Influence of level of nutrition during late pregnancy on reproductive productivity of red deer I. Adult and primiparous hinds gestating red deer calves

The present study aimed to relate feed intake of red deer hinds during late pregnancy to dam body condition, foetal development and calf growth. Across 3 years, multiparous (n=33) or primiparous (n=18) hinds with known conception dates were housed in individual pens from days 150-220 of pregnancy, during which time they were each offered one of three daily allowances of pelletised rations (11 MJME/kg DM; 16% CP): high (H; ad libitum), medium (M; approximately 30% less; multiparous hinds only) and low (L; approximately 50% less). Restricted intake levels were retrospectively calculated from the mean intake of H hinds in the previous week. Hinds were returned to pasture at day 220 and calving was closely monitored. Liveweights, body condition score (BCS), and lactation score (LS) of hinds were recorded weekly from day 130 of pregnancy until calves were weaned at 12 weeks of age. Calves were tagged and weighed at birth, and subsequently weighed at 7 and 12 weeks of age. Additionally, hinds in the first year of study underwent CT scans on days 150 and 215 of pregnancy to assess compositional changes of the dam and conceptus. Mean daily ad libitum intakes of H hinds increased from 1.8 to 2.0 kg DM (0.6-0.7 MJME/kg0.75) at around day 150 to 2.8-3.2 kg DM (0.8-0.9 MJME/kg0.75) by day 220. Those of M and L hinds peaked at 1.8 and 1.6 kg DM, respectively, by day 220. This was reflected in significant treatment effects on liveweight gain and change in BCS and LS by the time of calving. CT scans indicated a significant treatment effect by day 215 on the mass of hind tissues (fat and lean) and a non-significant trend on conceptus/foetal weights. Despite apparent differences in foetal growth trajectories, there were no discernable treatment effects on sex-adjusted birth weights. However, there was an unexpectedly wide spread in calving dates that reflected considerable variation in gestation length. Furthermore, gestation length was negatively correlated with change in hind liveweight (but not BCS) between days 150 and 220 of pregnancy for all groups of hinds (P<0.05). Of three neonatal calf mortalities, none were related to overweight (dystocia) or underweight (non-viability) calves. Subsequent growth rates (g/day) of surviving calves did not reflect prior treatment of their dams, although variation in birth date influenced weights on specific dates. It is concluded from this study that while variation in nutrition to hinds during the last trimester may strongly influence foetal development, under conditions of modest feed imbalance, variation in gestation length compensates to ensure optimisation of birth weight.     

The effect of conception date on gestation length of red deer (Cervus elaphus)

Recent studies have demonstrated that gestation length of red deer (Cervus elaphus) is highly variable and influenced by various environmental factors, and this may confer survival advantages for neonates. The current study investigated the relationship between conception date and gestation length to test the hypothesis that within-herd synchrony of red deer births is facilitated by a 'push/pull' control over gestation length, such that hinds conceiving early and late in the breeding season have longer and shorter gestation periods, respectively. In Study 1, data on conception and calving dates were obtained for 393 naturally cycling hinds across two herds. In Study 2, conception and calving dates were obtained from 91 hinds in which oestrus/conception were artificially synchronised across a 4-week range of dates spanning the natural rut. Gestation length for each population was analysed by linear regression, fitting conception day followed by terms for the fixed effect which included hind age (pubertal vs. adult), hind genotype (Cervus elaphus scoticus vs. Cervus elaphus hippelaphus and their crossbreds), calf sex, sire genotype (Study 1 only), birth weight and year. In Study 1, both populations of naturally cycling hinds exhibited highly significant (P<0.001) negative slopes (-0.36, -0.49) for the regression of gestation length against conception date, with indications of a significant hind genotype effect favouring shorter overall gestation lengths for crossbred hinds. Other effects for hind age, calf sex, birth weight, sire genotype and year were not significant. In Study 2, in which conception dates were artificially induced, there was a highly significant negative slope (-0.19), with a notable but non-significant effect of hind age favouring shorter overall gestation length for primiparous (pubertal) hinds (P>0.05). Other effects for hind live weight, calf sex and calf birth weight were not significant. All data sets support the hypothesis, and indicate that for every 10 days difference in conception date there was a change in gestation length of 1.9-4.9 days. This hints at the adaptive importance of optimisation of birth date in wild populations of red deer but the precise physiological mechanisms remain to be resolved. It is postulated that variation in fetal age during the latter stages of pregnancy, when feed quality and voluntary feed intake cycles are in a state of flux, may drive differential growth trajectories for early and late conceived fetuses, leading to nutritional control over fetal maturation and induction of parturition. However, consideration is also given to a putative direct effect of prevailing photoperiod on control of parturition processes in red deer.     

