Adult Red Deer Research Articles

Conceptus development and associated fertility in red deer ( [formula omitted]) from days 11 to 25 after mating

The role of androgens and insulin-like growth factor 1 (IGF-1) in antler growth has been disputed. We predicted that the secretory of IGF-1 may be associated with an acceleration of body growth rather than with antler growth. Furthermore we anticipated a relationship between the increase of testosterone and the progress of antler growth. If IGF-1 is involved in the stimulation of antler growth, this should be more obvious in young than in mature stags. Eight two-year-old red deer stags (Cervus elaphus), and twelve adult red deer stags were blood sampled and the length of their velvet antlers was measured in one-week intervals during the period of antler growth. Concentrations of testosterone, cortisol, IGF-1, luteinizing hormone (LH), and prolactin were determined in plasma by enzyme immunoassay or radioimmunoassay. Antler growth per day was primarily dependent on changes in testosterone concentration per day in both groups of stags. As expected, only in two-year-old stags we detected a possible role of IGF-1 in the antler growth regulation, but that was not in agreement with previously published studies. Nevertheless, this effect was still utilized in interaction with testosterone. In addition to total antler length, only concentrations of testosterone and LH were significantly higher in adult males in comparison to two-year-old males. Our present results lead us to conclude that it is not IGF-1 but testosterone which is responsible for the intensity of antler growth in subadult and adult red deer stags.

Use of long-acting neuroleptics to reduce the stress response to management practices in red deer

Three groups of six adult red deer hinds were used to determine whether long-acting neuroleptic (LAN) tranquillisers were able to modify the behavioural and physiological responses of the deer to a range of routine management stressors: such drugs may eventually prove useful in capture procedures for wild animals. While the stressors increased moving activity and decreased inactive lying and inter-animal distances, these changes were reduced in LAN-treated animals. Blood samples, collected remotely using automatic equipment, showed that following application of the stressors there was a distinct rise in plasma cortisol concentrations which returned to pre-treatment levels more rapidly in LAN-treated animals. However, there was no effect of LAN treatment on plasma concentrations of creatine phosphokinase (CPK), aspartate aminotransferase (AST), total protein or testosterone. Overall, LAN-treated animals had higher concentrations of plasma thyroxine. Heart rate increased in response to the stressors and while the LAN-treated deer showed a greater increase, as with plasma cortisol concentrations, heart rate returned to baseline more rapidly in these animals. We conclude that LANs may have a role to play in wild deer capture and habituation to farming conditions through a reduction in fear and anxiety, but that further work is required to determine an optimal strategy.

Regulation of reproductive seasonality in the red deer hind: oestradiol-dependent and -independent influences on the patterns of LH concentrations

The control of reproductive seasonality was studied in farmed adult red deer hinds that had been either ovariectomized or ovariectomized and oestradiol-treated (s.c. implants). The breeding season, delineated by progesterone secretion in intact hind herdmates, was characterized by high (mean 0.6, range 0.1-2.5 ng ml-1 plasma) LH concentrations in ovariectomized oestradiol-treated hinds. In contrast, during the non-breeding season plasma LH concentrations in these animals were significantly lower (mean 0.1, range 0-0.9 ng ml-1 plasma). LH secretion in ovariectomized untreated hinds also displayed a marked seasonal pattern, approximately the inverse of daily photoperiod (that is, a winter peak and summer trough). The pituitary LH response to 10 micrograms exogenous GnRH was also maximal during the breeding season in ovariectomized (mean 7.4, range 1.2-14.6 ng ml-1) and ovariectomized, oestradiol-treated (mean 16.4, range 1.4-32.3 ng ml-1) hinds. These results indicate that LH secretion in the hind is regulated by both steroid-dependent and -independent mechanisms.

Seasonality in digestion and rumen metabolism in red deer (Cervus elaphus) fed on a forage diet

