Livestock Research for Rural Development 27 (7) 2015 Guide for preparation of papers LRRD Newsletter

Citation of this paper

Milk yield and reproductive performance of pure Jersey dairy cattle in the Central Highlands of Ethiopia

Direba Hunde1, Gábor Mészáros2, Tadelle Dessie3, Getnet Assefa1, Million Tadesse1 and Johan Sölkner2

1 Holetta Agricultural Research Center, P. O. Box 31, Holetta, Ethiopia.
direbahu@yahoo.com   ;   getazb@yahoo.com   ;   mill_tadsse@yahoo.com
2 University of Natural Resources and Life Sciences, Vienna, Austria. Department ofSustainable
Agricultural Systems, Gregor Mendel str. 33, A-1180 Vienna, Austria
gbaorr@gmail.com   ;   johann.soelkner@boku.ac.at
3 International Livestock Research Institute, P. O. Box 5689, Addis Ababa, Ethiopia
t.dessie@cgiar.org

Abstract

The reproductive and productive performances of dairy cows are essential for the profitability of dairy farmers. The aim of this study was to determine milk yield and reproductive performance of pure Jersey dairy cattle at Adea Berga Dairy Research Center in the central highlands of Ethiopia. General linear model was used to estimate the effect of fixed factors. Overall 3015 performance records were used. The least squares mean of reproductive performances were 30 months for age at first calving, 497 days for calving interval and 2 for number of services per conception. The least square mean of lactation milk yield was 2155 kg in 336 days lactation length. The influence of birth year and birth season were significant on age at first calving (P<0.001). Lactation milk yield, lactation length, calving interval and number of services per conception were significantly affected by year and parity (P<0.001). However, calving season did not have significant influence on calving interval and lactation milk (p>0.05). The results indicate that Jersey cows under the particular management of Adea Berga Farm produced reasonable amounts of milk. The value of age at first calving (30 months) recorded for a Jersey cow in this study was promising. The feeding and animal health intervention is essential to reduce the environmental stress. Since the farm is being used as genetic pool to recruit bulls for crossbreeding activities, better breeding schemes should be designed for further improvement of reproductive and productive performances of Jersey cattle.

Keywords: age at first calving, calving interval, number of services per conception


Introduction

In Ethiopia, the genetic improvement of dairy cattle is mainly based on cross breeding and adoption of improved exotic breeds. Even though there is a concern about adaptation of pure exotic dairy cattle to tropical environment (climate, feed and disease challenge), pure Friesian and Jersey dairy breeds have been raised by large scale private and state dairy farms in Ethiopia. Improved exotic breed would potentially serve selected niches in milk supply and have been also used as a genetic pool for the national artificial insemination center (NAIC) to recruit AI bulls for genetic improvement program in the country. Million and Tadelle (2003) reported 3183 kg milk yield in 362 days lactation length and 458 days calving interval for Holstein Friesian cows in Debrezeit area of Ethiopia.  Similarly, 39.2 months age at first calving and 445 days calving interval were reported for Holstein Friesian herds at Holetta, Stella and Dinkity areas located in urban and peri-urban dairy production system in Ethiopia (Tadesse et al 2010).

 

There is limited information on reproductive and productive performance of pure Jersey breed in Ethiopia. Research reports in the tropics revealed that Jersey cows are characterized by small body size, hardy and adaptable, low maintenance requirement, high feed conversion efficiency, high milk fat content, and good reproductive performance and has been selected for tropical research and development programs (Cunningham and Syrstad 1987; Njubi et al 1992). Thus they could be a good alternative in Ethiopian highland environment to use as an additional option for intensive and large scale dairy farms as well as genetic pool for genetic improvement activities. Having information on performance of pure Jersey cows in Ethiopia will help to suggest the future genetic improvement options for this herd. The aim of this study was therefore to determine the reproductive and productive performance of pure Jersey dairy cattle at Adea Berga Dairy Research Center in the central highlands of Ethiopia


Materials and methods

Description of the study area

 

This study was conducted at Adea Berga Dairy Research Center in West Shewa Zone of Oromia Regional State of Ethiopia. Adea Berga wet land is situated in the central highlands of Ethiopia at 90 16’ N latitude and 380 23’ E longitude, 70 km West of Addis Ababa and 35 km North West of Holetta on the main road to Muger. It lies at an altitude of 2500 meter above sea level. It is characterized by cool sub-tropical climate with the mean annual temperature and rainfall of 180C and 1225 mm, respectively (HARC, 2010). The vegetation is mainly composed of perennial grasses and sedges. Clovers, Pennisetum and Andropogon are the most common species dominating the pasture in the area.

