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Reproductive performance of Korean native goats under natural and intensive conditions
Small Ruminant Research 65 (2006) 284–287
Technical note
Reproductive performance of Korean native goats under natural and intensive conditions H.B. Song ∗ , I.H. Jo, H.S. Sol Department of Animal Science, College of Natural Resources, Daegu University, 15 Naeri, Jillyang, Gyeongsan, Gyeongbuk 712-714, Republic of Korea Received 16 September 2004; received in revised form 2 August 2005; accepted 4 August 2005 Available online 5 October 2005
Abstract This study was conducted to compare the reproductive performance of Korean native goats (KNG) under range (n = 199) and intensive (n = 269) conditions. Ages at first kidding were 412.1 ± 32.7 and 382.0 ± 25.2 days, with the mean kidding interval being 207.8 ± 1.7 and 211.6 ± 2.7 days under range and intensive environments, respectively. The percentage of single, twins, triplets and quadruplets born were 40.6, 50.4, 8.0 and 1.0% under range and 33.8, 54.4, 11.4 and 0.4% under intensive environments, respectively. The mean litter sizes were 1.69 ± 0.03 and 1.78 ± 0.16 at birth and 1.31 ± 0.03 (77.5%) and 1.52 ± 0.17 (85.4%) at weaning for the range and intensive groups, respectively. The management system affected the reproductive performance of the KNG does, especially, the age at first kidding and litter size at weaning which were higher under intensive conditions. The kidding interval, birth type and litter size at birth were not influenced by rearing environment. The reproductive performance of KNG obtained in this study was higher than those found in the other breeds such as Saanen, Alpine and Anglo-Nubian. However, it agrees with the results obtained in the Boer goats. © 2005 Elsevier B.V. All rights reserved. Keywords: Reproductive performance; Rearing environment; Litter size; Kidding interval
1. Introduction The Korean native goat (Capra hircus coreanae; KNG) or the black goat is the only indigenous breed in Korea and the population is approximately 500,000 head, distributed in over 50,000 farms. These goats ∗ Corresponding author. Tel.: +82 53 850 6723; fax: +82 53 850 6729. E-mail address: [email protected] (H.B. Song).
0921-4488/$ – see front matter © 2005 Elsevier B.V. All rights reserved. doi:10.1016/j.smallrumres.2005.08.001
comprise the highest proportion of small ruminants in the country (Ministry of Agriculture and Forestry, 2003). The level of reproductive performance of the goats is dependent on genetic and environmental factors, but this performance is particularly sensitive to the latter. So, for example, the management system, which include the nutritional requirement and rearing environment can affect reproductive performance considerably (Song, 1997). Reproduction efficiency is determined by many different processes (Shelton,
H.B. Song et al. / Small Ruminant Research 65 (2006) 284–287
1978) and these processes include age at first kidding, kidding interval, birth type and the litter sizes at birth and the weaning rate (Greyling, 2000). This study was conducted to compare the reproductive performance in KNG kept either under range or intensive conditions.
285
Table 1 Mean value (±S.E.) for age at first kidding of Korean native goats under extensive and intensive environments Management system
Number of goats
Age at first kidding (days)
Extensive Intensive
199 267
412.1 ± 32.7a 382.0 ± 25.2b
2. Materials and methods
Means with different superscript letters (a and b) differ (P < 0.05).
Records of 635 and 1003 kiddings from 199 and 269 KNG does (30–40 kg body weight) kept under range (natural pasture) or stall environments (intensive feeding), respectively, between 1994 and 2003 were used in this study. The flocks were maintained in a year-round free mating system. These matings produced 1075 and 1789 live kids under the range and intensive conditions, respectively. The farms were at an altitude of 300 m with an annual precipitation of 1100 mm and a mean annual temperature of 14 ◦ C. The goats under natural range conditions were maintained in open sheds with adequate space and shelter for the harsh summer and winter. Goats were maintained on cultivated pastures (clover-grass leys) from the morning to afternoon, and fed a balanced commercial concentrate (100 g/(head day)) with mineral salt and water ad libitum. Goats under stall or intensive conditions were reared in pens (20 head/32.4 m2 ) and fed rice straw (400–600 g/(head day)) twice daily and a balanced commercial concentrate (200– 400 g/(head day)), with mineral salt and water ad libitum. All goats were regularly dipped and dewormed and were identified using ear tags. The kidding dates were recorded and the number of kidding intervals was 436 and 736 for the extensive and intensive environments, respectively. Records were also kept regarding the age at first kidding, kidding interval, litter sizes at birth and weaning. Data were analyzed using sigma plot 2001 or SAS (SAS, 1997). Differences were analyzed using the t-test or Duncan’s multiple range test.
