Survey on 'lumpy jaw' on deer farms in western Canada: prevalence and distribution, and identification of associated factors

AIM: To investigate the prevalence and geographical distribution of 'lumpy jaw' (LJ) in a population of white-tailed deer (WTD; Odocoileus virginianus) and mule deer (MD; Odocoileus hemionus) farms from the western Canadian provinces of Saskatchewan and Alberta, and to identify factors associated with its occurrence. METHODS: A cross-sectional study, in which the target population was all farmers of WTD and MD registered in Saskatchewan and Alberta, was conducted between July 2004 and January 2005. A questionnaire was mailed to all farmers requesting information about the presence of LJ and other necrobacillosis- related syndromes (footrot and fawn death syndrome), and various farm characteristics, during 2002, 2003 and 2004. Herd and within-herd incidences of disease were estimated. Global and local spatial analyses were performed to identify possible clusters of occurrence of LJ in the region. Logistic regression analysis was used to identify factors associated with the occurrence of LJ. RESULTS: A total of 139/268 (52%) deer farmers responded to the survey. Over the entire study period, 108/139 (78%) of farmers reported having cases of LJ in their herds, and in any given year the incidence amongst herds was about 40%. The presence of footrot was not associated with the presence of LJ. The proportion of fawns dying suddenly in 2004 was higher on farms affected by LJ than in those considered LJ-free (median of 11.1% and 0%, respectively; p<0.001). Two areas in Saskatchewan were identified as having a higher herd prevalence of LJ (clusters) than all other areas. Density of animals, moving and handling animals, lack of basic hygiene measures, and bottle- feeding of fawns increased the odds of a herd being affected by LJ. CONCLUSIONS AND CLINICAL RELEVANCE: LJ should be considered a common disease in farmed deer in western Canada. The observed relationship between the occurrence of LJ and acute mortality of fawns emphasises the potential of this infection to result in significant economic loss. Intensive management of deer, characterised by high densities and frequent moving and handling of animals, may contribute significantly to the occurrence of LJ. Observed geographical clusters may reflect areas where management of deer was more intensive or the trading of deer more common.     

Experimental transmission of chronic wasting disease (CWD) of elk (Cervus elaphus nelsoni), white-tailed deer (Odocoileus virginianus), and mule deer (Odocoileus hemionus hemionus) to white-tailed deer by intracerebral route

To compare clinical and pathologic findings of chronic wasting disease (CWD) in a natural host, 3 groups (n = 5) of white-tailed deer (WTD) fawns were intracerebrally inoculated with a CWD prion of WTD, mule deer, or elk origin. Three other uninoculated fawns served as controls. Approximately 10 months postinoculation (MPI), 1 deer from each of the 3 inoculated groups was necropsied and their tissues were examined for lesions of spongiform encephalopathy (SE) and for the presence of abnormal prion protein (PrP(d)) by immunohistochemistry (IHC) and Western blot (WB). The remaining deer were allowed to live until they developed clinical signs of the disease which began approximately 18 MPI. By 26 MPI, all deer were euthanatized on humane grounds. Obvious differences in clinical signs or the incubation periods were not observed between the 3 groups of deer given CWD. In 1 of 3 nonclinical deer euthanatized at 10 MPI, minimal microscopic lesions of SE were seen in the central nervous system (CNS) tissues, and PrP(d) was observed by IHC in tissues of all 3 deer. In the clinical deer, CNS lesions of SE and PrP(d) accumulations were more severe and extensive. It is concluded that the 3 sources of CWD prion did not induce significant differences in time to clinical disease or qualitative differences in signs or lesions in WTD. However, this observation does not imply that these CWD agents would necessarily behave similarly in other recipient species.     

