Insemination Service Research Articles

Association of milk production level and milk urea content with date and efficiency of the first insemination service in cows

Association of milk production level and milk urea content with date and efficiency of the first insemination service in cows

Should home-based ovulation predictor kits be offered as an additional approach for fertility management for women and couples desiring pregnancy? A systematic review and meta-analysis

IntroductionTo inform the WHO Guideline on self-care interventions, we conducted a systematic review of the impact of ovulation predictor kits (OPKs) on time-to-pregnancy, pregnancy, live birth, stress/anxiety, social harms/adverse events...

Exogenous β-mannanase supplementation improved immunological and metabolic responses in lactating dairy cows

Exogenous enzymes have been used to improve nutrient utilization in several species of livestock, particularly swine and poultry. In addition, improved immunological and metabolic traits have been reported in nonruminants. The objective of this study was to determine the effects of β-mannanase supplementation on milk yield and composition, and immunological and metabolic responses in lactating Holstein dairy cows. Two weeks after calving, 20 Holstein cows (10 multiparous and 10 primiparous) were blocked by parity and assigned to 1 of 2 diets for 182 d. All cows were housed in the same environment and fed the same basal diet. The basal diet of the treatment group was supplemented with β-mannanase (CTCBio Inc., Seoul, South Korea) at 0.1% of concentrate dry matter. No differences were detected between the control and enzyme supplement groups in milk yield parameters or milk composition. Supplementation of β-mannanase enzyme reduced blood haptoglobin levels in supplemented multiparous cows compared with controls. Furthermore, nonesterified fatty acid concentration levels tended to be lower in cows fed β-mannanase, regardless of parity. Neither immunoglobulin G nor milk somatic cell count was affected by β-mannanase supplementation, regardless of parity. The number of insemination services tended to be lower in cows fed diets supplemented with β-mannanase. Results from this study suggest that supplementation of β-mannanase exogenous enzyme could help to reduce instances of systemic inflammation and decrease fat mobilization in lactating Holstein cows. Multiparous cows are considered susceptible to acute infections and inflammation; thus, the enzyme had a greater effect in multiparous cows.

Review Work on Productive and Reproductive Performance of Crossbreed Dairy Cattle in Ethiopia

Ethiopia enowed with alarge livestock population in africa as well as in the world. Dairy farming is one of the world wide practiced farming including Ethiopia. The main aim of this review is to know the overall preformance (both productive and reproductive) of crossbred dairy cattle in Ethiopia. According to inputs, agro-ecology, intensity of production dairy farming is catagoized as low land pastoralism, high land smallholder, urban and peri-urban small scale dairy farm and intensive (specialised comercial) dairy farming systems. The feed resourse for low land pastoralism and highland small holders is mostly natural pastures and crop by products. However, for urban and peri-urban small scale and intensive farms is purchased hay, green legum and other concentrats. Ethiopia has divrrsified dairy cattle breeds and the cross breeds have different production performance. Those differences in performance with in and between breeds could be due to management activity. There are also constraints that can influence the performance of dairy cattle like shortage of feed, poor genetic performance and poor management systems. The existing opportunities to improve thire performance includes the presence of diversified breeds as well as introducing of artificial insemination service technology. Besides these, the productive and reoroductive performance can be improve through good management. Therefore, good forage development strategy and good breeding strategies must be under taken by the government as well as other concerned bodies. Keywords : Productive, Reproductive, Preformanec, Dairy Cattle, Management DOI : 10.7176/JBAH/9-6-04 Publication date :March 31 st 2019

Evaluation of the oxidative status of periparturient mares supplemented with high amount of α-tocopherol

