Number Of Services Per Conception Research Articles

Genetic parameters for milk yield and reproductive traits in Honduran Holstein cattle.

The aim of this study was to estimate the (co)variance components and genetic parameters for milk yield adjusted to 305d (MY305), calving-to-conception interval (CCI), number of services per conception (NSC) and calving interval (CI) of Honduran Holstein cows, by fitting a bivariate animal model using Maximum Restricted Likelihood procedures. Model included the fixed effects of calving number, the contemporary calving group (farm-season-year of calving and the cow age as covariate). The estimated means and standard deviations for MY, CCI, NSC and CI were, 5098.60 ± 1564.32kg, 168.27 ± 104.71 days, 2.46 ± 1.69 services, and 448.73 ± 109.16 days, respectively; and their estimated heritabilities were 0.21 ± 0.05, 0.03 ± 0.028, 0.02 ± 0.024 and 0.06 ± 0.04, respectively. The genetic correlations between MY305 and CCI, NSC and CI were positive and antagonist, with values of 0.64 ± 0.52, 0.99 ± 0.56, and 0.32 ± 0.24 respectively. Even though moderate to low heritability was estimated for MY305, systematic selection for milk yield, with a reduction in reproductive efficiency, if considered as the only selection criterion is important to be considered. By including reproductive traits and considering permanent environment effects into the breeding program, might yield a slow, but constant and permanent improvement over time.

Breeding practices and evaluation of hormonal estrus synchronization and mass artificial insemination of dairy cattle in southwest Ethiopia

Estrus synchronization is the process of controlling or guiding a cow/heifer estrous cycle so that they can mate at roughly the same time. It may be used to increase the probability of detecting estrus, increase the rate of calving in response to feed availability and market demand for dairy products, and increase the possibility of pregnancy in dairy cattle. The aim of this study was to assess breeding practices, evaluating of hormonal estrus synchronization and mass artificial insemination of dairy cow/heifers in Andracha and Masha districts of Southwestern Ethiopia. Three hundred eighty-nine (389) synchronized cows were selected from record of artificial insemination center (logbook). For experimental (action) study a total of 210 (103 from Andracha and 107 from Masha) dairy cows/heifers were selected and injected single dose of prostaglandin. Cow/heifers which do not respond by single injection were re-injected another single dose of prostaglandin. The data were analyzed using SPSS version 21 software. The study revealed that cows or heifers treated with single dose of prostaglandin 157(74.8 %), and 53(25.2 %) responded to heat and none response respectively in the study location. The study also revealed that overall conception rate (CR) and number of services per conception (NSPC) for single dose of prostaglandin injection in the researched areas were 68 (43.3 %), and 2.3 respectively. It was concluded that the effectiveness of PGF2α used to synchronize estrus in dairy cows/heifers was good and the overall conception rate 43.1 higher than national level conception rates (7.14–40.23) to first inseminations.

Productive and Reproductive Performance of Indigenous Milch Cows under Different Herd Structure of Gaushalas

Background: The present investigation was carried out to study the “productive and reproductive performance” of Indigenous Milch Cows reared under Gaushalas. This study describes productive and reproductive performance of milch cows through onsite observation and interviews with structured questionnaires of 30 (no.) Gaushalas randomly selected from 10 districts of Haryana. Methods: The total 30 Gaushala in 10 districts of Haryana were studied, which were rearing more than 34,279 indigenous cows (mostly Hariana and Sahiwal cow). These Gaushalas were divided into three categories based on the total number of animals present in Gaushalas as small (100-500 animals), medium (501-1000 animals) and large size Gaushalas ( greater than 1000 animals). To assess the productive performance of the milch cows, milk yield per day (MY/D), lactation length (LL) and lactation yield (LY) were utilized as indicator traits. In addition, age at first calving (AFC), service period (SP), number of services per conception (NSPC) and calving interval (CI) were considered as an indicator of the reproductive performance traits. Result: It was observed that the average milk yield per day and lactation yield in large size gaushala were significantly (P less than 0.05) higher than the medium size Gaushalas and small size Gaushalas. Large Gaushalas had a significantly higher lactation length (P less than 0.05) than small size Gaushala. The average service period, number of services per conception and calving interval in large size Gaushalas were significantly (P less than 0.05) lower as compared to small size Gaushalas. From the above finding, it could be concluded that the productive and reproductive performance were better in large size Gaushalas.

