weight of sheep in the elite I and control groups are presented in Table 2.The first selection had improved birth and weaning weights of males and females (Table 2).This is indicated by the larger birth and weaning weight in the elite I group when compared to those in the control group.The selection also significantly increased the male tail width, however selection on mature weight did significantly increased body length, body height, heart girth and tail length of both male and female animals (Table 3).The estimated heritability values at all ages were moderate to high (Table 4), however, due to the small number of animals used, the Standard errors of heritability values were relatively high.As the animals were getting older, the additive genetic (V A ), environmental (V E ) and phenotypic (V P ) variances were also getting larger (Table 4 ).The differential selection and the genetic progress summarised in Table 5 indicate first selection results that there was a positive genetic progress in both birth and weaning weight.Selection had increased 7.17% and 5.48% of male and female birth weight, respectively, and 9.48% and 9.78% of male and female weaning weight, respectively.The female reproduetive Performance in the elite I and control groups are (Table 6), showed that selection on mature weight did not significantly affect reproduetive traits.Positive genetic progresses of birth and body weight were also found after the second selection.Birth weights of males and females were 6.75% and 7.20% higher than those in the control group.Male and female weaning weights were 5.60 % and 8.19% higher than those in the control group (Tables 7 and 8).

Discussion
The Variation of body measurement traits between districts were high (Fig. 2).Considering that the feed quality and management system in those districts are almost similar, it was suggested that this high Variation is caused by the genetic Variation due to the fact that no selection had been done before.The significant test results between male and female in all traits indicate a distinct sexual dimorphism, where body measurement traits of male are significantly larger than those of females.
The javanese fat tailed sheep is a prolific breed.They produce single (34.41%), twins (42.16%), and triplets and quadruplets (23.43%), however, the mortality rate of twins, triplets and quadruplets are higher than Singles (9.89% for twins, 12.49% for triplets and quadruplets vs. 0.01% for single).The causes of this high mortality of twins, triplets and quadruplets were due to low birth weight and lack of milk.This high mortality at birth may be significantly reduced by providing better feeding to pregnant ewes at the last quarter of the pregnancy period and by giving sufficient milk to the new-born sheep.Considering the available facilities and knowledge of local farmers, it is recommended that selection should also be aimed at producing twins rather than triplets or quadruplets.In most cases, farmers can still manage twin born sheep properly, hence, the mortality can be kept low.The first selection results indicated that positive genetic progress in both birth and weaning weight.Selection had increased 7.17% and 5.48% of male and female birth weight, respectively, and 9.48% and 9.78% of male and female weaning weight, respectively.It should be noted that if the genetic progress is calculated using the formula AG = h 2 x i o> where, AG is the genetic progress, h 2 is heritability values, i is selection intensity and o> is phenotypic variance, then the genetic progress must be higher because of high selection intensity.As, in this experiment it was decided to reduce the environmental effects by maintaining both selected and control group under the same environmental condition.The small genetic progresses found in this experiment suggest a larger environmental impact in the districts or probably among farmers.
The results indicate that local sheep can be improved genetically using a conventional selection method.Occasionally black and brown spot colour still appeared in the elite group.However, the percentage of this oecurrence was very low.During the experiment no abnormalities are apparent in the elite group.Tail shape is also an important trait in this experiment.The tail size is closely related to the ability of the animal survive in the dry area.The fat deposit in the tail may function as a body reserve and utilized when the environmental conditions and feed quality are poor.The tail size will appear small in this condition, however, when the environmental condition is retumed to normal, the tail size become large.INIGUEZ et al. (1991) found that among the fat-tailed populations in Indonesia, those on the island of Madura had on the average the most extreme fat tails.Under good feeding conditions, fat mass of the tails interfered substantially with the ability of the rams to serve ewes (OBST et al., 1980).
Selection also improved the size of tail (Figures 3 and 4) and the large size ofthe tail made it difficult to mate naturally.The tail has to be Iifted up during the mating.In order to solve this problem several females were docked.

Table 1 (
continuation) NOOR et al.: Selection to improve birth and weaning weight of Javanese Fat Tailed Sheep *Note:

Table 2
Birth and weaning weight of male and female javanese fat tailed progenies sheep in the elite I and control groups after the first selection (Geburts-und Absetzgewichte von männlichen und weiblichen Nachkommen in der Elite

Table 3
The t-test result between the means of body weight, body length, body height, heart girth, tail length and tail width in the elite I and control groups (Ergebnisse des t-Tests ftlr die Merkmale der Körperkonformation in der

Table 6
Pregnancy rate, birth rate, prolification and reproduction rate of sheep in elite 1 and control group progenies

Table 7
Birth and weaning weight of male and female javanese fat tailed sheep progenies at elite II and control group Note: SD : Standard Deviation, n: number of Observation

Table 8
The differential selection and genetic progress of birth and weaning weight of males and females javanese fat tailed sheep after the second selection (Selektionsdifferenz und Selektionserfolg im Geburts-und Absetzgewicht The docking result indicate that males do not want to mate if the tail of the female is too short.The male tend to mate female animals with normal tail.Based on these results it is recommended that selection should aim to produce sheep with large body size and optimum tail size so they still couid mate naturally.ConclusionSelection on weaning weight of javanese fat tailed sheep substantially improved birth and weaning weights, however, this selection did not significantly affect reproduetive traits.Further improvement could still be expected if the selection is continued.Considering the high mortality rate in triplets and quadruplet lambs, under the present local farmer management condition in Indonesia, it is recommended to select ewes towards producing Singles and twins.Jahre des vorigen Jahrhunderts fing man während des auf Hochtouren laufenden Wirtschaftswunders allmählich an, sich über die Schwermetallemissionen und die dadurch bedingten Immissionen auf Nutzund Futterpflanzen Gedanken zu machen.Das Hauptinteresse galt damals dem Blei, zu dem schnell Arsen, Cadmium und Quecksilber kamen.Da die Höchst-bzw.Richtwerte für die Futter-und Lebensmittel nicht aufeinander abgestimmt festgelegt wurden, müsste ihre gegenseitige Verträglichkeit durch Carry-over-Experimentc überprüft werden.Man stellte schnell fest, dass die Schwermetellbelastungen einiger Lebens-und Futtermittel aus toxikologischer Sicht recht hoch waren und man Maßnahmen ergreifen müsste, die Immissionen als ihre Quellen zu reduzieren.Einige Änderungen der technischen Anleitung Luft zusammen mit stufenweisen Reduzierungen der Bleigehalte in Vergaserkraftstoffen waren die Folge.Die dort festgelegten Höchstwertregelungen wurden laufend verschärft mit der Folge, dass die Schwermetallbelastung vor allem bei Blei, Cadmium und Quecksilber in den Folgejahren bis zum heutigen Tage laufend abnimmt.Heute sind z.B. die Bleigehalte der Lebern und Nieren, also in den Akkumulationsorganen der Tiere für diese Elemente niedriger als sie es damals im Fleisch waren.Im Fleisch sind die Blei-, Cadmium und Quecksilbergehalte mittlerweile so niedrig, dass sie mit den modernsten Spurenelement-Nachweismethoden nicht mehr oder gerade noch nachgewiesen werden können.Die fallenden Trends der Umweltbelastung können mit Hilfe standorttreuer Wildtiere gezeigt werden.