Biomedical subjects

R S Morris

Publications and source records attributed to R S Morris.

At least 55 records · Page 3Linked to original sources

PubMed1999

Reproductive performance of farmed red deer (Cervus elaphus) in New Zealand: II. Risk factors for adult hind conception.

A 2-year longitudinal observational study of 15 red deer farms was carried out in New Zealand from March 1992. About 2600 adult hinds were individually monitored for reproductive success. After mating, hinds were pregnancy-tested by ultrasound and were classified as having conceived before 1 May, after 1 May or as being not pregnant. Risk factors potentially affecting the probability of conception before 1 May or of conception that year were investigated using path analysis. Final path diagrams were used to formulate a putative management strategy for farmers to achieve the desired reproductive performance from adult hinds. To achieve a high pregnancy rate early in the mating season, farmers should wean calves early, exclude hinds which failed to rear a calf to weaning and hinds with a body condition score < or = 2.0 at mating, join hinds early with one or more sire stags, use only experienced sires for mating, limit the hind: stag ratio, use at least one back-up sire after the peak of mating, keep mating mobs away from disturbance and avoid shifting or handling mating mobs. The farmer should choose paddocks with high green pasture allowance and grazed down to no less than 5 cm high.

Animal Husbandry↗

PubMed1999

Reproductive performance of farmed red deer (Cervus elaphus) in New Zealand: III. Risk factors for yearling hind conception.

A 2-year longitudinal observational study of 15 red-deer farms was carried out in New Zealand from March 1992. Seven hundred yearling hinds were individually monitored for reproductive success. After mating, hinds were pregnancy tested by ultrasound and were classified as having conceived before 1 May, after 1 May, or as being not pregnant. Risk factors potentially affecting the probability of conception before 1 May or of conception that year were investigated using path analysis. To increase the probability of conceiving early, this study suggests yearling hinds should be selected prior to mating for high bodyweight and height. Young stags and hinds should be joined late summer (14 months of age) before mating. Mobs of yearling hinds should not be combined with large mobs of adult hinds. Paddocks with limited gullies, hills and trees should be chosen for mating. Finally, paddocks for mating should be away from human disturbance. To increase the probability of yearling hinds conceiving that year, yearling hinds should be in moderate-to-low body condition (around 2.5), and nutrition during mating should be prioritised to ensure optimal growth rates. Short and/or lightweight hinds may be mated successfully if they are well fed but they generally conceive later. Trees should be limited in the mating paddocks.

Animal Husbandry↗

PubMed1999

Reproductive performance of farmed red deer (Cervus elaphus) in New Zealand. IV. Biological markers as risk factors for yearling and adult hind conception.

A 2-year observational study of 15 red deer (Cervus elephus) farms was carried out in New Zealand from March 1992. In each year of study, approximately 1650 hinds were individually monitored for reproductive success. During farm visits in March 1992 and 1993, five yearling and five adult hinds per farm were randomly selected and blood sampled to define their haematological, biochemical and blood mineral profile. Faecal samples were taken for parasite egg and larvae count. Biological markers potentially affecting the probability of conception before May 1 or of conception that year were investigated separately using multivariable logistic regression analysis. Adult hinds with low serum phosphorus concentrations were more likely to conceive before May 1. Lower conception rates were observed in yearling hinds when blood glutathione peroxidase, serum vitamin B12, and serum albumin concentrations were low, and when faecal lungworm larval counts were high. While these associations have yet to be proven as causal, data suggests that monitoring and maintaining adequate blood elements, and controlling internal parasites in yearling hinds, may assist farmers to achieve optimum reproductive performance in farmed red deer herds.

Animals↗

PubMed1999

Reproductive performance of farmed red deer (Cervus elaphus) in New Zealand. I. Descriptive data.