Genetic relationships between reproductive and production traits in Jersey crossbred cattle

The study aimed to estimate the genetic parameters of different reproductive traits namely age at first calving (AFC), calving interval (CI), days open (DO) and number of service per conception (NSPC) and their associations with productive traits including 305-day milk yield (305DMY), total lactation milk yield (TLMY) and lactation length (LL) of Jersey crossbred cattle maintained at Kalyani, Nadia, West Bengal, India. Genetic parameters of reproductive traits and their correlations with productive traits were estimated by Restricted Maximum Likelihood method and Bayesian approach. Using both analytical approaches, the estimates of heritability for AFC, CI, DO and NSPC ranged from 0.12 −0.15, 0.05–0.08, 0.08–0.09 and 0.04–0.06, respectively. Low proportion of variances associated with permanent environmental effect of animals (c2 effect) were detected for CI (0.08–0.10), DO (0.09–0.11) and NSPC (0.05–0.06) in both the methods. Repeatability measures for all the reproductive traits considered in this study were low to moderate in nature, which ranged from 0.09 to 0.17. Genetic correlations between different reproductive traits were positive and low (0.05) to high (0.98) in magnitude except AFC-NSPC. Low and negative genetic correlations of AFC with 305DMY and TLMY were favourable and indicated animals with high milk yield had early age of maturity. Positive genetic correlations between CI, DO and NSPC with all production traits implied the antagonism relationships among these traits, therefore in any breeding program for improvement of production traits via selection, the reproductive traits should be taken into account as well.

A REVIEW ON EFFICIENCY OF ARTIFICIAL INSEMINATION IN CATTLE BREEDING IN ETHIOPIA

Ethiopia has large cattle population in Africa. The output of decades of crossbreeding programme in Ethiopia through AI service was quite insignificant because the exotic breeds and their crossbreds of the country accounted for about 1.44%. The objective of this review is to present the efficiency of Artificial Insemination (AI) service in cattle breeding in Ethiopia. The optimum recommended mean number of services per conception (NSC) for profitable dairy cow is about 1.4. However, conventional cattle AI breeding indicated that the mean NSC of different studies ranged from 1.14 in local cows up to 2.47 in different genotypes of cows kept under different management systems and conception rate at first insemination (CR1) ranged from 7.14% to 75.5% in different genotypes of dairy cows kept under extensive and intensive management systems. Estrus synchronization followed AI breeding indicated that CR1 ranged from 24.69% to 70.6% in Zebu cows kept under semi-intensive management system. Calving rate (CR) is the most appropriate measure of fertility of dairy cows which is defined as the number of calves born per 100 services. The poor efficiency of the country cattle AI service is a huge biological economic loss in cattle production and managerial monetary losses. Strategic interventions on cattle AI service efficiency improvement options should be identified and practiced considering breed type, production system and agro-ecology.