and 382.0 ± 25.2 days, respectively (Table 1). The difference was significantly (P < 0.05) earlier for the intensively housed group. Kim and Chung (1979) reported the age at first breeding to be 8.0 ± 2.7 months for young (<6 months) and older (>12 months) does. The age at first kidding was highly variable and dependent on the growth rate and management system used. Ribeiro et al. (2000) reported the mean age at first kidding in Saanen goats to be 402.3 ± 19.1 days, with a range of 252–732 days. These values recorded are similar to values reported by Galina et al. (1995). The age at first kidding however in the present study was earlier than that obtained in native goats in Africa, where this reproductive event occured approximately 20 months of age (Wilson et al., 1989). Age at first kidding has been found to be largely dependent on an adequate nutritional regime (Delgadillo and Malpaux, 1996).
3. Results and discussion 3.1. Age at first kidding The mean age at first kidding in the KNG does under extensive and intensive conditions was 412.1 ± 32.7
3.2. Kidding interval The mean kidding interval of KNG does was recorded as 207.8 ± 1.8 and 211.6 ± 2.7 days under extensive and intensive environments, respectively (Table 2). These intervals for does were considerably shorter than the values for KNG does (8.7 ± 2.5– Table 2 Mean (±S.E.) kidding interval (days) according to season of birth in Korean native goats under extensive and intensive environments Season
Extensive
Intensive
N
Kidding interval
N
Kidding interval
Spring Summer Autumn Winter
113 91 93 138
192.1 ± 2.9b 197.1 ± 3.4b 218.0 ± 3.5a 220.6 ± 3.1a
228 117 171 220
194.7 ± 2.5b 189.7 ± 2.9b 224.6 ± 2.9a 237.4 ± 3.5a
Mean
436
207.8 ± 1.7
736
211.6 ± 2.7
N, number of goats observed; means with different superscript letters (a and b) in the same columns differ (P < 0.05).
286
H.B. Song et al. / Small Ruminant Research 65 (2006) 284–287
Table 3 Birth type in Korean native goats under extensive and intensive environments Management system
Number of kiddings
Number of parturition (%)a Single
Twin
Triplet
Quadruplet
Extensive Intensive
635 1003
258 (40.6) 339 (33.8)
320 (50.4) 546 (54.4)
51 (8.0) 114 (11.4)
6 (1.0) 4 (0.4)
a
No significant differences between groups.
10.7 ± 3.2 months) reported by Kim and Chung (1979). These short kidding intervals are generally associated with year-round free mating systems (Song, 1997). In the present study the KNG does were maintained under free ranging conditions, thus, matings were at random throughout the year as KNG does tend to show estrus year-round (Kim and Chung, 1979). The kidding intervals were longer (P < 0.05) for does born in the autumn and winter, compared to those born in the spring and summer—regardless of the rearing system. The effect of season of birth on the kidding interval could be attributed to the sexual activity of does, which tends to be highest in autumn and winter and declines in spring and summer (Na, 1987). These significant differences in kidding intervals due to season of birth could be explained by the lactation period, which determines the month of parturition, as weak or strong ovarian activity was observed at the onset of the year season (Galina et al., 1995). 3.3. Litter size The percentages of singletons, twins, triplets and quadruplets born were 40.6, 50.4, 8.0 and 1.0% under the extensive and 33.8, 54.4, 11.4 and 0.4% under the intensive environments, respectively (Table 3). These differences were not significant and the litter size recorded in the present study compare favorably with the 35.3, 46.3, 15.5 and 2.9% reported for singletons, twins, triplets and quadruplets, respectively, in the same
