Reproductive performances of crossbred dairy cattle at Holetta Agricultural Research Center

Kefale Getahun, Direba Hunde, Million Tadesse and Yosef Tadesse¹

Ethiopian Institute of Agricultural Research, Holetta Agricultural Research Center. PO Box 2003 Addis Ababa or 31 Holetta, Ethiopia
kefalegetahun@gmail.com
¹ Haramaya University, School of Animal and Range Science, PO Box 138 Dire Dawa, Ethiopia

Abstract

Reproductive traits are critical for production, herd replacement and overall profitability of dairy farming. This study was intended to evaluate the reproductive performances of crossbred dairy cattle at Holetta agricultural research center dairy farm. A total of 7538 (779 AFS, 788 AFC, 1735 CI, 1704 DO and 2532 NSC) crossbred dairy cattle performance records collected during 40 years were used for the study. The fixed effects used in the data analysis were birth and calving period, birth and calving season, parity and genetic group. The General linear models were used for statistical analysis of data. The overall least square means for age at first service (AFS), age at first calving (AFC), calving interval (CI), days open (DO) and number of service per conception (NSC) were 26.8 months, 37.4 months, 476 days, 197 days and 1.8, respectively. Result of fixed effect analysis revealed that period and genetic group caused variation (p<0.001) on reproductive traits. Similarly, CI and DO were influenced by parity and season. Among the genetic groups, 50% F1 (Borena x Holstein Friesian) genetic group showed better reproductive performance (reached early for first service, calved early, shorter CI and DO). Therefore, from the result of this study, it can be noted that improving feeding, health and other husbandry practices are essential for further genetic enhancement of this herd.

Keywords: Borena, Ethiopia, Holstein Friesian

Introduction

The reproductive performance of the breeding female is the most important factor that is considered as a prerequisite for sustainable dairy production and productivity (Kiwuwa et al 1983). Optimizing reproductive performance needs measurement of current performance, assessment of factors affecting the performance and design suitable interventions (Hare et al 2006). Reproductive performance traits like NSC, CI and DO are important criteria for profitable dairy farming (Mukasa-Mugerewa 1989). Crossbreeding has been principally applied in Ethiopia to increase total milk production and productivity per individual animal. However, in recognition of the need to maintain reproductive performance as breeding goal has got less attention in the process of selection. Some studies have been done on dairy herd reproductive performance at Holetta dairy cattle research center by using parts of the center data. However, due to environmental variability, ongoing selection and use of different sires to create genetic variation in the farm, periodic evaluation for the reproductive performances of dairy cows at the research center is vital for the future breeding program. Therefore, the objective of this study was to evaluate the reproductive performances of Borena and Holstein Friesian crossbred dairy cattle maintained at Holetta research center in the last 40 years.

Materials and methods

Description of the study area

The current research was conducted at Holetta Agricultural Research Center (HARC). Holetta is located in the central highland of Ethiopia at 35 km west of Addis Ababa (3°24´N to 14°53´N latitude and 33°00´E to 48°00´E longitude) with an altitude of 2400 meter above sea level. The average annual rainfall is 1100 mm and average temperature is 15°C with minimum 6°C and maximum 24°C, respectively (Yohannes et al 2016). The average monthly relative humidity is 60% (Gebregziabhere et al 2013).

Figure 1. Average weather trend over the years. Source; HARC metrology station (1969-2017)

Data source and collection

Data for the study were obtained from the long-term (1974 - 2017) crossbreeding research on herd of Ethiopian Borena x Holstein Friesian dairy crossbred cattle maintained at the Holetta research station. Different crossbreds ranging from 50% to 75% HF (Holstein Friesian) inheritance were used for the study.

