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Context Beekeepers and honeybee queen breeders alike currently have few tools at their disposal for the management of genetic diversity inside their populations. Pedigree information is often absent, beekeepers cannot afford to genotype selection candidates due to costs, and acquisition of material for genotyping without risk to individual queen bees is difficult. However, in New World honeybee populations where import of additional genetic material to refresh the population is restricted (e.g. Australia) or impossible (e.g. New Zealand), management of genetic diversity is important for population sustainability. While the role of individual beekeepers in maintaining genetic resources becomes crucial under these circumstances, a more holistic approach to the management of genetic diversity is needed to allow for maximum impact of their contribution. Aims The establishment of affordable genotyping methodologies for successful strategies in managing honeybee genetic diversity, as well as the necessary delivery systems for the results to support the beekeeping community by providing interpretation in the context of the wider population. Methods Genotyping-by-sequencing of honeybee samples collected as part of a national survey were used as the basis for assessment of New Zealand’s honeybee genetic diversity and development of a tool with largely self-explanatory outputs that can be used directly by beekeepers. Key results It would appear that New Zealand’s honeybee population is sufficiently diverse to maintain population viability. However, both within regions and within companies, genetic diversity is significantly reduced, especially in the case of specialised queen breeders, indicating that active management will be necessary to achieve long-term sustainability. Conclusions Interactive tools are needed to help beekeepers understand their role in maintaining overall genetic diversity in the honeybee population as well as the potential impact of planned bee movement and queen acquisitions. Regular rounds of voluntary bee sampling can be used as the basis for management decisions without concentrating genotyping load on specific operators and restricting diversity assessments to subpopulations. Implications The described strategy is expected to both improve the outlook of New Zealand’s honeybee population as a whole and facilitate stringent genetic improvement programs by enabling queen breeders to make informed selection decisions and giving beekeepers confidence in the viability of their population.

International audience; The absence of a full pedigree can hinder selective breeding efforts. In honeybees, definitive maternity and especially paternity of queens is difficult to determine, even under managed mating schemes (e.g. using artificial insemination) due to the negative effects of single-drone mating on colony fitness. Here we genotyped 388 living queens from two beekeeping operations using Genotyping-by-Sequencing (GBS). We evaluate two methods to call single-nucleotide polymorphism (SNPs), Tassel 5 and Stacks, for their ability to supply SNPs that can recover known relationships. While Stacks discovered more SNPs (29,433), SNPs called with Tassel 5 (16,757) were found to be more accurate for the derivation of relationships. This methodology presents a low-cost genotyping approach and can be used to support commercial honeybee breeding schemes.

While other livestock breeders routinely refer to individual estimated breeding values based on large datasets, honey bee selection remains focused on personal preferences and ad hoc selection sche...

Using internet-based software known as 1000Minds, choice-experiment surveys were administered to experts and farmers from the Irish sheep industry to capture their preferences with respect to the relative importance – represented by part-worth utilities – of target traits in the definition of a breeding objective for sheep in Ireland. Sheep production in Ireland can be broadly separated into lowland and hill farming systems; therefore, each expert was asked to answer the survey first as if he or she were a lowland farmer and second as a hill farmer. In addition to the experts, a group of lowland and a group of hill farmers were surveyed to assess whether, and to what extent, the groups’ preferences differ from the experts’ preferences. The part-worth utilities obtained from the surveys were converted into relative economic value terms per unit change in each trait. These measures – referred to as ‘preference economic values’ (pEVs) – were compared with economic values for the traits obtained from bio-economic models. The traits ‘value per lamb at the meat processor’ and ‘lamb survival to slaughter’ were revealed as being the two most important traits for the surveyed experts responding as lowland and hill farmers, respectively. In contrast, ‘number of foot baths per year for ewes’ and ‘number of anthelmintic treatments per year for ewes’ were the two least important traits. With the exception of ‘carcase fat class’ (P < 0.05), there were no statistically significant differences in the mean pEVs obtained from the surveyed experts under both the lowland and hill farming scenarios. Compared with the economic values obtained from bio-economic models, the pEVs for ‘lambing difficulty’ when the experts responded as lowland farmers were higher (P < 0.001); and they were lower (P < 0.001) for ‘carcase conformation class’, ‘carcase fat class’ (less negative) and ‘ewe mature weight’ (less negative) under both scenarios. Compared with surveyed experts, pEVs from lowland farmers differed significantly for ‘lambing difficulty’, ‘lamb survival to slaughter’, ‘average days to slaughter of lambs’, ‘number of foot baths per year for ewes’, ‘number of anthelmintic treatments per year for ewes’ and ‘ewe mature weight’. Compared with surveyed experts, pEVs from hill farmers differed significantly for ‘lambing difficulty’, ‘average days to slaughter of lambs’ and ‘number of foot baths per year for ewes’. This study indicates that preference-based tools have the potential to contribute to the definition of breeding objectives where production and price data are not available.

The present paper provides an indication (using selection index theory) of the contribution of genetics to a reduction in methane emissions through the current selection for productivity traits (defined as the inherent rate). This is then compared with potential new approaches that incorporate measurements or estimates of methane production as selection criteria. The predicted value of the inherent reduction in methane at a price (all costs and prices are in Australian dollars) of $25/t carbon dioxide equivalent (CO2-e; methane × 25) is $0.38/cow mated per year. The direct value of the estimated annual genetic gain in productivity (about $3/cow mated) is about eight times the value of the savings in methane. The value of the carbon savings doubles to ~$0.75 if methane yield (methane per unit feed intake) is included in the index. This is due to a reduction in methane emissions of 0.78% of the mean (1.20 kg methane/cow mated per year at a carbon cost of $25/t CO2-e) which increases to 1.0% at $50/t CO2-e. If selection is on methane alone, the annual response is ~1.45%, which is valued at $1.39 at a price of $25/t CO2-e. However, adoption is less than 100% at the breeder level, so that realised gains will be less than predicted here.

Breeding objectives for meat sheep in Ireland have been defined and used in the development of selection sub-indices to provide commercial producers with an economic comparison of animals for specific performance trait groups. Using trait-by-trait bio-economic models and a range of methodologies, economic weights (in € per lamb born per genetic standard deviation in the trait) have been calculated for maternal and terminal sire performance traits as follows: production traits; −€1.41 for days to slaughter, €0.35 for carcase conformation class, −€0.52 for carcase fat class, lambing traits; −€0.69 for lambing difficulty for single-bearing ewes, −€0.37 for lambing difficulty for multiple-bearing ewes, €1.15 for lamb survival, maternal traits; €0.83 for number of lambs born, −€1.49 for ewe mature weight, health traits; −€0.09 for lamb foot rot, and −€0.82 for ewe foot rot. Results indicate the significant value of improving the ability of lambs to survive to weaning, without increasing number of lambs born. The highly negative economic weight for both days to slaughter and mature size represents a powerful unfavourable relationship between the two traits. Economic values for lambing difficulty and foot rot represent the significant costs these traits have in the Irish sheep production system. In the early stages of the development of the genetic improvement program for sheep in Ireland the breeding objective defined in this paper provides directed emphasis for trait recording, selection strategies, and mating systems. In addition the economic weights provide indications as to how much genetic improvement in a specific trait would be worth paying for. The proposed formulation of the total economic index as sub-indices provides the ability for commercial farmers to adjust breeding emphasis towards specific market outcomes or address key production aspects in their particular farming system.