ASSESSMENT OF EFFICIENCY OF ARTIFICIAL INSEMINATION SERVICE IN CATTLE PRODUCTION IN THE WESTERN ZONE OF TIGRAY REGION, ETHIOPIA

The study was conducted before the ignition (before October 2020) of the war in Tigray Region, Ethiopia. Artificial insemination (AI) is the first generation biotechnology and is one of the assisted reproductive techniques (ART) that greatly plays for a faster genetic improvement of farm animals. Though AI was implemented in cattle crossbreeding for many decades in Ethiopia, there is quite insignificant national output of crossbred cattle population (1.54 %). The aim of the survey was to assess the efficiency of AI service in cattle production in the Western Zone of Tigray Region, Ethiopia. Twenty (20) Kebeles and 353 small-scale farmers were purposively involved in the household face-to-face survey interview. The data were analyzed using Statistical Package for Social Sciences (SPSS), and summarized by mean, frequency and percentages. The survey indicated that the existing reproductive efficiency of cattle AI service in the Western Zone of Tigray Region, Ethiopia was extremely poor. The mean number of services per conception (NSC) was very high that could be due to mainly inappropriate heat detections. The recommended, acceptable and excellent grade of NSC fall in the range of 1 − 1.7. The overall conception rate at first insemination (CRFI) was also very poor (20.4 %) and thus calving rate (CR) was poor (20.5 %). About one-third (33.4 %) of the respondents indicated that cows and heifers exhibited heat in 0:01 − 6:00 am of the day. About 30.9 % and 28.6 % of the respondents reported that their cows and heifers were inseminated in 9 − 12 hours and 4 − 8 hours after the onset of heat, respectively. The majority (70.8 %) of the respondents did not practice controlled mating and breeding, and the first preference of 50.1 % of the respondents was natural mating. The most common source of bulls for about 34.3 % of the respondents was from neighbors and followed by own bred bulls (30.0 %). Cattle AI feasibility study and identification of AI strategic interventions should be the first focus to improve the existing poor AI efficiency of the study area.

Reproductive performance of Horro and Horro-crossbred dairy cows in Ethiopia's subhumid tropical environments.

Estrus detection, timing of insemination, feeding, and health care practices are all factors that can significantly affect cattle breeding efficiency and lifetime production. In Ethiopia's subhumid environment, the age at first calving, number of days open, duration from calving to first heat, and number of services per conception are economic traits that affect reproductive performance of Horro and Horro-crossbred dairy cows. Data collected at Ethiopia's Bako Agricultural Research Center between 1980-2019 was used to study the reproductive performance of Horro and Horro-crosses with Holstein Friesian and Jersey dairy cows. We identified overall mean ± standard error values of factors that affect reproductive performance, including age at first service (AFS) (29.2 ± 0.2 months), age at first calving (AFC) (39.8 ± 0.2 months), number of services per conception (NSC) (1.76 ± 0.4 months), calving interval (CI) (13.2 ± 0.3 months), days open (DO) (94.3 ± 4.3 days), conception rate (CR) (75.0 ± 1.3%), and replacement rate (RR) (28.4 ± 0.3%). The odds ratios of the 60-day and 90-day nonreturn rates (NRR) were 0.22 and 0.96, respectively. Sire and dam breed and birth period had significant (P < 0.001) effects on AFS and AFC, while season and dam parity had significant effects on CI and DO. Inconsistencies regarding feeding, heat detection, inseminator skills, insemination timing, animal health, and other husbandry practices may extend periods of AFS, AFC, CI, and DO. To optimize reproductive performance in Horro cows and Horro crossbreeds in Ethiopia's subhumid environments, improving management practices should be a priority.

