Farmed red deer home range, habitat use and daily movement patterns in a Southland, New Zealand, tussock grassland over calving and lactation

Considerable expansion of red deer farming has occurred in the South Island high country of New Zealand. On these farms, breeding hinds are usually continuously grazed (set-stocked) at low population densities in large highly modified native-tussock grassland paddocks during their calving and lactation seasons. The present study determined how these hinds use the tussock grassland over this critical period, identifying the most essential resources for them and also some potential long-term consequences of their behaviour on the grassland ecosystem. This was achieved by tracking nine GPS-collared hinds over 2 years on a high-country deer farm in Te Anau, Southland, New Zealand. The home ranges of the GPS-tracked hinds varied widely, occupying between 15% and 52% of the total paddock area. Vegetation dominated by naturalised exotic pasture species covered the greatest proportion (>60%) of eight of nine hind home ranges. In contrast, tussock-dominant vegetation coverage was far more variable (0.4–46%), with several indicators suggesting that this vegetation type was used as a substitute for pasture areas under high intra-specific competition among the deer. Both pasture- and tussock-dominant vegetation was used in proportion to its availability. In contrast, shrub-dominated vegetation was used less than its proportional availability, indicating that it was not being put under as much foraging or grazing pressure. This has implications for the further ingression of this vegetation type over time. There was also clear evidence that certain paddock topography was being favoured by the hinds, namely steeper and higher-altitude areas of a paddock. On the basis of these findings, some potential methods for aiding in the management of these extensive tussock grassland paddocks under deer grazing are suggested.

A time-reversibility relationship between two Markov chains with exponential stationary distributions

The stationary non-negative Markov chains {Yn} and {Xn} specified by the relations for {η n} a sequence of independent identically distributed (i.i.d.) random variables which are independent of {Yn}, and for {ξ n} a sequence of i.i.d. random variables which are independent of {Xn}, are mutually time-reversed if and only if their common marginal distribution is exponential, relating the exponential autoregressive process of Gaver and Lewis (1980) to the exponential minification process of Tavares (1980).

Discrete minification processes and reversibility

Discrete minification processes are introduced and it is proved that the discrete first-order autoregression of McKenzie (1986) and the discrete minification process are mutually time-reversible if and only if they have common marginal geometric distribution, corresponding to a result for continuous processes given by Chernick et al. (1988). It is also proved that a discrete minification process is time-reversible if and only if it has marginal Bernoulli distribution.

A reversibility relationship for two Markovian time series models by stationary exponential tailed distribution

The continuous autoregressive and minification stationary non-negative time series models discussed by Chernick et al. (1988) are generalized to model marginal distributions which have atoms of mass at zero. The reversibility theorem relating these processes with exponential marginal distributions is extended to the case where the marginal distribution has exponential tail.

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.

The design and use of a device to detect deer pedicle growth

The design, construction and use of a device to detect changes in deer pedicle volume are described. The device is highly sensitive for detecting the initiation of pedicle growth. Between-sample differences of 170 mm3 in the pedicle volume of live deer were detected (triplicate measurements) using the detector; these correspond to a change in height of the pedicle of at most 0.67 mm. The within sample coefficient of variation was 1.4%. The pedicle growth detector enables more precise measurements to be obtained for identifying the onset of pedicle development to the nearest week than is currently possible with palpation.

Effect of melatonin implants on the incidence and timing of puberty in female red deer (Cervus elaphus)

A study was conducted to test the hypotheses that exogenous melatonin treatment of 11-13 month-old red deer hinds: (1) advances the timing of first ovulation, (2) increases the proportion of individuals attaining puberty at ∼16 months of age, and (3) reduces the live-weight threshold for attainment of first pregnancy. A total of 3901 rising-2-year-old (R₂) hinds within two herds (A and B) across two years either received single melatonin implants on two occasions in summer (n=1399) or were untreated controls (n=2502). Hinds were joined with stags from mid January to mid May, and were subjected to real-time rectal ultrasonography in early June to assess pregnancy status (proxy for puberty attainment) and foetal age for conception date assignment. Live-weights were recorded for each hind in January (12 months of age) as a proxy for weight at puberty. Melatonin treatment of hinds was associated with a significant advancement in mean conception dates in both herds in both years (P<0.05), with a cohort difference in mean dates between treated and control hinds ranging from 9 to 17 days. Analysis of the temporal distribution of conception dates for each cohort revealed bi-modal or tri-modal patterns of conception indicative of conceptions to first or subsequent ovulations (oestrous cycles). Across all cohorts, melatonin treatment was associated with higher conception rates to first ovulation (P<0.05) resulting in greater overall synchrony of conceptions. Regression analysis demonstrated a significant negative slope for conception date against live-weight (P<0.001), but there was no evidence that this slope varied with treatment, herd or year (P>0.05); for every 10kg increase in live-weight conception date was advanced by an average of 1.3 days. In Herd A, melatonin treatment was associated with significantly higher pregnancy rates in both years (90.3% vs. 78.0% in Year 1 and 84.4% vs. 57.1% in Year 2; P<0.05). The principle effect of melatonin treatment was to increase the pregnancy rate of hinds of low body-mass. In Year 1, at 60kg live-weight a logit regression model indicated a pregnancy rate of 52% for untreated hinds and 83% for treated hinds. At 105kg the rate for both cohorts was 90%. In Herd B, melatonin treatment was associated with higher conception rates in both years but these differences were not significant following correction for slight differences in mean live-weight (P>0.05). The study has demonstrated that factors influencing puberty attainment in R₂ red deer hinds can vary between populations. In Herd A, in which body mass of hinds immediately prior to their first potential breeding season may have been the principle limiting factor, melatonin treatment appears to have instigated the pubertal process in hinds that would otherwise be of insufficient body mass.

Short-term measurement of N2O emissions from sheep-grazed pasture receiving increasing rates of fertiliser nitrogen in Otago, New Zealand

The purpose of this short-term study was to investigate the effect of increasing fertiliser nitrogen (N) application rates on nitrous oxide (N2O) emissions over the late winter/early spring period from sheep-grazed pasture in Otago rolling hill country. We measured N2O gas emissions from plots on a mottled Fragic Pallic hill soil receiving 0, 100 and 500 kg N/ha.year for 2 years. Plots were sampled weekly for 10 weeks over the 2006 winter/spring period using a static chamber method. Increased N fertiliser rate and the attendant increase in stocking rate significantly increased total N2O emissions (P < 0.05). Total N2O emissions for the measurement period were estimated to be 0.08, 0.13 and 1.36 kg N2O-N/ha (s.e.m, 0.1, 0.18 and 0.45) for the 0, 100 and 500 N treatments, respectively. Our results suggest that high application rates of fertiliser N (i.e. 500 kg N/ha.year) and attendant increased stocking rates may significantly increase emissions of N2O even in dry winter/spring conditions in Otago rolling hill country. These results will assist in the development of best management guidelines for reducing N2O emissions from fertiliser N in hill country.