Compensatory extension of gestation length with advance of conception in red deer (Cervus elaphus)

Calving date in many mammals is matched to the time of greatest food availability. Out of season calving results in heavy penalties in terms of own and offspring survival or body condition. This study examined whether gestation length is affected by advancing fertilisation. Thirty-six red deer hinds (of the Iberian and Scottish subspecies) were subjected to a synchronisation treatment of oestrus, ovulation, and artificial insemination on three dates, with remaining non-pregnant females mated with an intact male in a last group. Gestation was longer the more the fertilisation was advanced; gestation lasted 241.5+/-1.3 days (d) in the first group, 237.4+/-1.2 d in the second, 235.1+/-1.3 d in the third, and 231.2+/-1.6 d in the last. Mean gestation lasted 234.2+/-0.7 d. Hinds gained less weight during gestation the more the fertilisation was advanced. The difference was due at least in part to net body weight of the hind after calving compared to that at mating, and calves did not differ in birth weight. As early born calves suffer greater mortality in the field, this enlargening of gestation might be a compensatory response of the hinds to match calving with food availability. Under natural conditions, similar small modifications of gestation length may help hinds to overcome short-term adverse conditions for calving. Because calf mortality is correlated with birth weight, hinds may have kept calf birth weight constant at the expense of greater body weight loss.     

Effect of reproductive rest on the subsequent breeding in Iberian red deer hinds (Cervus elaphus hispanicus)

The objective of this study was to examine the effects of reproductive rest during the preceding year on subsequent breeding in captive Iberian hinds. To achieve this, influences were assessed on hind weight at mating, precalving and postcalving weight, hind body condition at mating, hind weight gain during gestation, hind weight loss at calving, total milk yield and calf birth weight during the following breeding season. Sex ratio was examined according to hind age class (sub-adults or adults), precise age, body condition and weight at mating, and reproductive rest. One hundred and twenty seven gestations and their subsequent lactations were analyzed in pluriparous Iberian red deer (Cervus elaphus hispanicus) kept in captivity for two years. Sixty four of these gestations (50.4%) took place after no gestation during the preceding year.Hinds that did not gestate the preceding year were heavier at mating and after calving, gained less weight during gestation, and their body condition at mating was better than those hinds that had gestated. Also, calves from hinds that had reproductive rest the preceding year were heavier at birth than the others. Nevertheless, the probability of bearing a male was greater with increasing age, but not with reproductive rest or any other variable. Total milk yield was positively affected by hind postcalving weight and hind age at mating, but not by reproductive rest.In conclusion, reproductive effort during the preceding breeding influenced the subsequent gestation, having an effect on the following variables: hind weight and body condition at mating, hind weight gain during gestation, postcalving weight, and calf birth weight.     