Management practices of dairy animals in Tarai region of Uttarakhand

The existing dairy farm housing, milking, feeding and calf management practices in Tarai region of Uttarakhand along with performance traits were studied. Total 30 households with 596 livestock were considered for this work. Agriculture is the mainstay in the locale with animal husbandry as subsidiary occupation. Dairy animals mainly comprise 76% crossbreds and 21% Murrah buffaloes. Farms with 43% concrete, 30% bricks on edge and 10% kuchha flooring were recorded. Only 37% herds had 24 hour access to drinking water, 43% farmers fed commercial concentrate preparations, Stripping was practiced by 70% at the end of milking, 93% herdsman bred their cows within 12-18 hour of estrus with 3-5 months service period, and 60% dairymen consulted a veterinarian for services. Least squares mean (LSM) and standard error for Age at first calving (AFC), Calving Interval (CI), Dry Period (DP), Number of service per conception (NS/C), Milk yield per day (MY/D) and Lactation length (LL) were 427.31±5.80 days, 706.74±6.23 days, 378.76±1.48 days, 95.17±2.06 days, 1.32±0.03, 8.98±0.11 litre/day/animal, 315.14±1.65 days, respectively in cattle and 708.06±6.05 days, 948.62±10.09 days, 384.82±2.65 days, 139.08±6.07 days, 1.31±0.03, 9.54±0.15 litre/day/animal and 311.80±2.7 days, respectively in buffaloes. Effect of location on MY/D, LL and CI; of parity on CI and DP; and of AFC on DP was significant in cattle. In buffaloes, CI was significantly affected by location; MY/D, DP and LL by parity; and CI and NS/C by AFC. The results revealed a requisite to focus on stress management, calf care and sick animal management to improve animal performance.

Genetic parameters of fertility traits in Murrah buffaloes

The data pertaining to 662 Murrah buffaloes of 24years (1996-2019) collected from history cum pedigree sheets maintained at Buffalo Farm, department of LPM, LUVAS, Hisar studied to determine the influence of non-genetic factors viz.period, season and parity and to estimate the genetic parameter of fertility performance traits using mixed linear model. The traits studied were: age at first calving (AFC), service period (SP),conception rate (CR), calving interval (CI), number of services per conception (NSC) and pregnancy rate (PR). Period of calving had non-significant effect on all fertility traits viz. SP, CR, CI,NSC and PR, except AFC. Season of calving reported to have highly significant (P&lt;0.01) effect on SP, NSC and PR and significant (P&lt;0.05) effect of season of calving was obtained onCR and CI. Highly (P&lt;0.01) significant effect of parity was reported on SP and NSC and significant effect of parity at P&lt;0.05 was also seen on CR, CI and PR. The least squares means of AFC, SP, CR,CI, NSC and PR were 1345.75±13.88 days, 153.87±4.34 days,67.08±1.18 %, 459.53±4.50 days, 2.01±0.05 and 0.27±0.01 %,respectively. The heritability estimates among traits in overall lactation fertility traits viz. AFC, SP, CR, CI, NSC and PR were0.36±0.21, 0.11±0.03, 0.09±0.02, 0.23±0.10, 0.04±0.01 and 0.07±0.01,respectively. PR had negative genetic and phenotypic correlations with SP, CI and NSC whereas positive genetic and phenotypic correlation with CR. It was concluded that selective breeding and better management can lead to enhancement inperformance of buffaloes

Evaluation of Reproductive Performance and Disorders in Holstein-Friesian and its Crossbreds with Montbeliarde under Egyptian Conditions

The objective of this study was to assess the reproductive performance and disorders of pure Holstein-Friesian (HO) and Montbeliarde (MO) crossbred cows in a commercial dairy herd under Egyptian conditions. Analysis was done for age at first calving (AFC), number of services per conception (NSPC), days open (DOPN), gestation period (GP), and calving interval (CI). The results revealed that the AFC, NSPC, DOPN, and CI of crossbred cows (MO×HO) were significantly lower than those of pure HO cows. GP was numerically shorter in HO cows than in MO × HO crossbred cows. In both breeds, the NSPC was significantly lower in the winter than it was in the summer. During the summer season, pure HO cows had the longest DOPN. However, the shortest DOPN was recorded in MO × HO crossbred cows in the winter season. A significant difference between calving seasons was found with regard to the calving interval. MO × HO crossbred cows had a higher percentage of affected cows with retained placenta, endometritis, and repeat breeding than pure HO breeds. It was concluded that MO×HO crossbred cows had higher fertility than pure HO cows. Additionally, MO×HO crossbred cows were minimally affected during different seasons under Egyptian conditions. However, pure HO cows likely performed better than MO×HO crossbred cows in terms of reproductive disorders.