breed of goats (Kim and Chung, 1979). The percentage of singletons, twins, triplets and quadruplets in Boer goats are reported as being 24.5, 59.2, 15.3 and 1.0%, respectively (Campbell, 1994). It would thus seem as if the KNG can be considered as a prolific goat breed. The mean litter sizes at birth were 1.69 ± 0.03 and 1.78 ± 0.16 for goats maintained under extensive or intensive conditions, respectively (Table 4). These differences however were not significant. This mean litter size at birth agree with that reported by other workers for KNG does (1.87) (Kim and Chung, 1979) and other goat breeds (Odubote, 1996). The mean litter size at weaning was 1.31 ± 0.03 and 1.52 ± 0.17 for goats maintained under extensive or intensive conditions, respectively, with an overall weaning rate of 77.5 and 85.4% (Table 4). These differences in litter sizes were significant (P < 0.05) with the survival rate (85.4%) being higher in the intensive group. This mean litter size at weaning (which could passively been seen as an indication of mothering ability) reported compares favorably with that reported by other workers (Ebozoje and Ikeobi, 1998). For goats raised under extensive conditions, a primary concern of management at kidding is kid mortalities due to predators, cold stress, or abandonment by the dams (Shelton, 1978). These feeders however were not experienced in this study and the mortality rate could generally be described as acceptable. In conclusion, the management system can affect the reproductive performance of KNG does—especially
Table 4 Litter size at birth and weaning and weaning rate in Korean native goats under extensive and intensive environments Management system
Extensive Intensive
Number of goats observed
Litter size At birth
At weaning
635 1003
1.69 ± 0.03 1.78 ± 0.16
1.31 ± 0.03b 1.52 ± 0.17a
Means with different superscript letters (a and b) in the same columns differ (P < 0.05).
Weaning rate (%)
77.5 85.4
H.B. Song et al. / Small Ruminant Research 65 (2006) 284–287
traits such as the age at first kidding and the weaning rate which were higher under the stall or intensive conditions, compared to those under the range environment.
Acknowledgement This research was supported in part by the Daegu University Research Grant, 2004.
References Campbell, Q.P., 1994. Information regarding the improved Boer goat. Boer Goat News 11, 49–50. Delgadillo, J.A., Malpaux, B., 1996. Reproduction of goats in the tropics and subtropics. In: Proceedings of the 6th International Conference on Goat, Beijing, China, pp. 806–808. Ebozoje, M.O., Ikeobi, C.O.N., 1998. Colour variation and reproduction in West African dwarf (WAD) goats. Small Ruminant Res. 24, 125–130. Galina, M.A., Silva, E., Morales, R., Lopez, B., 1995. Reproductive performance of Mexican dairy goats under various management systems. Small Ruminant Res. 18, 249–253.
287
Greyling, T.T.C., 2000. Reproduction traits in the Boer goat doe. Small Ruminant Res. 36, 171–177. Kim, C.K., Chung, Y.C., 1979. A study on the estrus and kid crop in Korean native goats. Korean J. Anim. Sci. 21, 27–133. Ministry of Agriculture and Forestry, 2003. Livestock Bureau Data, Seoul, Korea, 691 pp. Na, J.S., 1987. Monthly manifestation of behavioural estrus and induction of estrus in Korean native goats. Korean J. Anim. Sci. 29, 288–294. Odubote, I.K., 1996. Genetic and non-genetic sources of variation in litter size, kidding interval and body weight at various ages of West African dwarf goats, Ph.D. Thesis Obafemi Awolowo University, Ile-Ife, Nigeria, 161 pp. Ribeiro, A.C., Queiroz, S.A., Lui, J.E., Ribeiro, S.D.A., Resende, K.J., 2000. Genetic and phenotypic parameters estimates of kidding interval and age at first kidding in Saanen goats in Brazil. In: Proceedings of the 7th International Conference on Goats, France, pp. 258–259. SAS, 1997. User’s Guide, Version 6, Statistical Analysis System Institute Inc., Cary, NC, USA, 943 pp. Shelton, M., 1978. Reproduction and breeding of goats. J. Dairy Sci. 61, 994–1010. Song, H.B., 1997. Korean Native Black Goat. Daegu University Press, Daegu, Korea, pp. 175–177. Wilson, R.T., Murayi, T.H., Rocha, A., 1989. Indigenous African small ruminant strain with potentially high reproductive performance. Small Ruminant Res. 2, 107–117.