To assess the relationship between the radiographic and microscopic appearance of the physeal regions of the distal third metacarpal (Mc3) and metatarsal (Mt3) bones of Thoroughbred foals at 160 days of age, and to clinically assess changes in contour of the distal Mc3 and Mt3 physeal regions from birth to 160 days of age. To assess relationships between maximum clinical physis scores and age, time of year, foal's sex, condition score, growth rate, copper (Cu) concentration in the liver of the foal, and supplementation of the dam with Cu in late gestation.Dams were given Cu (n=5 and n=11, in Years 1 and 2, respectively) or saline (n=5 and n=12, in Years 1 and 2, respectively) injections in late gestation. Liver biopsies were harvested from foals in the first week of life, and the whole liver homogenised after the animals were euthanised at around 160 days of age, to determine Cu concentrations. Pasture samples were collected every 4-8 weeks for analysis of mineral composition. During Year 1, 10 foals were weighed and examined every 2 weeks from birth to 160 days of age for evidence of pain and lameness in the distal Mc3/Mt3. In Year 2, 23 foals were weighed, condition-scored and examined for evidence of pain and lameness weekly for the first 5 weeks of life, then every 2 weeks from birth to 160 days of age, and a clinical physis score for the distal Mc3/Mt3 given. Cabinet radiographs of frontal slices of the physeal region of the distal Mc3/Mt3 at around 160 days of age were given a radiographic physis score. Physes were then examined histologically for evidence of abnormal endochondral ossification.Gross enlargements of the distal Mc3 and Mt3 were observed in all foals in this study, but were not associated with lameness, pain or inflammation. The most severe clinical physis scores occurred over 2 months in late summer/autumn, and were not influenced by the foal's growth rate, sex, or Cu concentration in the liver, or treatment of dams with Cu in late gestation. The clinical physis score was highly correlated to radiographic evidence of shouldering in the forelimb and hindlimb (both p0.001). Focal disturbances in endochondral ossification were evident radiographically and histologically in the some of the physes at 160 days of age. The mineral composition of pasture was similar in Years 1 and 2, and concentrations of Cu and zinc were below those currently recommended for growing horses.Gross enlargements of the distal Mc3 and Mt3 were not consistent with previous descriptions of physitis. Results suggest that while many Thoroughbred foals at pasture will have visible boney enlargements of the distal Mc3/Mt3 in the first 5 months of life, few have physeal cartilage abnormalities or significant compromise of endochondral ossification. The importance of these clinical swellings may be overestimated, and they may more appropriately be called physiological enlargements associated with remodelling of bone.

Pregnant mares in New Zealand are often kept at pasture with inadequate copper (Cu) concentrations according to National Research Council (1989) recommendations. Many authors recommend Cu supplementation of pregnant mares to reduce the degree and severity of developmental orthopaedic disease (DOD) in their foals. Few data exist on the efficacy of Cu injections in mares in raising liver Cu concentration in pregnant mares or their foals, or the pattern of normal decline in liver Cu concentration of foals after birth. In this study pregnant mares were treated with injectable Cu, or saline, in two different regimens, in 2 consecutive years. Mares and foals had liver biopsies harvested to determine the effect of mare Cu supplementation on liver Cu concentration, and to identify normal patterns of decline in foal liver Cu concentration from birth to 160 days of age. Injectable Cu supplementation had no significant effect on dam or foal liver and plasma Cu concentration. A mathematical model to describe...

To determine the chemical body composition of Thoroughbred foals born in two consecutive years, and to investigate several techniques used to predict body composition in foals born in the second year, with particular reference to fat.The chemical composition of 20 foals at around 160 days of age, born in two years, was determined. In vivo techniques to predict body composition were assessed in 23 foals born in Year 2, before and after euthanasia; 10 of these foals were used for chemical body composition analysis. Techniques to assess body composition in vivo included liveweight (LW), overall and regional condition scores, ultrasonic fat thickness measurements over the ribs and rump, linear measurements and bioelectrical impedance analysis. Correlations were determined between ultrasonic fat thickness, and bioelectrical impedance analysis, before and after euthanasia. Stepwise regression analysis was used to determine the relationships between in vivo techniques used to assess body composition and the chemical body composition of 10 animals.Foals used for analysis of chemical composition weighed between 220.5 and 260.0 kg before euthanasia. Fat content ranged from 5.5-13.0% of the partial empty bodyweight (LW less head, gastrointestinal contents, distal limbs and skin). Fillies had significantly more fat mass and percentage fat than colts (p=0.031 for both measurements). The mean chemical composition of the fat-free partial empty body was 73.2% (SD 0.6) water, 22.7% (SD 0.9) protein, and 4.1% (SD 0.4) ash. Most of the variation in the concentration of empty body water was associated with variation in the concentration of fat (p0.001). The live animal overall condition scores were correlated with fat mass and concentration (p=0.006 and p=0.013, respectively; n=10). Condition score over the rib region was highly correlated with fat mass and fat concentration (p=0.004 and p0.001; n=10). Ultrasound measurements taken 10 cm cranial to the tailhead and 4 cm from midline, used to assess the thickness of rump fat, were correlated with condition score (p=0.001), and explained 71% of the variation in body fat mass (p=0.002; n=10).Nearly 50% of the variation in fat-free mass and partial empty body water mass were associated with variation in the impedance indices calculated from length and bioelectrical impedance analysis measurements (p=0.023 and p=0.026, respectively; n=10).At around 42% of expected mature weight, fillies were significantly more fat than colts. Condition scores were correlated with partial empty body fat mass, and there was a trend for higher scores in fillies compared to colts. Much of the variation in water or protein mass of the partial empty body could be explained by variations in LW.Measurements of LW, rump fat and condition score are useful predictors of the chemical composition of foals at 5 months of age.

The unique Pere David's (Elaphurus davidianus) x red deer (Cervus elaphus) backcross hybrid has been used to search for evidence of quantitative trait loci (QTL) for antler pubertal (date and live weight at pedicle initiation) and antler seasonality (date of antler cleaning and casting) traits in temperate species of deer. Analyses using marker information revealed evidence for a QTL for date at pedicle initiation (LOD = 3.7) and live weight at pedicle initiation (LOD = 3.1). These QTL explained 13% and 11% of the phenotypic variance in these traits, respectively.

Asian markets for velvet antler perceive the colour of the core as a primary indicator of quality. The factors which influence colour are not known, but the market preference in Korea is for an even mid‐red colour. The aim of the present study was to determine whether removal technique and post‐removal handling influence velvet colour. Investigations took place at AgResearch Invermay and at Mount Hurt Station in mid Canterbury, New Zealand. The influences on velvet antler colour of sedative drug, mild stress, local anaesthetic administration, timing of tourniquet application, and restraint of the stags in a crush or workroom for velvet antler removal were investigated. The effects of antler orientation post‐removal and post‐removal environmental temperature on velvet antler colour were also investigated. In all studies, velvet antler was frozen and held at ‐20°C before being dried either by freeze drying or commercially. In all trials, a consistent pattern of both lightness and hue angle was show...

Objective To determine the changes in Ca, P, Mg, Na, K, S, Cu, Fe and Zn concentrations of milk during the lactation in pasture-fed Thoroughbred mares and then calculate the dietary mineral requirements of the sucking foal and the lactating mare. Procedure Milk was sampled on days 1, 3, 7, 14, 21, 28 and at various times between 55 to 65, 85 to 95 and 135 to 150 days after parturition from 21 pasture-fed mares. The concentrations of macro- and micro-elements in the milk were determined by inductively coupled plasma emission spectrometry. Results Concentrations (mg/L) of these elements were highest in colostrum (Mg 302, Na 561, K 955, S 1035, Cu 0.76, Fe 0.79 and Zn 5.5) except for Ca (1245) and P (895), which where highest on day 7. The mean milk mineral element concentrations (mg/L) over days 55 to 150 were Ca 843, P 543, Mg 47, Na 120, K 590, S 219, Cu 0.19, Fe 0.34 and Zn 2.1. The mean plasma element concentrations (mg/L) over the same period were Ca 120, P 77.1, Mg 17.0, Na 3110, K 168, S 983, Cu 1.1, Fe 1.5 and Zn 0.49. Concentration gradients between plasma and milk were observed and, in the case of Ca, P, Mg, K and Zn, their concentrations in milk were greater than those in plasma, while a reverse situation was observed for Na, S, Cu and Fe. Conclusion With the exception of Ca and P, the highest concentrations of mineral elements were observed in the colostrum. The nursing foal should have access to good pasture or creep feed, because the intakes of Ca, P and Cu from milk may be less than optimum to meet the daily mineral element requirements.