Evaluation of management variables to advance conception and calving date of red deer (Cervus elaphus) in New Zealand venison production systems

The ability to shift the supply of New Zealand chilled venison from farmed yearling red deer stags to obtain premium prices in seasonal European markets necessitates early calving of hinds combined with high growth rates of their calves. Two studies over a three-year period evaluated three management variables that offer potential to advance calving date. Under the conditions of the studies there was no consistent evidence that the management practices of early stag introduction, early weaning and enhanced hind nutrition prior to conception (lactation) and pre-calving (third trimester of pregnancy) advanced conception date and calving date in red deer hinds. However, the nutrition effect was diminished by the difficultly in achieving the dietary contrast necessary for the targeted 5kg differentiation in hind live weight at strategic times of the year. Across all hinds there was a significant pre-mating (mid-March) live weight effect on conception day in the one year in which a 5kg difference between nutritional regimens was achieved, but the driver was live weight and not nutrition. There were significant effects of nutrition on calf growth, with the growth rates of calves weaned in mid-March significantly higher when their dams grazed a high plane of nutrition pre-conception. There were significant and consistent inverse relationships between conception day and calving date that implied variation around gestation length, with early- and late-conceiving hinds exhibiting longer and shorter gestation lengths, respectively. Across all treatments, calving date was predicted to advance by approximately 5 days for every 10-day advance in conception date. However, there was a significant carry-over effect of nutrition pre-conception on calving date, with hinds on a high plane of nutrition pre-conception exhibiting shorter (2-4 days) gestation lengths. There were also indications that hinds may manipulate gestation length in response to live weight gain pre-calving. These findings suggest that fetal growth trajectory may be the principle driver of gestation length and calving date. Although there were no direct effects of hind nutrition pre-mating on conception dates, nutrition remains an important component of the management of hinds and their calves in venison production systems. The outcomes of the 3-year program suggest that there are limited opportunities to manipulate calving date through manipulation of management variables.

Growth hormone and ghrelin receptor genes are differentially expressed between genetically lean and fat selection lines of sheep

The objective of this study was to determine whether differences in mRNA levels of key pituitary genes that regulate GH production, pituitary development, and growth were present and/or associated with divergent body composition phenotypes observed between sheep from genetically divergent lean and fat selection lines. Real-time PCR transcription profiles for pituitary specific transcription factor 1, prophet of pit1, GH, GH receptor, GH secretagogue receptor, GHRH receptor, leptin receptor, and somatostatin receptors 1 and 2 were determined in pituitary tissue. There was a difference in the amount of both GH (P < 0.001) and GH secretagogue receptor (P < 0.001) mRNA between the selection lines (5 females and 5 males per line; 20 wk of age); the lean line had greater abundance than the fat line, irrespective of which endogenous control gene was used. The results obtained for GHRH receptor were equivocal but suggestive; there were greater GHRH receptor mRNA levels (P < 0.001) in the lean line using beta-2-microglobulin as the endogenous control but not when hypoxanthine phosphoribosyltransferase and glyceraldehyde-3-phosphate dehydrogenase were used. No difference in pituitary specific transcription factor 1, prophet of pit1, GH receptor, leptin receptor, or somatostatin receptors 1 and 2 mRNA concentration was observed between the lines. The greater abundance of GH mRNA in the pituitary somatotropes from genetically lean animals appears to be associated with increased levels of GH secretagogue receptor mRNA and possibly GHRH receptor mRNA. This suggests that the difference in GH secretion between the lines may be due to differences in the afferent signals, such as ghrelin and/or GHRH, arising from the hypothalamus, or as a result of differential pituitary sensitivity to these hormones.

Reproductive performance of pubertal red deer (Cervus elaphus) hinds: effects of genetic introgression of wapiti subspecies on pregnancy rates at 18 months of age

Low reproductive productivity of young red deer (Cervus elaphus) hinds on New Zealand deer farms appears to reflect high incidences of puberty failure at 16 months of age. This is despite the general attainment of average liveweights 15-25 kg in excess of the accepted minimum threshold for puberty in subspecies of western European origin (scoticus, elaphus and hippelaphus) that form the basis of the national herd. The present study tests the hypotheses that introgression of the larger North American wapiti subspecies (nelsoni, manitobensis and roosevelti) into breeding herds (1) can be assessed from morphological features of individuals, (2) that there is a relationship between the level of wapiti parentage and non-pregnancy rate at 18 months of age (a proxy for puberty failure) and (3) that minimum liveweight thresholds for puberty increase with increasing levels of wapiti parentage. A total of 4329 18-month-old hinds across four "red" deer farms in southern New Zealand were scanned for pregnancy status. Each hind was assigned a wapiti score (WS) as a subjective assessment of the obviousness of wapiti features. Various body measurements were additionally recorded for each hind. A hair sample was collected for DNA analysis (14 markers) to objectively assign subspecies pedigree (i.e. "Elkmeter") on a subset of 1258 individuals. A total of 506 (11.7%) hinds were not pregnant at 18 months of age with rates varying between 4.1 and 37.3% between farms and years. Mean WS differed significantly between farms and reflected the genetic management policy of each farm. WS was positively correlated to Elkmeter for each farm/year (<0.05) although regression slopes varied significantly. WS was able to be adjusted for these differences to assign a corrected WS (CWS) for all 4329 individuals that estimated the proportion wapiti parentage. Discriminant analysis of morphological variables relative to Elkmeter supported the first hypothesis and showed that shoulder height and body length were good indicators of the degree of wapiti parentage within individuals. This enabled the development of an objective estimate of wapiti parentage (EWP). The actual level of such parentage within herds ranged from <5 to >55%. There was a significant negative association between wapiti parentage and pregnancy, which was strongly influenced by liveweight, supporting the second and third hypotheses. This was manifest as marked displacement of pregnancy probability curves in relation to liveweight between genotype groups, particularly for those groups with >20% wapiti parentage. For example, predicted threshold liveweights required to achieve a 90% pregnancy rate for EWP values that represent 0, 10, 20, 30, 40 and 50% wapiti parentage were 81, 81, 85, 106, 127 and approximately 137 kg, respectively. Within the study herds, the majority of hinds of 0-20% wapiti parentage exceeded the predicted 90% threshold liveweights for their genotype cohort. However, hinds with higher levels of wapiti parentage generally fell below the predicted threshold for their genotype group. The data strongly suggest that under liveweight performance levels measured for red deer, hinds with >20% wapiti parentage are at high risk of puberty failure.

Behavioural and heart rate responses to velvet antler removal in red deer

Heart rate and behaviour during and following velvet antler removal were monitored in yearling red deer stags to determine the extent to which this procedure was perceived by the deer to be aversive. Nine stags normally kept at pasture were habituated over 5 weeks to the following daily handling procedure. Each deer was fitted with a harness containing a heart rate monitor. It was then allowed to run through a fixed course in a deer yard, restrained for 40 s in a mechanical deer crush, and then confined for 3.5 h with the remainder of the group of stags in an indoor pen containing food and water. In Week 6, the deer were subjected to either restraint for 6 minutes (the control treatment) or removal of one velvet antler under local anaesthesia. Each velvet antler was removed on separate occasions, either on Days 1 and 2 (five deer) or Days 3 and 4 (four deer). The control treatment was applied to all deer when velvet antler was not being removed, and on Day 5. Heart rate and behaviour (time taken to enter the treatment area, and number of struggles made during restraint) were measured before and during treatment, and post-treatment activities were recorded at 0, 1 and 3 h (indoors), and at 6 and 9 h (at pasture). Heart rate was higher during the second velvet antler removal treatment than during the first, but lower during the second control treatment than the first (P<0.05). During velvet antler removal, stags struggled more, and after the treatment flicked their ears, shook their heads, and groomed themselves more than control stags (P<0.05). Stags whose velvet antler had been removed spent less time eating than control stags, and spent progressively more time sitting during the 3.5 h of confinement (P<0.05). However, during the paddock observation at 9 h post-treatment, stags which had had their velvet antler removed grazed more than control stags (P<0.05). The increase in heart rate over the two velvet antler removal treatments and the greater amount of struggling during velvet antler removal indicated that it was more aversive than the control treatment. Post-treatment differences in behaviour may have been due to pain following velvet antler removal.

Activities and social relationships of red deer at pasture

AIM

To provide baseline data for research into behaviourally appropriate management systems for deer.