                 

Description of the farm and data sources

 

Adea Berga Dairy Farm was established at Adea Berga wetland in 1986 for commercial milk production under government state farms by using 400 introduced pure Jersey pregnant heifers and two sires (foundation stock) from Denmark. The farm had been engaged in the production and rearing of pure Jersey breed from imported foundation stock for milk production by the dairy development enterprise and also serving as a bull dam station for the National Artificial Insemination Center (NAIC). Then it was transferred to Holetta Agricultural Research Center for genetic improvement research program since 2007.

 

The data for this study was obtained from long-term records of pure Jersey breed that has been kept for dairy production in the farm. Recorded data for the last 24 years (1986-2010) on production and reproduction were used for this study.

 

Herd management

 

Herds are managed separately based on sex, age, pregnancy and lactation. Calves were allowed to suckle their dam until 5 days to obtain sufficient colostrum and then separated from their dams and offered fresh milk twice a day for about 6 months. Cows and heifers were allowed to graze natural pasture for about 4 hours a day and supplemented with hay and concentrate feeds up on return to barn during dry and small rainy season. The concentrate was usually composed of 60% wheat bran (sometimes with wheat middling), 38% noug seed cake (Guizotia abyssinica) and 2% salt. The amount consumed is not exactly known, since it depends up on the amount of feed available on stock. However, all animals were restricted from grazing and managed indoor during main rainy season. There was regular over flood of river in the pasture land as a result of heavy rains during this period and the farm has a regular plan to harvest and stock up hay for dry and short rainy season supplementation. Calves less than 6 months, bulls and late pregnant cows and heifers were usually isolated and managed indoor.

 

Milking was done twice a day at equal interval and the milk produced by each cow was measured and recorded on prepared format immediately after milking. Routine vaccination was conducted against Blackleg, Anthrax, Pasteurellosis, Foot and mouth disease (FMD) and Lumpy Skin Disease. Animals were de-wormed against internal parasites and treated against other infectious diseases by tentative diagnosis.

 

Breeding program

 

Pure breeding program was carried out starting on imported foundation stock of 400 pregnant heifers and two sires. Controlled mating program was practiced using both natural mating and artificial insemination. Mating was continuous and practiced throughout the year. NAIC rarely introduce new exotic Jersey semen since this farm has been used as a bull dam station for semen production to dispatch Jersey semen for national crossbreeding activities. Thus, very few young bulls were recruited based on dam performance and physical conformation for NAIC semen collection and on station breeding activities through natural mating. The rest of the male calves were culled from the farm at an early age.

 

Data analysis

 

A retrospective type of study was conducted to evaluate productive and reproductive performances of the cows. Abortion and still birth records were removed from analysis of age at first calving and calf crop. General linear model were used for analysis of the fixed effects (SAS 2002). The fixed effects fitted were animal group (imported and farm bred; farm bred animals were the progeny of imported animal that were raised in the farm); year period (grouped in to 5-7 classes based on birth, service and calving years; each year period represent three years); season; grouped in to three classes, based on pattern of annual rain fall distribution as dry period (October to February), light rain (March to May) and main rain (June to September); and parity (grouped in to eight classes 1,2,3,4,5,6,7and 8+). Lactation records of eighth and above parities were pooled. Preliminary analysis showed that interaction effects of the fixed factors were not significant and thus not included in the model. The statistical model is described as follows:

 

Experimental models

 

1.      Reproduction traits

1.1.  Age at first calving

Yijk = µ + Yi + Sj + Gk +eijk

 

Where, Yijk is the age at first calving trait; µ is the overall mean; Yi is the fixed effect of ith year period of birth; Sj is the fixed effect of jth season of birth; Gk is the fixed effect of kth animal group; eijk = random residual term.

 

1.2.   Calving interval

Yijk = µ  + Yi + Sj + Pk + eijk

 

Where, Yijk is the calving interval trait; µ is the overall mean; Yi = the fixed effect of ith year period of calving; Sj is the fixed effect of jth season of calving; Pk is the fixed effect of kth cow parity; eijk is random residual term.