Review on Dairy Cattle Reproductive Performance Under Different Production System in Ethiopia

Reproductive performance of dairy cattle under different production system was reviewed in Ethiopia. The reproductive performance parameter of dairy cattle like age at first serves (AFS), age at first calving (AFC), calving interval (CI), Day opens (DO) and number of service per conception (NSPC) under different production system was quite different. Age at first calving was in Pastoral (43.5±1.5) months, Agro-pastoral (43.5±1.5) and Urban (33.2±0.79) months. Days open, for local breeds were in Pastoral (141±7 days), Agro-pastoral (141±7 days) and urban (185±51.2. The calving interval for local breed were in pastoral (14.63±10 months), agro-pastoral (14.36± 1.03 months) and pre-urban (22.17±0.79 months) whereas for cross dairy cows were, urban 14±0.56 months, pre-urban 15.820±.41months and intensive12.42±5.9 months. The number of service per conception were for Horro x Jersey (1.8), Horro (2.1) Borana (1.6), Fogera (1.28), Friesian x Zebu (1.56), respectively. This difference was due different production system. It could be concluded that proper management in terms of nutrition, health care, housing, heat detection, timely insemination would improve reproductive performance under different production system. Beside this, to boost dairy cattle reproductive performance, intensification of dairy cattle production should be promoted in Ethiopia to meet increasing demand for dairy products and to reduce imports of dairy commodities. Thus, all coordinated works of all concerned bodies should be in place to boost the production and productivity and thereby enhance the livelihood of the dairy farmers.

Success rate of artificial insemination, reproductive performance and economic impact of failure of first service insemination: a retrospective study

BackgroundA retrospective cohort study using a 10 year artificial insemination (AI) and cow reproductive performance data was conducted to study the success rate of AI; associations between effectiveness of AI and breed, AI season and, number of service per conception, and economic impact of failure of FSC in Dessie town, Dessie zuria and Kutaber districts. A total of 3480 dairy cows’ AI and reproductive performance records which were performed between 2003 and 2013 in the three selected districts of South Wollo were used. The economic losses and costs for cows that failed to conceive at their first AI associated with the larger number of days open were estimated.ResultThe prevalence of conception has a statistically significant difference between breeds of cows (P = 0.019). The non-return rate for first service was 58.54%. The median days to first service (DFS), inter-service interval (ISI) and gestation length (GL) were 126, 30 and 278 days respectively. Whereas, the mean + SD days open, calving interval (CI), number of inseminations (NOI) and number of services per conception (NSPC) were 147.2 ± 60.26, 424.5 ± 60.55, 1.14 ± 0.38 and 1.15 ± 0.39 respectively. Based on AI season there was a significant difference in conception between winter and spring (P = 0.021). There is a 45.04 days extension in the mean calving to conception interval in cows that did not conceive at their first AI but conceived by 2nd and 3rd AI than in cows that did conceive at their first AI. A total of 21,665.3 ETB extra costs was spent on reproductive treatment and other management for cows that failed to conceive at their first AI but conceived by second and third service. In cows that did not conceive totally the owner losses on average 473.7 ETB per cow per day extra costs until the cows will be culled.ConclusionTherefore to increase the conception rate and decrease the economic loss the owners of the dairy cows should supervise the cows regularly and should be trained on how to identify cows on estrous, the AI technicians should be trained to conduct the AI service accurately.