Aim of the study was to investigate the oxidative status during peripartum period in mares fed high amount of dietary α-tocopherol. α-Tocopherol, ferric reducing ability of plasma (FRAP) and reactive oxygen metabolites (d-ROMs) levels were measured in blood samples from 17 Thoroughbred mares at three intervals: (1) 20 days before the expected foaling date; (2) 12 h following parturition; (3) 7 days post-partum. The levels of α-tocopherol, d-ROMs and FRAP were retrospectively analysed in relation to the number of insemination services (Ins) after foaling performed per conception. The parameters α-tocopherol and d-ROMs evidenced minimal fluctuations during peripartum period while FRAP levels showed a linear decrease. The α-tocopherol did not show significant variations and was numerically higher in mares >10 years old while FRAP levels were significantly higher in older mares in the post-partum. Mares receiving three natural insemination services showed higher levels of FRAP in the pre-partum period (p = .009) and lower values of α-tocopherol (p = .015) in the postpartum compared to mares receiving one service. No d-ROMs level differences appeared among service classes. Oxidative stress is not present in periparturient mares fed 2.750 IU of supplementary α-tocopherol. Differences in redox metabolism are detectable between young and old mares. Plasma antioxidant potential is higher in older mares particularly in the post-partum period.HighlightsOxidative stress is not present in periparturient mares fed 2.750 IU of supplementary α-tocopherol.Antioxidant potential of plasma is higher in mares older than 10 years compared to younger mares.The increased plasma antioxidant potential seems related to an increase in services per conception.

Access to agricultural technology alternatives and household resilience to food insecurity

Agriculture is the main livelihood source for rural population in ethiopia. however, the sector is blamed for its dismal performance having resulted from low level of agricultural technology utilization. to redress this bottleneck, agricultural technology alternatives were promoted to solve the long-term problem of food insecurity. Although the program has supported the introduction and use of different agricultural technologies, whether this strategy has contributed to household food security is not clear. A study was conducted in five districts of North Western ethiopia with the objective to identify and analyze most relevant agricultural technology alternatives that make rural households resilient to food insecurity and their contribution to food security outcomes. Relevant data was collected from 509 rural households using structured questionnaire, supplemented with focus group discussion and key informant interview. Factor analysis and ordinal logistic regression were used to identify relevant variables and their contribution to food security outcomes, respectively. The finding of the factor analysis revealed that chemical fertilizer, improved seeds, improved livestock breeds, artificial insemination, organic fertilizer, and veterinary service were the most important variables in building households'food security resilience, while the result of the regression analysis revealed that chemical fertilizer, veterinary service, improved livestock breeds and organic fertilizer were contributed significantly to household food security. Recommendations include strengthening intensive crop production and improving veterinary services for intensive livestock production system.

Constraints of Artificial Insemination Service in Selected Districts of Wolaita Zone

Constraints of Artificial Insemination Service in Selected Districts of Wolaita Zone

Calves Sex Ratio in Artificial and Naturally Bred Cattle at Adami Tulu Agricultural Research Center

Breeding and calving records from 2013- 2016 maintained at Adami Tulu Agricultural Research center was used for current study with aim of assessing ratios of calves born and identifying some of the factors affecting ratios of calves born. The data was cleared, arranged, categorized and pulled into years and analyzed by using Statistical Package for Social Science Version 20.0 (SPSS). The probability of a male calf being born was analyzed by chi square test. A threshold significance level was determined at the P <0.05. The result indicated that the overall sex ratio of calves born was i.e. the ratio of male to female is 57.1 to 42.9. Parity of the breeding cow doesn’t have statistically significant effect on the sex ratio of calves born. The statistically analysis also shows that breeding year and season had not have the significant effect the sex ratio of calves born. In addition the sire line with which the animals inseminated has no significant effect. The result also indicted for the presence of significant difference of breeding method on sex ratio of calves born. From this it was concluded that breeding method has a significant effect on sex ratio of calves born in which number of male calves were higher in animals inseminated artificial and vice versa. Modern dairy reproductive technologies which enables to get more number of female calves has to be look into consideration to increase number of female animals for dairy producers in addition to providing efficient artificial insemination service in the country. Keywords: Calf sex ratio, Breeding method, Adami Tulu DOI : 10.7176/JBAH/9-1-01

Reproductive management practices on dairy farms: The Canadian National Dairy Study 2015

