Laurent Audigé

A BODY CONDITION SCORE SYSTEM AND ITS USE FOR FARMED RED DEER HINDS

Abstract A longitudinal observational study of 15 red deer farms in New Zealand was carried out for a 2‐year period. To assess the body condition of deer, a scoring chart was developed with scores ranging from 1 (lean) to 5 (fat) with half‐unit increments. Scores were given after palpating the tuber coxae, sacrum, and rump area of the deer standing straight and quiet. Repeatability and reproducibility were evaluated on 39 yearling hinds and 90 adult hinds on four properties which were independently scored twice by two assessors to investigate assessor bias and consistency. A body condition score (BCS) was assigned to 1400 and 2100 hinds in consecutive years in March before mating, in September before calving, and in March of the next year at weaning. There were wide variations of individual hind body condition and mean hind body condition between farms. Overall, yearling hinds lost body condition during winter and subsequently during lactation up to weaning. Repeatability and reproducibility were above 0....

Osteochondrosis, skeletal abnormalities and enzootic ataxia associated with copper deficiency in a farmed red deer (Cervus elaphus) herd

A red deer herd of 150 mixed-age hinds, 48 stags and 102 weaners was identified as severely copper deficient during an observational study of 15 deer farms in the lower North Island of New Zealand during 1992 and 1993. Severe lameness was observed in nine weaners in 1992 (8.8% prevalence) and 15 in 1993 (12% prevalence). Typical abnormalities included swollen hocks and carpal joints and outward rotation of hind legs with hocks touching. At postmortem examination, there were epiphyseal fractures of the femoral head, severe degenerative arthropathy of the coxo-femoral joints and erosions of cartilage in many other limb joints. Osteochondrosis was confirmed histologically. Concurrently, three adult hinds and one adult stag developed into-ordination typical of enzootic ataxia which was confirmed histologically. Blood and liver copper concentrations in untreated affected weaner deer ranged from undetectable to 16.0 micromol/l (mean 7.6 micromol/l) and 25 to 53 micromol/kg (mean 39 micromol/kg), respectively. Mean blood copper concentrations in unaffected weaners in March 1992 and 1993 were 5.3 micromol/l and 4.4 micromol/l, respectively. The mean blood copper concentration in seven hinds in September 1992, prior to onset of clinical signs of enzootic ataxia, was 1.5 micromol/l (range 1.0-2.4 micromol/l). At other times of the year, mean blood copper concentrations ranged up to 12.5 micromol/l in adults and 8.9 micromol/l in weaners before treatment began in 1993. Pasture analyses showed copper contents of 6-11 ppm in 11 samples collected during 1992 and 1993. Sulphur ranged from 0.18 to 0.37%, molybdenum from 0.51 to 3.56 ppm and iron from 130 to 2886 ppm. These measurements supported a diagnosis of secondary copper deficiency. Supplementation with oral oxidised copper wire particles was undertaken from December 1992, resulting in an improvement in blood copper concentrations in some classes of deer. No further clinical abnormalities have been observed.

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.

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.

Disease and mortality on red deer farms in New Zealand

A longitudinal observational study of 15 red deer farms was carried out in New Zealand for two years from March 1992. The deer were monitored for performance and health problems, and farm management practices were recorded. Numbers at risk were 4683 hind-years, 2459 stag-years and 3202 weaner-years. The numbers of primiparous and adult hinds at risk of losing their progeny by weaning were 653 and 3364, respectively. Where possible, postmortem examinations were carried out, and organs were sampled for histological and microbiological investigation. Rates of mortality varied with season with most stag and hind deaths in winter and weaner deaths in autumn and winter. Overall mortality rates were 1.77, 2.60 and 5.87 per 100 deer-years for hinds, stags and weaners, respectively. Malignant catarrhal fever accounted for 0.53 stag and 0.17 hind deaths per 100 deer-years at risk. Misadventure, including broken bones, accounted for 15.4 per cent of weaner mortalities, or 0.53 weaner mortalities per 100 weaner-three months in autumn. Yersiniosis was confirmed in 18.6 per cent of weaner deaths, or 1.09 weaners per 100 weaner-years during the first six months after weaning, but was also suspected but unconfirmed in a further 41 per cent of weaner mortalities. Overall, 17 per cent of yearling hinds, and 9.2 per cent of adult hinds lost their progeny between pregnancy diagnosis in June and weaning in March. One outbreak of osteochondrosis was recorded. Mortality rates varied between farms and many mortalities were preventable.

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.

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.

Reproductive performance of farmed red deer (Cervus elaphus) in New Zealand: V. Mob and individual-hind risk factors associated with calf rearing to weaning.

A 2-year longitudinal observational study of 15 red deer farms was carried out in New Zealand from March 1992. Both years combined, 3364 adult and 653 yearling hinds were diagnosed pregnant in June by ultrasound scanning and monitored for reproductive success up to weaning. At weaning, pre-rut at approximately 100 days after calving, udders were palpated or observed by the farmer and hinds were categorised as lactating (wet) indicating survival of calf, or not lactating (dry). Farm management practices during calving and early lactation were recorded. Analysis of risk factors associated with progeny survival was done using path analysis (separately for adult and yearling hinds). Adult hinds >3 years old at calving, conceiving before 1 May and having a body-condition score >2 in September had 2.8, 2.4 and 2.9 times significantly higher odds of rearing a calf to weaning than other hinds, respectively. Adult hinds had about 5 times lower odds of rearing a calf to weaning when they were mixed with mature stags during calving. When farmers visited calving paddocks and checked for calving problems, adult hinds had 1.7 times higher odds of rearing a calf to weaning. When the farmer entered calving paddocks at least every second time they observed the hinds, yearling hinds had a twice higher odds of rearing a calf up to weaning. Sunny weather and high maximum temperatures were positively and negatively associated, respectively, with the probability of an adult hind being in lactation at weaning.