Zoo-technical performance of indigenous dairy cows under small holder farmers management system in Hawella-Tulla district, Ethiopia

Ethiopia's dairy production system is predominantly extensive, with poor cattle performance constrained by a variety of factors such as poor genetics, low reproductive performance, and poor quality of feed, among others. So far, little work aimed at increasing dairy production has been undertaken. The objective of the study was to characterize the zoo-technical performance of indigenous dairy cows under small holder farmer management system. The study was undertaken in Hawella-Tulla district, Sidama Region; Sothern Ethiopia from November 2020 to March 2021. From three peasant associations (PA), 180 smallholder dairy farmers who owned local cows were selected using a simple random selection technique. Data were collected using a structured questionnaire. The majority of farmers (75%) practiced in mixed crop-livestock farming primarily produce milk for income generation. Farmers hold an average of 1.95±0.063 local lactating cows. The productive performance of the indigenous cow mean of daily milk yield was 1.53±0.09 liters and 6.5±0.89 months of lactation length. The mean age at first service (AFS) was 38.5 ± 2.71 months, Age at first calving (AFC) was 45.3±2.82 months, calving interval (CI) was 20.08±0.9 months, and number of services per conception (NSPC) was 2.5 ±0.63. It can be concluded that the zoo-technical performance of local cows was very low. Therefore, planned technical and institutional intervention to improve the feeding system, provide better health management, genetic improvement of local breeds through crossbreeding and synchronization should be carried out for the betterment performance of local cows.

Efficiency of Artificial Insemination (AI) Technology in Different dairy Herd Management Systems in the Southern Highland Zone (SHZ) of Tanzania

The objective of the study was to establish the information on the performance of Artificial Insemination (A.I) in different production systems in the Southern Highlands Zone of Tanzania. Three districts namely, Njombe, Mbeya and Mbozi were purposively selected for data collection in smallholder farms and three large scale farms of ASAS, Sao Hill and Kitulo were selected for data collection. Data from 1486 and 163 dairy cow’s records from large and smallholder farms, respectively were used and analyzed using General Linear Model (GLM) procedure of Statistical Analysis System (SAS). The overall number of services per conception (NSC) were 2.49 and 1.39 in smallholder farms and large farms, respectively. In smallholder farms, NSC was influenced by district, breed, parity, AI technician, age at first service, calving to first service Interval (CFSI) (days) and who detect heat. In large farms NSC was influenced by farm location, source of semen and effect of year. First service to conception (FSC) were 43.56% and 72.48% in smallholder farms and large farms, respectively. It was revealed that the value of NSC and FSC under smallholder farms were lower compared to recommended values, indicating inefficiency of AI performance under smallholder farmer’s conditions in SHZ of Tanzania. Contrary NSC and FSC under larger farms were good indicating that AI is efficiency under large farms in SHZ of Tanzania. Hence there is a need to train smallholder dairy farmers on heat detection and good herd management so as to improve dairy reproductive efficiency in the country.

Economic values for production, fertility and mastitis traits for temperate dairy cattle breeds in tropical Sri Lanka.

Economic values for annual milk yield (MY, kg), annual fat yield (FY, kg), annual protein yield (PY, kg), age at first calving (AFC, days), number of services per conception (NSC), calving interval (CI, days) and mastitis episodes (MS) were derived for temperate dairy cattle breeds in tropical Sri Lanka using a bio‐economic model. Economic values were calculated on a per cow per year basis. Derived economic values in rupees (LKR) for MY, FY and PY were 107, −162 and −15, while for AFC, NSC, CI and MS, economic values were −59, −270, −84 and −8,303. Economic values for FY and PY further decreased with higher feed prices, and a less negative economic value for FY was obtained with increased price for fat. Negative economic values for FY and PY show that genetic improvement for these traits is not economical due to the high feed costs and/or the insufficient payment for fat and protein. Therefore, revision of milk fat and protein payments is recommended. Furthermore, the breeding objective developed in this study was dominated by milk production and fertility traits. Adaptability and functional traits that are important in a temperate dairy cattle breeding programme in tropical Sri Lanka, such as longevity, feed efficiency, disease resistance and heat tolerance should be recorded to incorporate them in the breeding objective. Continued trait recording of all traits is recommended to ensure dairy cows can be selected more effectively in a tropical environment based on a breeding objective that also includes adaptability and functional traits.