Animal management

The cattle were managed based on breed, pregnancy, lactation stage, sex and age. Uniform feeding and management practices were adopted for all animals within each category. Natural grazing, hay and concentrate supplement constitute the major feed supply. During the day time animals were allowed to graze from early morning 8.00 AM to 4.00 PM in the afternoon. Natural pasture hay was provided as additional feed during the evening. Concentrate mixture composed of wheat middling (32%), wheat bran (32%), noug (Guizocia abyssinica) cake (34%) and salt (2%) was supplemented based on their body weight, productivity and physiological category. Milking cows, heifers and calves were supplemented with concentrate mixture at a rate of 4, 1-1.5 and 0.25-1kg per day, respectively depending on availability of supplemental feed. The cows had free access to clean water all the time.

Calves were allowed to suckle their dam immediately after birth for about four days to provide sufficient colostrum. Weighing and ear tagging were also engaged within 24 hours after birth. After 4 days calves were taken into calf rearing pen and continued to be fed 260 liters of whole milk for 98 days through bucket feeding. Weaned calves were transferred to other pens and kept indoor until 6 month of age.

Milking was by hand early morning and evening, until 2001 when milking machines were installed. Animal management was supported with vaccination and treatment against major disease.

Breeding program

Pure Borena dams were mated with Friesian semen to produce F1 which were back crossed with Friesian semen to produce the 75% generation. The later generations F2 (50% F1 dam x 50% F1 sire), F3 (F2 dam x F2 sire) and 75% second generations were produced by inter se mating using 50% and 75% Friesian genotypes. The Borena cattle used for crossbreeding were from Borena pastoralists in southern Ethiopia (their center of origin) and reared on station then inseminated randomly to produce required generations.

Seasonal breeding was undertaken until 2000. Since then the mating practice was changed and undertaken throughout the year using locally recruited crossbred bulls or Friesian semen from NAIC and WWS. Sometimes natural mating was practiced when animals became repeat breeders with AI. Teaser bulls were reared with cows for heat detection. Cows detected in heat were mated by AI. Cows not seen in heat within 45-60 days of service were diagnosed as pregnant.

Data management

Screening of data was made to avoid errors during data entrance. Age at first service (AFS) below 10 and above 80 months and age at first calving (AFC) below 20 and above 90 months were removed from the data set. Cows had on average 285 days gestation length and 45 days voluntary waiting period (VWP) after calving (330 days CI). Cows that recorded less than 330 days CI were removed from the analysis considering gestation period and uterine involution period. A cow needs some rest period after calving for the uterus to involute and normal cycle to take place. VWP ranging from 45 to 60 days were allowed before the cow was inseminated or bred (Gebregziabher et al 2005). As a result, animals which had shown estrus and were bred earlier than 45 days, were removed from the analysis. Repeat breeder cows (more than10 times) were very few compared to the rest of the population and were removed. In addition, cows that had abnormal calving (i.e., abortion and stillbirths) were not included in the model analysis.

Method of data analysis

The GLM procedures of SAS (2004) version 9.0 were employed to determine and compare the fixed effects of different genetic groups, period, season and parity. Genetic groups included in the analysis were broadly classified into two groups 50% F1, F2, F3 and 75% first and second generations.

Different genetic groups were developed in different years depending on the objective of the research station and breeding design during the past 40 years. The years of birth and calving ranging from 1974 to 2017 were grouped into 7 periods considering the similarity within year groups. Thus, each period contained 5 years except for the first birth period (1974-1987), which comprised 13 years and first calving and service period (1977-1987) comprised 10 years due to small number of observations.

For analysis of effect of birth and calving season, months of the years were classified into three seasons based on rainfall distribution. Dry season from October to February, short rain season from March to May and main rain season from June to September. The presence of any significant differences between fixed effects were checked using least squares means procedure. AFS, AFC, CI, DO and NSC were analyzed by the following models;

Model 1: For CI, DO and NSC traits;
Y_ijklm = μ + Y_i + S_j + G_k + P_l + e_ijklm

Where;
Y_ijklm =mth record of ith group of period of calving, jth season of calving, kth genetic group and lth parity
μ = overall mean
Y_i = effect of ith period of calving
S_j = effect of jth Season of calving
G_k = effect of kth Genetic group (50% F1, F2, F3 and 75% first generation, 75% second generation)
P_l = effect of lth parity of cow (1, 2, 3, 4, 5, 6, 7, 8)
e_ijklm = random error associated with each observation

Model 2: Data for AFS and AFC were analyzed as model 1 but without the fixed effect of parity. The effects, period of birth and season of birth were fitted in this model instead of period of calving and season of calving on model 1.