METHODS

Activities and their relationships with weather conditions, and social interactions both at pasture and during yarding, were investigated in two groups of yearling stags over summer in Otago, New Zealand. Over 8 weeks from November to January, activities, individual distances, weather conditions and use of shade from trees and shelter from windbreak cloth were recorded at 5 minute intervals for 4-hour periods at dawn, noon, and dusk. Over 2 further weeks, inter-individual distances and aggressive behaviours were recorded for each group over two 3-hour periods in both the home pasture and yard pen environments.

RESULTS

Days were classified as being predominantly dry or wet, and use of shade and shelter and activity patterns differed between dry and wet days (p< 0.05), with grazing and sitting cycles being disrupted on wet days. Fenceline pacing, a possible indication of motivation to escape, was observed most frequently at dusk on wet days (14.8 % of observations compared with 5.6 % for dry days, s.e.d. 4.1 %; p <0.05). There was significant evidence (p <0.001) for close association between specific pairs of deer. More aggression was observed in the yard pen than in the paddock (p <0.05). Aggressive interactions showed a linear dominance hierarchy in one group, and a near-linear hierarchy in the other group. Relationships between distance scores, both at pasture and in the yard pen, and aggression hierarchy rankings were found, with lower-ranking stags maintaining greater distances from their neighbours (p <0.05).

CONCLUSIONS

It was concluded that as the use of shade and windbreak cloth shelter was related to weather conditions, these amenities probably assisted with thermoregulation. A need for shelter from the rain was indicated by disrupted activity cycles and fenceline pacing on wet days. Further work into the needs of deer for protection from the weather is warranted. Evidence of association between individual deer within groups, and avoidance of social contact by some individuals within groups, indicated that research into the social effects of different handling and management techniques for established groups of deer is also warranted.

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.

Influence of level of nutrition during late pregnancy on reproductive productivity of red deer (2) Adult hinds gestating wapitixred deer crossbred calves

The present study aimed to relate feed intake of red deer hinds in the later stages of gestating wapitixred deer crossbred foetuses on dam body condition, gestation length, birth weight and calf growth. Multiparous hinds (N=18) conceiving at known dates to either wapiti (n=12) or red deer (n=6) sires were housed in individual pens from days 150-220 of pregnancy, during which time they were offered either ad libitum access to pelletised rations (n=6 crossbred-bearing hinds [HH] and n=6 red deer-bearing hinds [RH]) or a restricted offer (n=6 crossbred-bearing hinds [HL]) set at 70% of the average ad libitum intake of HH hind 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. HH and RH hinds exhibited similar patterns and levels of MEI/kg0.75, which peaked at 7.8 MJME/kg0.75 at day 220. HL hinds peaked at approximately 5 MJME/kg0.75 and showed significantly lower rates of liveweight gain during pregnancy. Interestingly, both crossbred-bearing groups initiated mammary development in advance of the RH hinds. While there were significant effects of foetal genotype on mean gestation length (239 days versus 234 days for crossbred versus red deer) and mean birth weight (14.5 kg versus 10 kg), the nutritional contrast for gestation length of crossbred-bearing hinds (i.e. HH versus HL) was not significant but approached significance for birth weight (14.5 kg versus 11.9 kg; P=0.06). Regression analysis revealed weak relationships between changes in hind liveweight and gestation length (P>0.05) but a significant relationship with birth weight (P<0.05). However, change in hind BCS was significantly related to both gestation length and birth weight. Crossbred calves reared by HH hinds were 30% heavier at 7 and 12 weeks of age than the red deer calves. However, those reared by HL hinds were significantly lighter than their genotype contemporaries and only marginally heavier than the red deer calves. These results generally contrast with the previous studies on red deer hinds gestating red deer foetuses [Asher, G.W., Mulley, R.C., O'Neill, K.T., Scott, I.C., Jopson, N.B., Littlejohn, R. 2004. Influence of level of nutrition during late pregnancy on reproductive productivity of red deer, (1) Adult and primiparous hinds gestating red deer calves. Anim. Reprod. Sci., in press] and indicate that the genetically determined higher growth requirements of crossbred foetuses may override any mechanism of compensatory control of gestation length at the expense of calf birth weight. Furthermore, there were marked carryover effects of late gestational feeding on crossbred calf growth and their dam's BCS that highlight the high nutritional demands of lactation.

Colour stability and water-holding capacity of M. longissimus and carcass characteristics in fallow deer (Dama dama) grazed on natural pasture or fed barley

The effects of feeding regimen on carcass characteristics, meat colour and water-holding capacity of M. longissimus were studied in 24 female fallow deer (Dama dama). All animals were farm raised; twelve were grazed on pasture and twelve were fed barley and a small amount of hay prior to slaughter. The animals were slaughtered at two occasions (during the Southern Hemisphere spring); after 19 weeks of feeding (n=12; 6 grazing and 6 barley fed animals; group 1) and after 24 weeks of feeding (n=12; 6 grazing and 6 barley fed animals; group 2). The barley/hay-fed deer had significantly higher body condition scores and carcass weights than the pasture raised group. No difference in meat ultimate pH values between the treatment groups was recorded. The meat from the pasture raised deer had significantly longer colour display life after 2 and 3 weeks of refrigerated storage (+ 2.0 ºC) in vacuum bags. There was no difference in drip loss between the two treatment groups. However, significantly lower drip losses were found in meat from the animals in group 2 compared with the ones in group 1 (P ≤ 0.001). It was concluded that the feeding regimen of the animals is an important factor that contributes to the variation in quality of fresh chilled deer meat (venison), mainly the colour stability and display life of vacuum packaged meat.Abstract in Swedish / Sammanfattning: I denna undersökning ingick 24 dovhjortshindar (Dama dama) för att studera effekterna av olika typer av foder (bete och korn) på slaktkroppskvalitet samt färg och vattenhållande förmåga i köttet (M. longissimus). Alla djur var uppfödda på en hjortfarm, 12 betade gräs och 12 utfodrades med korn och en liten mängd hö före slakt. Djuren slaktades vid två olika tillfällen (under våren på det södra halvklotet); efter 19 veckors utfodring (n=12; 6 betesdjur och 6 kornfodrade djur; grupp 1) och efter 24 veckors utfodring (n=12; 6 betesdjur och 6 kornfodrade djur; grupp 2). De dovhjortar som utfodrats med korn och hö var i bättre kondition och hade högre slaktvikter jämfört med de djur som betat gräs. Ingen skillnad i köttets pH-värde mellan de två utfodringsgrupperna kunde dock påvisas. Köttet från de betande dovhjortarna hade bättre färgstabilitet efter lagring i 2 och 3 veckor (+ 2.0 ºC) i vakuumförpackning. Det fanns ingen skillnad mellan kött från betande och korn/hö-utfodrade djur i vattenhållande förmåga. Däremot hade kött från djur i grupp 2 (slaktade efter 24 veckors utfodring) bättre vattenhållande förmåga jämfört med grupp 1 (P ≤ 0.001). Vi kunde konstatera att de olika fodertyperna påverkade kvaliteten hos färskt kyllagrat kött, framförallt färgstabiliteten hos vakuumförpackat kött.

Evaluation of the effectiveness of a commercially available defined substrate medium and enumeration system for measuring Escherichia coli numbers in faeces and soil samples*

AIMS

To determine if a commercially available defined substrate medium and enumeration system could be utilized as an effective and accurate means of enumerating Escherichia coli in environmental samples containing faeces and soil.

METHODS AND RESULTS

The samples tested were either inoculated with laboratory grown E. coli or natural E. coli populations in cow faeces. The number of E. coli recovered from faeces and soil samples using the defined substrate medium and enumeration system and a miniaturized MPN method (using traditional media) was compared by analysing the difference between the two methods in relation to the mean. For four of five groups of samples analysed there was no significant difference in the number of E. coli recovered by the two methods (P > 0.05). In one batch the difference was 0.30 log, which while being statistically significant (P < 0.01) was not considered to be biologically significant.