The objective of this study was to determine whether Mo causes secondary Cu deficiency in pasture‐fed horses. Twelve Thoroughbred weanling fillies were divided into two groups and fed either high Mo pasture (8 to 15 mg Mo kg−1 DM) or a low Mo pasture (0.6 to 1.2 Mo kg−1 DM) for 84 days. Both pastures contained 6 to 9 mg Cu kg−1 DM. The animals were challenged with Cu over the last 14 days to determine change in their Cu status to 1.0 mg Cu kg−1 liveweight d−1 given orally three times a week. Copper status was assessed from liver, plasma, blood cell, and plasma trichloroacetic acid‐insoluble Cu concentrations as well as the enzyme activities of plasma caeruloplasmin and red blood cell superoxide dismutase. None of these indices was affected by the increase in Mo intake. Horses grazing pasture high in Mo responded no differently to Cu challenge than did those on low Mo pasture. The results of this study suggest that Mo is unlikely to increase dietary Cu requirements and induce secondary Cu deficien...

Summary The effect of copper supplementation of pasture fed mares and foals on the copper status of the foals, in terms of plasma, soft tissue and bone copper concentrations and caeruloplasmin activity, was investigated. Twenty-one Thoroughbred foals from either control mares (n = 9), or copper-supplemented mares (n = 12) were divided randomly into control (pasture only, n = 10) or supplemented (pasture and oral copper sulphate, n = 11) groups. The pasture diet was grazed by all animals, and contained 4.4–8.6 mg Cu/kg dry matter (DM). The copper supplement for the mares contained copper sulphate equivalent to 0.5 mg Cu/kg liveweight (LW)/day. This daily dose was converted to allow administration as a thrice weekly dose (i.e. multiplied by 7/3) which was given for 13–25 weeks prior to foaling. The supplemented foals, also dosed 3 times a week, received 0.2 mg Cu/kg LW/day at age 21 days, which was increased to 0.5 mg Cu/kg LW/day at 49 days and was continued at this level until euthanasia at 150 days. Foal plasma copper concentration and caeruloplasmin activity increased from birth to 21 days post partum and then plateaued at a concentration similar to the mare, but the rise in these indices was not affected by copper supplementation of the mare or foal. Copper supplementation of the foal increased foal liver copper concentration at 150 days (P

The effect of copper status on the evidence of bone and cartilage lesions was investigated in 21 Thoroughbred foals. The foals and their dams were grazed on pasture containing 4.4-8.6 mg Cu/kg dry matter (DM). Four treatment groups were created by randomly allocating mares and their foals to either copper supplemented (0.5 mg Cu/kg liveweight (LW)/day), or control (pasture only) groups. This experimental design allowed the effect of copper supplementation of mare and foal to be examined independently. Parameters of bone and cartilage development were assessed in the foals both in vivo, and at post mortem at approximately age 150 days. Mare copper supplementation significantly (P

The breeding season in temperate species of deer is characterized by the rut, a period of intense sexual activity when the male eats very little and competes for access to females. Males have been reported as losing proportionately up to 0·30 of live weight over a 6- to 8- week period. The majority of the live-weight loss is accounted for in loss of depot fat, with smaller losses in muscle reserves. The effects of body composition, hormone status and season on these changes in fat and muscle reserves were examined in mature fallow bucks (Dama dama).The experiment was conducted in two stages, the ‘rut’ (February to May), and ‘spring’ (June to November). For the ‘rut’ period, bucks were randomly allocated to either ad libitum feeding, entire (HiEnt), matched group feeding, castrated (CAST), or entire bucks restricted to 7·6 kg dry matter per week (LoEnt) treatment groups (no. =4, 4 and 6, respectively). Three bucks from each of the HiEnt and LoEnt groups were selected for the ‘spring’ period. Bucks were given food ad libitum until mid October, whereupon they were restricted to 2·5 kg dry matter per week for 4 weeks (SPRING). Group food intake and individual live weights were measured weekly throughout both, periods. Body composition was measured by computed tomography on five and three occasions during the ‘rut’ and ‘spring’ stages, respectively.Comparisons of the relative losses of total fat and muscle relative to empty body weight (EBW) using the allometric model (y = aXb) revealed significant treatment differences. HiEnt bucks had a high relative rate of fat and a low rate of muscle mobilization (b = 5·23 and 0·38, respectively). Only the CAST group had lower (P < 0·1) b coefficient for fat than the HiEnt group at 2·79. The LoEnt group was the only group in which the b coefficient for muscle (at 1·07) was not significantly lower than 1·0. Visceral organ weight was lost at the same rate as EBW across all treatments. There was no net loss or gain of bone for any treatment group as the b coefficients were not significantly different from zero. Fat depots were analysed relative to the total fat depot using the allometric model. The HiEnt group displayed a pattern of fat mobilization whereby the external depots were mobilized at the greatest relative rate and the internal fat depots at the lowest rate (b coefficients were 1·86, 1·23 and 0·68 for the subcutaneous, intermuscular and internal fat depots, respectively). CAST and SPRING groups were not significantly different from HiEnt bucks in the relative mobilization of fat depots. All fat depots in the LoEnt group were mobilized at the same relative rate as total fat, as the b coefficients were not significantly different from 1·0.

Objective To evaluate standing, percutaneous, ultrasound-guided, transthoracic liver biopsy in mares, and transabdominal, laparoscopically-guided, liver biopsy under general anaesthesia in foals, as techniques for obtaining tissue for assessment of copper status. The techniques were evaluated with respect to ease of use and effect on the animal. Procedure Twenty of 24 Thoroughbred mares and 21 of their foals were biopsied. The animals were part of a larger study of the effect of copper supplementation on copper status and the prevalence of developmental orthopaedic disease. Livers were also collected from unrelated horses and sampled to investigate the variability in the distribution of copper in liver tissue. Result The biopsy technique caused no lasting effect on the mares, but there was an increased risk of viscus penetration associated with taking multiple biopsy cores. The use of ultrasonography to scan the target area for the liver identified four cases that were not appropriate candidates for liver biopsy, because of large intestine being located in the biopsy area. In the foals there were no serious postoperative adverse effects, nor was there any evidence of problems caused by the procedure when the abdomen was examined post-mortem at 5 months of age. In livers collected to investigate the variability of copper concentration, copper appeared to be relatively evenly distributed through the liver. Conclusion Standing, percutaneous, ultrasound-guided, transthoracic liver biopsy in mares, and transabdominal, laparoscopically-guided, liver biopsy under general anaesthesia in foals are convenient procedures for obtaining liver tissue for assessing copper status in horses. The use of ultrasound to identify liver tissue is recommended, especially in older mares.

Optimum reproductive efficiency of farmed deer is often constrained by apparent maladaptation of wild cervids to a given farm environment or components of that environment. Seasonal breeding amongst forest-fringe species of northern temperate origin (e.g. red deer, fallow deer) benefits the species within its natural range, but often creates misalignment in southern temperate zones between the high nutritional demands of lactation in summer and the earlier peak of pasture production and quality occurring in spring. This can lead to increased calf mortality, decreased calf growth rates and depressed dam liveweights. Much emphasis has been placed on manipulating either pasture production patterns or the timing of birth to create better synchrony between the two. The latter largely involves artificial manipulation of the timing of conceptions (e.g. melatonin treatment), but there may also be options for genetic selection of deer for earlier calving patterns. Tropical cervid species farmed in temperate environments can exhibit either aseasonal reproduction (e.g. chital deer) or autumn-wintering calving patterns (e.g. rusa deer), leading to high mortality of neonates (hypothermia, predation) under uncontrolled breeding management. However, there are simple management options to synchronise and shift calving patterns to better align tropical species to temperate environments. The effects of chronic and acute stress on reproductive efficiency of farmed deer are often discussed but seldom demonstrated. Many farmed deer populations exhibit high pregnancy rates (i.e. > 90% females pregnant), indicating robust reproductive physiology and general habituation to the farmed habitat. Low reproductive rates of pubertal red deer hinds in some herds may be partly indicative of the effects of chronic stress, although other factors such as social facilitation and nutrition cannot be discounted. While species of cervids that are used for farming generally display a high degree of behavioural plasticity, the farm environment and associated management practices may impinge on important components of the social environment. Thus, practices such as controlled breeding (e.g. single-sire mating) and confinement during calving may have effects on reducing overall reproductive potential by disrupting social processes (e.g. dam—calf bonds). This highlights the paucity of knowledge on the complexities of cervid behaviour and their implications in both wild and farmed deer.