Results

Age at first service and age at first calving

Least squares means and standard errors for by breed group and non-genetic factors on AFS and AFC are summarized in Table 1. The over-all mean and standard error for AFS was 26.8 ± 0.34 months or 804 ± 10.4 days with maximum and minimum values of 40.4 and 24.5 months, respectively. For AFC the mean value was 37.4 ± 0.35 months ranging from 35.5 to 50.9 months. Both AFS and AFC were affected by genetic group and birth period.

Calving interval and days open

The overall mean value for CI trait was 476 ± 3.91 days and for DO 197 ± 3.88 days (Table 2). Genetic group, calving period, season of calving and parity affected CI and DO traits.

Number of services per conception

The least squares means and standard errors by breed group and non-genetic factors (service period, service season and parity) are summarized in Table 3. The overall mean and standard error of NSC of Borena x HF crossbred in the present study was 1.8 ± 0.03. NSC was affected by genetic group and service period.

Discussion

Age at first service

The mean AFS obtained in the present study (26.8 months) is lower than the value reported by Gebeyehu et al (2005), Haile et al (2009), Berhanu and Chakravarty (2014) and Wassie et al (2015) who found 36.8 for Fogera x HF crosses, 29 months for Borena x HF crosses, 29.3 months for Borena x HF x Jersey crosses and 32.1 months for HF x Borena and Arsi crosses, respectively. However, it was higher than the finding of Suhban et al (2000) and Ashit et al (2013) who reported 752 days and 21.6 months, respectively. The difference of value of the present study from other reports might be due to type of breeds involved for crossing, level of gene inheritance, environment and management effects.

The analysis of variance showed that AFS was affected (P<0.001) by genetic group and birth period. This result agreed with the finding of Yosef (2006), Haile et al (2009) and Belay (2014). The 50% F1 genetic group had shortest (27 ± 0.45 months) AFS where as 50% F2 had longest (34.8 ± 0. 82 months) AFS. AFS was significantly increased by 4.1 months when crossbred inheritance upgraded from 50% F1 to 75% first generation. The heterosis effect in F1 generation might be declined in backcrossed generations depending on additive merit of the pure breeds involved (Cunningham and Syrstad 1987; Arthur et al 1999). The extended AFS displayed in the F2, F3 and backcrossed genetic groups could bring an economic loss due to extended unproductive period of heifers.

Animals born during 2008-2012 and 2013-2015 exhibited lower AFS. No increasing or decreasing trend was observed across the year. AFS was reduced by 9.1 months during 2003-2007 to 2013-2015. This might be due to application of selection and improvement on animal management (feed, health and other husbandry practices) in recent than earlier years.

Age at first calving

The overall mean AFC (37 months) result of the present study was similar with 37.9 months estimated for Borena x HF and Jersey crosses (Berhanu and Chakravarty 2014). However, it is lower than (41.2 months) estimated for HF x Sanga in Ghana by Obese et al (2013), 52.3 months for Fogera x HF at Metekel ranch, Ethiopia by Belay (2014) and 41.2 months for Arsi and Borena crossed with HF by (Wassie et al 2015). This value is also higher than some other studies in the tropical countries. Suhban et al (2000) found 31.2 months for Pakistani crossbred and Djoko et al (2003) reported 877 days for HF x Red Fulani in Cameron. The variations among studies might be due to differences in breed and animal management (feeding management, heat detection and timely insemination, health control and climate).