Six adult castrated male red deer (Cervus elaphus), fitted with rumen cannulas, were offered chaffed lucerne hay ad lib. during winter and summer, with voluntary food intake (VFI) being respectively 59 and 89 g dry matter intake (DMI)/kg bodyweight 0.75 per d. The same animals were also offered the same feed during summer, with intake restricted to that of winter VFI. The apparent digestibility of gross energy (0.60) or fibre (0.41) and the total capacity (volume) of the rumen were unaffected by season or level of intake. Relative to winter ad lib. feeding, N retention, total rumen pool size (DM + water), rumen pool size as a proportion of capacity, and rumen total volatile fatty acid (VFA) pool size were increased during summer ad lib. feeding. Relative to winter ad lib. feeding, N retention, rumen ammonia irreversible loss rate (IRL), total rumen pool size, rumen pool size as a proportion of capacity, and rumen ammonia and total VFA pool sizes were also increased during summer restricted feeding. Rumen lignin fractional disappearance rate (FDPR) was lower in summer than in winter, and there was a non-significant trend for rumen fractional outflow rate (FOR) of liquid to follow the same trend. Molar proportions of acetate and propionate were unaffected by season, proportions of n-butyrate were slightly higher in summer, and proportions of iso-butyrate and iso-valerate were higher for summer restricted than for winter ad lib. feeding. When intakes were equalized there were no seasonal changes in rate of rumen water outflow, net rumen water balance or intestinal water absorption. It is concluded that there is a seasonal change in rumen physiology in red deer during summer causing increased total rumen pool size (DM + water), an increase in rumen ammonia production and pool size, and an increase in rumen total VFA pool size which are all independent of the increase in VFI. The increased total rumen pool size in the summer restricted group may indicate an increased mean retention time (MRT) of digesta in the rumen. MRT for particulate matter was calculated to be 29.2 and 34.8 h during winter and summer respectively. This, together with increased rumen ammonia production, may function to maintain rumen fibre digestion when VFI normally increases during summer. The increased rumen VFA pool size may indicate increased VFA production during summer, in the same way as ammonia IRL was increased.

Cloprostenol-induced luteolysis in the red deer hind: the effects of age, dose, number of corpora lutea and the later stages of the oestrous cycle

The luteolytic effectiveness of the prostaglandin F 2α analogue, cloprostenol, was investigated by monitoring plasma progesterone concentrations. In Experiment 1, pubertal ( n=20) and adult ( n=20) hinds had their oestrus synchronised by intravaginal delivery of exogenous progesterone for 14 days. Fourteen days after progesterone withdrawal 0, 100, 250 or 500 μg of cloprostenol was administered intramuscularly and blood samples were collected by jugular venepuncture. All cloprostenol treatments were equally effective in lowering progesterone concentrations in both age groups. Twelve hours after administration, progesterone concentrations averaged 41% of pretreatment values for the three treated groups and at 24 h were 26% of pretreatment values. However, in some hinds (eight pubertal and four adult) luteal regression was incomplete and progesterone concentrations increased within 24–48 h of the onset of treatment. In Experiment 2, adult hinds ( n=28) were treated to induce synchronised oestrus with either mono-ovulation or superovulation induced with combinations of pregnant mare's serum gonadotrophin (PMSG), follicle stimulating hormone (FSH) and gonadotrophin releasing hormone (GnRH). Hinds were then allocated to receive 750 μg of cloprostenol intramuscularly at either 11 or 15 days after progesterone withdrawal (9–10 or 13–14 days after oestrus). Plasma progesterone concentrations in hinds with single and multiple corpora lutea, were reduced within 6 h of cloprostenol administration, and continued to decline thereafter. Cloprostenol induced complete luteolysis in all 13 hinds treated on Day 15 but in only six out of the 12 hinds treated on Day 11. The six hinds (four mono-ovulation, two superovulation) in which luteolysis appeared incomplete were characterised by short-lived reductions in progesterone concentrations. These results indicate that cloprostenol is luteolytic in both young and adult red deer hinds and in hinds with multiple corpora lutea. However, its effectiveness may be incomplete in some animals.

Haematological reference values for farmed red deer (Cervus elaphus) in New Zealand

An automatic haematology analyser (Technicon H6000/C) providing red cell, white cell and platelet parameters was calibrated for the blood of red deer Cervus elaphus. Haematology reference values for these parameters, plasma viscosity and plasma fibrinogen are presented for defined groups of female weaner red deer (n = 123), adult red deer hinds (n = 86) and weaner male red deer (n = 37), the latter being bled using physical restraint and also using xylazine sedation. Age, sex, sedation and season-related differences were found. Reference values are also presented for serum haptoglobin in adult hinds and levels were similar to those seen in cattle.

Manipulation of reproductive seasonality of farmed red deer ( Cervus elaphus) and fallow deer ( Dama dama) by strategic administration of exogenous melatonin

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.