A comparison of the calving behaviour of farmed adult and yearling red deer (Cervus elaphus) hinds

Mortality of newborn red deer (Cervus elaphus) calves is a major concern on New Zealand farms, as perinatal losses average approximately 10% of calves born. Primiparous red deer (calving as yearlings) lose more calves than multiparous hinds (adults). We performed a study on yearling and adult red deer hinds in order to improve knowledge of their calving behaviour and determine any apparent reasons for calf mortality. Pacing along fence lines was observed frequently during the 24 h period before birth (individuals were pacing in 43% of observations during this period). Adult hinds had a significantly earlier onset and longer duration of pacing (P<0.05). Hinds were often observed isolated (>20 m) from the rest of the herd during the 2 days prior to parturition, and this behaviour was also observed earlier in the adults than in the yearlings (P<0.05). Forty-four percent of adult hinds and 60% of yearlings experienced some form of interference from other hinds during parturition. Among hinds that were interfered with, yearlings had a higher average number of interferences from other hinds during parturition than adults (P<0.05). Calves born to yearling hinds took significantly longer to suckle for the first time (mean=44 min) from their dams than calves born to adult hinds (33 min; P<0.05). We concluded that an inability of hinds to express natural isolation behaviour was likely to contribute to calf mortality due to increased anxiety (indicated by fence line pacing) and encroachment on the birth areas of others, and that calves of yearlings were at an increased risk of mortality due to the higher number of interferences taking place during parturition and the longer time interval between birth and suckling.     

Influence of prenatal photoperiod on postnatal prolactin secretion in red deer (Cervus elaphus).

Plasma prolactin concentrations were higher (P < 0.001) in newborn red deer calves whose mothers had been maintained for the last 14 weeks of gestation in long days (18 h light) (group L, n = 9) than in those whose mothers had been kept over the same period in short days (6 h light) (group S, n = 5). After transfer of all hinds and suckled calves on the day of birth to constant intermediate daylength (12 h light), prolactin concentrations decreased exponentially (P < 0.001) in group L calves, but not in group S, during the first 21 days. Thereafter, prolactin fell to a nadir in group L calves and rose to peak values in group S calves at 8-12 weeks post partum (P = 0.003), before converging again by 14 weeks. The pattern of prolactin secretion over the first 14 weeks of life was therefore significantly affected by prenatal photoperiod. Plasma prolactin concentrations in the adult hinds were higher (P < 0.001) in group L than group S at 4-10 weeks before parturition; they were similarly high around parturition and fell thereafter to baseline values after 7 weeks. These results provide evidence that deer fetuses respond to photoperiodic information, thereby acquiring a photoperiodic history in utero that influences postnatal responses to photoperiod.     

Great expectations: dominance,breeding success and offspring sex ratios in red deer

Differences in dominance rank among red deer (Cervus elaphus) females (hinds) on Rhum were related to their breeding success as well as to the comparative success of male and female offspring. Males (stags) born to mothers above median rank were more successful than hinds, while hinds born to subordinate mothers were more successful than stags. The ratio of male to female calves produced by dominant mothers was significantly higher than that produced by subordinates. Since dominance rank among hinds is related to their body weight as adults and to their birth weight, these results suggest that the birth sex ratio may be affected by environmental factors operating during a female's early development.     

Induction of early breeding in red deer (Cervus elaphus) by melatonin

Lactating (N = 12) and non-lactating (N = 6) red deer hinds and one stag at pasture were given concentrates (500 g/head) containing melatonin (5 mg/head) daily at 16:00 h from 18 June to 16 October. The stag shed the antler velvet and started rutting 5 weeks ahead of untreated stags, and hinds had their first oestrus and ovulation of the breeding season in mid-September, 5 weeks in advance of control lactating (N = 9) and non-lactating (N = 5) hinds. Treated hinds were allowed to mate with the treated stag and control hinds ran in an adjacent paddock with an untreated stag. All hinds became pregnant during the study with all but 2 melatonin-fed hinds (1 lactating, 1 non-lactating) and 1 control hind (lactating) conceiving at the first oestrus. Melatonin-treated hinds lost slightly more live weight than did controls from June to November, but their suckled calves grew throughout at a rate similar to those of control hinds.     