Genetic group and birth period had affected (P<0.001) AFC. The list square analysis showed that among genetic groups, 50% F1 had shortest AFC and 50% F2 had longest value. AFC was significantly increased by 5.4 months from 50% F1 to 75% first generation and by 7.6 months from 50% F1 to 50% F2 crosses. However, there are no significant difference between 50% F2 and F3 and between 75% first and second generations. Result comparison among genetic groups for AFC in this study was higher than the report of Demeke et al (2004) who found 36.0, 39.6 and 36.7 months for 50% F1, F2 and 75% first generation crosses, respectively. Million et al (2006) also reported lower AFC (35.9 and 41.9 months) for 50% F1, F2 and, higher (40.8 and 45.3 months) for 75% first and second generations, respectively. The difference of this comparison of genetic groups from others literature might be due to difference in environment, number of observation considered for the study and level of management.

Lower (p<0.001) AFC was observed during 2008-2012 and 2013-2015 whereas higher value was recorded during 1978-1987. It was expected that variation on management and climatic condition across the year and application of selection started from 2005 in the farm might be the cause of positive change on value of AFC. The significant year variation on AFC were also reported by some other authors (Ababu et al 2006; Yosef 2006; Haile et al 2009; Million et al 2010; Belay 2014).

Season of birth had no significant (p>0.05) effect on AFC. The report of Demeke et al (2004) and Million et al (2006) were in agreement with the result of the present study. However, Yosef (2006), Haile et al (2009), Million et al (2010) and Hunde et al (2015) found significant effect of season on AFC. These might indicate that management; breed (genotype), geographical location and environment are showed clear difference across the studied population.

Calving interval

Bourchier (1981) indicated that calving interval of 365 days is considered as ideal for dairy cattle. The result of CI (476 days) in this study is somewhat comparable with 473 days reported for Borena x HF and Jersey reported by Kefena et al (2011) and 476 days for Arsi and Borena crossed with HF reported by (Wassie et al 2015). This result is lower than the report of Suhban et al (2000) 612 for Pakistani crossbred and Ababu et al (2006) 534 days for Borena and Friesian crosses at Abernosa ranch, Ethiopia. However, the figure of this study is higher than the finding of Belay (2014) for Fogera x HF crosses (468 days) and Niraj et al (2014) for HF x local around Mekelle, Ethiopia (454 days). The difference of the present finding from others might be due to animal management, climate and geographical differences.

The result showed that 75% first generation had longest (520 days) and 75% second generation had shortest (388 days) CI as compared to other genotypes. Mean CI increased by 42 days from 50% F1 to 50% F2 and 58 days from 50% F1 to 75% first generation. The difference in CI might be related to higher heterosis effect on 50% F1 genotype and associated with shorter lactation length. Cows showed longer CI when lactation length was longer and shorter CI was associated with shorter lactation length.

Calving interval was affected (p>0.001) by period of calving and this is in agreement with the finding of several research reports (Million and Tadelle 2003; Ababu et al 2006; Million et al 2006; Gebeyehu et al 2007; Haile et al 2009). However, the result was contradicted with the finding of Yosef (2006) and Hunde et al (2015). This difference might be due to type of breeds involved for crossbreeding, animal management and geographical location. Animals calved during 1993-1997 period was affected by specific environment and observed longer calving interval. However, it has been declined then after.

Cows that calved during short rainy season had longer CI (491 days) as compared to those calved during dry season and main rainy season. The farm feeding system that allowed animals to graze on pastureland during dry season might have a positive effect to cyclicity in the breeding cows. However, during the main rainy season, animals might not get optimum feed, as the pastureland was restricted from grazing during this season. The significant (p<0.05) effect of season on CI was disagreed with the finding of some reports (Million and Tadelle 2003; Haile et al 2009; Belay 2014).

The highest and lowest CI was observed in parity two and parity eight, respectively. The significance effect of parity on CI in this result is in agreement with Yohannes et al (2016) but inconsistent with the finding of (Haile et al 2009; Belay 2014). Parity trend of CI was a gradual decreased to the 5^th parity with the difference of 85 days between 2^nd and 5^th parity. The decrease in CI as parity increase might be due to the ability of the animal to recover the uterine environment within shorter period as body weight and age increases, adaptation to parturition and lactation stress and selection.