CONCLUSION

The commercially available enumeration system was significantly more precise than the miniaturized MPN method (P < 0.001).

SIGNIFICANCE AND IMPACT OF THE STUDY

We conclude that the commercially available defined substrate medium and enumeration system is a suitable method for the measurement of E. coli numbers in faeces and soil samples and should provide advantages of increased precision and a reduction in laboratory analysis time.

Effects of testosterone on pedicle formation and its transformation to antler in castrated male, freemartin and normal female red deer (Cervus elaphus)

Pedicles and antlers are male deer secondary sexual characters. As such, development of these structures is under the control of androgen hormones. Pedicle growth is caused by increasing and elevated plasma testosterone (T) levels, whereas first antler transformation from a fully formed pedicle occurs when the T levels are decreasing. Castration prior to pedicle initiation abrogates future pedicle and antler formation. Female deer also have the potential to develop pedicles and antlers, but they do not normally express this phenotype due to lack of sufficient androgen stimulation. Previous studies have shown that female white-tailed deer could be readily induced to grow pedicles as well as antlers by singular administration of exogenous androgens (EA), but in red deer (Cervus elaphus) singular or irregular EA treatment could only stimulate castrated male, normal or ovariectomised females to grow pedicles, but not antlers. The present study was set out to test whether these EA-induced pedicles in red deer failed to give rise to antlers was because they were constitutively incapable of doing so, or because the plasma T profile naturally exhibited in intact stags was not achieved by the androgen treatment used in these previous studies. Eight castrated red deer stag calves, 3 freemartins (females which were born co-twin to males), and 3 normal female red deer were used in the present study and treated with EA, either as biweekly injections for the castrates or as implants for freemartin and females until the late stage of pedicle growth. Blood sampling was carried out biweekly for the analyses of plasma T and IGF1 concentration. The results showed that the natural plasma T profile in the experimental deer was successfully mimicked through regular EA treatment and subsequent withdrawal at late pedicle growth stage. All castrated males, 2 out of 3 freemartin, and 1 out of 3 normal female red deer formed not only pedicles, but also antlers. Based on these results, we conclude that EA-induced pedicles at least in red deer of the genus Cervus, like those in the genus Odocoileus, are constitutively capable of giving rise to antlers, if they are of sufficient height.

Effects of testosterone either alone or with IGF-I on growth of cells derived from the proliferation zone of regenerating antlers in vitro

Deer antlers are male secondary sexual characters and are the fastest growing mammalian tissue. As such, both androgens and growth factors play a major role in antler development. The timing of the antler cycle is controlled by the seasonal fluctuations of testosterone, and the actual growth of antlers is mainly stimulated by growth factors including insulin-like growth factor-1 (IGF-I). However, whether or not testosterone at low levels plays a growth-promoting role during antler formation is controversial. In the present study, we took an in vitro approach to investigate whether testosterone either alone or with IGF-I had mitogenic effects on mesenchymal or cartilaginous cells derived from the proliferation zone of regenerating antlers. In addition, a binding assay was carried out to determine whether the specific binding sites for testosterone were preserved after cell disaggregation. The results showed that testosterone either in physiological concentrations or at low levels did not exert direct mitogenic effects on antler cells derived from the proliferation zone in serum-free medium in vitro (P>0.05), even if the specific binding sites for testosterone in these cells were well preserved. Likewise, testosterone in a very wide range of concentrations not only failed to enhance (P>0.05), but at certain levels (0.1-5 nM) impaired the mitogenic effects of IGF-I on these antler cells in vitro (P<0.001). Therefore, these results support neither a conclusion that low level testosterone has growth-promoting effects on antler formation nor the hypothesis that testosterone effects may be achieved through sensitizing these antler cells to the mitogenic effects of IGF-I.

Genetic variation within the Merino sheep breed: analysis of closely related populations using microsatellites

Genetic relationships among six populations of Merino sheep were investigated using microsatellites. The history of the six populations is relatively well documented, with all being derived from the Spanish Merino breed within the last 400 years. Genetic variation was highest amongst the Spanish and Portuguese populations, although the preservation of genetic diversity within the other populations was high. By a variety of different statistical tests the French Mutton, German Mutton and New Zealand Merino populations could be differentiated from each other and the Iberian Merinos, indicating that microsatellites are able to track relatively recent changes in the population structure of sheep breeds. The dendrograms constructed on the basis of microsatellite allelic frequencies showed that populations that have shared selection criteria (meat vs. wool) tend to cluster together.

Plasma glucose and insulin levels in genetically lean and fat sheep

This study investigated whether genetically lean and fat sheep displayed differences in insulin and glucose statuses. Lean genotype sheep had significantly (P < 0.05) greater basal glucose concentrations than fat genotype sheep (4.78 versus 4.52, SED = 0. 104 mmol/l), although basal plasma insulin was not significantly different (mean 304, SEM = 37.3 pmol/l) between the genotypes. During glucose tolerance tests (GTT), carried out at 4 levels of injection: 0, 0.28, 1.39 or 2.78 mmol glucose/kg liveweight, the area under the plasma insulin curve was significantly (P < 0.05) greater for fat than lean genotype sheep, although there were no differences in any glucose parameters. There were no significant differences between genotypes in insulin or glucose concentrations during or following glucose infusion (GINF) experiments at 0, 0.09, 0.46 or 0.93 mmol glucose/kg live-weight/h over 3 hours. Elevated plasma insulin concentrations after a glucose tolerance test are concluded to be associated with increased fatness in this genetically selected line of sheep. However, the differences in insulin and glucose levels between the lean and fat genotype sheep are minor, relative to the differences in carcass composition.

Effects of insulin-like growth factor 1 and testosterone on the proliferation of antlerogenic cells in vitro

Androgen hormones and growth factors are implicated in pedicle formation and antler transformation in deer. The potential to form a pedicle and an antler is only found in the antlerogenic periosteum (AP) overlying the presumptive antler growth region. Histological studies (Li and Suttie, '94) showed that AP consists of an inner cellular layer and an outer fibrous layer. Pedicle and antler are mainly derived from the cellular layer cells of the AP. Ossification takes place in four stages: intramembranous (IMO), transitional (OPC), pedicle endochondral (pECO) and antler endochondral (aECO). However, the precise mechanism whereby androgen hormones and growth factors control pedicle and antler formation is unknown. The aim of this study was to use cell culture techniques to investigate how testosterone and IGF1 affects the proliferation of antlerogenic cells from the four ossification stages of pedicle/antler in vitro. The results showed that in serum-free medium IGF1 stimulated the proliferation of antlerogenic cells from all four ossification stages in a dose-dependent manner. In contrast, testosterone alone did not show any mitogenic effects on these antlerogenic cells. However, in the presence of IGF1, testosterone increased proliferation of the antlerogenic cells from the IMO and the OPC stages (pedicle tissue), and reduced proliferation of the antlerogenic cells from transformation point (TP) and aECO stages (antler tissue). Therefore, the results from the present in vitro study support the in vivo findings that androgen hormones stimulate pedicle formation but inhibit antler growth. The change in the mitogenic effects of testosterone on antlerogenic cells from positive to negative occurs approximately at the change in ossification type from OPC to pECO. Therefore, these results reinforce the hypothesis that the transformation from a pedicle to an antler takes place at the time when the ossification type changes from OPC to pECO rather than at the time when the pedicle grows to its full species-specific height.