The objectives of this cross-sectional study were to characterize reproductive management practices on Canadian dairy farms and describe differences based on regional and demographic factors. A questionnaire was offered to all licensed Canadian dairy producers and included 189 questions regarding producer and farm background information, herd dynamics, biosecurity, disease prevalence, calf health, animal welfare, milking practices, reproduction, and internet use. Twenty-four questions were related to estrus detection, hormonal protocols for reproduction, insemination, and pregnancy diagnosis. A total of 1,373 producers responded to the survey, representing a response rate of 12.5%. Estrus detection practices in lactating cows were associated with herd size, barn type, region, organic production, breeding method, and age of respondent. The most commonly used estrus-detection method in cows was visual (51.0% of farms for first insemination; 45.5% for subsequent inseminations). Estrus detection for nulliparous heifers was associated with herd size, barn type, region, and breeding method, with visual detection also the most common method for heifers (71.3% of farms). Eighty percent of farms used strictly artificial insemination, 2.8% used natural service only, and 16.8% used a combination of artificial insemination and natural service. Breeding method was associated with herd size, barn type, region, and education level of the respondent. Pregnancy diagnosis method was associated with herd size, barn type, region, and organic production. Ultrasound was the most commonly used method of pregnancy diagnosis (used by 52.2% of farms). Sixty-nine percent of farms rechecked cows for pregnancy, and rectal palpation was the most commonly used method (employed by 48.7%). Reproductive management practices vary considerably among Canadian dairy farms and decisions are associated with farm-level factors, including region, herd size, and barn type, as well as producer-level factors, such as age, managerial role, and education level.

Reproductive performance of replacement dairy heifers submitted to first service with programs that favor insemination at detected estrus, timed artificial insemination, or a combination of both

Our objective was to compare the insemination dynamics and time to pregnancy for up to 100 d after the beginning of the artificial insemination period (AIP) for heifers managed with first artificial insemination (AI) service programs that relied primarily on insemination at detected estrus (AIE) after PGF2α treatments, timed artificial insemination (TAI), or a combination of both. Holstein heifers were randomly assigned to receive first AI service with sex-selected semen after 368 ± 10 d of age with (1) AIE after synchronization of estrus with up to 3 PGF2α treatments every 14 d starting on the first day of the AIP (PGF+AIE; n = 317). Heifers not AIE up to 9 d after the third PGF2α received a 5-d Cosynch protocol with progesterone supplementation [GnRH + controlled internal drug release insert (CIDR)-5 d-CIDR removal and PGF2α-3 d-GnRH and TAI] before TAI. Heifers detected in estrus from CIDR removal and PGF2α until the day before TAI received AIE with no GnRH treatment; (2) 2 PGF2α treatments 14 d apart with the second treatment at the beginning of the AIP (PGF+TAI; n = 334). Heifers received AIE for up to 9 d after the second PGF2α treatment. Heifers not AIE received TAI after the 5-d Cosynch protocol and (3) TAI after the 5-d Cosynch protocol (ALL-TAI; n = 315). Heifers failing to conceive to a previous AI received a subsequent AI with conventional semen at detected estrus or TAI after the 5-d Cosynch protocol. Binomial outcomes were analyzed by logistic regression, whereas time to AI and pregnancy were analyzed with Cox's regression. The hazard of first AI up to 45 d of the AIP was greater for ALL-TAI than for PGF+AIE [hazard ratio (HR) = 1.72; 95% confidence interval (CI) =1.45 to 2.03] and PGF+TAI (HR = 1.51; 95% CI = 1.28 to 1.77), but similar for PGF+AIE and PGF+TAI (HR = 1.14; 95% CI = 0.97 to 1.33). A greater proportion of heifers received AIE in PGF+AIE (98.7%) than in PGF+TAI (78.5%). Overall, first service pregnancy per AI did not differ (PGF+AIE = 42.0%; PGF+TAI = 47.3%, ALL-TAI = 43.8%). Time to pregnancy was reduced for ALL-TAI compared with PGF+AIE (HR = 1.20, 95% CI = 1.02 to 1.42), but was similar to that of PGF+TAI (HR = 1.13, 95% CI = 0.96 to 1.33). Time to pregnancy did not differ for PGF+AIE and PGF+TAI (HR = 1.07, 95% CI = 0.91 to 1.25). Median days to pregnancy were 27, 23, and 21 for heifers in PGF+AIE, PGF+TAI, and ALL-TAI, respectively. We concluded that an ALL-TAI program for first service reduced time to pregnancy, albeit a relatively small reduction, when compared with a program that relied primarily on AIE after induction of estrus with PGF2α treatments. The program that combined synchronization of estrus and TAI (PGF+TAI) resulted in similar time to pregnancy than the predominant TAI and predominant AIE programs.

127 Comparison of long-term progestin-based protocols to synchronize estrus prior to fixed-time artificial insemination or natural service in Bos indicus-influenced beef heifers.

127 Comparison of long-term progestin-based protocols to synchronize estrus prior to fixed-time artificial insemination or natural service in Bos indicus-influenced beef heifers.