Days open

The result of DO (197 days) in the present study is lower than 305 days for Fogera x HF at Andassa livestock research center by Gebeyehu et al (2005), 306 days for Borena x HF crosses at Abernosa ranch by Ababu et al (2006) and 200 days for Borena x HF in central highland of Ethiopia by (Kefena et al 2006). However, it is higher than the estimate of Gifawosen et al (2003) 181 days for Borena x HF at Holetta research center, Niraj et al (2014) 157 days for crossbred cows in and around Mekelle, Ethiopia and Wassie et al (2015) 195 days for Arsi and Borena crossed with HF.

Days open was affected (p>0.001) by genetic group, calving period, calving season and parity. The highest and lowest DO were observed on 75% first and second generations. The 75% second-generation crosses had return to conception 71 days and 135 days earlier than 50% F1 and 75% first generation crosses, respectively. The high milk production potential of 75% first generation and 50% F1 crossbred cows might cause to required longer time to return to their reproduction.

There was no clear year trend for DO. It has been fluctuating along the years considered. The shortest DO (156 days) was observed during 1998-2002 followed by 2013-2017 (163 days) and 2008-2012 (170 days) while longest DO was observed during 1993-1997 (249 days) followed by 1978-1987 (211 days).

Days open was also influenced by season. Cows calved during short rainy season has shown longer days open compared to cows calved during dry and main rainy season. This might be due to variation of feeding regime across the seasons particularly scarcity of feed resource in the grazing area and variation of concentrate supplementation. The significance (p<0.05) of season on DO in this study was deviated from earlier studies (Gifawosen et al 2003; Demeke et al 2004; Haile et al 2009).

DO was higher at 2^nd parity than the rest parities. Cows at 2^nd parity required 62 more days than the average DO and 102 more days than 8^th parity. The highest DO observed at 2^nd parity in the present study could be due to lactation stress during the early parity. The significant effect of parity on DO is in agreement with the finding of several studies (Demeke et al 2004; Gebeyehu et al 2005; Haile et al 2009).

Number of services per conception

The result of NSC (1.8) in the present study is close the report of Gifawosen et al (2003) who found 1.7 for Borena x HF. This result is slightly higher than the report of Gebeyehu et al (2005) 1.6 for Fogera x HF crosses and Ababu et al (2006) 1.5 for Borena x HF crosses but lower than the result of Haile et al (2009) 2.3 for Borena x HF crosses. In fact, excellent herd management and performance of cows can be associated with lower services per conception.

Genetic group and calving period had a significant effect on NSC but parity and calving season had no influenced on NSC. This is inconsistent with the finding of Demeke et al (2004) who reported significant (p<0.05) effect of parity on NSC and Gifawosen et al (2003) who reported that genetic group had no significant (p>0.05) effect on NSC. The higher NSC recorded on high producing 75% first generation crosses might be related with high lactation performance, which lately respond for reproduction.

Cows calved during 1977-1987 required lower (1.5) NSC and those during 1998-2002 and 2013-2017 required higher (1.9) NSC. The significant difference in period of calving on NSC might be due to inconsistent management such as feeding, heat detection, skill of inseminator, time of insemination, semen quality and other husbandry practices.

Conclusion

• This study indicated that the reproductive performance of crossbred dairy cattle at Holetta Agricultural Research center was comparable with other literature in the tropical countries and showed that F1 genotype cows were performed better (calved early, had shorter calving interval and days open) than other genotypes.
  
  
• Most of the reproductive traits were significantly influenced by birth period, calving period, birth season, calving season and parities.

Acknowledgment

The authors would like to thank Ethiopian Institute of Agricultural Research, Holetta Agricultural Research Center for allowing us to exploit long term crossbreeding data.

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Received 7 May 2019; Accepted 16 August 2019; Published 1 September 2019

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