Purification, partial characterization, and heterologous radioimmunoassay of growth hormone (cGH) in red deer

Red deer growth hormone (cGH; 3.3 mg) was purified from an aqueous extract of seven pituitary glands (4.01 g wet weight) by preparative gel filtration on Sephadex G-100, gel filtration on Sephadex G-100 SF, and anion exchange chromatography on DEAE-Sepharose CL-6B. Purified cGH gave a single band on sodium dodecyl sulfate-polyacrylamide gel electrophoresis with a molecular weight under reducing conditions of 20,000 Da and gave a single peak on reverse-phase high-performance liquid chromatography. N-Terminal amino acid determination of 42 residues gave a sequence identical with those published for bovine and ovine GH. In a radioreceptor assay based on binding of iodinated recombinant bovine GH ( rbGH) to liver microsomes prepared from a pregnant ewe, cGH was equipotent with an ovine GH (oGH) standard. In an oGH radioimmunoassay, cGH diluted in parallel with oGH and rbGH. Using this assay plasma GH concentrations were determined in adult nonpregnant red deer hinds over a 12-month period. There was a significant seasonality in plasma GH concentrations with concentrations consistently low between mid-May and mid-September. This is the period when voluntary food intake and liveweight gain are greatest. It is suggested that in the presence of low plasma GH concentrations nutrients may be diverted toward lipogenesis and hence promote fat deposition.

Seasonal pattern of luteinizing hormone and testosterone pulsatile secretion in young adult red deer stags (Cervus elaphus) and its association with the antler cycle

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)

Effects of melatonin implants on insulin-like growth factor 1 in male red deer ( Cervus elaphus)

Red deer stags have a seasonal pattern of growth, alternating between periods of summer weight gain and winter weight loss that are influenced by photoperiod and by exogenous melatonin. A seasonal pattern of plasma insulin-like growth factor 1, also influenced by photoperiod, underlies the seasonal growth pattern. The present studies aimed to determine the influence of exogenous melatonin, administered at various times of the year, on plasma IGF1 in adult red deer stags in New Zealand at 45°S. In one study, 7-year-old stags ( N = 9) were allocated to one of three treatment groups, either control or subcutaneous melatonin (3 × 18-mg coated implants (Regulin) per month) from November to February or from December to February. Blood was sampled, the stags were weighed, and antler status was recorded over 17 months. Melatonin treatment advanced the seasonal patterns of rise and fall of plasma IGF1 and of weight gain and loss. The cessation of melatonin treatment in February produced early antler casting and a second (out-of-season) antler and increased IGF1. In a second study, 4-year-old stags ( N = 30) were allocated to one of six treatment groups as follows: three melatonin implants per month for 6 consecutive months beginning on 22 June, i.e., winter solstice, 4 August, 16 September, and 23 October; three melatonin implants per month for 12 months beginning on 22 June; and an untreated group. All animals were sampled as before for 12 months. Melatonin treatment beginning in July and August did not prevent the seasonal peak in IGF1, but the amplitude was lowered and antler casting delayed. In contrast, melatonin treatment beginning in September and October advanced the seasonal decrease in plasma IGF1, thus the duration of elevated IGF1 was shortened. In the stags treated with melatonin for 1 year, the amplitude of the IGF1 peak was reduced but the seasonal pattern was unaffected. Treatment with melatonin tended to reduce antler size and liveweight gain in all groups. The results indicate that the effect of melatonin treatment on IGF1 differs in June and December. Initially melatonin does not influence the seasonal increase in IGF1 although its amplitude is lowered. Later melatonin treatment advances the seasonal decrease in IGF1 to shorten the duration of elevated IGF1. Melatonin treatment uncoupled antler growth from the IGF1 seasonal pattern either by delaying casting or advancing cleaning to give a decreased antler size.

A note on melatonin-treated red deer stags advancing the onset of the calving season in hinds

ABSTRACTThe effects of treating adult red deer hinds nutritional demands to coincide better with and stags with exogenous melatonin on the food production on improved pastures. One calving season in hinds were evaluated in a 2 such method has been the administration of × 2 factorial experiment. Treated stags were implanted with melatonin monthly beginning in December and hinds post calving in January, Melatonin advanced the timing of rutting behaviour in both treated stags. Calving date was significantly influenced by melatonin treatment of hinds (a mean 10-day advancement; P &lt; 0·01) or stags (12-day advancement; P &lt; 0·001). The interaction of hind and stag treatments was not significant, however treatment of both sexes resulted in the greatest advancement in mean calving date (21 days; P &lt; 0·001). These results indicate that treatment of red deer hinds or stags with exogenous melatonin can result in an earlier calving season and suggest seasonally advanced stags can stimulate earlier breeding activity in hinds.

A note on the induction of ovulation in lactating red deer hinds prior to the breeding season

Methods of inducing ovulation 3 weeks prior to the onset of the breeding season were evaluated in lactating adult red deer. Following 11 days of intravaginal progesterone pre treatment, hinds were either untreated (control), or given 300 i.u. PMSG i.m. or 500 mglh GnRH s.c. by osmotic pump. All hinds were laparoscoped 7 days after progesterone withdrawal to record the presence or absence of a corpus luteum on the ovaries, Laparoscopy showed 0113 control, 11113 PMSG and 8/13 GnRH-treated hinds ovulated indicating that during lactation, both methods of inducing ovulation are similarly effective, However, although these treatments induced ovulation, fertility as assessed from calving records, was poor.