Technical note
Reproductive performance of Korean native goats under natural and intensive conditions H.B. Song ∗ , I.H. Jo, H.S. Sol Department of Animal Science, College of Natural Resources, Daegu University, 15 Naeri, Jillyang, Gyeongsan, Gyeongbuk 712-714, Republic of Korea Received 16 September 2004; received in revised form 2 August 2005; accepted 4 August 2005 Available online 5 October 2005
Abstract This study was conducted to compare the reproductive performance of Korean native goats (KNG) under range (n = 199) and intensive (n = 269) conditions. Ages at first kidding were 412.1 ± 32.7 and 382.0 ± 25.2 days, with the mean kidding interval being 207.8 ± 1.7 and 211.6 ± 2.7 days under range and intensive environments, respectively. The percentage of single, twins, triplets and quadruplets born were 40.6, 50.4, 8.0 and 1.0% under range and 33.8, 54.4, 11.4 and 0.4% under intensive environments, respectively. The mean litter sizes were 1.69 ± 0.03 and 1.78 ± 0.16 at birth and 1.31 ± 0.03 (77.5%) and 1.52 ± 0.17 (85.4%) at weaning for the range and intensive groups, respectively. The management system affected the reproductive performance of the KNG does, especially, the age at first kidding and litter size at weaning which were higher under intensive conditions. The kidding interval, birth type and litter size at birth were not influenced by rearing environment. The reproductive performance of KNG obtained in this study was higher than those found in the other breeds such as Saanen, Alpine and Anglo-Nubian. However, it agrees with the results obtained in the Boer goats. © 2005 Elsevier B.V. All rights reserved. Keywords: Reproductive performance; Rearing environment; Litter size; Kidding interval
1. Introduction The Korean native goat (Capra hircus coreanae; KNG) or the black goat is the only indigenous breed in Korea and the population is approximately 500,000 head, distributed in over 50,000 farms. These goats ∗ Corresponding author. Tel.: +82 53 850 6723; fax: +82 53 850 6729. E-mail address: [email protected] (H.B. Song).
0921-4488/$ – see front matter © 2005 Elsevier B.V. All rights reserved. doi:10.1016/j.smallrumres.2005.08.001
comprise the highest proportion of small ruminants in the country (Ministry of Agriculture and Forestry, 2003). The level of reproductive performance of the goats is dependent on genetic and environmental factors, but this performance is particularly sensitive to the latter. So, for example, the management system, which include the nutritional requirement and rearing environment can affect reproductive performance considerably (Song, 1997). Reproduction efficiency is determined by many different processes (Shelton,
H.B. Song et al. / Small Ruminant Research 65 (2006) 284–287
1978) and these processes include age at first kidding, kidding interval, birth type and the litter sizes at birth and the weaning rate (Greyling, 2000). This study was conducted to compare the reproductive performance in KNG kept either under range or intensive conditions.
285
Table 1 Mean value (±S.E.) for age at first kidding of Korean native goats under extensive and intensive environments Management system
Number of goats
Age at first kidding (days)
Extensive Intensive
199 267
412.1 ± 32.7a 382.0 ± 25.2b
2. Materials and methods
Means with different superscript letters (a and b) differ (P < 0.05).
Records of 635 and 1003 kiddings from 199 and 269 KNG does (30–40 kg body weight) kept under range (natural pasture) or stall environments (intensive feeding), respectively, between 1994 and 2003 were used in this study. The flocks were maintained in a year-round free mating system. These matings produced 1075 and 1789 live kids under the range and intensive conditions, respectively. The farms were at an altitude of 300 m with an annual precipitation of 1100 mm and a mean annual temperature of 14 ◦ C. The goats under natural range conditions were maintained in open sheds with adequate space and shelter for the harsh summer and winter. Goats were maintained on cultivated pastures (clover-grass leys) from the morning to afternoon, and fed a balanced commercial concentrate (100 g/(head day)) with mineral salt and water ad libitum. Goats under stall or intensive conditions were reared in pens (20 head/32.4 m2 ) and fed rice straw (400–600 g/(head day)) twice daily and a balanced commercial concentrate (200– 400 g/(head day)), with mineral salt and water ad libitum. All goats were regularly dipped and dewormed and were identified using ear tags. The kidding dates were recorded and the number of kidding intervals was 436 and 736 for the extensive and intensive environments, respectively. Records were also kept regarding the age at first kidding, kidding interval, litter sizes at birth and weaning. Data were analyzed using sigma plot 2001 or SAS (SAS, 1997). Differences were analyzed using the t-test or Duncan’s multiple range test.