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

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

Lactation under induced five-month delay reproduction in Iberian red deer (Cervus elaphus hispanicus)

In Iberian deer, calf birth date affects both milk production and composition, as well as the weight change of hind during lactation and calf growth. This study examines a five-month induced delay in calving (autumn group) in a group of 19 Iberian hinds compared to a group of 13 standard calving hinds (spring group). Fertility in the autumn group was half that of the spring one. From the former, a further two calves out of six died before or soon after birth. Successfully lactating hinds showed a greater concentration in protein, fat and lactose (P < 0.001), but did not differ from spring group in total milk yield, calf gain or weight change of hinds during lactation. However, after correcting for the greater calf or hind body weight at calving of the autumn group, this group showed lower values for these variables than the spring group. Results show that at least in Iberian deer, counter-season reproduction is possible, and that the effects on lactation variables are similar to those of a natural delay in calving.     

Calving times of Red deer (Cervus elaphus) on Rhum

The distribution of calving times in a population of Red deer on the Isle of Rhum, Inner Hebrides, between 1971 and 1976 is described. Two-thirds of calves were born during a three-week period beginning in the last week of May, though calving extended from early May to late August. Except in 1976, when calving occurred late, the timing of births was similar in all years. Variation in calving time within years resulted from (i) individual differences in calving time, (ii) late conception in hinds which failed to conceive at first oestrus, and (iii) the effect of previous reproductive history: on average, hinds calved one week later after rearing a calf in the previous winter. Gestation lengths of wild hinds were longer than in a captive group. This may have been due to overestimation of a proportion of gestation lengths in wild hinds, but supplementary feeding could also have shortened gestation length in captive animals.     

Factors affecting reproduction in red deer (Cervus elaphus) hinds on Rhum

In a population of free-ranging red deer hinds on the Isle of Rhum (Inner Hebrides) we investigated relationships between four aspects of reproductive performance (fertility, calf birth weight, birth sex ratio and calving date) and four variables likely to affect the mother's condition: age, reproductive status, home range area and year of calving. Fertility was significantly related to mother's age, reproductive status and home range area as well as to year of calf's birth. Stag calves were heavier than hind calves and birth weight was significantly related to mother's age, home range area and year of (calf's) birth but not to mother's reproductive status. Birth sex ratio did not differ from parity, and was not significantly associated with any of the four variables examined. Birth date was significantly related to the mother's reproductive status, home range area and year of (calf's) birth but not to mother's age or the sex of the calf.     

Selectivity of wolf predation on red deer in the Bieszczady Mountains, Poland

A pattern of wolfCanis lupus Linnaeus, 1758 predation on red deerCervus elaphus Linnaeus, 1758 was studied in Bieszczady Mountains in 1991–2002. In total 324 remains of red deer > 4 months old, killed by wolves throughout the year, were found. The sex, age and bone marrow fat content of wolf kills were compared with the same characteristics within the free living red deer population. The overall contribution of calves killed by wolves (24%) in October-May was higher than in the population (17%), and decreased from autumn to spring. Adult males were more vulnerable to wolf predation than adult females: stags constituted 62% and hinds 38% of adult red deer killed by wolves, whereas in the population, the percentages were 37 and 63%, respectively. Stags killed by wolves were younger ([`(x)] = 4.1\bar x = 4.1 years old) than hinds ([`(x)] = 8.9\bar x = 8.9 years old). Wolves killed more > 8 years old hinds and < 5 years old stags than available in the population. In wolf kills, the average fat content in femur marrow was higher among hinds (84.9%) than stags (69.3%) and calves (66.1%). Only 8% of hinds had < 70% femur marrow fat content, whereas 40% of calves and 38% of stags had marrow fat values below that level. Marrow fat content showed seasonal variation and was the lowest in March among all sex-age classes. The monthly share of stags in all kills, and hinds in hind-calf part of the sample was negatively correlated with their monthly average bone marrow fat content, and monthly share of calves was positively correlated with monthly average bone marrow fat content of adults. The segregation of social units (hind-calf and stag groups), except during the rutting season, and the low fat reserves of males from midwinter until spring contribute to the high overall incidence of calves and adult males and the relatively low incidence of adult females among wolf kills.     