A series of six studies were carried out in red deer stags to test hypotheses concerning the importance of steroid control of velvet antler growth and to investigate mechanisms by which these hormones exert their effects. Medroxyprogesterone acetate (MPA) an LH inhibitor administered to stags during hard antler caused premature antler casting, reduced subsequent antler weight and caused a reduction in the LH and testosterone responses to GnRH. In two separate studies blockade of testosterone receptors with cyproterone acetate (CPA) administered to stags, either during early velvet antler growth or during the hard antler stage, significantly reduced LH and testosterone responses to GnRH. In both studies antler length, but not weight, was increased by CPA treatment. In another study testosterone implants were used to prevent the gradual decline in plasma testosterone levels normally observed during winter. Implants were removed 3 weeks before the anticipated date of antler casting. The implants significantly increased plasma testosterone levels and subsequent antler growth (expressed as a proportional increase compared with the previous year) compared with untreated controls. To determine whether the annual cycle of plasma testosterone response following GnRH stimulation was due simply to a lack of LH stimulation, ovine LH was injected on six occasions at defined stages of the antler cycle to red deer stags and the testosterone response measured. The testosterone responses were low at antler casting and during velvet antler growth compared with antler cleaning and peak rut. It appears low testosterone levels are due, in part, to a loss of responsiveness by the testes to LH as well as a low level of secretion of LH during the antler growing season. Finally synthetic ACTH was injected at the same defined stages of antler growth as in the previous study to determine whether cortisol and adrenal androgen production altered with the stage of the antler cycle. No significant differences were found in the dehydroepiandrosterone (DHEA) response, but cortisol responses were higher from late velvet antler growth to peak rut, compared with the times of antler casting and early velvet growth. Overall it was concluded that velvet antler growth can occur without testosterone stimulation during the period of velvet growth, but the data reinforce the concept that the timing of antler growth is linked to the annual cycle of testosterone.

The allometric relationship (Y = AX b ) between velvet antler weight (Y) harvested at 2, 3, and 4 years of age and the respective winter lean liveweight (X), was examined in 145 farmed red deer stags (Cervus elaphus). The stags which were the progeny of 10 sires, were born in 1982 and 1983. The allometric coefficients (b) for the 1982‐and 1983‐born stags were 2.4 and 1.7 respectively which indicated that velvet antler was late maturing relative to winter lean liveweight. Sire had a significant effect on the scaling factor (A, P < 0.05) of the allometric equation, which indicated that over the liveweight range in this study, there was up to a 30% difference in velvet antler weight adjusted for winter lean liveweight for stags from the different progeny groups. The sire effect on the relationship between velvet antler weight and winter lean liveweight indicates the possibilities for selection of genetically superior sires for velvet antler production relative to winter lean liveweight.

The rapid growth in deer farming and interests in the conservation of various deer species have stimulated development of embryo transfer procedures. The protocols developed are based on those used in sheep and cattle and generally involve surgical embryo recovery following FSH-induced superovulation. Data are limited, but pregnancy rates of around 3.0 per donor female for red deer, and around 1.5 for fallow deer are being achieved.

The application of artificial insemination technology within the red deer and fallow deer farming industries is in its infancy. However, its future potential is enormous, particularly in relation to genetic improvement programmes and international exchange of genetic material. This paper reviews the present state of such technology for these two species by discussing the major components of oestrous synchronisation, semen collection/cryopreservation and insemination techniques. Artificial oestrous synchronisation overcomes problems associated with the detection of natural oestrus. Synchronisation can be achieved through the administration of progestagens or strategic administration of prostaglandin analogues. Most studies have investigated the use of the controlled internal drug release (CIDR) device, with 12–14 day insertion plus 200–250 IU pregnant mares' serum gonadotrophin (PMSG) at device withdrawal (red deer) or 14 day insertion alone (fallow deer) being the more common treatment regimens within the natural breeding season. Administration of cloprostenol on Days 13–14 of the oestrous cycle is also highly effective in fallow deer. Future studies need to refine synchronisation regimens to increase oestrous synchrony. Semen collection, which is under seasonal constraints, is mainly by electro-ejaculation, with semen processed for cryopreservation using standard techniques. The development of artificial vagina (AV) collection methods holds promise for safer and more efficient semen collection from deer. Transcervical access to the uterine lumen has proven difficult in red and fallow deer. Presently, most fixed-time inseminations are performed per vaginam (intravaginal or intracervical) or laparoscopically (intrauterine). Conception rates to per vaginam inseminations ((20–80) × 10 6 motile spermatozoa) at approximately 48 h after CIDR device withdrawal have been highly variable and generally low (less than 40%) for both species, with a tendency towards better rates (40–60%) with double inseminations (44 and 68 h) in red deer and higher concentrations of motile spermatozoa (more than 100 × 10 6 ) for fallow deer. Conception rates to laparoscopic intrauterine inseminations ((10–40) × 10 6 motile spermatozoa) at 54–56 h (red deer) or 65–70 h (fallow deer) after CIDR device withdrawal have been more consistent and generally higher (60–70%) for both species.

There is often a poor synchrony between the high energy demands of lactation in summer and the peak of pasture production and quality occurring in spring for red deer (Cervus elaphus) and fallow deer (Dama dama) farmed under pastoral conditions in temperate climates. Considerable research within the last decade has investigated either daily administration or constant infusion of exogenous melatonin in order to advance the breeding season and hence the seasonal pattern of births of farmed deer and, therefore, align lactation and feed production. Melatonin is the hormone involved in the transduction of photoperiodic information to the endocrine system leading to precise timing of reproduction. Owing to the absence of pregnancy and lactation, the pubertal hind/doe provides the simplest model for exogenously controlling the seasonality of oestrus, ovulation and conception. All forms of exogenous melatonin delivery initiated in summer (10–12 months of age) are effective in advancing the onset of puberty. However, the degree of advancement relative to control females has been highly variable, reflecting a wide range of treatment protocols. The most significant variables appear to be the time of onset of treatment and the degree of social interaction between treated and control animals. Initiation of treatments less than 100 days after the winter solstice are likely to delay puberty by impinging upon a possible photoperiod entrainment period. Initiation of treatments more than 100 days after the solstice advances puberty, with progressively later initiation dates generally resulting in smaller degrees of advancement. Melatonin-treated red deer hinds and stags appear to influence the timing of puberty of contiguous control hinds. The maximum degree of puberty advancement so far achieved by melatonin treatment has been 54 days for red deer and 56 days for fallow deer. In adult female deer, lactation does not appear to markedly influence the degree of phase shifting by melatonin treatment. However, because melatonin treatment initiated before the end of pregnancy, 140–170 days after the winter solstice, may prevent lactogenesis, the use of melatonin is contra-indicated during pregnancy. Treatment initiation after the onset of lactation does not appear to influence milk yields, as evidenced by calf/fawn growth rates. Treatment of adult male red and fallow deer during summer advances all aspects of reproductive seasonality. Coincident treatment of males and females appears to result in coincident early rutting and oestrous activity, leading to high conception rates. Long-term consequences of treatment of red deer stags include early sexual quiescence and occasional expression of transient testicular cycles, with re-synchronisation of treated and control stags occurring 14–15 months after the initiation of treatment. However, initiation of treatment of red deer stags less than 50 days after the winter solstice delays sexual quiescence and sexual recrudescence, indicating that increasing photoperiod in early spring is important in the entrainment process. While seasonal birth/lactation patterns for red and fallow deer can be advanced by exogenous melatonin treatment, research is needed to elucidate the actual effects on overall productivity, particularly in relation to calf/fawn growth rates and the impact of precocious puberty in early-born animals.