Effects of photoperiod on the cessation of growth during autumn in male red deer and growth hormone and insulin-like growth factor-I secretion

Male red deer undergo seasonal cycles of food intake and growth rate, which are high during spring and low during winter, despite high quality food ad libitum. Hormonal profiles during the cessation of growth in autumn and the potential role of photoperiod in the timing of the observed changes have been investigated. Whether this seasonal decrease in growth affected the response of GH and IGF-I to fasting was also examined. Two groups of six male 1-year-old red deer were exposed to different photoperiods after the summer solstice. One group (C) was given a simulated natural photoperiod while the other group (SS) was maintained on a summer solstice photoperiod (16L:8D). GH was measured in blood collected continuously and divided into pools every 5 min for 24 h in the fed state and after a 48-h fast on two occasions; the first was in November before photoperiod manipulation began and the second was in April approximately 16 weeks after initiating treatments. IGF-I, prolactin, and testosterone were measured in weekly samples. Individual live weight and group food intake were also measured each week. The normal growth pattern seen in the C group was delayed in the SS group. Thus, from 7 March until the second GH sampling on 11 April the live weight of deer in group C fell; in contrast, deer in group SS continued to grow (-43 vs 186 g/day s.e.d. = 65.5, P < 0. 01). Food intake changes reflected the pattern of growth in both groups. Mean GH (P < 0.05), GH pulse amplitude (P < 0.01), and IGF-I (P < 0.001) declined in both groups from November to April. This decline was more marked in group C and in April these parameters were all lower in group C than in group SS (GH, P < 0.05; IGF-1, P < 0.01). Prolactin levels in April were also lower in group C than in group SS (P < 0.01); testosterone was not affected by treatment. Fasting increased mean GH and GH pulse amplitude in both groups in November (P < 0.05). In April, the fasting response differed between the groups. In group C, mean GH, pulse amplitude, and pulse frequency were all greater in the fasted state than in the fed state (P < 0.05), while in group SS there were no significant differences (P > 0.05). IGF-I was lower in the fasted state than in the fed state at both sampling dates (P < 0.001). The seasonal decline in food intake and growth is associated with decreased GH, IGF-I, and prolactin concentrations, and increased testosterone and the GH response associated with fasting. All these changes except those of testosterone were delayed or reduced by continued exposure to a summer solstice photoperiod in autumn. The decreased photoperiod in autumn may thus influence the normal timing of the seasonal growth cycle.

Recent information on iodine deficiency in New Zealand sheep flocks

AIMS

To determine the value of pasture iodine, serum thyroxine (T4) and tri-iodothyronine (T3) concentrations and thyroid (g) to body weight (kg) ratios in lambs as criteria to predict and diagnose increased litter size and decreased perinatal mortality in response to iodine supplementation.

METHODS

Results from ten iodine response trials in ewes using an oil-based intramuscular iodine preparation were reviewed along with results from investigations into goitre on five farms in the Manawatu.

RESULTS

In two trials, litter size was increased by 14% and 21% in iodine-treated ewes. In only three of the 10 trials was there a significant reduction in perinatal mortality in iodine-treated ewes.

CONCLUSIONS

Pasture iodine and serum thyroxine (T4) and tri-iodothyronine (T3) concentrations appeared to be unhelpful in predicting the occurrence of increased litter size and reduced perinatal mortality in response to iodine supplementation. New-born lambs from ewes not supplemented with iodine, that had a mean thyroid weight (g) to body weight (kg) ratio of 0.40 g/kg or greater, generally had a significant increase in perinatal mortality compared to lambs from iodine-supplemented ewes.

Embryo development and placentome formation during early pregnancy in red deer

Early embryo development and placentome formation were assessed in red deer between Days 27 and 55 of gestation. Uteri were collected from 12 pregnant hinds in which mating was observed following a synchronized oestrus, and the tissues retained for measurements and histological processing for light microscopy. Twelve embryos were recovered with mean embryo weights increasing from 0.02+/-0.01 g at Day 27 to 7.56+/-1.39 g at Day 55 of gestation. Similarly, crown-rump lengths increased from 5.7+/-0.7 mm to 55.3+/-5.9 mm over this period. The trophoblast had extended throughout both uterine horns and gastrulation was completed by Day 27. Limb buds were apparent by Day 34, and by Day 48 the phalanges had separated into hooves and dew claws. Plaques were evident on the trophoblast at Day 34 and, by Day 41, placentomes had formed adjacent to the embryo. These placentomes grew in size as pregnancy advanced; by Day 55 most caruncles had formed placentomes. It is therefore confirmed that placentome formation occurs at about the sixth week of gestation. These results indicate that embryo growth and placentome formation in red deer are generally typical of that observed in other ruminants.

Neuroleptic treatment of red deer calves at weaning

AIMS

To determine whether neuroleptic drugs could be useful in reducing weaning stress in red deer, two groups of 30 calves were studied following separation from their dams for weaning at 3-4 months of age.

METHODS

Within each group, on the day of separation (Day 0), 15 calves were given 0.2 mg/kg haloperidol (a short-acting neuroleptic) and 1 mg/kg perphenazine enanthate (a long-acting neuroleptic) by intramuscular injection (the treated calves) and 15 calves were given a 3 ml intramuscular injection of saline (the control calves). The calves were weighed on Days 0, 14 and 28 and the behaviour of eight individuals (four treated and four control calves) within each group was observed for 2 hours on Days 0, 1, 2, 3, 7, 8, 14 and 15.

RESULTS

No significant effect of the treatment on weight gain to Days 14 or 28 was observed (mean increases for treated and control calves to Day 14 were 3.4 kg and 3.5 kg, respectively (s.e.d. 0.26 kg), and 6.0 kg for both treatments to Day 28 (s.e.d. 0.36)). Behavioural variables (standing, grazing, moving, fenceline pacing, proximity to other deer and proximity to the fenceline) did not differ significantly between treatments, but in one group sitting in sternal recumbency was lower in treated calves compared with control calves (p < 0.05). Disturbed behaviour declined over the observation days with fenceline pacing, being within 2 m of a fence, and being within 1 m of another deer decreasing, and sitting and grazing both increasing (p < 0.01).

CONCLUSIONS AND CLINICAL RELEVANCE

It was concluded that we could not provide evidence from the present study that treatment with haloperidol and perphenazine enanthate at these dose rates was beneficial in reducing weaning stress in red deer calves.

The physiological effects of natural variation in growth hormone gene copy number in ram lambs

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 (P < 0.05). 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 (P < 0.05 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.

Effects of season, protein and nutritional state on glucose tolerance during an annual cycle of growth in young red deer stags

Two hypotheses were tested in gonad-intact, young (aged 6-18 months), growing red deer stags during an annual growth cycle. First, that glucose clearance rate is faster during summer than during winter. Secondly, that increased dietary protein availability will enhance winter growth. Stags were randomly assigned into one of two groups: group 1 (n = 5) had 16% while group 2 (n = 6) had 48% of dietary protein naturally protected against fermentative degradation in the rumen. Total crude protein and energy remained similar for each diet (12 and 14% respectively for protein and 11 MJ metabolisable energy/kg dry matter). Stags were kept indoors in individual pens for 12 months and given monthly intravenous glucose tolerance tests (IVGTT), at a dose of 200 mg/kg, in the fed and fasted (48 h) states to determine both growth and steady-state tissue requirements. Protein level had no effect on food intake, weight gain, insulin kinetics, or glucose clearance rate. In the fed state, insulin peak (highest level' after IVGTT) increased (P < 0.01) from October (139 pmol/l) to December (247 pmol/l) (S.E.D. = 42) and remained elevated during the summer, before declining (P < 0.01) from February (223 pmol/l) to April (130 pmol/l) (S.E.D. = 25). Glucose clearance rate was faster (P < 0.05) in December (1.69 litres/min) than June (0.61 litres/min) in the fed state (S.E.D. = 0.30), and decreased (P < 0.05) from February (1.75 litres/min) to April (0.92 litres/min) (S.E.D. = 0.39). During fasting, the pattern of glucose clearance was similar to that observed in the fed state, but the amplitude was lower, while the pattern for insulin peak was similar to that of the fed state. We concluded first, that additional protected protein does not benefit growth during winter. Secondly, we concluded from the fasted, steady-state data that stags are insulin resistant during summer. Thirdly, despite insulin resistance, data on the fed state demonstrated that stags have higher tissue energy requirements during summer growth.