A longitudinal observational study of 15 red deer (Cervus elaphus) farms was carried out in New Zealand for 2 years from Mar 1992. Management of hind mobs and their composition during mating, calving, and weaning were recorded. About 2700 hinds were individually monitored for live weight, body condition score and reproductive success. All hinds were pregnancy tested in June by ultrasound and classified as having conceived before May 1, after May 1, or as being not pregnant. Calving dates and dam-offspring pairs were recorded on four farms. The lactational status of hinds and live weight of calves were recorded at weaning. Mean pre-mating live weights of yearling hinds were 81.3-82.8 kg and of adult hinds 98.0-98.7 kg, respectively, for each year of study. The percentage of yearling and adult hinds conceiving before May ranged from 8.3 to 95.0% and from 77.6 to 98.4%, respectively, between farms. Overall, the proportion of yearling and adult hinds not pregnant was 15.3% and 3.2%, respectively. Pregnancy rates at scanning of adult hinds within mating mobs were generally over 90%, and 41.7% of mating mobs had 100% pregnancy rates. In contrast, the pregnancy rates of yearling hind mobs were more variable, with five mobs below 50%, and 34.1% of mating mobs achieving 100% pregnancy rate. Estimated in utero loss rates from pregnancy diagnosis to calving were 0.66 and 0.79% for yearling and adult hinds, respectively. From four farms, median calving dates of yearling and adult hinds were Dec 13 and Nov 30, respectively. Overall, calf survival rates to weaning of yearling and adult offspring were 84.1 and 91.6%, respectively, while the reproductive efficiencies (number of calves weaned per hind mated) were 70 and 83.6%, respectively. Farm mean weaner live weights standardised on Apr 1 ranged from 42-59 kg and 39-51 kg for stags and hinds, respectively. These data are currently the best estimates of reproductive parameters of New Zealand red deer herds, and highlight a wide variability in reproductive indices between farms.

Animal Husbandry↗

PubMed1999

An on-farm study of the epidemiology of Actinobacillus pleuropneumoniae infection in pigs as part of a vaccine efficacy trial.

Thirty cohort pigs were followed from birth to slaughter to study epidemiological patterns of porcine pleuropneumonia caused by Actinobacillus pleuropneumoniae. The study was conducted within a larger 380-animal study of vaccination against Mycoplasma hyopneumoniae and A. pleuropneumoniae in a 340-sow farrow-to-finish piggery with 4-month weaning, operating a continuous system of intensive production in the North Island of New Zealand. The cohort pigs were randomly allocated into two equal groups: vaccinated and control. Pigs in the first group were vaccinated at 2 and 4 weeks of age with both M. hyopneumoniae vaccine and A. pleuropneumoniae vaccine at separate vaccination sites. A series of nasal swabs was taken at 4, 8, 10, 11, 12, 14, 16 and 18 weeks of age. Each swab was streaked onto the surface of a selective medium on the farm and the plates were immediately transported to a laboratory and incubated at 37 degrees C for 5 days. After the trial, pigs were slaughtered at an average of 132 days of age, lungs were examined and samples taken for bacteriological culture and isolation. Thirty-five out of 256 samples produced haemolytic colonies which were Gram-negative, V-factor-dependent and positive to the CAMP test. A. pleuropneumoniae was first isolated at 4 weeks of age from one vaccinated pig. This finding suggests that piglets became infected in the farrowing pen and the source of infection might be a carrier sow. The interval-specific cumulative incidence of A. pleuropneumoniae infection reached a maximum of 54% and 40% at 11 weeks of age in the vaccinated and control groups, respectively. Infection status of the litter is considered to be a factor influencing morbidity in infected herds during weaner and grower periods. Our results suggest that simultaneous vaccination with M. hyopneumoniae and A. pleuropneumoniae vaccines at 2 and 4 weeks of age might lessen the prevalence but cannot absolutely prevent A. pleuropneumoniae infection during the weaner or grower-finisher periods.

Actinobacillus Infections↗

PubMed1999

Field efficacy of a combined use of Mycoplasma hyopneumoniae and Actinobacillus pleuropneumoniae vaccines in growing pigs.

The effectiveness of simultaneous administration of commercial Mycoplasma hyopneumoniae and Actinobacillus pleuropneumoniae vaccines was tested in an indoor commercial piggery which had experienced continuing respiratory-disease problems confirmed as due to both of these pathogens. Piglets were randomly assigned in equal numbers to vaccination and control groups, and each vaccine was administered at a separate site to assigned piglets at two and four weeks of age. Live weight of vaccinates immediately prior to slaughter was 2.49 kg higher (p = 0.04) than for controls at equal mean slaughter age of 132 days. Average daily gain (ADG) from 16 weeks to slaughter of vaccinates was also significantly higher (33 g/day) than in controls (p = 0.05). Daily gain was not significantly different in younger age groups. Active enzootic pneumonia lesions were more likely in control than in vaccinated pigs. There were no significant differences between vaccination groups with regard to severity of pleurisy or presence of pleuropneumonia lesions at slaughter. Log-linear modelling was used to test the statistical association between vaccination, enzootic pneumonia lesions, pleurisy lesions and pleuropneumonia lesions. It showed a reduction in the severity of enzootic pneumonia lesions for vaccinated pigs, and the presence of pleuropneumonia lesions increased the likelihood of pleurisy lesions. No other association was significant, and no evidence of synergy between the vaccines in influencing lesion severity for pleuropneumonia was detected (within the limitations set by the trial design).