The reproductive performance of farmed fallow deer (Dama dama) in New South Wales

Observations on the reproductive performance of fallow deer on 47 farms in New South Wales were made over 6 consecutive years. The minimum fawning rate for does varied significantly (p less than 0.001) between years, the corresponding fawning percentages varying from 75.0% to 96.4%, with an overall mean of 88.8%. The weaning rate also varied significantly (p less than 0.001) between years, the corresponding percentages varying from 65.0% to 89.1% with a mean over 6 years of 81.4%. Weaning rates were low given the known high fertility of fallow deer. The ratio of male to female fawns at weaning varied significantly (p less than 0.05) between years, although the ratio was exactly 1:1 for all births recorded over the 6-year period. The mean birthweights for female and male fawns were 4.01 kg +/- 0.61 (n = 330) and 4.23 kg +/- 0.72 (n = 348) respectively. Mean birthweights varied significantly (p less than 0.001) between the sexes and between years. There was a greater difference between birthweights of male and female fawns in years with higher mean fawn birthweight. Fawn birthweights generally approximated 10% of the pre-rut weight of their mother. Handling of newborn fawns for tagging and weighting did not increase the chance of mismothering and rejection. The mean weaning weight for doe fawns and buck fawns over 6 years was 18.7 kg (n = 227) and 21.2 kg (n = 231) respectively, with a mean birth to weaning interval of 108.4 +/- 4.89 (n = 458). Growth rates of male fawns from birth to weaning were significantly higher (p less than 0.01) than for female fawns, and the growth rates of fawns were significantly different (p less than 0.01) between years.(ABSTRACT TRUNCATED AT 250 WORDS)     

A cross-sectional study of the causes of morbidity and mortality in farmed white-tailed deer

Two questionnaires were designed and administered. The first was to a random sample of 340 farmers of white-tailed deer (Odocoileus virginianus) in Canada and the United States. The second was a 10-year retrospective survey of deer submissions to veterinary diagnostic pathology laboratories in Canada and the United States. One-year rates of mortality and common causes of morbidity and mortality for the deer are reported. The primary diagnosis for each record was used to classify diseases into categories, such as parasitic, infectious, toxicological, and neoplastic. Submissions were further classified according to the anatomical location, the pathological change, and the etiology associated with each lesion. Trauma was the most important reported cause of farmed white-tailed deer mortality; necrobacillosis was a major cause of morbidity and mortality, especially in fawns.     

Rusa deer (Cervus timorensis russa) farming in New Caledonia: impact of different feed levels on herd breeding rate and performance of newborn fawns

Objective To measure the impact of undernourishment during the rutting period on the breeding rate of Javan rusa deer and performance of fawns from birth to weaning.
Design A random controlled trial.
Animals Two groups of 37 hinds.
Procedure Group P grazed improved pasture and group M native grassland through the rutting period. Hinds were weighed at the beginning and the end of rutting, at ultrasound scan and prior to fawning. Fawning was monitored.
Results At the end of the rutting period, the mean difference in weight between the two groups was 8.5 kg and the pregnancy rate was 95% for group P and 57% for group M. Fifty births were recorded which equates to a fertility rate at 24 hours of 60% for group P and 30% for group M. Fawn mortality occurring in the first 24 hours affected 26% of all fawns. In 54% of the cases, newborn deaths were subsequent to abandonment by the hind. Average rusa fawn weight at birth was 3.6 + 0.1 kg, regardless of sex or group. Among fawns that weighed less than 3.0 kg, the mortality rate was 55%. The newborn fawn weight was related to the weight of the hind at ultrasound scanning. The weaning rate at 20 weeks was 84% for both groups. Mean weight gains for sucking fawns were 150 g per day for the first 2 months and 108 g per day from 60 to 120 days regardless of sex or group. The mean weight at 60 and 120 days was 12.7 kg and 18.5 kg, respectively. Two regression equations enable the calculation of the weight at 60 and 120 days using the fawn weight at birth and hind weight at the beginning of the rutting period.
Conclusion A 5% weight loss for the hinds resulting from undernourishment during the rutting period causes a 32% reduction in the herd fertility rate, without affecting the weight of newborn fawns, the survival rate nor growth performances in the sucking phase.     

An epizootic of adenovirus-induced hemorrhagic disease in captive black-tailed deer (Odocoileus hemionus).