Prolactin does not enhance glucose-stimulated insulin release in red deer stags

Red deer stags have a seasonal pattern of insulin secretion that is characterized by both elevated basal and glucose-stimulated insulin release in summer compared with winter. Since the seasonal timing of this pattern is similar to that of prolactin and growth rate, the objectives of this study were: first, to determine whether prolactin is associated with the enhanced secretion of insulin during the summer growth period, and second, to determine whether a chronic reduction in plasma prolactin levels would alter body composition. Prolactin was suppressed in plasma using a long-acting form of the dopamine agonist bromocriptine (parlodel LA), which was administered at one of four doses (0-0.3 mg/kg) to each of four groups of castrate stags. Bromocriptine was administered during two 6-wk periods; the first in winter and the second in summer. During the sixth wk of each period, each animal was given three IVGTT at the following glucose doses (10 mg/kg, 70 mg/kg, and 200 mg/kg). Two d later, ovine prolactin was administered to each animal (0.08 mg/kg) and a single IVGTT (70 mg/kg) was given 2 hr later. Body composition was determined by the tritriated water dilution method at the beginning and end of each 6-wk treatment. Chronic suppression of prolactin during winter or summer did not significantly alter the amount of insulin released after each IVGTT, nor did it significantly alter body composition. Furthermore, acute administration of prolactin did not significantly enhance the release of insulin following an IVGTT, during winter or summer treatment periods. It is concluded that elevated levels of prolactin in summer do not enhance the release of insulin to glucose in red deer. Furthermore, a reduction in growth rate following a reduction in plasma prolactin is not associated with a change in body composition.

The effects of a duplication in the ovine growth hormone (GH) gene on GH expression in the pituitaries of ram lambs from lean and fat-selected sheep lines

Growth hormone (GH) gene expression was investigated in pituitaries of 14- to 15-month-old ram lambs from flocks selected for high (fat) or low (lean) back fat depth, which were also homozygous for a single GH gene allele, heterozygous or homozygous for a duplication in the GH gene. The pituitaries of lean sheep of all three GH genotypes were significantly heavier than those of fat sheep, but there were no pituitary weight differences between GH genotypes. No significant lean-fat selection line- or GH genotype-specific differences were measured in pituitary GH concentration. However there was a significant increase (P < 0.01) in the total pituitary content of GH in lean compared with fat animals and a significant interaction between GH genotype and lean-fat selection line (P < 0.05) was noted for GH content. No significant differences were measured in the relative concentration of GH mRNA, suggesting that the ratio of GH mRNA per mg total cellular RNA remained constant across lean-fat selection line and GH genotype. We conclude that the pituitary glands of Coopworth sheep selected for low backfat depth (lean) are bigger and have an increased GH content, but appear to contain similar concentrations of GH mRNA and immunoreactive GH as the pituitaries of fat sheep. The presence of the GH gene duplication in sheep has little measurable effect on the expression and storage of GH in the pituitary.

Effects of glucose or insulin infusions on growth hormone secretion in male red deer

The growth hormone (GH) secretory pattern in male red deer is associated with the seasonal growth cycle. During this cycle metabolic state changes from weight gain in spring to weight loss in winter. However, short-term metabolic changes due to feeding could also alter the GH pattern. To investigate the effect of such changes on GH secretion, the acute feedback of blood glucose level on the GH secretory pattern was examined. Six yearling male red deer were infused iv with glucose (G; 150 mg/kg/hr) or insulin (I; 30 mU/kg/hr) for a 12-hr period, 1 week apart. GH was measured in jugular venous blood every 10 min, for 12 hr before, during, and 6 hr after the infusions. Glucose, insulin, IGF-1, and haematocrit were also measured. There was no difference (P > 0.05) in glucose levels between G and I prior to infusions (5.8 vs 6.0 mmol/liter, SED = 0.42). Glucose levels rose to 8.7 mmol/liter during G and fell to 3.4 mmol/liter (SED = 0.72, P <0.001) during I, then returned towards normal postinfusion. Insulin levels increased during G and I (P < 0.01) with no difference (P > 0.05) between G and I during preinfusion (163 +/- 7.6 pmol/liter) or infusion (259 vs 264 +/- 16. 5 pmol/liter) periods. There were no differences (P > 0.05) in GH secretory characteristics, mean IGF-1, or haematocrit between G and I. However, there were significant effects of infusion within the treatments. Mean GH declined (P < 0.05) from 1.8 ng/ml (both treatments) preinfusion to 1.13 and 1.31 ng/ml during G and I infusion, respectively. GH pulse amplitude was lower during I infusion (5.6 ng/ml vs 8.2 ng/ml preinfusion, P < 0.05, SED = 1.0) and the change in amplitude from preinfusion to infusion differed (P > 0.05) with an increase in G and a decrease in I (+0.6 and -2.6, SED = 1.1). IGF-1 levels were stable and averaged 555 and 520 ng/ml (SED = 34.9) for G and I, respectively. Haematocrit declined from 34.3 +/- 1.85% over the first 4 hr of sampling to 25.7 +/- 0.97% for the remainder of the sampling period. The finding that there were no major alterations in GH secretory patterns during 12 hr of hypoglycemia and hyperglycemia suggests that GH secretion in the male red deer is relatively insensitive to short-term changes in metabolic state.

Microsatellites from the beluga whale Delphinapterus leucas

Fifteen microsatellites were isolated from a beluga whale Delphinapterus leucas, genomic library. The microsatellites were amplified in 100 beluga obtained from two widely separated locations. An average of 8.6 alleles per locus were detected and the average heterozygosity was 0.65 with a range of 0.27-0.86. All microsatellites were polymorphic and 13 of the genotype distributions observed were in Hardy-Weinberg equilibrium. It was possible with these microsatellites to assign correctly individual whales to their stock-of-origin 98% of the time. Microsatellites were amplified in 15 other cetaceans with these beluga-derived primers.

Effects of season and nutrition on growth hormone and insulin-like growth factor-I in male red deer