Milk yield and reproductive performances of crossbred dairy cows with different genotypes in Ethiopia: a review paper

Crossbreeding for improving milk yield and reproductive performances had started and implemented been long in Ethiopia in different locations. The present study focused on reviewing and generating compiled information about the status (potential) of milk yield and reproductive performances of crossbred dairy cows, which have been done at different stations and farm conditions in different eras. Review results of milk production and reproductive performances in Ethiopia varied greatly from one genotype to another. The on-station lactation milk yield and lactation length were ranged from 1293 to 2957 kg and 303 to 374 days, respectively, whereas the on-farm review results were within the values of on-station conditions. The on-station reproductive performances had also obtained in the range from 25.5 to 30.3 for age at first service (AFS), 28.5 to 46.9 for age at first calving (AFC), 351 to 546 for calving interval (CI), 76 to 243 for days open (DO) and 1.3 to 2.7 for the number of service per conception (NSC), respectively. The on-farm review results for reproductive performances had also within the range of on-station conditions. Among the genotypes, the 50% F1 and 75% Holstein Friesian first generations were considered suitable for milk production parameters, whereas Jersey crosses, especially 50% F1 are recommended for better reproductive performances. The on-station development of 50% F2, F3, and 75% second generations showed low milk production and reproductive performances and the likelihood of producing synthetic breed in this step did not give us a promising result. Regardless of blood level and genotype difference, the performance of on-farm crossbred cows was almost similar to on-station experimental cows. Crossbred cows were affected by non-genetic factors like year, season, and parity, depending on the breed and study location. In general, crossbred cows have good milk yield and reproductive performances compared to indigenous (local) breeds. However, crossbred animals could not exploit their maximum potentials because animals are subjected to different environmental effects.

Genetic evaluation for productive and reproductive traits in Holstein Friesian cows under subtropical condition

Lactation records (1,017) of Holstein cows, kept in private dairy farm in Egypt, from 2008 to 2015 were used for the study. The objectives were to estimate the effect of some factors on performance and estimate some genetic parameters. Traits studied were 305 day milk yield (305-dMY), lactation period (LP), peak milk yield (PY), number of services per conception (NSC), days open (DO) and calving interval (CI). Data were analyzed using Multi Traits Animal Model. Least squares means were 4436 kg, 215 d and 37 kg for 305-dMY, LP and PY, respectively, and 3.45, 182 d, and 452 d for NSC, DO and CI, respectively. Season and year of calving and parity had significant effects on all traits, except that of year of calving on PY and parity on NSC. Sire had significant effect only on 305- dMY and PY. Estimates of heritability for 305-dMY, LP, PY, NSC, DO and CI were 0.20, 0.07, 0.19, 0.07, 0.03 and 0.07, respectively. Phenotypic correlations among productive or reproductive traits were positive and between productive and reproductive traits were likewise positive. Genetic correlations among productive or reproductive traits ranged from 0.75 to 0.80 and 0.22 to 0.45, respectively.

Restricted Selection Index to Relieve the Negative Repercussion in Reproductive Performance of Holstein Cows

The aim of this investigation was to develop restricted selection index aiming to improve 305-day yields of milk (MY), fat (FY) and protein (PY), while keeping the deterioration in days open (DO), calving interval (CI) and number of services per conception (NSPC) at minimum levels in Holstein cows. The data represent 3682 records of 1122 cows, daughters of 95 sires and 712 dams. The data were analyzed by multi-trait animal model with repeated measures. Eight selection indexes (five unrestricted and three restricted) were derived using MY, FY, PY, CI, DO and NSPC in various combinations as sources of information in the indexes. However, the true breeding value included MY, FY and PY. The highest accuracy of selection (0.60) resulted from selection based on the full index. Milk yield and SPC appeared to be the most valuable traits in the full index. Combining the two traits into one index (the best reduced index) gave 0.57 accuracy of selection. The index based on MY alone (the most accurate single trait index) gave 0.53 accuracy. It seems possible to reduce the expected genetic deterioration in the reproductive traits by restricting the full index to result in zero genetic change in NSPC (rTI=0.48). This restriction will allow the breeder to mitigate the deterioration in DO and CI by 12 and 16 days respectively, by sacrificing with part of the expected genetic improvement in productive traits (29, 40 and 48% in MY, FY and PY, respectively).