and 382.0 ± 25.2 days, respectively (Table 1). The difference was significantly (P < 0.05) earlier for the intensively housed group. Kim and Chung (1979) reported the age at first breeding to be 8.0 ± 2.7 months for young (<6 months) and older (>12 months) does. The age at first kidding was highly variable and dependent on the growth rate and management system used. Ribeiro et al. (2000) reported the mean age at first kidding in Saanen goats to be 402.3 ± 19.1 days, with a range of 252–732 days. These values recorded are similar to values reported by Galina et al. (1995). The age at first kidding however in the present study was earlier than that obtained in native goats in Africa, where this reproductive event occured approximately 20 months of age (Wilson et al., 1989). Age at first kidding has been found to be largely dependent on an adequate nutritional regime (Delgadillo and Malpaux, 1996).
3. Results and discussion 3.1. Age at first kidding The mean age at first kidding in the KNG does under extensive and intensive conditions was 412.1 ± 32.7
3.2. Kidding interval The mean kidding interval of KNG does was recorded as 207.8 ± 1.8 and 211.6 ± 2.7 days under extensive and intensive environments, respectively (Table 2). These intervals for does were considerably shorter than the values for KNG does (8.7 ± 2.5– Table 2 Mean (±S.E.) kidding interval (days) according to season of birth in Korean native goats under extensive and intensive environments Season
Extensive
Intensive
N
Kidding interval
N
Kidding interval
Spring Summer Autumn Winter
113 91 93 138
192.1 ± 2.9b 197.1 ± 3.4b 218.0 ± 3.5a 220.6 ± 3.1a
228 117 171 220
194.7 ± 2.5b 189.7 ± 2.9b 224.6 ± 2.9a 237.4 ± 3.5a
Mean
436
207.8 ± 1.7
736
211.6 ± 2.7
N, number of goats observed; means with different superscript letters (a and b) in the same columns differ (P < 0.05).
286
H.B. Song et al. / Small Ruminant Research 65 (2006) 284–287
Table 3 Birth type in Korean native goats under extensive and intensive environments Management system
Number of kiddings
Number of parturition (%)a Single
Twin
Triplet
Quadruplet
Extensive Intensive
635 1003
258 (40.6) 339 (33.8)
320 (50.4) 546 (54.4)
51 (8.0) 114 (11.4)
6 (1.0) 4 (0.4)
a
No significant differences between groups.
10.7 ± 3.2 months) reported by Kim and Chung (1979). These short kidding intervals are generally associated with year-round free mating systems (Song, 1997). In the present study the KNG does were maintained under free ranging conditions, thus, matings were at random throughout the year as KNG does tend to show estrus year-round (Kim and Chung, 1979). The kidding intervals were longer (P < 0.05) for does born in the autumn and winter, compared to those born in the spring and summer—regardless of the rearing system. The effect of season of birth on the kidding interval could be attributed to the sexual activity of does, which tends to be highest in autumn and winter and declines in spring and summer (Na, 1987). These significant differences in kidding intervals due to season of birth could be explained by the lactation period, which determines the month of parturition, as weak or strong ovarian activity was observed at the onset of the year season (Galina et al., 1995). 3.3. Litter size The percentages of singletons, twins, triplets and quadruplets born were 40.6, 50.4, 8.0 and 1.0% under the extensive and 33.8, 54.4, 11.4 and 0.4% under the intensive environments, respectively (Table 3). These differences were not significant and the litter size recorded in the present study compare favorably with the 35.3, 46.3, 15.5 and 2.9% reported for singletons, twins, triplets and quadruplets, respectively, in the same