GH and insulin-like growth factor (IGF)-I are important components of the growth axis. We undertook to determine how plasma levels of these hormones altered with different seasonal and nutritional states in young male red deer to provide an insight into how the growth axis changes under these conditions. Growth rate alters dramatically with season in male red deer, providing an opportunity to sample the same animals at two different growth rates within a short period of time. GH was measured every 15 min for 24 h in the fed state and after a 48-h fast, during slow growth in winter (23 June to 16 July), and during rapid growth in spring (8 September to 2 October). At the end of each sampling period, the animals were treated with N-methyl-D, L-aspartic acid (NMDA) (5 mg/kg live weight) and sampled for a further 1 h, 45 min. Glucose and IGF-I were measured hourly during each sampling period. Live weight was measured at weekly intervals. GH was secreted in a characteristic pattern in which pulses tended to occur in rapid succession, termed a volley, that was separated from the subsequent volley by a period of baseline GH levels, termed a latent period. There were more GH pulses/24 h in the fasted state than in the fed state in winter (12.4 vs. 7.8, standard error of the difference [SED] = 1.07, P < 0.001) and in spring (11.5 vs. 8.8, SED = 1.04, P < 0.05). The increased number of GH pulses in the fasted state could be attributed to a higher number of pulses per volley (winter = 3.7 vs. 2.5, SED = 0.16, P < 0.001; spring = 3.1 vs. 2.8, SED = 0.19). Consequently, the volleys were wider in the fasted state than the fed state (winter = 197 min vs. 122 min, SED = 25, P < 0.05; spring = 173 min vs. 154 min, SED = 24, P > 0.05), and the latent periods between volleys were shorter in the fasted state than the fed state (winter = 175 min vs. 280 min, SED = 14, P < 0.001; spring = 183 min vs. 262 min, SED = 11, P < 0.001). The main differences between seasons in the fed state were larger amplitude pulses (12.4 vs. 8.3 ng/ml, SED = 1.57, P < 0.05) and higher mean GH concentrations (4.1 vs. 2.3 ng/ml, SED = 0.44, P < 0.01) in spring than in winter. The number of volleys and the intravolley pulse interval did not change significantly with nutritional state or season. NMDA administration was followed by an increase in GH with higher GH levels found in the fed state than in the fasted state in both seasons. Fed animals also had a larger initial increase in GH (until 60 min post NMDA) than fasted animals in spring (P < 0.01). Plasma IGF-I was higher in the fed state than the fasted state in both winter (315 vs. 221 ng/ml, SED = 21.0, P < 0.001) and spring (651 vs. 494 ng/ml, SED = 37.5 P < 0.001) and in the fed state was higher in spring than in winter (SED = 29.1, P < 0.001). Blood glucose was higher in the fed state than fasted state in winter (6.1 vs. 5.5 mmol/l, SED = 0.07, P < 0.001) and there was a strong trend toward this same effect in spring although it did not reach statistical significance (6.0 vs. 5.7 mmol/l, SED = 0.26, P > 0.05). Growth rate in winter at 117 g/day was less than that in spring when 220 g/day was recorded (SED = 36.8, P < 0.05). These results demonstrate that the secretory pattern of GH and plasma IGF-I levels alter in response to changes in season and nutrition. The alterations in response to a 48-h fast show that the control of GH and IGF-I secretion may be rapid and is probably a response to maintain energy balance, whereas alterations with season reflect long term control that underlies the seasonal growth pattern of the animal.

Histogenesis of antlerogenic tissues cultivated in diffusion chambers in vivo in red deer (Cervus elaphus)

In a previous study we showed that formation of deer pedicle and first antler proceeded through four ossification pattern change stages: intramembranous, transition, pedicle endochondral, and antler endochondral. In the present study antlerogenic tissues (antlerogenic periosteum, apical periosteum/perichondrium, and apical perichondrial of pedicle and antler) taken from four developmental stages were cultivated in diffusion chambers in vivo as autografts for 42-68 days. The results showed that all the cultivated tissues without exception formed trabecular bone de novo, irrespective of whether they were forming osseous, osseocartilaginous, or cartilaginous tissue at the time of initial implant surgery; in two cases in the apical perichondria from antler group, avascularized cartilage also formed. Therefore, the antlerogenic cells, like the progenitor cells of somatic secondary type cartilage, have a tendency to differentiate into osteoblasts and then form trabecular bone. Consequently, the differentiation pathway whereby antlerogenic cells change from forming osteoblasts to forming chondroblasts during pedicle formation is caused by extrinsic factors. Both oxygen tension and mechanical pressure are postulated to be the factors that cause this alteration of the differentiation pathway.

Plasma FSH, LH and immunoreactive inhibin concentrations in FecBB/FecBB and FecB+/FecB+ Booroola ewes and rams from birth to 12 months of age

Endocrine and developmental changes were examined in Booroola FecBB/FecBB (BB, n = 16) and FecB+/FecB+ (++, n = 20) ewe lambs, and BB (n = 17) and ++ (n = 19) ram lambs from 2 to 53 weeks of age. Blood samples were taken weekly for the measurement of plasma concentrations of FSH, LH, immunoreactive inhibin, progesterone (ewe lambs) and testosterone (ram lambs). Behavioural oestrus in the ewe lambs and testicular volume and the breakdown of foreskin adhesions in ram lambs were recorded. Blood samples were taken from another flock of BB (n = 134) and ++ (n = 109) ram lambs at 20 weeks of age for the analysis of immunoreactive inhibin. In ewe and ram lambs, there appeared to be genotype differences for FSH, LH and immunoreactive inhibin at specific times during the neonatal period. In BB and ++ ewe lambs, respectively, mean FSH concentrations were 4.3 and 2.0 ng ml-1 (SED 0.54) between 4 and 6 weeks, 2.6 and 3.4 ng ml-1 (SED 0.33) between 12 and 28 weeks, and 1.8 and 1.9 ng ml-1 (SED 0.18) between 34 and 53 weeks of age. Mean plasma LH concentrations were lower in BB than in ++ ewe lambs from 26 to 53 weeks of age (P < 0.05) but not earlier. Mean concentrations of immunoreactive inhibin were also lower in BB than in ++ ewe lambs between 2 and 11 weeks (16.0 and 27.4 iu ml-1, respectively; P < 0.01), but thereafter no differences were apparent.(ABSTRACT TRUNCATED AT 250 WORDS)

Determination of evolutionary relationships among sheep breeds using microsatellites

Eight ovine microsatellite loci were amplified in 40 to 50 unrelated individuals from six sheep populations representing five breeds: Romney, Border Leicester, Suffolk, Awassi, and both Australian and New Zealand Merino. For all of the microsatellite loci analyzed, there were highly significant differences in allele frequencies between samples from the different breeds. The allele frequencies generated can be used to determine the breed of an individual, given that it comes from one of the above breeds, to a high degree of accuracy. There were also some alleles that were found in only one breed, although these alleles were at such low frequencies that they are unlikely to be useful as markers for a breed. Genetic distances between breeds were obtained using Nei's formula to construct a phylogenetic tree. The tree grouped the Merino's in one branch and the Border Leicester, Suffolk, and Romney in another branch, while the Awassi, which was used as an outgroup, had its own branch. Using Nei's unbiased genetic distance formula to calculate the time of divergence of the British breeds from the Merino and the time of divergence between the Australian and the New Zealand Merino, we obtained t = 1094 and t = 227 years, respectively. Microsatellite genotyping in sheep appears to provide a useful tool for examining the evolutionary relationships between breeds.

Changes in liveweight and behaviour of alpaca dams and offspring following weaning

The effects of offspring sex, weight, age, and level of interaction with the dam on responses to weaning were examined to assist in the development of a weaning protocol for alpacas. In the first study, preand post-weaning activities, and weight change over Days -12-0,0-7 and 7-16 with respect to weaning, were recorded for 20 dam-offspring (hembra-cria) pairs aged 81-200 days. Pre-weaning changes in dam and offspring weights were positively related (P<0.05). Although heavier crias tended to be found closer to their dams than lighter crias (P<0.05) no additional effect of age on the dam-offspring relationship was found. Following weaning, cria growth rates were low over Days 0-7 but improved over Days 7-16, and hembra weight change followed the same pattern. Over Days 0-2, grazing and sitting activities of hembras and crias were replaced by standing and walking along paddock fencelines, although by Day 2 fenceline activities had decreased (P<0.05). Crias which were more frequently observed at fencelines had lower post-weaning growth rates (P<0.05). In the second study, pre-weaning sucking behaviour, and weight change over Days -30-0, 0-8 and 8-16 with respect to weaning, were recorded for 19 hembra-cria pairs aged 124-160 days. During 10 hours of observation on Days -5 and -4, the total duration of sucking by individual crias varied from 0-18 minutes, and the mean +/- SEM duration of sucking was 1.94 +/- 0.113 minutes. Cria sucking behaviour was positively related to growth rate prior to and weight at weaning (P<0.05). As in the first study, pre-weaning changes in dam and offspring weights were positively related (P<0.05). Following weaning, growth rates of the crias were depressed and the hembras lost weight over Days 0-8 and 8-16. The changes in growth rate and behaviour in Studies 1 and 2 indicated that weaning can be stressful for hembras and crias. However, there was no evidence from either study that pre-weaning behavioural or physical characteristics were related to the changes.