Ten fawns and four adult black-tailed deer (Odocoileus hemionus) in a captive herd died as a result of adenovirus-induced hemorrhagic disease. Acute, systemic infections were characterized by hemorrhagic enteropathy, pulmonary edema, and occasional ulceration of the upper alimentary tract. Localized infections were limited to the upper alimentary tract and included stomatitis, pharyngitis, mandibular osteomyelitis, and rumenitis. In deer with acute, systemic infections, a diagnosis was made by histopathology and immunohistochemistry. The serum neutralization test was useful for confirming a diagnosis in animals with prolonged, localized infections. Deer originating from herds with a history of adenovirus infection should not be transferred to other captive herds or released into free-ranging populations because they may serve as carriers of adenovirus.     

An estimation of reproductive performance of farmed elk (Cervus elaphus) in North America

North American farmed elk (Cervus elaphus) producers were surveyed to determine period specific rates of calving, abortion, and dystocia, and to examine the effect of reproduction-related mortality on the productivity of farmed elk. The overall calving rate was 86.3% and the calving rate for adult cows was found to be significantly higher than that for heifers. Abortions were seen on 7.6% of farms and the overall abortion rate was approximately 0.6%. Dystocia was experienced in 5.9% of births. Neonatal mortality, summer mortality, weaning mortality, and postweaning mortality rates were calculated and compared. Failure to produce a live neonate was responsible for 64% of the total reproductive loss and calf mortalities from birth to 1 year of age accounted for 36%. Failure to produce a live neonate had a more significant effect on productivity than did mortalities from birth to 1 year of age, suggesting that reproduction has a greater economic effect on elk farms than neonatal mortality.     

Pregnancy detection and the effects of age, body weight, and previous reproductive performance on pregnancy status and weaning rates of farmed fallow deer (Dama dama)

Fallow does (n = 502) of different ages (mature, 2-yr-old, and yearling) were maintained with bucks for a 60-d breeding season to determine whether previous reproductive performance and changes in BW affect doe pregnancy rates and to compare the effectiveness of ultrasonography and serum pregnancy-specific protein B (PSPB) for the detection of pregnancy in fallow does. Ultrasonography was performed, blood samples collected, and BW recorded at buck removal (d 0) and at 30 and 90 d after buck removal. Lactational status (lactating = WET; nonlactating = DRY) were determined from farm records taken at weaning prior to each breeding season (autumn 1990 through autumn 1994). Ultrasonography and PSPB for determining pregnancy were in agreement 93% of the time. Overall pregnancy rates did not differ (P>.10) relative to age of the doe; the combined pregnancy rate was 92%. We also determined that 82.9% of does conceived early in the breeding season and that the incidence of embryonal-fetal mortality during the first 90 d after buck removal was 2.8%. In general, mature and 2-yr-old DRY does were heavier and had lower pregnancy rates than WET does. The overall weaning rate for all does was 77.9%. Loss in the number of fawns from pregnancy detection to weaning was equivalent to 14.8% for mature does, 24.7% for 2 yr old does, and 42.5% for yearling does. These data indicate that even though pregnancy rates were relatively high, further study is needed to determine the causes associated with subsequent fawn losses, particularly among yearling does. As a production tool, lactational WET/ DRY status testing was found to be an acceptable means for determining the reproductive potential of individual does within the herd. In addition, serum PSPB may be used in place of ultrasonography for pregnancy diagnosis in fallow deer as early as d 30 after buck removal.     

Risk factors for dystocia in farmed red deer (Cervus elaphus).

OBJECTIVE: To analyse data from a study of deer herd health and productivity to identify potential risk factors for the occurrence of dystocia. DESIGN: A 2-year longitudinal observational study of 14 red deer farms was carried out in New Zealand. About 2700 hinds were monitored each year for individual characteristics including body condition score (BCS), and reproductive performance. Grazing and calving management practices were recorded. During calving, farmers recorded calving difficulties (dystocia) that needed human assistance or caused the death of the hind. Risk factors potentially affecting the occurrence of dystocia were identified and analysed by multivariable statistical techniques. RESULTS: The percentage of hinds with dystocia was 0.52% (95% CI 0.32 to 0.78). Hinds with a post-winter BCS over 3.5 were 2.7 times as likely to experience dystocia as hinds scoring 3.5 or less. Given the same BCS class, bodyweight gain in late pregnancy was associated with an increased risk of dystocia. Grazing steep paddocks in the last trimester of pregnancy decreased the risk of dystocia in hinds with a BCS over 3.5. CONCLUSIONS: The risk of dystocia on red deer farms may be reduced if key individual animal, management and environmental factors are optimal.     