Women farmers’ adoption challenges on artificial inseminations service in outskirt of Addis Ababa

The study was conducted in purposively selected Oromia National Regional State aiming at to suggest strategies to better involve women farmers in Artificial Insemination service. Experts from office of livestock and fishery represented the study population. Group discussion were undertaken separately for Women and men farmers. Collected information was analyzed qualitatively and interpreted accordingly. The study found that institutional and cultural barriers hindered many number of women AI (Artificial Insemination) technicians less involved in AI service delivery. Specifically, institutions don’t encourage women applicant to apply on AI, they thought the position is full of hardship and risky for women to give a service basing in rural areas. In addition to that, the service needs some physical fitness and it would be more difficult for women to move long distance caring containers. Moreover, there is animal disease (brucella) that can be easily transmit to human and can cause gynaecological problem for women. Culturally, even if it is not boldly pronounced by the community, there is a feeling of indignity when women provide AI services. On the other hand, the community also ashamed women farmers, if they ask AI service provision. Moreover, culturally women farmers are not allowed to watch inseminations service. So, in order to increase number of women AI technicians: nominating women technicians from local communities (at least grade 8 completed) and animal science graduate, and train more in practical way would made women AI technicians to be more capable. Support women AI technicians to work privately through post payment service for a while, would raise women acceptance by community. In order to increase number of women farmers attendees on training: conduct on farm training, invite women farmers directly for training, organize training between march to May seasons, prepare pictured based training (including production manuals) would change the number of women dairy producer on AI service provision.

PENGARUH SISTEM PENGAWINAN (INSEMINASI BUATAN DAN ALAMI) DAN PARITAS INDUK BABI TERHADAP LITTER SIZE DI USAHA PETERNAKAN BABI PT. ADHI FARM, SOLO

The aims of this study was to determine the optimal litter size which produce from the mating system and the sow parity by noticing the litter size born alive, the age of weaning, litter size at weaning, mortality during the suckling period and litter size at weaning percentage. Fourty one farrowing and weaned sows are used in this research. The first factor is the mating system, included artificial insemination and natural service. The second factor is the parity of the sow (1 up to 5). The data collected were litter size born alive, the age of the weaning, the weaned litter size, mortality of the suckling period and litter size at weaning percentage.The result showed that the mating system had significant effect (P0.05) on the age of the weaning, the litter size at weaning, mortality during the sucling period and litter size at weaning percentage. The parity had significantly effect (P0.05) on the litter size born alive, mortality during the sucling period and litter size at weaning percentage. The interaction between the mating system and the parity was significantly effected (P

Participatory Evaluation of Artificial Insemination (AI) Service Delivery and Semen Quality in Northern Ethiopia

Participatory Evaluation of Artificial Insemination (AI) Service Delivery and Semen Quality in Northern Ethiopia

Perception of dairy farmers regarding effectiveness of artificial insemination services of different dairy service delivery systems

Perception of dairy farmers regarding effectiveness of artificial insemination services of different dairy service delivery systems

English

This study was conducted to assess the problems associated with the artificial insemination service in Essera woreda of Dawuro zone, southern Ethiopia from December, 2016 to August, 2017. The study was conducted using questionnaire survey and records in targeted human and dairy cow’s population, respectively. There was no statistically significant association (P>0.05) in the conception and delivery of cows with different risk factors. But the management of the cows showed significant association (P<0.05) with their conception and delivery. There was no statistically significant difference (P>0.05) in weekends artificial insemination service among studied kebeles. However, there was a statistically significant difference among the studied kebeles in shortage of artificial insemination technician and inputs (P<0.05). The major animal health problem identified by dairy cow owners was conception failure (39.1%) followed by mastitis (23.4%) and mixed (mastitis and calving problem) (20.3%). A total of 58 (90.6%) of the respondents were not satisfied with the overall artificial insemination service. In addition, equal percentage of non-satisfaction levels of respondents were recorded in Ofa and Guza kebeles (93.8%). The result of the present study indicated that dairy cow owners were not satisfied with artificial insemination service and the service is not doing well in all kebeles of the of study site. Therefore, an immediate action is required to change the problem facing artificial insemination service in the study area and to achieve maximum benefit from the sector.   Key words: Essera woreda, artificial insemination, assessment, households.