Although it is known that growth hormone (GH) influences body composition in ruminants, the precise role of the pattern of GH secretion is not known. We have studied the pulsatile release of GH and insulin-like growth factor 1 (IGF 1) secretion in the male progeny of rams from lines selected either for {fat genotype) or against (lean genotype) fatness. Seventy-two lambs (36 each of the fat and lean genotype) were kept on high-quality pasture and randomly allocated within genotype to treatment at 2, 3, 3·5, 4,5 or 6 months of age. The procedure, which was identical for each sampling period, was to sample each lamb through a jugular cannula every 10 min for 6 h, and then, following an overnight fast, to slaughter and analyse the carcass for fat. All blood samples were analysed for GH and samples taken each hour for total plasma IGF 1. The GH data were further analysed with the pulse detection routine PULSAR. Carcass fatness, adjusted for cold carcass weight, was greater for fat genotype animals than for the lean genotype. GH was pulsatile in all profiles but the pattern differed with time and genotype. Mean GH and pulse amplitude decreased with time but did not differ between genotype, although the lean genotype had higher mean GH at five of the six sampling periods. In contrast, GH pulse frequency and IGF 1 were significantly higher for the fat compared with the lean genotype lambs. GH mean and amplitude correlated negatively with carcass fatness in both genotypes and GH pulse frequency and total IGF 1 correlated positively with fatness for the lean genotype only. When carcass weight and genotype were fitted to these relationships, GH mean and total IGF 1 were found to have independent negative and positive effects, respectively, on carcass fatness. Because GH mean had a separate effect on fatness independent of genotype or cold carcass weight, it is likely that GH secretion influences composition by the same basic mechanism in both genotypes. However, although the slopes of these relationships did not differ significantly between the genotypes, the intercepts were significantly different indicating that over and above the basic mechanism, at any level of GH, the lean genotype lambs were leaner than the fat genotype lambs. This may indicate a measure ofGH resistance in the fat genotype lambs.

Ram lambs were selected from a total of 1206 lambs in 8 industry Coopworth ram breeding flocks. Eight rams were selected randomly (one from each flock), 8 were selected on the basis of a low live weight-adjusted ultrasonic backfat thickness (lean) and 8 for a high post-weaning growth rate (PW gain). Rams from a Coopworth line specially selected and bred for low ultrasonic backfat (lean selection) were also included in the progeny test in which the rams were single sire mated to 1.5 year old Coopworth ewes. Birth and weaning weights were recorded for a total of 474 female and 371 male progeny. The males (progeny of 31 sires) were slaughtered between January and April at an average hot carcass weight (HCW) of 12.56 kg and carcass growth and carcass fatness parameters recorded. The carcass composition data were analysed using the allometric equation by covariance on HCW. The adjusted mean values of carcass water content were significantly higher for the progeny of the lean selection rams (7.58 kg) than forthe other 3 sire classes (7.49, 7.46 and 7.41 for the lean, PW gain and controls respectively) indicating that they were leaner. Other indicators of carcass fatness also revealed marked differences between the sire classes. There were also marked effects of slaughter date with lambs slaughtered earlier being leaner (after adjustment for HCW) than lambs slaughtered later in the season. The results indicate that selection of sires on the basis of ultrasonic backfat thickness or post weaning live weight gain can be expected to result in the production of leaner lamb carcasses.

The five fattest and five leanest rams were selected on the basis of their liveweight-adjusted ultrasonic backfat thickness from a flock of 100 Coopworths at around 6 months of age. A total of 110 male progeny of these 10 rams were slaughtered between January and April at a mean hot carcass weight (HCW) of 17.13 kg. There were no significant differences between sire classes (i.e., lean, fat) in the weights of the progeny (HCW of 16.95 and 17.31 kg, SED ±0.621). However, there were very marked differences in the regression slopes for the allometric relationships between several carcass variables and HCW, with the lean class having significantly lower slopes for carcass chemical fat content and three subcutaneous fat depths than the fat class. The estimated heritability for backfat thickness (progeny-sire regression) was 0.25. The results indicate that significant progress in terms of carcass leanness should be achievable through the use of suitable ultrasonic devices for measuring backfat thicknes...

Ewes hcterozygous (1+) for the Inverdale prolificacy gene (FecX’) located on the X chromosome have ovulation rates about 1.0 units higher than noncarriers. The purpose of this study was to examine the reproductive performance of ewes that were either heterozygous or homozygous (II) carriers of the Inverdale gene. Carrier rams (I) were mated with heterozygous ewes (1+) to produce females, half of which were expected to be 1+ and half II. The 59 female progeny were examined by laparoscopy at 8 mo or 1.5 yr of age; 48% were found to have nonfunctional “streak” ovaries, which were about one eighth the volume of normal ovaries and showed no sign of follicular activity. There were four examples of full sib pairs where within each pair one had normal ovaries and the other had streak ovaries. Since these streak ovaries have not been observed in ewes known to be 1+ or noncarriers (+ +), it is concluded that this condition is associated with animals homozygous for the Inverdale gene.

Blood samples were taken from six tame red deer stags at 3–15 months of age once a month from a jugular catheter every 30 min for 24 h to investigate hormonal secretion during puberty and during growth of the pedicle and first antler. All plasma samples were analysed for LH and testosterone concentrations and the resultant data were analysed using the PULSAR pulse detection routine. In addition each stag was injected with gonadotrophin-releasing hormone (GnRH; 20 ng/kg body weight) after the above samples had been taken and the bleeding regimen was continued for a further 2 h. Body weight, antler size and status (i.e. whether the stags had a pedicle or antler) were also recorded. The pulsatile secretion of LH could be considered to have occurred in three phases. The first of these was one of development, with the LH pulse frequency increasing to 8 pulses/24 h, the second a phase of regression, with a decrease in LH pulse frequency to 2 pulses/24 h, and finally a second phase of development characterized by increased LH pulse frequency to 12 pulses/24 h. Testosterone secretion generally followed the same pattern. During the period before the permanent bony pedicles grew, there were less than five LH pulses/24 h. When the pedicles were growing, LH and testosterone pulsatile secretion increased but the pulse frequency of both hormones fell during velvet antler growth. However, the overall mean testosterone level did not significantly decrease between the growth stages (2·74 and 2·29 nmol/l respectively) although mean testosterone plasma rose during pedicle growth and fell during velvet antler growth. Both hormone plasma concentrations increased dramatically, and testosterone was particularly high (11·82 nmol/l), at the time of antler cleaning. All stags responded to exogenous GnRH by secreting LH and testosterone in all sampling periods. The LH response to GnRH increased during pedicle growth and fell during antler growth before rising again in autumn as the breeding season approached. Testosterone responses largely paralleled those of LH except that they remained high in early antler development. The results are consistent with the following hypotheses. (1) Pedicle initiation is caused by increased plasma level of testosterone stimulated by increasing LH pulse frequency and (2) testosterone is stimulatory for pedicle growth but not necessarily so for velvet antler growth. Journal of Endocrinology (1991) 131, 467–474

Insulin-like growth factor 1 (IGF1) correlates with antler growth and body growth in penned red deer stags. The present study aimed to investigate the relationships among plasma concentration of IGF1, body growth and carcass composition in grazing stags. Twenty-eight 10-month-old stags were kept at pasture from September to February. They were bled, weighed and their antlers measured fortnightly. Plasma was analysed for total IGF1. All stags were slaughtered in February (aged 15 months); organ weights were recorded and the carcasses were analysed chemically for water, fat and ash. The stags began the study weighing 60·7 (s.e. 1·4) kg and were 96·3 (s.e. 2·0) kg at the end. They grew rapidly in spring and early summer but growth rate slowed in mid summer before increasing again in late summer.Total plasma 1GF1 for each stag throughout the study correlated positively with antler length (P < 0·001), total live-weight gain (P < 0·001), hot carcass weight (P < 0·01), fat-free carcass weight (P < 0·01), carcass fat weight (P > 0·05) and carcass fat percentage (P > 0·05). Thus IGF1 correlated significantly with all measures of body weight except fat. IGF1 correlated positively with antler growth rate (P < 0·001) calculated individually for each stag during each fortnight. IGF1 correlated positively with the spring phase of live-weight gain calculated as above (P < 0·001) but negatively (P < 0·01) with live-weight gain during the late summer growth phase. The relationships between IGF1 and growth in penned stags also pertain in grazing animals, and in addition 1GF1 is closely associated with carcass lean mainly via an overall effect on body size.