Causes of perinatal mortality in farmed fallow deer (Dama dama)

The causes of perinatal mortality in farmed fallow deer in the Camden region of New South Wales were determined between 1982 and 1987. The results of 144 necropsies on fawns showed that ante-parturient and parturient deaths occurred in 33 (22.9%) of cases, with post-parturient deaths accounting for 99 (69.8%), and undiagnosed causes the remaining 12 (8.3%). The most common cause of post-parturient death (43.1%) was exposure/starvation of fawns that had birthweights lower than the average for surviving fawns on these same farms (3.01 kg and 4.12 kg, respectively). These results provide good evidence of the correlation between low birthweight and perinatal mortality in fallow deer on Australian deer farms.     

A study of health and productivity of traditionally managed cattle in Zambia

A three-tiered survey was devised comprising a detailed questionnaire, a serological survey and a sentinel herd scheme for disease surveillance. The survey was carried out in the traditional farming sector in 7 districts of Zambia to obtain background information on cattle management and productivity, data on the prevalence of tick-borne and other disease problems in these areas and to monitor changes in individual herds.In the questionnaire survey, 288 farmers were interviewed. They owned a total of 15 360 head of cattle, representing approximately one percent of the national herd. Mean herd sizes ranged from 31 to 114 for each district. Mean calving percentages were 44–80%. Average national offtake from these herds was 10%. Calf mortality rates ranged from 4 to 32%, while adult yearly mortality rates ranged from 4 to 16%. Factors affecting the regional variation of these figures are discussed.     

Evaluating use of cattle winter feeding areas by elk and white-tailed deer: Implications for managing bovine tuberculosis transmission risk from the ground up

Transmission of bovine tuberculosis (Mycobacterium bovis) among wildlife and livestock has created important risks for conservation and agriculture. Management strategies aimed at controlling TB have typically been top-down, regionally focused, and government-led programs that were at best only partially successful. The purpose of this study was to quantify co-mingling of elk and white-tailed deer (WTD) with cattle at multiple spatial scales (i.e., the regional farm scale and winter cattle feeding area patch) in southwestern Manitoba, Canada, to assess the potential for bovine tuberculosis transmission and identify alternative management strategies. For each spatial scale we quantified use of cattle farms by elk and white-tailed deer. We mailed questionnaires to rural households and then conducted personal interviews with 86 cattle farmers to map the spatial distribution of their cattle winter feeding areas at a fine scale. We deployed Global Positioning System (GPS) collars on 48 wild elk and 16 wild white-tailed deer from 2003 to 2011. Elk were observed on farms by 66% of cattle producers, including 5% and 20% who observed direct and indirect contact, respectively, between elk and cattle. Cattle producers consistently (≈100%) observed white-tailed deer on their farms, including 11% and 47% whom observed direct and indirect contact, respectively, between white-tailed deer and cattle. A higher probability of white-tailed deer–cattle contact at the regional scale occurs on farms that (1) left crop residues specifically for wildlife, (2) had larger cattle herds, (3) used round bale feeders, and (4) were farther away from protected areas. None of the GPS-collared elk locations overlapped with cattle winter feeding areas. In contrast, 21% of GPS-collared white-tailed deer locations overlapped with winter cattle winter feeding areas (22% of these were from male WTD and 78% were from female WTD). White-tailed deer selected cattle winter feeding areas with higher (1) forage crop, (2) grassland/rangeland, and (3) forest cover around the cattle feeding area. Farmers overall expressed strongly negative attitudes toward eradicating the elk population or fencing the park to eradicate TB, but were generally supportive of less invasive and farm-based approaches. Our results suggested that management efforts to prevent TB transmission at the wildlife-agriculture interface can be effectively implemented using a ‘bottom-up’ approach that focuses on practical, farm-based mitigation strategies. This approach can be implemented by individual farm operators, is relatively low cost, and is generally well supported by farmers relative to other more extreme and controversial measures like wildlife eradication.     