Development of body condition in hinds of Iberian red deer during gestation and its effects on calf birth weight and milk production

Reproductive effort affects body reserves and subsequent ability to reproduce. In fact, the energy costs of gestation and lactation in hinds of red deer have a marked effect on maternal condition. The objectives of this study were to examine the development of hind monthly body condition during gestation in relation to reproductive rest, age and age class, just as its effects on total milk yield and calf birth weight. Eighty hinds of Iberian red deer were used as subjects during 2 years of study. They had ad libitum access to food and water. Animals were weighed weekly, and body condition was individually assessed. Milking was carried out under anesthesia with a milking machine followed by hand milking to collect the remaining milk.Age and reproductive rest influenced body condition, improving with age (coefficient: 0.10+/-0.01; P<0.001) and reproductive rest (mean+/-SEM, 3.75+/-0.05 vs. 3.25+/-0.02, with and without rest respectively; P<0.001). Hind age correlated positively with her body condition (R=0.62, P<0.001), however, when age class was included in the model, age was not significant. The greater the age class (up to age class 4) the greater the body condition; however, hinds of age class 5 had a lower body condition, but no significant differences were observed. Development of the body condition during gestation was different to age class 1 with respect to the others, just as between hinds that rested the preceding year and those that did not.     

Seasonal luteal cyclicity of pubertal and adult red deer (Cervus elaphus)

Reproductive failure of rising-two-year-old (R(2)) hinds and seasonal misalignment between calving and pastoral feed production are two factors limiting reproductive productivity of farmed red deer hinds in New Zealand. This study aimed to better understand processes around female puberty and breeding seasonality by describing the potential breeding season (i.e., oestrous cyclicity) of three red deer genotypes. A total of 27 hinds born in December 2005, representing Eastern European (Cervus elaphus hippelaphus), Western European (C.e. scoticus) and F1 crossbred (C.e. hippelaphus×scoticus) red deer, were blood sampled thrice-weekly for 7-8 months (February-September/October) across two years spanning the potential breeding seasons as R(2)'s in 2007 (i.e., puberty) and as adults in 2008. Plasma progesterone profiles were used to construct breeding cycle histories for each hind. Four R(2) hinds failed to initiate oestrous cycles (i.e., puberty failure). The remaining R(2) hinds, including all F1 hinds, exhibited between two and seven oestrous cycles. F1 hinds were significantly earlier to initiate, and later to terminate, cyclic activity, resulting in a longer mean pubertal breeding season (139 days) than for Eastern (86 days) and Western hinds (86 days). However, the data for R(2) hinds are confounded by live-weight, with the F1 hinds being significantly heavier than other genotypes. There were significant correlations between live-weight and seasonality parameters in 2007. All hinds were cyclic as adults in 2008, exhibiting between four and nine oestrous cycles, and a mean breeding season duration of between 132 (Western) and 137 (F1) days. For adult hinds there were no significant genotype differences in cyclic onset and cessation timing, and no observable relationships between live-weight and any reproductive parameter. However, the mean dates for the onset of the breeding season for all genotypes in 2008 were 2-3 weeks later than normally expected for adult hinds in New Zealand. The reasons for this are unclear but may relate to chronic stress of frequent animal handling. The study has demonstrated that puberty in red deer hinds is associated with a shorter potential breeding season than for adult hinds, and that perturbation of breeding activity appears to be quite common, leading to incidences of puberty failure and possibly other aberrant cyclic events. Live-weight×genotype interactions may influence puberty but do not appear to be strongly expressed in adults. However, the relatively late onset of oestrous cyclicity in the adult hinds may be an artefact of the study that has masked genetic influences on seasonal breeding patterns.     