In a flock of highly prolific Romney ewes obtained from industry flocks, one ewe (A281), with a production record of 33 lambs born in 11 lambings, produced a number of female descendants with high ovulation rates. The mode of inheritance of this trait was determined in a series of four progeny tests of male descendants of this ewe. The first progeny test produced strong evidence for a new major gene affecting ovulation rate in this family line; this finding was supported by two subsequent progeny tests. The fourth progeny test was designed to test the hypothesis that this gene is carried on the X chromosome. The results showed that six sons of a carrier ram did not inherit the gene, but it was passed on to three of his five maternal grandsons. This finding, together with evidence of genetic segregation in the progeny of carrier females, demonstrates for the first time the presence of a major gene for prolificacy specifically located on the X chromosome. The effect of the gene is to increase ovulation rate by about one additional egg per ewe.

The aim of this study was to compare the ovine growth hormone (oGH) responses of 5 genetically lean and 5 genetically fat 9 month old ram lambs (selected on the basis of their ultrasonic backfat thickness) given two 0.3 micrograms kg-1 liveweight intravenous injections of synthetic human pancreatic GH releasing factor analogue Nle27 hGHRF29 -NH2 (GRF-29) 150 minutes apart. Plasma oGH response curves were analysed using an exponential 2 compartmental model and comparisons made through parallel curve analysis. Plasma oGH levels over 200 ng ml-1 were detected in response to GRF-29. Exponential model parameters indicated that lean lambs had a significantly higher rate of oGH release into the plasma after both consecutive GRF-29 injections, and a significantly lower rate of oGH clearance from the plasma after the second GRF-29 injection only. Significantly smaller peak oGH responses to the second GRF-29 injection were shown by the fat lambs. These results suggest that oGH release is impaired in genetically fat lambs and that either the synthesis of releasable oGH is reduced or the inhibitory tone is greater in the fat lambs. The lean and fat sheep may provide a useful model for the study of hormonal control of factors affecting leanness and fatness.

The concurrent and long-term effects of feeding high (H) and low (L) levels of nutrition from weaning to 4 years of age were measured in 188 high fecundity heterozygous Booroola Merino × Coopworth (BC) ewes (FecB Fec+) and 58 low fecundity New Zealand Merino × Coopworth (MC) ewes. Following the cessation of differential feeding, all groups were grazed on a common plane of nutrition for 2 years. There were no significant nutrition by genotype interactions for liveweight, lamb performance, or ewe lambing performance. During common feeding, carryover effects of restricted feeding were apparent only for liveweight and barrenness. The mature liveweight of H ewes was 60–70 kg throughout differential feeding, which was 12–15 kg heavier than L ewes. L ewes showed 58% compensatory growth but were still 5.1 kg lighter than H ewes (P < 0.05) at the end of the experiment. Ovulation rates of L ewes were 0.07–0.51 lower than their H contemporaries during differential feeding and this was significant (P < 0.05 ...

Multiple births were induced in 20 hinds subjected to a progesterone plus gonadotropin treatment to advance the breeding season by about 4 to 5 weeks. In total, over 2 years, 92 hinds were treated and run with melatonin-treated stags. Of the 59 hinds that calved to the induced oestrus, 39 produced single calves, 19 produced twins and one produced triplets. Birth weight, gestation length, perinatal mortality and growth rate to weaning at ca. 20 weeks of age were compared for singles and twins. There was a significant effect of birth type on birth weight with twins being proportionately 0·30 lighter than singles (6·27 and 8-94 kg; P < 0·001), with a significant interaction between the birth weight of a calf and the sex of its co-twin (P < 0·05); males born as co-twins to females were proportionately 0·18 heavier than their co-twin females (P < 0·06), while in contrast twin male sets were substantially lighter than twin female sets. Gestation lengths were similar for both singles and twins, with significant negative relationships between gestation length and birth weight for both singles and twins, with a 2-day decrease in gestation length for a 1-kg increase in mean birth weight. There was a strong quadratic relationship between perinatal survival and birth weight; the expected mortality rates at 5, 8 and 11 kg birth weight derived from the relationship were 0·39, 0·11 and 0·39 respectively, indicating reduced probability of survival at both low and high birth weights. The regression relationships between weaning weight or growth rate to weaning and birth weight indicate that at the same birth weight, twin-reared calves were about 5 kg lighter than singles at 20 weeks, while an extra 1 kg weight at birth was associated with an extra 2 kg weight at 20 weeks.

The effect of the timing of melatonin treatment during spring and summer on the onset of ovarian activity, the summer moult and winter coat regrowth and live weight change was investigated in yearling red deer hinds by administering melatonin beginning on 21 October, 10 and 30 November, 20 December and 9 and 29 January. Treatment begun in November resulted in all animals displaying ovarian activity before the normal onset of the breeding season whereas October, December and January treatments resulted in only a proportion (0–3/5) of animals responding. The timing of the summer coat moult, winter coat regrowth and the phase of minimal body growth which occurred in control hinds in autumn were all advanced by up to 4 weeks by melatonin treatment. The results indicate that the time melatonin treatment is administered is important in determining the timing of puberty as well as seasonal changes in coat growth and live weight in the red deer hind.

In a series of experiments, involving 372 lambs over 2 years, the effects of subcutaneous implants of Cimaterol (CL263, 780; anthranilonitrile, 5-[1-hydroxy-2-(isoproplyamino)ethyl]-), in young sheep grazing pasture were examined. Treatment with Cimaterol increased carcass weight gain by 37% averaged over the experiments. Wool growth was reduced by 16% in the experiments where it was measured. Cimaterol treatment also increased dressing percentages by 1.3-3.7 percentage units, increased the cross-sectional area of L. dorsi muscle, and decreased fat depot weights and subcutaneous fat thickness measurements in all experiments. These changes were accompanied by increased protein and water contents and a decreased fat content in the carcass. Analysis of the growth rates of carcass components revealed that the changes were a consequence of marked increases in the rates of carcass protein deposition (up to c. 3-fold) in Cimaterol-treated lambs accompanied by markedly reduced rates of lipid deposition. ...

To determine the influence of copper (Cu) supplementation by injection of mares in late gestation on the frequency and severity of osteochondrosis (OC) lesions in their foals at around 160 days of age. To determine if there was any influence of the concentration of Cu in the liver, growth rate, birthweight, weight at 160 days of age, fatness, sex, or year of birth of the foal on the frequency and severity of OC lesions. To determine the influence of dam's age, and sex and birthweight of the foal on the growth rate from birth to 160 days of age, and weight at 160 days of age.Thirty-three Thoroughbred foals, born in two consecutive years, were weighed every 2 weeks from birth. The dams had been supplemented with parenteral Cu or saline during late gestation, and the supplementation regimens were different in each year. Foals had liver biopsies harvested at birth for determination of Cu concentration. Pasture samples were collected every 4-8 weeks for analysis of concentration of Cu and zinc (Zn). At 160 days of age, articular cartilage of long bones was examined. Gross lesions were counted and scored, then sawn and radiographed, and processed for histopathology. Lesions were given radiographic scores and histopathological scores. Maximum scores for each lesion were combined to give a total OC score for each joint and each foal. The fatness of 20 foals (10 each from Years 1 and 2) at 160 days of age was determined chemically.Supplementation of dams with Cu had no significant effect on the concentration of Cu in the liver of foals at birth, or on the frequency or severity of lesions in articular cartilage at 160 days of age. The Cu and Zn concentrations of pasture were similar in Years 1 and 2, and were lower than current recommendations. All foals in Year 2, and 9/10 foals in Year 1 had irregularities in cartilage that was confirmed histologically to be indicative of OC. The average number of lesions per foal was 4.7 (SD 1.1) and 5.7 (SD 1.1) in Years 1 and 2, respectively. However, the severity of the lesions was considered mild, and no foals showed any clinical evidence of OC while alive. The number of lesions in the tarsocrural (TC) joint and the TC OC score at 160 days were positively associated with average daily weight gain (ADG) in the previous 4 weeks (p=0.005 and p=0.001, respectively). There was no significant effect of sex, fatness, birthweight, weight at 160 days of age, or year of birth of the foal on the frequency and severity of OC lesions.Many of the lesions classified as OC, using classification systems described by other authors, were likely to be normal variations of the process of endochondral ossification. Despite the high frequency of such lesions, they were considered to be of minor significance and none were clinically evident. The distribution of lesions was not typical, and most probably reflected the subtlety of the lesions. These results support the hypothesis that Cu is an over-emphasised factor in the aetiopathogenesis of OC. The relationship between subtle macroscopic lesions and lesions resulting in clinical signs of disease requires further investigation.