Newborn calf welfare: A review focusing on mortality rates

Calf mortality control is vitally important for farmers, not only to improve animal welfare, but also to increase productivity. High calf mortality rates can be related to larger numbers of calves in a herd, employee performance, severe weather, and the neonatal period covering the first 4 weeks of life. Although the basic premise of preventing newborn calf mortality is early detection and treatment of calves at risk for failure of passive transfer of immunoglobulins, calf mortality due to infectious diseases such as acute diarrhea increases in the presence of these physical and psychological stressors. This suggests that farmers should not ignore the effects of secondary environmental factors. For prevention rather than cure, the quality of the environment should be improved, which will improve not only animal welfare but also productivity. This paper presents a review of the literature on newborn calf mortality and discusses its productivity implications.     

Rearing conditions, morbidity and breeding performance in dairy heifers in southwest Sweden

We carried out a longitudinal study of 122 dairy herds in southwest Sweden to investigate relationships of rearing conditions and health with heifer breeding performance and to estimate the incidence of clinical diseases and survival until 1st calving. A total of 3081 animals born in 1998 (47% Swedish Red; 50% Swedish Holstein breed) were followed from birth until calving, culling or death. Information about housing, management, breeds and dates of birth, breeding and calving was obtained from farmers. Diseases were recorded by farmers and veterinarians; antibiotic treatment was used in <25% of all cases.Median time to breeding was 17.5 months, 64% of all heifers bred by AI conceived at 1st breeding, and median time to calving was 27.6 months. Age at 1st breeding (log-transformed), conception at 1st breeding (binary), and age at 1st calving (log-transformed) were analysed with three mixed models, accounting for clustering by considering random-intercept and random-slope effects at the herd level. Around 40 potential predictors or confounders were recorded and considered for modelling. Time to breeding and calving increase greatly with the time heifers spend grazing, although up to 5 months of grazing before 1st calving appears to be more favourable than no grazing at all. The effect of grazing differs depending on the season of birth. Zero-grazed heifers calve 20% later if exposed to indoor ammonia concentrations >10 ppm after start of breeding. There is considerable variation between herds in breeding performance, except for conception at 1st breeding—limiting the potential for improving conception by herd measures.Observed total disease incidence rate was 14 per 100 animal-years from 7 months of age to estimated conception and 4.7 per 100 animal-years from conception to calving, with great variation between herds. Infectious diseases were predominant, and diarrhoea, respiratory disease and ringworm were the most common diagnoses. Eight hundred and fifty-three heifers left the study before calving, due to herd exits (incidence risk 0.073%), selling off live (0.061%), spontaneous deaths (0.050%) or slaughter (0.092%).     

Longevity, lifetime pig production and productivity, and age at first conception in a cohort of gilts observed over six years on commercial farms.

An observational cohort study was conducted using a producer group of 33 farms selected based on their completeness of reproduction data, including dates of birth, entry to a herd, and removal. Average lifetime pig production and parity at removal in a cohort of 2,265 females born in 1990 were 67.2 pigs born alive and 5.6 parities, respectively. Approximately 90% of farrowings occurred from the second through the fourth year from birth. Farrowing rates between parities of 2 and 4 were higher than other parities, and pigs born alive from parities 3 to 5 were the greatest among parities. The 10th and 90th percentiles of age at first conception were 227 and 322 days. Increasing the age at first mating was associated with low farrowing rate (P<0.01) in parity 0. Older age at first conception was associated with lower parity at removal, shorter reproductive herd life, and fewer lifetime pigs born alive (P< 0.01). Of the 2,265 breeding females, 253 (11.2%) were re-mated at parity 0 and farrowed. These sows with a record re-mating at parity 0 had lower parity at removal, less lifetime pig production and lower lifetime productivity than those with no re-mating at parity 0 (P<0.01). It is recommended that unbred gilts 230 days of age or older should be mated soon.     