 

1.3. Number of services per conception

Yijkl = µ + Yi + Sj +Gk + Pl +eijkl

 

Where, Yijkl is the number of service per conception trait; µ is the overall mean; Yi is the fixed effect of ith year period of service; Sj is the fixed effect of jth season of service; Gk is the fixed effect of kth animal group; Pl  is the fixed effect of lth cow parity; eijkl is random residual term.

 

2.         Production traits (Lactation milk yield and lactation length)

Yijkl = µ + Yi +Cj + Sk + Pl + eijkl

 

Where, Yijkl is milk yield and lactation length trait; µ is the overall mean; Yi is the fixed effect of ith year period of birth; Cj is the fixed effect of jth year period of calving; Sk is the effect of kth season of calving; Pl is the effect of lth cow parity; eijkl is random residual term.


Results and discussion

Age at first calving (AFC)

 

Age at first calving is an economically important trait that determines the age when an animal begins its economic return from milk production and reproduction. The overall least squares mean and standard error for AFC of pure Jersey breed in this study was 29.9 ± 0.17 months. 

 

The result obtained in this study is comparable with 31 months reported for pure Jersey in humid areas of Kenya (Njubi et al 1992). However the value of present finding is inconsistent with the report of Makuza et al (2000) and Banga et al (2009) who found higher AFC (54 months) in Zimbabwe and lower AFC (25 months) in South Africa, respectively for Jersey cows. This could be due to environmental difference associated with management condition. On the other hand, Demeke et al (2004) reported higher AFC (38 months) for Boran and its crosses with Friesian and Jersey breed in tropical highlands of Ethiopia. This could also indicate better potential of Jersey cattle with regard to AFC.

 

The least squares means and standard errors of AFC for fixed effects of birth year period, birth season and animal group are summarized in Table 1. Analysis of variance revealed that AFC was significantly affected by birth year periods (p< 0.01), birth season (p< 0.01) and animal group (p< 0.05).  The result also indicated that trend of AFC is increasing in recent born animal. This may be due to management fluctuation among years and seasons as a result of feed shortage. It might be also related with sires used for mating that breeding value of recently used sire could increase AFC.

 

The result showed that cows born during dry and main rainy seasons, respectively attained AFC 3 and 2.4 months earlier than those born during light rainy season. This might be due to post weaning stress of main rainy season on calves born during light rainy season because of shortage of feed during rainy season as the pasture land is restricted from grazing. The significant effect of birth year and birth season obtained in this study is in agreement with various other reports (Amani et al 2007; Ahmad et al 2007; Gebeyehu 1999; Kefena et al 2004). Imported heifers were pregnant when introduced to the country. Imported animals attained AFC 9 months earlier than the farm bred cows. Similarly Lateef (2007) observed a significant difference between imported and farm bred animals in Pakistan. These could be attributed to the difference of environment (management condition and climate) where the animals were kept.

 

Table 1. Least squares means and standard error of age at first calving

Effect

N

Mean ± SE (months)

Overall

751

29.92 ±0.17

Birth year group

 

p< 0.0001

1985 - 1987

326

31.0 ± 2.33abcd

1988 - 1990

78

28.9 ± 2.38ce

1991 - 1993

39

30.5 ± 2.43bc

1994 - 1996

76

25.4 ± 2.38d

1997 - 1999

63

27.9 ± 2.32de

2000 - 2002

62

29.1 ± 2.39ce

2003 -2005

77

32.3 ± 2.38ab

2006 - 2008

28

33.6 ± 2.47a

Birth season

 

p< 0.0001

Dry

452

28.6 ± 1.74a

Short rain

100

31.7 ± 1.80b

Main rain

197

29.2 ± 1.77a

Animal group

 

p < 0.05

Imported

327

25.2 ± 4.05a

Farm bred

422

34.5 ± 0.63b

N= number of observation, Least squares means with same superscripts in the same fixed effect indicate non significance.

Calving interval (CI)

 

Calving interval is a fertility trait which refers to the period between consecutive calving and is a function of open period and gestation length. Longer calving interval could reduce number of lactation initiated in total life and the total number of heifers in the herd which would consequently reduce the chances of producing adequate replacement herd. 