Actinobacillus Infections↗

PubMed1999

Increased angiotensin-converting enzyme activity in a patient with severe ovarian hyperstimulation syndrome.

OBJECTIVE: To assess plasma angiotensin-converting enzyme (ACE) activity in a patient with severe ovarian hyperstimulation syndrome (OHSS). DESIGN: Case report. SETTING: Private, university-affiliated infertility practice. PATIENT(S): A 35-year-old woman with OHSS. INTERVENTION(S): Clomiphene citrate induction of ovulation. MAIN OUTCOME MEASURE(S): Plasma ACE activity. RESULT(S): The patient had a brain stem infarction as a result of thrombosis caused by severe OHSS. Plasma ACE activity was significantly elevated and persisted long after resolution of the OHSS. CONCLUSION(S): Elevated ACE activity appears to have been associated with the development of OHSS in this patient. Further study of the ovarian renin-angiotensin system in the development of OHSS is warranted.

Adult↗

PubMed1999

Octreotide is not useful for clomiphene citrate resistance in patients with polycystic ovary syndrome but may reduce the likelihood of ovarian hyperstimulation syndrome.

OBJECTIVE: To determine whether octreotide is effective for ovulation induction in patients with polycystic ovary syndrome (PCOS) and clomiphene citrate resistance or for reduction of the risk of ovarian hyperstimulation syndrome (OHSS) with gonadotropin therapy. DESIGN: Prospective, double-blind, placebo-controlled, crossover trial. SETTING: Private infertility practice. PATIENT(S): Twelve patients with PCOS undergoing therapy for infertility. INTERVENTION(S): The patients were assigned randomly to receive either octreotide or placebo. Those with clomiphene citrate-resistant PCOS received clomiphene citrate, 150 mg. Patients at risk for the development of OHSS received urinary FSH for ovulation induction. MAIN OUTCOME MEASURE(S): Ovulation, pregnancy, the development of OHSS, and levels of fasting insulin, insulin-like growth factor 1, insulin-like growth factor binding proteins 1 and 3, testosterone, androstenedione, DHEAS, E2, LH, and FSH. RESULT(S): Octreotide significantly reduced levels of fasting insulin, insulin-like growth factor 1, and LH in both clomiphene citrate- and urinary FSH-stimulated cycles. Levels of insulin-like growth factor binding protein 3 were increased. Two of six clomiphene citrate-stimulated cycles reached ovulation with the use of either octreotide or placebo. In urinary FSH-stimulated cycles, patients who received octreotide had significantly lower E2 levels at the time of hCG administration and fewer mature follicles. No cases of OHSS occurred in either group. One pregnancy occurred in each group. CONCLUSION(S): Octreotide was no more effective than placebo for clomiphene citrate resistance in patients with PCOS, but it did reduce E2 levels and follicle numbers when combined with urinary FSH. Thus, octreotide may reduce the incidence of OHSS in patients with PCOS.

Adult↗

PubMed1999

Economic evaluation of three anthelmintic strategies for lamb flocks affected by benzimidazole-resistant nematodes.

OBJECTIVE: To compare the profitability of three anthelmintic strategies in growing lambs in flocks with nematodes resistant to benzimidazole anthelmintics. METHOD: A partial-budgeting analysis was carried out by means of a stochastic simulation model, which allows inputs to be described as distributions rather than as fixed values, and hence permits variation between farms to be considered in the analysis. RESULTS: The results show that control of nematode parasites by use of an effective anthelmintic provides the highest net returns, yielding a margin over ineffectively treated lambs of A$114 per 100 lambs on average. Suppressive treatment based on the administration of two controlled-release capsules and monthly with moxidectin resulted in an average loss of A$131 per 100 lambs in comparison with animals treated with an ineffective anthelmintic. Analysis of the results from capsule-treated lambs did not take into account the unmeasured benefits associated with less contamination of pastures. Sensitivity analysis using a stochastic model indicates that apart from the effect of treatment on weight gain variation in carcase price greatly influences the profitability of all the parasite control programs examined. CONCLUSION: The results suggest that it is economically important for farmers to adjust their strategy in the presence of anthelmintic resistance. But as a result of uncertainty in the factors influencing economic return, the expected economic benefit is likely to vary substantially.