breed of goats (Kim and Chung, 1979). The percentage of singletons, twins, triplets and quadruplets in Boer goats are reported as being 24.5, 59.2, 15.3 and 1.0%, respectively (Campbell, 1994). It would thus seem as if the KNG can be considered as a prolific goat breed. The mean litter sizes at birth were 1.69 ± 0.03 and 1.78 ± 0.16 for goats maintained under extensive or intensive conditions, respectively (Table 4). These differences however were not significant. This mean litter size at birth agree with that reported by other workers for KNG does (1.87) (Kim and Chung, 1979) and other goat breeds (Odubote, 1996). The mean litter size at weaning was 1.31 ± 0.03 and 1.52 ± 0.17 for goats maintained under extensive or intensive conditions, respectively, with an overall weaning rate of 77.5 and 85.4% (Table 4). These differences in litter sizes were significant (P < 0.05) with the survival rate (85.4%) being higher in the intensive group. This mean litter size at weaning (which could passively been seen as an indication of mothering ability) reported compares favorably with that reported by other workers (Ebozoje and Ikeobi, 1998). For goats raised under extensive conditions, a primary concern of management at kidding is kid mortalities due to predators, cold stress, or abandonment by the dams (Shelton, 1978). These feeders however were not experienced in this study and the mortality rate could generally be described as acceptable. In conclusion, the management system can affect the reproductive performance of KNG does—especially
Table 4 Litter size at birth and weaning and weaning rate in Korean native goats under extensive and intensive environments Management system
Extensive Intensive
Number of goats observed
Litter size At birth
At weaning
635 1003
1.69 ± 0.03 1.78 ± 0.16
1.31 ± 0.03b 1.52 ± 0.17a
Means with different superscript letters (a and b) in the same columns differ (P < 0.05).
Weaning rate (%)
77.5 85.4
H.B. Song et al. / Small Ruminant Research 65 (2006) 284–287
traits such as the age at first kidding and the weaning rate which were higher under the stall or intensive conditions, compared to those under the range environment.
Acknowledgement This research was supported in part by the Daegu University Research Grant, 2004.
References Campbell, Q.P., 1994. Information regarding the improved Boer goat. Boer Goat News 11, 49–50. Delgadillo, J.A., Malpaux, B., 1996. Reproduction of goats in the tropics and subtropics. In: Proceedings of the 6th International Conference on Goat, Beijing, China, pp. 806–808. Ebozoje, M.O., Ikeobi, C.O.N., 1998. Colour variation and reproduction in West African dwarf (WAD) goats. Small Ruminant Res. 24, 125–130. Galina, M.A., Silva, E., Morales, R., Lopez, B., 1995. Reproductive performance of Mexican dairy goats under various management systems. Small Ruminant Res. 18, 249–253.
287
Greyling, T.T.C., 2000. Reproduction traits in the Boer goat doe. Small Ruminant Res. 36, 171–177. Kim, C.K., Chung, Y.C., 1979. A study on the estrus and kid crop in Korean native goats. Korean J. Anim. Sci. 21, 27–133. Ministry of Agriculture and Forestry, 2003. Livestock Bureau Data, Seoul, Korea, 691 pp. Na, J.S., 1987. Monthly manifestation of behavioural estrus and induction of estrus in Korean native goats. Korean J. Anim. Sci. 29, 288–294. Odubote, I.K., 1996. Genetic and non-genetic sources of variation in litter size, kidding interval and body weight at various ages of West African dwarf goats, Ph.D. Thesis Obafemi Awolowo University, Ile-Ife, Nigeria, 161 pp. Ribeiro, A.C., Queiroz, S.A., Lui, J.E., Ribeiro, S.D.A., Resende, K.J., 2000. Genetic and phenotypic parameters estimates of kidding interval and age at first kidding in Saanen goats in Brazil. In: Proceedings of the 7th International Conference on Goats, France, pp. 258–259. SAS, 1997. User’s Guide, Version 6, Statistical Analysis System Institute Inc., Cary, NC, USA, 943 pp. Shelton, M., 1978. Reproduction and breeding of goats. J. Dairy Sci. 61, 994–1010. Song, H.B., 1997. Korean Native Black Goat. Daegu University Press, Daegu, Korea, pp. 175–177. Wilson, R.T., Murayi, T.H., Rocha, A., 1989. Indigenous African small ruminant strain with potentially high reproductive performance. Small Ruminant Res. 2, 107–117.