Plasma LH and testosterone responses to gonadotrophin-releasing hormone in adult red deer (Cervus elaphus) stags during the annual antler cycle.

Eight adult red deer stags were given an i.v. injection of synthetic gonadotrophin-releasing hormone (GnRH) on seven occasions at various stages of the antler cycle, namely hard antler in late winter, casting, mid-velvet growth, full velvet growth, antler cleaning and hard antler both during the rut and in mid-winter. The stags were allocated at random on each occasion to one of four doses, i.e. 1, 3, 10 or 95 micrograms GnRH. Blood samples were taken before GnRH injection and for up to 2 h after injection. Pituitary and testicular responses were recorded in terms of plasma LH and testosterone concentrations. There was an increase in plasma concentration of LH after the GnRH injection in all stags at all stages of the antler cycle. Dose-dependent responses of LH to GnRH in terms of area under the curve were apparent at all stages of the antler cycle. The lowest responses were recorded at casting, during velvet antler growth and at the rut sampling. The pattern of testosterone response reflected the inter-relationship of the antler and sexual cycles with very low testosterone responses occurring at casting and during velvet antler growth. The responses were higher at antler cleaning and then increased to a maximum at the rut before declining to reach their nadir at casting. The results are consistent with a hypothesis that the antler cycle, as a male secondary sexual characteristic, is closely linked to the sexual cycle and its timing is controlled by reproductive hormones. Low plasma concentrations of testosterone, even after LH stimulation, are consistent with the hypothesis that testosterone is unnecessary as an antler growth stimulant during growth.

Lung, heart and liver lesions in adult red deer: A histopathological survey

Between September 1982 and January 1983 lung, heart and liver samples for histological examination were obtained from 170 free-living stags and hinds and from 78 farmed stags. A further eight liver and four lung samples were collected from additional wild stags. Protostrongylid eggs and larvae were present in 76% of the wild deer lungs but in only 4% of the farmed deer. Fourteen per cent of the wild deer showed an interstitial pneumonia associated with the protostrongylid infection. Conversely, pulmonary lesions of the type associated with Dictyocaulus spp. were extremely common in the farmed deer but only 12 free-living animals had dictyocaulus-type lesions. Sarcocysts in the myocardium, with or without accompanying interstitial cellularity, affected 42% of the wild deer and 4% of farmed deer. Parasitic lesions in the liver were found in 3% of wild deer and 21% of farmed deer.

Energy requirements for the penetration of heads of domestic stock and the development of a multiple projectile.

The forces and kinetic energy required to penetrate the isolated heads of calves, adult beef cattle, sheep and red deer with a metal probe the same diameter as the bore of an experimental pistol were determined. Approximately 16 and 127 Joules were required to penetrate the heads of adult sheep and cattle, respectively. Using these data a 10 g projectile, consisting of 49 lead pellets and a lead disc in a polyethylene sleeve, was constructed. This projectile, when fired by a charge sufficient to produce a muzzle velocity of 165 m/second, had sufficient kinetic energy to penetrate the heads and brains of cattle, sheep, horses and deer. The projectile was fired from a new design of humane killer with a spring loaded barrel and fitted with a silencer. After penetration of the frontal bones the projectile fragmented and the kinetic energy of its individual particles were insufficient for them to penetrate the opposite side of the head of any of the animals, including one-week-old calves. Fragmentation also caused more brain damage and inhibition of spinal reflexes than a solid free bullet or captive bolt. It is suggested that the use of such a projectile for the emergency slaughter of animals is less hazardous than a solid free bullet and is easier to use and more effective than either a solid free bullet or captive bolt. The projectile was not suitable for killing adult pigs because of problems associated with the frontal sinus.

Winter mortality in Red deer (Cervus elaphus)

Previous analysis has suggested that inter‐year variation in mortality of adult Red deer in Scotland is principally affected by summer weather conditions. Data collected over fourteen years on the Isle of Rhum (Inner Hebrides) show that mortality was negatively correlated with winter temperatures and positively with rainfall in late winter. In conjunction, these two factors accounted for 82% of the observed variation between years.

Behavioural factors affecting male reproductive success in red deer ( Cervus elaphus)

Variation in reproductive success among adult red deer stags was related to harem size, and the duration and timing of breeding access. All three factors were affected by dominance (fighting success) during the rut. The number of hinds using a stag's rutting area and the duration of individual rutting activity also affected breeding access. Dominance rank in bachelor herds, which may affect access to hinds conceiving after the rut, was correlated with rank in the preceding but not the following rut.