Animals↗

PubMed1999

The enhancement of audience participation in telemedicine education by the use of electronic voting.

The rotation of trainee registrars in obstetrics and gynaecology to peripheral centres in South Australia was introduced for the first time in January 1998. A pilot study of the use of telemedicine to maintain the trainees' involvement in the established weekly training sessions conducted at the Women's and Children's Hospital (WCH) was also commenced at the same time. Sessions were problem based and required the trainees to be actively involved throughout. An electronic voting system (EVS) was used by the WCH audience, with the results of all responses being seen at the peripheral centres. Initial evaluation of the EVS as an educational tool was sufficiently positive to justify further studies of its use in this environment. The availability of voting units at the peripheral sites, used in conjunction with the main centre, will provide an exciting opportunity for further research.

Education, Medical, Graduate↗

PubMed1999

The application of economics in animal health programmes: a practical guide.

Economic analysis is a valuable technique in the planning and management of animal health programmes at the national policy level and at the level of individual livestock enterprises. Considerable experience has now been accumulated in the adaptation of methods of economics to address decisions on disease control issues. Different methods are appropriate for endemic diseases, for diseases which occur intermittently as local outbreaks, and for diseases which have the potential to cause an epidemic. A guide to the selection of the most suitable method is provided. The information required for analysis at individual herd level is much simpler than that required for national policy decisions and funding decisions by international agencies; an outline of the requirements for each level of analysis is provided. Issues surrounding the degree of risk of different choices are examined, and the application of decision analysis to higher-risk choices is introduced. Ways in which difficulties and hazards can be overcome are suggested for those unfamiliar with the techniques. Finally, procedures to provide confidence in the results of evaluations through sensitivity analysis are explained.

Animal Husbandry↗

PubMed1999

EpiMAN-FMD: a decision support system for managing epidemics of vesicular disease.

A comprehensive epidemiological information system (EpiMAN-FMD) has been developed to assist national disease control authorities contain and eradicate outbreaks of animal diseases as efficiently and cost-effectively as possible. The system was initially developed to control an incursion of foot and mouth disease (FMD) or any clinically indistinguishable vesicular disease, although it has since been progressively expanded to manage other exotic and endemic diseases. Design objectives for the information management elements of EpiMAN-FMD included the following: the need to manage the vast quantities of data that eradication procedures for an FMD epidemic would generate within a very short time the ability to innovatively apply epidemiological understanding of disease spread to the data processing tasks the reduction of some of the foreseen processing bottlenecks the provision of decision support tools for data entry personnel. Design objectives for the veterinary management elements of the system included the following: the presentation of up-to-date status reports in formats that facilitate decision-making at the national or regional level the ability to optimise manpower resource allocation the capacity to evaluate the relative merits of alternative technical decisions, each of which carry different implicit risks. The system combines a multi-user database management system, expert system elements, various computer simulation models of specific aspects of FMD epidemiology and a range of statistical analyses designed to monitor the state of the epidemic. Although designed in New Zealand, EpiMAN-FMD has been constructed in a flexible style which makes adoption of the system possible in other countries with broadly similar 'stamping-out' contingency plans.

Animals↗

PubMed1998

Risk factors for respiratory diseases in New Zealand pig herds.

AIMS: A survey of lung lesions and risk factors for respiratory diseases was conducted in order to estimate the prevalence of respiratory diseases in the New Zealand pig population and to identify influential management practices. METHODS: Eighty-nine New Zealand pig farms with a minimum herd size of 50 sows participated in the survey, and risk factor data were collected using a mailed questionnaire. Abattoir data were recorded once in winter 1995 and once in summer 1996. A total of 6887 lungs was inspected. RESULTS: The prevalence of enzootic pneumonia, pleuropneumonia and pleurisy in winter was 63.4%, 2.7% and 19.1%, respectively. Enzootic pneumonia was significantly less frequent in summer. Pleuropneumonia/pleurisy was found to be more prevalent in the South Island. The univariate risk factor analysis was consistent with earlier published evidence on the importance of environmental factors related to housing and management of the farm. The multivariate models for enzootic pneumonia and pleuropneumonia or pleurisy had a reasonably good predictive power of 81-91% for farms with high disease prevalence. CONCLUSION: The results are useful to model the disease process on high-risk farms, which account for a considerable proportion of the New Zealand pig population.

Journal Article↗

PubMed1998

Effects of calving induction on subsequent milk yield and reproductive performance of cows from seasonally mated New Zealand dairy herds.