Copper (Cu) supplementation of dams in late gestation may be protective against articular cartilage abnormalities in foals. Articular cartilage was harvested from 22 Thoroughbred foals at 160 days of age, at sites predisposed to osteochondrosis (OC), and examined for evidence of early cartilage abnormalities and established dyschondroplastic (DCP) lesions to determine if there were any significant differences due to mare Cu supplementation by injection during late gestation, or foal liver Cu concentration. Cu supplemented mares received calcium Cu edetate injections in late gestation (250 mg at around 220, 248, 276 and 304 days gestation, then every two weeks until foaling). Foals were euthanased at 160 days of age and articular cartilage was harvested from four defined sites. Samples were examined for histological appearance of chondrocytes after staining with haematoxylin and eosin, and were also stained with toluidine blue to indicate proteoglycan content. Alkaline phosphatase (ALP) activity was detected by histochemistry, and histocytochemical techniques were used to determine the expression of cathepsin B. Cu supplementation of the dam, or liver Cu concentration of the foal at birth or 160 days of age had no statistically significant effect on the frequency of cartilage irregularities observed grossly, or abnormalities detected histologically at four defined sites. ALP expression was similar in all samples. Cathepsin B expression varied between sites, and was seen in chondrocyte clusters. The intensity of toludine blue staining varied between sites. Minor histological cartilage abnormalities were observed in cartilage from clinically normal animals. These abnormalities might be 'early' dyschondroplastic lesions, which could resolve or progress. The role of Cu in the development, resolution or progression of dyschondroplastic lesions is poorly understood.

Despite the large number of active programs breeding improved forage plants, relatively little is known about the weightings that breeders consciously or sub-consciously give to specific traits when selecting individual plants, or that agronomists and producers use when assessing the relative merits of contrasting cultivars. This is in contrast to most modern animal breeding programs where the relative merits of novel genetics may be assessed against an index-based breeding objective. There are numbers of reasons why these technologies have not been used widely in plant breeding although applications in forest tree breeding are relatively common. A first step in defining breeding objectives for forage species can be to define the relative importance of specific traits and to interpret how these contribute to the relative potential advantage to a new plant or cultivar. One method of defining these weightings is through surveys of users followed by analyses of their combined experience. Therefore in this study, we have assessed the usefulness of discrete choice techniques in the development of weightings for specific traits in forage plant improvement based on views of both expert users (agronomists and farm consultants) and farmers who were asked to define their relative priorities when considering the renovation of a pasture. The surveys were conducted in three distinct regions of, or environments within, Australia of special relevance to meat production from beef and sheep (high rainfall, temperate (inland), and Mediterranean). In summary this study defines the focus of breeding objectives and selection criteria for different pasture species across production systems.

Objectives To monitor the change in liver copper concentration of Thoroughbred foals from birth to 160 days of age and to determine the effects of supplementation by two injections of copper edetate given to dams in late gestation on the liver copper concentration of their foals at birth. Procedure Ten mares pregnant to the same stallion were randomised into two groups on the basis of age, liver copper concentration and expected foaling date. The treatment group mares were given 100 mg and 250 mg copper edetate intramuscularly during the ninth and tenth months of gestation respectively. Foals had liver biopsies taken weekly in the first month of life, then monthly for four months. Foals were euthanased at 160 days of age; liver samples were taken and the copper concentrations were determined. Results Two distinct patterns of age dependant decline in liver copper concentration were evident. The mean (± SD) liver copper concentration of the foals was high at birth (374 ± 130 mg/kg DM), and for seven it declined to adult values by 160 days of age (21 ± 6 mg/kg DM). In three foals the decline was at a slower rate than in the other seven and at 160 days of age the mean concentration was 162 ± 32 mg/kg DM. Repeated measures analysis showed significant differences between each biopsy (P

Interspecies hybrids between Pere David's deer (Elaphurus davidianus) and red deer (Cervus elaphus) have proved to be a powerful resource in the search for quantitative trait loci (QTL) in deer. Several regions of the genome with significant effects on live weight and growth rates in backcross hybrids were detected. These include putative QTL for 6-month live weight (LOD 3.90) on linkage group 12, for 14-month live weight (LOD 3.19) on linkage group 1, three putative QTL for growth rate from 3 to 6 months (LOD 4.19 on linkage group 12, LOD 3.92 on linkage group 12, and LOD 3.34 on linkage group 5). In addition, linkage groups 20 and 1 appear to be associated with live weight traits between 9 and 16 months. The variance in traits explained by these QTL ranged between 5.3% and 11.2%. Allele substitution with Pere David's alleles at different loci had both positive and negative effects on live weights and growth rates.

Objective To determine the content and distribution of Na, K, Ca, P, Mg, S, Cu, Mn, Fe and Zn in the body of pasture-fed young horses and then use a factorial model to calculate the dietary mineral requirements for growth. Procedure Twenty-one foals were killed at about 150 days of age and the organs, soft tissues, skin and bones and a sample of muscle were dissected out and weighed. The mineral concentrations of elements in all soft tissues and bones were measured by inductively coupled emission spectrometry. The total mineral element composition associated with a tissue was determined from the weight of tissue and its mineral element concentration. Results Expressed as a percent of total body mineral elements, muscle contained 20% Na, 78% K, 32% Mg, 62% Cu, 36% Mn and 57% Zn, bone contained 47% Na, 99% Ca, 81% P, 62% Mg, 30% Mn and 28% Zn while the organs accounted for a smaller percentage ranging from 0.06% for Ca to 26% for Fe. In liver Cu accounted for 9.2% of total body Cu. Each kilogram of empty body weight was associated with 1.0 g Na, 2.5 g K, 17.1 g Ca, 10.1 g P, 0.4 g Mg, 1.1 mg Cu, 0.39 mg Mn, 52.5 mg Fe and 21.4 mg Zn. Conclusion The mineral element content of body weight gain is a component usedin the factorial model to determine dietary mineral element requirements for growth. The calculated dietary mineral requirements, expressed per kg dry matter, for a 200 kg horse gaining 1.0 kg/day were 1.0 g Na, 2.1 g K, 4.6 g Ca, 3.5 g P, 0.7 g Mg, 4.5 mg Cu and 25 mg Zn.

Pregnant Thoroughbred mares (n = 21) were grazed on tall fescue pasture containing 4.4-8.6 mg Cu/kg dry matter (DM). Twelve mares were supplemented with approximately 0.5 mg Cu/kg liveweight (LW)/day as copper sulphate for the final 13-25 weeks gestation. Plasma copper concentration declined during the third trimester for all mares and was not affected by copper supplementation. Liver copper concentration of mares and foals was determined when the foals were 4-10-days-old. Copper supplementation of the mares tended to increase mare liver copper concentration (P

The effects of natural variation in the number of copies of the growth hormone (GH) gene on growth parameters, plasma GH profiles, and the response to GHRH challenge were compared in Coopworth ram lambs from selection lines differing in body composition and GH levels. Different genotypes at the GH locus carried two, three, or four copies of the GH gene and GH secretion was studied under ad libitum feeding conditions and in the fasted state. There were no significant effects of GH genotype on any parameters of growth or body composition. Basal serum GH concentration, GH pulse frequency, and GH pulse amplitude differed significantly with selection line and fasting, but did not differ significantly between the GH genotypes. Significant differences of subtle nature were found between the GH genotypes in their responsiveness to GHRH. For the ad libitum-fed Lean selection line animals, the first GHRH challenge resulted in a higher mean maximum response for GH1/GH1 than GH2/GH2 (P0.05). Between the first and the second challenges there was a decrease in maximum response for the GH1/GH1 genotype and an increase for the GH2/GH2 genotype (P0.05 for GH genotype main effect). The differences between GH genotypes in response to GHRH challenge suggest that polymorphism in the number of GH gene copies in sheep may have physiological implications for the function of the GH axis, which may be manifested in growing lambs only under specific genotype-environment combinations.