Artificial insemination of red deer (Cervus elaphus) with frozen-thawed wapiti semen

Semen collected from wapiti (Cervus elaphus) in Canada in 1983 was frozen in two extenders. In 1988, the semen was used to inseminate 200 red deer hinds on 2 farms in New Zealand. Oestrus was synchronized in the hinds with progesterone-impregnated intravaginal devices (CIDR); 200 iu pregnant mares' serum gonadotrophin was given to each hind on Day 11. The CIDRs were removed on Day 12 at 20/h, as the numbers of the hinds were recorded. On Day 14, 54-56 h after CIDR removal, the hinds were brought into the yards in the same batches and laparoscopically inseminated. Semen from three sires was used. The overall conception rate was 51%. Gestation length ranged from 239 to 247 days. One hind was lost at calving, 3 calves had to be hand raised and there were 2 neonatal calf deaths.     

Birth weight and birth rate of heavy calves conceived by transfer of in vitro or in vivo produced bovine embryos

The aim of this study was to evaluate the difference in birth weight and gestation length between Japanese Black calves obtained from transfer of bovine embryos produced in vitro (IVP) and those developed in vivo (IVD). An additional objective was to clarify the sire effect on birth weight and gestation length and to examine the birth rate of heavier calves. Two Japanese Black bulls breed at our experimental station were used as a semen source for production of IVP and IVD embryos. Thirty-eight Japanese Black heifers and cows of various genetic backgrounds were used as embryo donors for IVD embryos. Ovaries for IVP embryos were collected at random at a local slaughterhouse from Japanese Black cattle of various genetic backgrounds. IVP embryos were produced using co-culturing with cumulus cells in 5% CS+TCM 199. Both the IVD and IVP embryos were transferred non-surgically to Holstein recipients on day 7+/-1 of estrous cycle. In this study, the birth weights and gestation lengths of half-sib single calves for bull A and B were analyzed.The numbers of single calves born by transfer of IVP and IVD embryos for bull A and B were 133 and 121, 243 and 465, respectively. The birth weight of the IVP calves was significantly higher (P<0.01) than that of the IVD (bull A: 31.0+/-0.4 kg versus 27.2+/-0.4 kg and bull B: 29.9+/-0.6 kg versus 26.6+/-0.2 kg). Gestation length of the IVP calves for bull A was significantly longer (P<0.01) than that of the IVD (291.9+/-0.9 days versus 283.6+/-0.5 days). However, for bull B, there were no differences in gestation length between the IVP and IVD calves (285.9+/-0.7 days versus 286.2+/-0.3 days). These results clearly indicated that IVP calves had heavier birth weights than IVD calves but that the average gestation length of IVP calves was not always longer than that of IVD calves. Furthermore, the birth rate of heavier calves and the incidence of stillbirth and perinatal mortality up to 48 h post partum in IVP calves (bull A: 11.3%, bull B: 7.8%) were greater (P<0.05) than those in IVD calves from both bulls (bull A: 4.1%, bull B: 3.7%).     

Artificial insemination following observational versus electronic methods of estrus detection in red deer hinds (Cervus elephus)