AIM: To identify some production and reproductive effects of calving induction in seasonally calving herds. METHODS: Forty seasonally calving herds entered on the DairyMAN management information system and whose milk yield and reproductive data were recorded, including pregnancy diagnosis results, were included in the study. Cows with an induced parturition were compared with normally calving contemporaries that had the same lactation number and calved at the same time. RESULTS: Milk yield was 1.2 +/- 0.2 litres/cow/day less over the entire lactation for cows induced to calve, with the greatest difference being 2.5 +/- 0.4 litres/cow/day measured in early lactation. The effects on milkfat and protein yield were similar, with 0.04 +/- 0.01 kg/cow/day less milkfat (p < 0.0001) and 0.03 +/- 0.01 kg/cow/day less protein (p < 0.0001). A higher milkfat percentage (+ 0.09 +/- 0.04 %) (p < 0.0001) and protein percentage (+ 0.10 +/- 0.02%) (p < 0.0001) for cows that were induced to calve reduced the effect of a lower milk yield on milkfat and protein production. The first service conception rate for cows induced to calve was 54.4 +/- 3.3%, which was significantly less (p = 0.03) than for cows that calved normally (59.5 +/- 3.3%). Cows induced to calve had a pregnancy rate at the end of mating of 91.4 +/- 2.1%, which was also significantly less (p <0.0001) than for cows that calved normally (93.6 +/- 1.7%). The 21-day submission rates were not significantly different between groups. CONCLUSIONS: This study indicates that, under some New Zealand management conditions, the induction of calving is associated with reduced daily milk yield and inferior reproductive performance.

Journal Article↗

PubMed1998

Epidemiology and pathogenesis of Mycobacterium bovis infection of red deer (Cervus elaphus) in New Zealand.

AIMS: This study was initiated to investigate aspects of the epidemiology, pathogenesis and transmission of tuberculosis in wild red deer, with the aim of determining whether this species may be considered a reservoir host of Mycobacterium bovis in New Zealand. METHOD: One hundred and six wild red deer (Cervus elaphus) carcasses from the Castlepoint and Hauhungaroa Range areas, which are endemic for bovine tuberculosis, were examined for the presence of M. bovis infection. Samples were also examined from 46 skin test-positive farmed deer killed at two deer slaughter premises. Where possible, a standard set of tissues and excretion site samples was collected for mycobacteriological examination. RESULTS: Fifty-eight infected deer were identified, and of these 28% showed no gross lesions. The prevalence of tuberculosis confirmed by culture in the wild deer was 32%. Only one of 18 deer younger than 1 year was infected. Mature deer (>2 years) were 12 times more likely to be infected than those under 1 year of age. Infected older deer were less likely to show typical gross lesions than younger animals. Mycobacterium bovis was isolated from the oropharyngeal tonsil of 34 of 56 (61%) of the infected deer, and this was the most commonly infected site. Gross lesions were found in 18 of the 34 infected tonsils and only one of these showed a purulent tonsillitis. Mycobacterium bovis was recovered from four of 53 nasopharyngeal tonsils, four of 53 oropharyngeal swabs, one of 53 tracheal and nasal swabs, and one of 46 faecal samples, but not from any urine specimens. CONCLUSION: These findings suggest that significant bacillary excretion from infected deer was uncommon, and is more likely to occur in severely affected animals. This study has confirmed the importance of mucosa-associated lymphoid tissues (MALT), particularly the oropharyngeal tonsil, in the pathogenesis of tuberculosis in deer. The findings justify investigation of the hypotheses that the prevalence of tuberculosis in wild deer in New Zealand is high due to transmission of infection from possums, and that in the absence of an infected possum population, the prevalence of tuberculosis in deer is likely to be low, and spatially patchy. CLINICAL RELEVANCE: The results suggest that about one quarter of infected deer show no detectable gross lesions. This implies that many infected carcasses may enter the food chain unrecognised and that the estimated sensitivity and specificity of diagnostic tests may be erroneous if there is a difference in test performance between those conducted on deer with or without gross lesions. Diagnostic sensitivity following slaughter may be improved by routine culture of oropharyngeal tonsils and careful examination of lungs for adhesions and small subpleural tubercles.

Journal Article↗

PubMed1998

A survey of internal parasites and parasite control on North Island deer farms.