 

The least squares means and standard errors of CI for fixed effects of parity, calving year period and calving season are summarized in Tables 2. The overall mean CI of pure Jersey cattle in this study was found to be 497± 3.69 days.

 

The value of CI recorded in this study is lower than the value (549 days) reported for 50% crossbred in Northern Ethiopia (Teferi 1994). However, it is higher than the findings of several authors from tropical countries (Mostert et al 2010; Rahman et al 2007; Njubi et al 1992; Sattar et al 2004; Demeke et al 2004). The variation may be attributed to the difference in the levels of management and genetic improvement programs among the countries or farms.

 

Analysis of variance revealed that CI was significantly affected by the fixed effects parity and calving year period (p<0.0001), but not significantly affected by calving season (p>0.05). The influence of fixed effect observed in this study is in line with the findings of several authors (Tadesse et al 2010; Amani et al 2007; Yosef 2006). The increasing trend of CI with parity observed in this study is in agreement with the report of Rege et al (1994) who concluded that CI was steadily increased to the 7th parity. Longest CI (670±12.4 days) was observed for cows calved between 1991 and 1993. These could be attributed to management problems like shortage of feed and health problems, because these years were the period of regime change and hence might be attributed to financial scarcity as the farm was funded by government.

Table 2. Least squares means and standard errors of calving interval by parity, calving year group and calving season

Effect

N

Mean ± SE (days)

Overall

2024

497±3.69

Parity

p<0.0001

1

678

470±7.54c

2

492

516±8.21a

3

334

518±9.45a

4

218

513±11.5ab

5

137

531±14.5a

6

90

473±17.8bc

7

37

489±27.5abc

8

38

529±27.4ab

Calving year group

p<0.0001

1988-1990

625

514±10.7b

1991-1993

251

670±12.4a

1994-1996

216

513±12.4b

1997-1999

243

443±11.3cd

2000-2002

287

428±10.7d

2003-2005

231

458±11.6c

2006-2008

171

508±13.3b

Calving season

p>0.05

Dry

1089

495±7.14

Short rain

438

508±9.41

Main rain

497

510±8.87

N= number of observation. Least squares means with same superscripts in the same fixed effect are not significantly different (p>0.05).

Number of services per conception (NSC)

 

Numbers of service per conception is a measure of reproductive efficiency of a cow and also reflects the efficiency of farm management. The overall mean and standard error of NSC of Jersey in this study was 2.02±0.02. The result of the present study is similar with the report of Yosef (2006) who found 2.01 NSC for Holstein breed in central highland of Ethiopia. But it is lower than the report of Lateef (2007) who found 3.30 for Friesian in Pakistan and higher than 1.80 for Friesian reported by Tadesse et al (2010) and 1.58 for Boran and its crosses with Friesian and Jersey (Demeke et al 2004) in Ethiopia.

 

 NSC was significantly affected by fixed effect of parity (p<0.0001), service year period (p<0.0001), service season (p<0.001) and animal group (p<0.05).The significant effect observed in the present study is in agreement with the finding of Asimwe and  Kifaro (2007) and Ahmad et al (2007). The report of some other studies like Gebeyehu et al (2007), Hammoud et al. (2010) and Tadesse et al (2010) are also in line with the present finding that year and parity had significant effect on NSC but contradictorily they revealed that season did not significantly influence the NSC in Friesian cows in Ethiopia and Egypt respectively.

 

Animal served during dry (2.06 ± 0.05) and light rainy (2.02 ± 0.05) season had fewer service for conception than those served during main rainy season (2.23 ± 0.05). These could reflect management problems like shortage of feed during the main reason because the pasture land was protected from grazing during this season. The least square mean of NSC showed that imported Jersey cows require more service per conceptions (2.20 ± 0.07) than farm born cows (2.00 ± 0.05) which could be associated with adaptation problem for imported generation. Similar result was reported by Lateef (2007) who revealed that imported cows required more service (3.18) than farm born cows (2.51).

 

Lactation milk yield (MY)

 

Increasing milk production is the ultimate goal of dairy sectors to attain milk self-sufficiency and to maximize the profitability of dairy industry. Thus, most genetic improvement programs of developing countries have focused on improving production performance of dairy cattle. Results of the least squares means and standard errors for fixed effects of birth year period, calving year period, calving season and parity are summarized in Table 3. The overall lactation milk yield and lactation length of pure Jersey cows were found to be 2155±16.4 kg and 336± 2.35 days respectively.