Growth in temperate and arctic deer is seasonal, with higher growth rates in spring and summer while growth rates are low or negative in autumn and winter. We have measured IGF1 concentrations in the plasma of reindeer calves exposed to a manipulated photoperiod, indoors, of either 16 hours light followed by 8 hours dark each day (16L:8D) (n = 3) or 8L:16D (n = 3) from about the autumnal to the vernal equinox, to determine whether the seasonal growth spurt normally seen in spring is associated with changes in the circulating level of IGF1. A high quality concentrate diet was available ad libitum. The animals were weighed, and bled every 2 weeks and plasma samples assayed for IGF1 by radioimmunoassay. 6-8 weeks after the start of the study those calves exposed to 16L.-8D showed a significant increase in plasma IGF1 concentration which was maintained until the close of the experiment, 24 weeks after the start. In contrast IGF1 plasma concentrations in those calves exposed to a daylength of 8L:16D did not significantly alter during the study. The elevated IFG1 in the 16L:8D group was associated with rapid weight gain compared with the 8L:16D group. We have shown that the seasonal growth spurt is preceded by an elevation in plasma IFG1 concentration. Further, this elevation in IGF1 is daylength dependent. For comparison IGF1 and growth rate seasonal profiles from temperate and tropical deer are included. This comparison reveals that seasonal increases in IGF1 take place only in animals with a seasonal growth spurt. Thus IGF1 plasma level elevations seem most closely associated with the resumption of rapid growth in spring following the winter.

Blood from stages aged 15 months (n = 6) was sampled at monthly intervals every 30 min for 24 h for 12 months, at 45 degrees S in New Zealand. Three extra samplings each for 24 h were carried out at about the anticipated time of antler casting. All samples were analysed for luteinizing hormone (LH) and testosterone and the resulting data further analysed by the Pulsar pulse detection routine. The animals were kept indoors under natural daylength and were fed ad libitum. All animals were weighed, antler status and size recorded and testes diameter was measured on each sampling day. Mean LH and testosterone pulsatily and plasma concentration varied seasonally. LH pulse frequency was low during autumn (2.5 pulses in 24 h), winter (1.0-1.5 pulses in 24 h) and early spring (1 pulse in 24 h) and lowest in late spring (0.2 pulse in 24 h) before rising in summer (1.0-4.0 pulses in 24 h). LH pulse amplitude and mean plasma concentration were low (< 1 ng ml-1) from March to November (autumn-spring); both rose to a peak in January (summer) of 3.4 and 1.6 ng ml-1, respectively. Testosterone pulse frequency was generally similar to LH except that slightly more pulses of testosterone than of LH were detected from March to November and more pulses of LH from November to February (summer). Testosterone pulse amplitude fell from March to November (5.3 ng ml-1 to undetectable) although there was a conspicuous peak in July (midwinter) of almost 5 ng ml-1.(ABSTRACT TRUNCATED AT 250 WORDS)

This study investigated the relationship between blood electrolytes and the annual reproductive cycle in red deer stags. Mature farmed red deer stags (n = 36) were slaughtered around the rut (February to May), at antler casting (September), full velvet antler (January), and the following rut (April), and blood samples and compositional data were collected. Blood samples were collected immediately after death. Blood was also collected monthly from a group of eight stags from June to April. Plasma and red blood cell sodium and potassium concentrations were measured. Analyses of blood revealed a pattern in plasma potassium in the slaughtered stags that was in phase with the annual reproductive cycle. Concentrations rose above the normal reference range (about 3.5 to 5.4 mmol/1) to reach a peak of 10.6 ± 0.69 (mean ± SD) in mid-March and returned to normal as antler casting approached in late August. There was a second peak in the live stags (10.6 ± 1.31 mmol/1) in mid-July which coincided with a late winter resurgence in rutting activity. However, an elevated plasma potassium concentration was not recorded over the second rut in either slaughtered or live animals. The data indicate that stags entered the first rut in poor condition with little fat reserves because of a spring drought, whereas stags in the second year were in much better condition. We suggest the elevated concentrations of plasma potassium may be an indication of muscle catabolism in the rut.

The timing of puberty in farmed red deer (Cervus elaphus) hinds can be altered by the strategic administration of melatonin, and the present study was undertaken to investigate the importance of the duration of treatment. Six groups, each of five hinds aged about 12 months were used. The control group was untreated throughout while the remaining five groups received approximately 30, 60, or 90 days of melatonin from subcutaneous implants. Treatment began in three groups in spring (on 30 November for 30,60, or 90 days), and in two groups in summer (on 30 December for 60 days and on 30 January for 30 days) so that each duration of treatment either started (30 November) or finished (approximately 1 March) at the same time. Treatment begun in spring lasting 60 or 90 days resulted in all hinds displaying ovarian activity about 20 March, representing about a 4-week advancement in the onset of puberty. Melatonin administered for 30 days in spring and 30 or 60 days in summer resulted in only a proportion (two or three of five) of hinds responding with early ovarian activity. In addition, melatonin treatment significantly advanced the seasonal patterns in live-weight gain and coat growth in some of the earlier treated groups, and reduced prolactin secretion in all treated groups. These results indicate that approximately 60 days of exogenous melatonin treatment is required to induce an alteration in the timing of puberty in red deer hinds, providing that it is given at an appropriate time of the year.

Stages of the antler cycle were recorded for up to 16 red deer stags (Cervus elaphus) as 2-, 3- and 4-year-olds. Antler dimensions were recorded at weekly intervals for five stags over 2 successive years; the pattern of growth in antler length and estimated volume were analyzed for these stags using the generalized logistic growth curve. The results show marked effects of age on the date of casting and the period in velvet, and indicate the appropriateness of the generalized logistic growth curve in analysing antler growth patterns. At the completion of growth, the main beam made up approximately 71% of the total volume, the brow tine 7%, the trez tine 8%, and the royal tines 14%.

This paper includes three rather diverse approaches to the study of antler regeneration in red and fallow deer. Each study, however, shares the same goal of attempting to improve our understanding of the process of antler regeneration. All studies took place in the Southern Hemisphere, in New Zealand; this accounts for the reversed seasons.

In two experiments, Red deer hinds were synchronized with intravaginal progesterone and were given 4 d of treatment (3 d before progesterone withdrawal and 1 d after) with an ovine follicle stimulating hormone (FSH) preparation which had a claimed low level of luteinizing hormone (LH) contamination. In Experiment 1, 12 hinds received one of four FSH levels by osmotic minipump. Hinds were run with fertile stags, and laparotomy and embryo recovery were performed 9 d after progesterone withdrawal. The ovulation rates (mean of three hinds per dosage) were 1.0, 2.0, 4.3 and 15.3 (number of corpora lutea counted) for estimated daily dosages rates of 0.036, 0.071, 0.11 and 0.14 units FSH preparation/day; the response to the increasing dosage was exponential (P 24 63 ), with all recovered ova being fertilized and of transferable quality. In Experiment 2, performed later in the breeding season, eight hinds received 0.14 units FSH/day either by minipump or by intramuscular injection. The mean ovulation rates were 3.0 and 11.0 (a significant difference, P 34 47 ), and with only 18 34 ova considered to be of transferable quality. The recovery rate in Experiment 2 was significantly higher than that in Experiment 1 (P