Artificial Insemination Service Efficiency and Constraints of Artificial Insemination Service in Selected Districts of Harari National Regional State, Ethiopia

The study was conducted to evaluate efficiency of artificial insemination (AI) service and constraints of AI service selected Districts of Harar National Region State, Ethiopia. A total of 320 dairy cows were randomly selected from six districts of Harari region; Jin’Eala, Shenkor, Hakim, Dire-Teyara, Aboker, Sofi. Data on dairy cattle management, artificial insemination (AI) service efficiency and constraints of AI service were generated using structured and semi-structured questionnaire. Forty three straws of frozen semen was sampled from the regional AI service centre, thawed and evaluated at the region level for its quality (motility, viability and morphology) following standard procedures. The overall mean percentage of frozen semen motility at regional level was 49.6. Semen production period (batch) and Breed (exotic blood level) had no effect on frozen semen motility. The mean percentage of viable (live) spermatozoa was 58.3. Sperm viability was not significantly influenced by Semen production period (batch) and, breed (exotic blood level). The overall mean percentages of major and minor sperm morphological defects were 5.6 and 21.8, respectively. Frozen sperm major morphological defects were significantly affected (p 0.05) on frozen sperm major morphological defects. Frozen sperm minor morphological defects were not significantly affected (P > 0.05) by both semen production period (batch) and sire breed (exotic blood level). The mean number of service per conception (NSC) in the current study was found to be 1.6. It was not significantly affected by previous season of calving, previous year of calving and parity. Non-return rate value of Harari region AI service center was 48.1%. Major constraints of AI service delivery system in the study area were feed shortage, problem in heat detection, service charge for AI, distance from AI service centre and husbandry problem. Additional shortage of input for AI service activity particularly semen and liquid nitrogen was reported as constraint of artificial insemination service in the study area, which interrupt smooth delivery of AI service.

Reproductive performance and herd exit dynamics of lactating dairy cows managed for first service with the Presynch-Ovsynch or Double-Ovsynch protocol and different duration of the voluntary waiting period

The objective of this experiment was to evaluate the reproductive performance and herd exit dynamics of dairy cows managed for first service with programs varying in method of submission for insemination and voluntary waiting period (VWP) duration. Holstein cows from a commercial farm in New York were randomly allocated to receive timed artificial insemination (TAI) after the Double-Ovsynch protocol (GnRH, 7 d later PGF2α, 3 d later GnRH, 7 d later GnRH, 7 d later PGF2α, 56 h later GnRH, and 16 to 18 h later TAI) at 60 ± 3 d in milk (DIM) (DO60 = 458), TAI after Double-Ovsynch at 88 ± 3 DIM (DO88 = 462), or a combination of AI at detected estrus (starting at 50 ± 3 d in milk) and TAI with the Presynch-Ovsynch protocol (PGF2α, 14 d later PGF2α, 12 d later GnRH, 7 d later PGF2α, 56 h later GnRH, and 16 to 18 h later TAI; PSOv = 450). Subsequent artificial insemination (AI) services were conducted at detected estrus or the Ovsynch protocol (32 ± 3 d after AI GnRH, 7 d later PGF2α, 56 h later GnRH, and 16 to 18 h later TAI) for cows not reinseminated at detected estrus. In a subgroup of cows, cyclicity (based on progesterone concentration), uterine health (vaginal discharge and uterine cytology), and BCS were evaluated at baseline (DO60 and DO88 = 33 ± 3 DIM; PSOv = 34 ± 3 DIM), beginning of the synchronization protocol (DO60 = 33 ± 3 DIM; DO88 = 61 ± 3 DIM; PSOv = 34 ± 3 DIM), and within -5 (PSOv) or -10 d (DO) of the VWP end (DO60 = 50 ± 3 DIM; DO88 = 78 ± 3 DIM; PSOv = 45 ± 3 DIM). Effects of treatments were assessed with multivariable statistical methods relevant for each outcome variable. Cows in the DO88 treatment had delayed time to pregnancy during lactation (DO60 vs. DO88 hazard ratio = 1.53, 95% confidence interval = 1.32 to 1.78; PSOv vs. DO88 hazard ratio = 1.37, 95% confidence interval = 1.19 to 1.61) and, within multiparous cows, the DO88 and PSOv treatments had greater risk of leaving the herd than cows in the DO60 treatment (DO88 vs. DO60 hazard ratio = 1.49, 95% confidence interval = 1.11 to 2.00; PSOv vs. DO60 hazard ratio = 1.39, 95% confidence interval = 1.03 to 1.85). Cows in the DO88 treatment had improved uterine health, greater BCS, and reduced incidence of anovulation than cows in DO60 and PSOv; however, overall pregnancy per AI 39 ± 3 d after AI was similar for the 3 treatment groups. In summary, reproductive management strategies that led to similar average DIM to the first service (∼60 d) through a combination of AI at estrus with TAI (PSOv) or all TAI (DO60) resulted in reduced time to pregnancy after calving when compared with an all TAI program (DO88) with a VWP of 88 d. Within the multiparous cow group, those that received all TAI with a VWP duration of 60 d were less likely to leave the herd than cows in the other treatments.