Microsatellites and associated repetitive elements in the sheep genome

To determine the frequency and clustering of a variety of simple di- and trinucleotide repeats, an Artiodactyl short interspersed element (SINE), an ovine satellite repeat, and a human Alu 1 repeat were used to screen a random selection of cosmids containing inserts of ovine genomic DNA. In total, 197 individual cosmids were digested with EcoRI and the fragments separated on 0.7% agarose gels. Southern blots of these gels were then sequentially probed with (AC)7, (CT)9, and (CAC)6 oligonucleotides, and the repeats described above. The frequency at which (AC)n, (CT)n, and (CAC)n repeats were found in the cosmids indicated that they occurred at average intervals of 65 kb, 367 kb, and 213 kb respectively within the ovine genome. The Artiodactyl SINE was the most common, occurring at an average interval of 20 kb. No human Alu 1 sequences were detected. There was a significant positive association between the (AC)n and the Artiodactyl SINE. This association is quite strong as there was significant clustering of the two repeats both within cosmids and also within the EcoRI fragments of the digested genomic fragments. With the exception of the sheep satellite sequence, which occurs in tandem arrays, none of the other repeats showed significant clustering within the 41-kb (average size) cosmid inserts. The first 25 ovine microsatellites we characterized had an average polymorphic information content (PIC) of 0.65. The different microsatellite types, containing either perfect, imperfect, or compound repeats, had similar average PICs of 0.64, 0.65, and 0.66 respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

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 degrees S. In one study, 7-year-old stags (N = 9) were allocated to one of three treatment groups, either control or subcutaneous melatonin (3 x 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 months 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.

Seasonal variation in venison quality of mature, farmed red deer stags in New Zealand

Two studies involving 20 red deer (Cervus elaphus) stags were conducted to determine the effects of season on venison quality. In each study, five sexually mature red deer stags were slaughtered immediately preceding the rut (autumn) and five were slaughtered after the rut. Stags slaughtered postrut had lower carcass weights (25 to 30%) than those slaughtered prerut. Average bodywall thickness measurements above the 12th rib (an indicator of fat thickness) were approximately 31 mm prerut compared with 3 to 7 mm postrut. Individual muscles and retail cuts (which included subcutaneous and intermuscular fat) were heavier in prerut carcasses. There were significant decreases in intramuscular fat in both the longissimus muscle and the semimembranosus muscle. Postrut longissimus muscle steaks appeared brighter and(or) fresher than the other groups; color acceptability was negatively correlated (P less than .05) with fat content. Prerut streaks from both muscles were more tender than postrut steaks from those muscles. Overall desirability and tenderness were highly correlated (r = .94 and .82 for longissimus muscle and semimembranosus muscle, respectively).

Pulsatile growth hormone secretion during the breeding season in male reindeer and its association with hypophagia and weight loss

Male deer reduce food intake and lose weight during the breeding season (rut) in autumn. Growth hormone (GH) is lipolytic in ruminants; therefore, pulsatile GH secretion was measured in three young reindeer (Rangifer tarandus tarandus) bulls during the natural period of weight loss during rut. Blood samples were withdrawn through a jugular cannula every 20 min for 16 hr on 5 occasions from late summer to early winter in unanaesthetised animals. The deer were group fed a pelleted concentrate ration ad libitum, and food intake, body weight, and testicular diameter were recorded. The hormone profiles were analysed by the pulse detection algorithm PULSAR. The bulls showed the normal pattern of rut-associated weight loss and reduced food intake followed by a period of weight increase in late autumn before weight plateaued in early winter. Mean GH was highest (P less than 0.05) at the time of minimum body weight and food intake compared with all other sampling periods. Neither the amplitude nor the frequency of GH pulses, as detected by PULSAR, differed significantly with sampling period, although the high mean GH values were associated with a different pulse shape; pulses were longer, with a large area under the curve, presumably reflecting a longer duration of secretion or reduced clearance. Thus weight loss and low food intake were associated with long, large area pulses of GH. An opioid antagonist, naloxone, was given to reindeer intravenously at hourly intervals for 4 hr and blood sampling was continued for 7 hr.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of melatonin implants on secretion of luteinizing hormone in intact and castrated rams

Rams were treated with melatonin implants in 2 experiments designed to examine the control of reproductive seasonality. In Exp. 1, rams (n = 12) were allocated to 3 treatment groups: 2 groups were treated with 2 melatonin implants per ram for 4 months from 11 November (N) and 9 December (D) and the remaining group was untreated (C). The seasonal increase in luteinizing hormone (LH) pulse frequency and testes size was advanced in Groups N and D. A second seasonal cycle in LH secretion and testes size occurred in Groups N and D after melatonin implants became exhausted. In Exp. 2, rams (n = 20) were allocated to 4 treatment groups: 10 rams were castrated on 6 October and 1 group of entire rams (EM) and one group of castrated rams (CM) were treated with 2 melatonin implants per ram each month from 3 November until 8 January. The other group of entire rams (EC) and castrated rams (CC) was untreated. An increase in LH pulse frequency occurred after castration. Melatonin treatment increased LH pulse frequency in entire rams and reduced LH pulse frequency in castrated rams. The results demonstrated that the advanced reproductive development as a result of treatment with melatonin implants was due to an effect of melatonin on the hypothalamic pulse generator to increase LH pulse frequency. The ability of melatonin to influence LH pulse frequency in entire and castrated rams indicated that an effect of melatonin on the hypothalamic pulse generator is independent of testicular steroids.

Genetically lean and fat sheep differ in their growth hormone response to growth hormone-releasing factor

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.

Concentrations of FSH are elevated in new-born ewe lambs carrying the Booroola F gene but not in lambs from a prolific Romney strain

Concentrations of FSH were measured in new-born lambs in Booroola Merino x Romney and Booroola Merino flocks where the Booroola F gene was segregating, and in progeny from sires of a prolific strain of Romney sheep. FSH concentrations increased with age and liveweight in Booroola Merino x Romney ewe lambs to reach peak concentrations at 4-6 weeks of age. Significantly higher mean concentrations were recorded in ewe lambs homozygous for the Booroola gene (FF) compared with non-carrier (+ +) ewe lambs. Concentrations in heterozygous (F+) ewe lambs were intermediate. Maximum differences between the genotypes were recorded at 6 weeks of age. Significantly higher FSH concentrations were also recorded in F-gene-carrier female lambs when compared to non-carriers in two other flocks. FSH concentrations remained low in ram lambs up to 12 weeks of age, and there were no differences between Booroola genotypes. The progeny of one ram from the prolific Romney family had high ovulation rates at 18 months of age. The progeny of other related rams showed no increase in ovulation rates at 18 months of age. Concentrations of FSH in the high-ovulation-rate progeny at 3 and 5 weeks of age did not differ from those in the low-ovulation-rate progeny, but were lower than those in the progeny of an FF Booroola Merino x Romney ram. These results support the hypothesis that neonatal concentrations of FSH are higher in lambs carrying the Booroola F gene, but not in all prolific strains since high FSH concentrations were not recorded in daughters from a prolific Romney flock.(ABSTRACT TRUNCATED AT 250 WORDS)