AIM: To evaluate internal parasite control practices and their effectiveness, and to investigate relationships between indices of parasitism and production outcomes by analysis of data collected during a deer herd health and production profiling project. METHODS: A longitudinal study of 15 red deer farms in the North Island of New Zealand was carried out from March 1992 to April 1994. Anthelmintic usage was recorded. Sentinel weaner, yearling and adult hinds and stags were blood and faecal sampled in early autumn, winter, spring and summer for serum pepsinogen and faecal egg and larval counts. A descriptive analysis of control programmes and egg and larval counts was produced. In addition, further measurements of parasitism and parasite control, including faecal egg count and faecal larval count data, individual pepsinogen concentrations, timing and numbers of anthelmintic treatments, and a farm calf faecal lungworm larvae count index were firstly subjected to univariate statistical association with production outcomes, followed by stepwise multivariable logistic regression analysis. Timing and numbers of anthelmintic treatments, along with other farm, herd or animal management risk factors, were included into path models. RESULTS: A wide range of anthelmintic programmes in all age groups, within farms between years and between farms was recorded. Weaner deer received three to nine treatments in their first year. Many farmers treated older deer in only one of the years of study. Older stags were treated more often than younger stags. Oxfendazole, ivermectin and moxidectin were the most commonly used anthelmintics. Egg and larval counts varied between properties and between years in some seasons but a higher proportion of deer shed larvae than eggs. In winter the number of weaners shedding eggs was the same as in autumn, but fewer shed lungworm larvae. Counts were lower at 12 months of age. Counts in older stags and hinds were highest in early spring, and counts were higher in yearling stags than in adult stags. Geometric mean pepsinogen concentration was lowest in weaners and rose to adult levels by early spring. Statistical analyses showed a lower weaning weight associated with higher faecal larval count index, and a reduced number of anthelmintic treatments prior to weaning. Weaners grew faster in spring after late winter anthelmintic treatment than those without treatment or with later treatments. There were inverse relationships between both farm mean weaner and adult serum pepsinogen and summer growth of weaners, and weaning percentage of adult hinds, respectively. CONCLUSION: This study has highlighted current parasite control practices, relationships between indices of parasitism and production outcomes, and has identified areas for further research into parasitism in farmed deer.

Journal Article↗

PubMed1998

EpiMAN-SF: a decision-support system for managing swine fever epidemics.

During an outbreak of classical swine fever (hog cholera) or African swine fever, decisions in emergency headquarters have to be made under conditions of time pressure, limited resources and uncertainty. The computer program EpiMAN-SF is designed to support decision-making in this situation by providing up-to-date information and a structured approach to choosing from among competing tasks by combining electronic data management with expert system components. EpiMAN-SF provides accurate and timely summaries of the epidemic, using both text and graphics. In addition, the program provides tools for the epidemiological analysis and forecasting of the emergency, and for assessing current and alternative control strategies. The expert system and simulation models integrated in EpiMAN-SF have been evaluated using sensitivity analysis, historic outbreak data and expert opinion. The results demonstrate that EpiMAN-SF is a valid alternative to traditional data management during exotic disease epidemics.

Animals↗

PubMed1998

Production and reproductive responses to use of DairyMAN: a management information system for New Zealand dairy herds.

To assess the benefits of on-farm use of a computerized management information system (DairyMAN, Department of Veterinary Clinical Science, Massey University, Palmerston North, New Zealand) on seasonally calving herds of New Zealand, data for 144 herds using this system were compared with a stratified random sample of 294 herds using only the centralized National Dairy Database system during the season 1993 to 1994. Demographic, reproductive performance, and milk yield indices were compared. Herds using DairyMAN had superior reproductive outcomes, measured as a higher percentage (+8.4%) of cows calving during the desired seasonal period (critical in this seasonal system) and a higher percentage of cows (+9.7%) mated at the optimal time to achieve a concentrated calving in the following year. Multiple analysis of covariance was used to differentiate effects. The superior performance was not associated with differences in some of the more commonly used reproductive indices (efficiency of estrus detection, first service nonreturn rate, and pregnancy rate), but the data used in the study do not accurately reflect true performance. Herds using DairyMAN had more information on breeding performance because pregnancy data were available and natural breedings were recorded for a longer period. With cows of equivalent genetic merit, herds using DairyMAN produced more milk (+1.2 L/d per cow) indicating that users achieved better management of the herd through improved attention to managerial details. This improved production was associated with the adoption of DairyMAN but is not shown by this study to be a direct consequence of it. DairyMAN user herds were larger (245 cows) than were herds not using the system (181 cows), but this difference did not significantly affect the various outcomes measured.

Animals↗