Effect of serum paraoxonase-1 (PON1) activity on follicular development and pregnancy rate in cattle

Paraoxonase-1 (PON1) activity has been associated with improvement in ovarian function in early postpartum dairy cows and improved in vitro embryo development. The aim of the current study was to evaluate the potential association among PON1 activity and follicular growth, diameter of the preovulatory follicle and pregnancy per artificial insemination (AI) service in cattle. In Experiment 1, cows (n=33) were subjected to an estradiol-progesterone based protocol to control time of ovulation. Starting on Day 8 of the protocol, follicular growth and serum PON1 activity were monitored. Cows were separated according to the occurrence of ovulation into two groups: Ovulatory (Ov; n=22) and Anovulatory (Anov; n=11). The serum activity of PON1 was not different between Ov and Anov cows (P=0.94). In addition, using a regression model there was no effect of serum PON1 activity on the diameter of dominant follicle (r2=0.00; P=0.99). In Experiment 2, cows (n=193) were submitted to the same hormonal protocol as in Experiment 1. On the day of the timed artificial insemination (TAI), the diameter of dominant follicle was evaluated and blood samples were collected for analysis of PON1 activity. According to the serum PON1 activity, cows were divided into three groups: Low (<70U/mL), Medium (70–90U/mL) or High (>90U/mL) PON1 activity. The overall pregnancy rate was 62.7% (121/193), with no difference among PON1 activity groups. Additionally, using a regression model there was no effect of serum PON1 activity on the diameter of the preovulatory follicle (r2=0.03; P=0.65) and pregnancy rate (r2=0.005; P=0.94). The results of this study indicate that there is no effect of serum PON1 activity on the diameter of preovulatory follicle or establishment of pregnancy in cows submitted to time of ovulation synchronization protocols.

The creation and evaluation of a model to simulate the probability of conception in seasonal-calving pasture-based dairy heifers

BackgroundHerd fertility in pasture-based dairy farms is a key driver of farm economics. Models for predicting nulliparous reproductive outcomes are rare, but age, genetics, weight, and BCS have been identified as factors influencing heifer conception. The aim of this study was to create a simulation model of heifer conception to service with thorough evaluation.MethodsArtificial Insemination service records from two research herds and ten commercial herds were provided to build and evaluate the models. All were managed as spring-calving pasture-based systems. The factors studied were related to age, genetics, and time of service. The data were split into training and testing sets and bootstrapping was used to train the models. Logistic regression (with and without random effects) and generalised additive modelling were selected as the model-building techniques. Two types of evaluation were used to test the predictive ability of the models: discrimination and calibration. Discrimination, which includes sensitivity, specificity, accuracy and ROC analysis, measures a model’s ability to distinguish between positive and negative outcomes. Calibration measures the accuracy of the predicted probabilities with the Hosmer-Lemeshow goodness-of-fit, calibration plot and calibration error.ResultsAfter data cleaning and the removal of services with missing values, 1396 services remained to train the models and 597 were left for testing. Age, breed, genetic predicted transmitting ability for calving interval, month and year were significant in the multivariate models. The regression models also included an interaction between age and month. Year within herd was a random effect in the mixed regression model. Overall prediction accuracy was between 77.1% and 78.9%. All three models had very high sensitivity, but low specificity. The two regression models were very well-calibrated. The mean absolute calibration errors were all below 4%.ConclusionBecause the models were not adept at identifying unsuccessful services, they are not suggested for use in predicting the outcome of individual heifer services. Instead, they are useful for the comparison of services with different covariate values or as sub-models in whole-farm simulations. The mixed regression model was identified as the best model for prediction, as the random effects can be ignored and the other variables can be easily obtained or simulated.