Evaluation of reproduction performance and calf sex ratio of dairy cattle in selected locations of South-East Oromia

Dairy farmers in many parts of the world complain about the deviation from the normal calf sex ratio following Artificial Insemination (AI). The prospective and retrospective studies were conducted to compare the sex ratio of the calves born following Artificial Insemination (AI) and Natural Mating (NM) under institutional and smallholder-managed dairy farms. This study also compared the reproductive performance of dairy cattle under institutional management and smallholder systems. The data encompassed farm records maintained between 1996-2014 G.C by dairy farms at Arsi University-Asela, crossbreeding center at Gobe ranch, and Agarfa ATVET College. These farms reared both F1 and crossbreds with higher (>75%) exotic inheritances (grade crosses). The study also considered household and progeny history surveys on smallholder dairy farms (n=90) adjoining to the institutional farms which were randomly selected from Tiyo, Kofele, and Sinana districts. The result indicates that most of the respondents at Tiyo (96.8%) and Kofale (100%) were concerned about the differences in the sex ratio of calves born from AI service and natural mating, while most of the respondents at Sinana (29%) did not report such differences. The respondents in Tiyo and Kofale districts reported higher numbers of male calves (58%) and higher numbers of female calves (58.1%) born from cows inseminated artificially respectively. The Average Age at First Calving (AFC) had no significant difference between genotypes (F1 and grade crosses) reared at the institutional farms. There were significant differences (p<0.05) in AFC across the ranches. The AFC was lower in the institutional farms when compared to those managed at smallholder management conditions. The number of services per conception (NSC) varied p<0.05) across the dairy farms. No significant differences were observed among the sex ratio of the calves born through natural and AI mating systems either at the institutional or smallholder farms. However, differences due to season and year were observed, indicating the effect of non-genetic factors influencing the sex ratio of the calves. In some seasons the numbers of male calves were higher while the reverse was true for some other seasons. Therefore, the reproduction traits of the cattle differed (P<0.05) across the institution and smallholder production systems having lower values observed among the cattle raised at the dairy farms and higher for the F1 crossbred than grade crosses, while production trait of the cattle differed (P<0.05) across the three dairy farms and there were no significant differences in calf sex ratio among the calves born from AI and NM.

Retrospective and current status of reproduction and Health Problems at Algae Dairy Farm, Central Ethiopia

Study was conducted between November 2015 and March 2016 at Alagae dairy farm. The objective of study was to evaluate ten years record and the current status of dairy farm. A total of 370 cow’s record and 105 monitored dairy cows’ were used for the study. The overall mean months of 27.68±6.48 age at first service, 37.8±6.88 age at first calving, 16.36±5.2 calving interval, 6.93±4.79 days open (DO) and 10.32±2.84 lactation length (LL) observed. Increasingly, 1.38±0.54 number of services per conception (NSC) and average daily milk yield of 8.22±2.2 liters/day/cow were observed in the dairy farm. Average daily milk yield had a significant difference (p&lt;0.05) between Holstein and their crosses. Reproductive performance did not show difference between retrospective and longitudinal studies using Mann Whitney U – test. Similar health problems like abortion, dystocia, metritis, repeat breeder, retained fetal membrane, mastitis and pre-weaning calf mortality observed in both retrospective and longitudinal studies cows. Physical damage and infectious diseases were also common in the farm. In conclusion, this study revealed that the reproductive performance of the dairy farm was below the acceptable standard. Therefore, appropriate measures should be implemented at Alagae dairy farm in order to leverage the existing poor reproductive performance of the farm.