The objectives were to determine the efficacy of the HeatWatch (HW) electronic estrus detection system for monitoring behavioral estrus (including duration and intensity) in red deer hinds and to evaluate pregnancy rate to AI after detected estrus. Red deer hinds (Cervus elephus; n = 50) were allocated into two treatment groups: AI following synchronization (CIDR/PMSG) and observed estrus (induced estrus group: IE; n = 25) or AI following the detection of natural estrus (NE; n = 25) without hormonal treatment. Hinds were fitted with two HeatWatch (HW) electronic estrus detection transmitters, one above the tail (bottom) and one between the tuber coxae of the pelvic girdle (top), and visual observations for mounting activity began with the aid of young sterile red deer stags (18 months old) fitted with marking harnesses. Hinds in both groups were inseminated (10-12h after observed estrus) with frozen-thawed red deer semen using a transvaginal/cervical AI approach. Following a 26-day period of AI, hinds were placed with a mature fertile stag for an additional 30-day natural breeding period. Pregnancy diagnosis was performed 57 and 86 days after the start of AI. While the hinds were housed with the young stags, 82% were detected in estrus by visual appraisal of stag crayon marks, but only 32% of these were detected by HW. In contrast, in the hinds housed with the mature stag, 93% detected in estrus by crayon marks were also detected by HW. The top HW transmitter consistently recorded more mounts (P < 0.05) than the bottom transmitter. The pregnancy rate was numerically better in IE versus NE hinds (42% versus 29%, P > 0.10). In summary, there were no differences (P > 0.10) in the intensity (number) or duration of mounts (detected by HW) during estrus in IE versus NE hinds, and HW was most effective in detecting estrus in the presence of a heavier, mature stag versus a younger stag. When used in combination with transvaginal AI, an overall first-service pregnancy rate of 36.6% was achieved with AI of frozen-thawed semen in red deer hinds following detected estrus.     

Age-related body weight constraints on prenatal and milk provisioning in Iberian red deer (Cervus elaphus hispanicus) affect allocation of maternal resources

Maternal phenotypic characteristics can influence key life history variables of their offspring through maternal effects. In this study, we examined how body size constraints on maternal weight in yearling and subadult compared to adult hinds (age class effects) affected prenatal (calf birth weight, calf to hind weight ratio) and postnatal (milk) provisioning of Iberian red deer calves. Age correlated with all prenatal and postnatal investment traits except calf gains, although correlations were weaker than those with maternal weight. Once the effect of linear increase in weight with age was removed from models, yearlings showed additional reductions in calf birth weight, calf gains, and milk provisioning. The low-calf birth weight might increase the risk of calf mortality during lactation, as this occurs primarily during the first day of life and is strongly related to birth weight. Yearlings showed a greater prenatal allocation of resources in terms of greater calf to hind weight ratio probably as an extra effort by yearling mothers to balance calf neonatal mortality. It might compensate young mothers to produce low-quality calves while still growing rather than waiting for the uncertain possibility of surviving to the next reproductive season.     

Effects of density, climate, and supplementary forage on body mass and pregnancy rates of female red deer in Spain

The influence of short- and long-term (cohort) effects of climate and density on the life-histories of ungulates in temperate regions may vary with latitude, habitat, and management practices, but the life-histories of ungulates in the Mediterranean region are less well known. This study examined the short- and long-term effects of rainfall and absolute density on hinds in two of the southernmost populations of red deer (Cervus elaphus hispanicus) in Europe. One population received supplementary forage. Unlike more northerly latitudes, where red deer hinds lose body mass in winter as a result of adverse weather, in the Spanish populations, hinds did not lose body mass. Hinds in the population that received supplementary forage were heavier and more likely to become pregnant than were the hinds in the unsupplemented population. The likelihood of pregnancy occurring was strongly influenced by hind body mass; the proportion of yearlings that became pregnant was consequently lower in the unsupplemented population than in the population that received supplementary forage. Cohort effects on hind body mass (negative for density and positive for rainfall at birth) and on the probability of pregnancy (negative for density at birth) were apparent only in the unsupplemented population, which implies that supplemental feeding may partially compensate for negative density-dependent factors during early growth, and that supplemented deer hinds may experience reduced selection pressures. These results reflect the particular seasonal variation in the abundance and quality of food in Mediterranean habitats. The delayed effects of climate and density at birth on adult hind body mass and the prevalence of pregnancy probably affects population dynamics and constitutes a mechanism by which cohort effects affect the population dynamics in Iberian red deer. The management of Iberian red deer populations should take into account cohort effects and supplemental feeding practices, which can buffer density- and climate-dependent effects and reduce natural selection pressures.