 

The result obtained in this study (2155 kg) is similar to the reports of Yosef (2006) and Lateef et al (2008). They found lactation milk yields of 2200 and 2229 kg for Jersey cattle in Ethiopia and Pakistan respectively. On the other hand, Njubi et al (1992) reported a milk yield ranging from 1257 kg to 1788 kg for Jersey cattle per lactation which was lower than the figure obtained in the current study. The result of this study is lower than the finding of Borland and Moyo (1996) who found 3504 to 5141 kg lactation milk yield in Zimbabwe.

 

Calving year period and parity had significant effect on MY (p<0.0001), but birth year period and calving season did not have significant effect (p> 0.05). Trend of lactation milk yield associated with period of calving had no clear pattern. This could be attributed to the inconsistent management practices across years and cows were not fed according to recommended amount. However, some progressively increasing trend observed in lactation milk yield over the period of calving is an indicative of improved management and adaptation of this breed to the prevailing environment through time. Low performance of cows which calved in between 1991 and 1993 could be related to financial problems of the farm to avail sufficient feed due to regime change. The pregnant heifers imported for foundation stock gave their first calf in between 1988 and 1990 and their milk yield was lower as compared to other calving period. This might be attributed to adaptation problem as the animals were exposed to new environment which could create more difficulty to express their genetic potential.

 

Lactation milk yield seems linearly increasing from 1st to 5th parity. But Milk yield recorded at 2nd parity was greater than that of 3rd parity which is contradictory with several literatures. The lactation milk showed a declining trend after the 5th parity. Similar observations were reported by several authors (Tadesse et al 2004; Yosef 2006; Lateef 2007; Njubi et al 1992; Tadesse et al 2010). Amimo et al (2007) and Amani et al (2007) also found that Ayrshire and Friesian cows attained their peak milk yields at the 4th parity. Season of calving did not have a significant effect on lactation milk yield in the present study.

Table 3. Least square means and standard error of milk yield and lactation length for fixed effects of birth year group, calving year group, calving season and parity

Effect

Variable

N

Milk Yield (kg)

Lactation length (days)

overall

2658

2155± 16.4

336±2.3

Birth year group

p > 0.05

p< 0.001

1985-1987

1193

2241±85.5

353±12.3a

1988-1990

266

2185±73.2

332±10.5b

1991-1993

168

1995±74.7

314±10.7b

1994-1996

362

2143±63.5

312±9.1 b

1997-1999

335

2100±86.3

328±12.4ab

2000-2002

189

1978±133.5

326±19.2ab

2003-2005

145

1872±169.5

356±24.3ab

calving year group

p< 0.0001

p< 0.0001

1988-1990

751

1759±166.2d

275±23.9c

1991-1993

374

1395±138.1e

337±19.8ab

1994-1996

301

2253±111.8ab

348± 16.1ad

1997-1999

327

1996±79.2cd

319± 11.4be

2000-2002

344

2212±59.1b

320± 8.5bcd

2003-2005

291

2526±64.4a

332± 9.2ab

2006-2008

223

2229±94.9bc

356± 13.6ae

2009-2010

47

2216±155.2bcd

367± 22.3ab

Calving season

p > 0.05

p > 0.05

Dry

1380

2101±46.9

330±6.7

Short rain

595

2067±54.4

334±7.8

Main rain

683

2052±50.6

332±7.3

Parity

p< 0.0001

p< 0.0001

1

803

2067±41.2b

355±5.9a

2

649

2363±41.1a

355±5.9a

3

442

2073±47.3b

323±6.8b

4

309

2262±57.7a

350±8.3a

5

190

2303±75.9a

350±10.9a

6

127

2006±94.3b

314±13.5bc

7

73

1986±125.2b

324±18ab

8

65

1528±141.1c

282±20.3c

N= Number of observation. Least squares means with same superscript in the same fixed effect indicate non significance.


Conclusions


Acknowledgment

The authors are grateful to European Master in Animal Breeding and Genetics (EMABG) for funding this research as a scholarship grant to the first author. The authors would like to thank also Ethiopian Institute of Agricultural Research for allowing us to use data.


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Received 24 February 2015; Accepted 29 May 2015; Published 2 July 2015

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