Rearing performance of farmed fallow deer (Dania dama)

The ability of fallow does to rear fawns to weaning age was examined in a group of 243 adult does of known age (Group 1) and 509 adult does of unknown age (Group 2). All does had between 1 and 8 opportunities to rear fawns. There was an increasing proportion of does that failed to rear a fawn to weaning age as the number of rearing opportunities increased, although most does (93.6%) only failed on one occasion. A small percentage of does in groups 1 and 2 failed repeatedly to rear fawns to weaning. At slaughter, the presumed causes of failure in chronic non-breeders included pyometron, cystic ovaries, cervical cysts, a vulval neoplasm and salpingitis. The overall rearing success of both groups of deer was 82.4% and there was no consistent pattern of rearing failure relating to parity or previous rearing history.     

The improvement of sow productivity,a review of recent experiments in France

The numerical productivity of the sow is the resultant of a triple product involving fertility rate (or reproductive rhythm), prolificacy rate (or litter size at birth) and survival rate of piglets. The calculation made on the basis of the year of reproductive life must be distinguished from that made on the basis of the year of reproductive life must be The difference between these two modes of estimation ranges about 3–5 weaned piglets/sow/year in favour of the former. Acceleration of the reproductive rhythm, which is inversely proportional to the interval between farrowings, largely depends on the production techniques chosen. It may be obtained by early weaning (0.3 to 0.5 litter/sow/year), by the induction of pregnancy during lactation (0.1 to 0.2 litter/sow/year) or by the utilization of crossbred sows (0.02 to 0.05 litter/sow/year). Furthermore, an early reproductive life, depending on the age at puberty of the sows, may increase the numerical productivity per year of presence of the sows in the herd (0.2 to 0.3 piglet less for a delay of 10 days at first farrowing).The mortality rate of the piglets is about 20% and is still to high. A marked progress may be obtained by improving the rearing and housing techniques and the environmental conditions at birth, as well as by using crossbred animals.The utilization of crossbred animals leads to the most rapid improvement of the litter size (8% at birth and 15% at weaning). However, this technique must be consisered as complementary to selection which, in the long term, remains the most efficient method in spite of a very slow genetic change. The utilization of artificial insemination by means of semen from boars subjected to litter size or female progeny recording may also improve the prolificacy. The slight reduction of the litter size observed after very early weanings is widely counterbalanced by the acceleration of the reproductive rhythm so that this modern technique leads to a spectacular increase in the numerical productivity of the sows. This is not the case for some physiological techniques such as superovulation which is not sufficiently controlled to allow current utilization.     

Management practices and their association with reproductive health and performance in Colorado beef herds

An observational study was conducted to quantify the effects of management practices on reproductive performance and disorders of beef cows. The study population consisted of 44 randomly selected Colorado cow-calf herds monitored for disease and reproductive events as part of the National Animal Health Monitoring System. The managers of the herds were surveyed with a standardized questionnaire to determine specific management characteristics of their operations. Data were analyzed using the random-effects multiple logistic regression model. Outcomes of interest were calving rate, herd incidence rates of dystocia and combined reproductive disorders, and calf mortality rate. A higher calving rate was associated (P less than .01) with a decreased percentage of replacement females in the herd, a shorter breeding season, a smaller herd size, and a lower percentage of bulls being used as yearlings. Incidence rates of both dystocia and combined reproductive disorders were found to be lower (P less than .01) in herds that were fed cottonseed cake as a winter supplement, but higher (P less than .01) in herds that were fed grass hay as a winter supplement. Herds located in the mountains of Colorado had lower (P less than .01) incidence rates of dystocia and reproductive disorders than herds located in the eastern plains. Calf mortality rate was found to be higher (P less than .05) with calving seasons that began earlier in the year. Higher calf mortality rates were associated (P less than .05) with an increased incidence of dystocia, the commingling of cattle on summer range, and smaller herd size.