The effects of depriving feed to facilitate transport and slaughter in sheep--a case study of cull ewes held off pasture for different periods.

AIM: To determine the ability of sheep to mobilise their body reserves after being deprived of feed prior to transport for slaughter. METHODS: A total of 240 3- and 4-year-old cull ewes were held off pasture for 0, 9, 18 or 30 hours (n=60 per group) then transported 1 hour by road, unloaded and washed, held in lairage for 3 hours then slaughtered. Blood samples were collected from a subsample of 60 unfasted ewes 1 week earlier, and from all ewes at exsanguination to determine concentrations of serum metabolites indicative of adaptation to fasting. In addition, several attributes of carcass quality were measured. RESULTS: At slaughter, increased time off pasture prior to transport resulted in no change in glucose concentrations in serum (p=0.140). There were differences (p<0.001) between the group fasted for 30 compared with 0 hours in mean concentrations of free fatty acids (0.98 (SD 0.32) vs. 0.58 (SD 0.23) mmol/L), ß-hydroxybutyrate (0.69 (SD 0.17) vs. 0.42 (SD 0.11) mmol/L), triglycerides (0.29 (min 0.13, max 0.83) vs. 0.22 (min 0.06, max 0.96) mmol/L) and urea (10.17 (SD 1.80) vs. 6.94 (SD 2.03) mmol/L). Different periods of feed deprivation had no effect (p>0.05) on carcass weights (mean 22.7, min 13.2, max 32.9 kg) or dressing out percentages (mean 40.9, min 27, max 49%). Meat ultimate pH was unaffected (p>0.05) by the period of feed deprivation but meat became darker (p<0.05) and had reduced redness (p<0.001) with increasing time off feed. CONCLUSIONS: The results suggest that sheep in variable body condition adapted to the periods of feed deprivation by mobilising their energy reserves without any evidence of metabolic depletion (e.g. depleted blood glucose or high meat pH). However, being deprived of feed they probably experience a degree of hunger.

Current practices on sheep and beef farms in New Zealand for depriving sheep of feed prior to transport for slaughter.

AIM: To assess current practices on sheep and beef farms that deprive sheep of feed prior to transport to facilitate effluent management and processing at slaughter. METHODS: A national telephone survey of 122 sheep and 346 sheep and beef farmers was conducted in March and April 2010. They were asked how long sheep were held off green feed prior to transport and why, what environment the sheep were held in, and if that period ever varied. RESULTS: Of the 468 respondents, 303 (65%) removed their sheep from green feed 3-12 h before transport for slaughter, with longer periods reported in the South than North Island. The main reasons given were to reduce the volume of effluent for transport operators (n=174), to prevent wool staining during transport (n=173), and that sheep were better suited to load and travel empty (n=171). Water was provided during feed deprivation by 313 farmers. The period of food deprivation could be altered in response to requirements of transporters and processors, the weather, and by the class of stock involved, although 115/468 (25%) farmers stated that they never changed their normal protocol. CONCLUSIONS: Amongst survey respondents, common practices compared favourably with recommendations to reduce effluent during transportation. Previous studies have investigated the effects of fasting lambs whilst in lairage prior to slaughter and focussed on carcass quality such as carcass weight and tenderness. Changes in liveweight and gastrointestinal tract contents suggest feed deprivation reduces the risk of defaecation and urination contributing to the accumulation of effluent during transport and of carcass contamination during processing. However, the point at which that risk is acceptable to transport and processing is unclear. Fasting results in physiological changes indicative of altered metabolism but it is not clear when those changes are indicative of adaptation to food deprivation or metabolic depletion and compromised welfare. There may be opportunities to improve the logistics of livestock preparation, transport and processing.

Invited review: Body condition score and its association with dairy cow productivity, health, and welfare.

The body condition score (BCS) of a dairy cow is an assessment of the proportion of body fat that it possesses, and it is recognized by animal scientists and producers as being an important factor in dairy cattle management. The scale used to measure BCS differs between countries, but low values always reflect emaciation and high values equate to obesity. The intercalving profile of BCS is a mirror image of the milk lactation profile. Cows lose condition for 50 to 100 d postcalving, because of homeorhetic changes that occur in the somatotropic axis and the sensitivity of peripheral tissues to insulin, and the upregulation of lipolytic pathways in adipose tissue. Management and feeding have little effect on early postcalving BCS loss (wk 1 to 4 postcalving) until the natural period of insulin resistance has passed and the somatotropic axis has recoupled. There is evidence, however, that management and diet can influence the timing of recoupling of the somatotropic axis and the sensitivity of peripheral tissues to insulin, and gene expression differences in adipose tissue 30 d in milk confirm an effect of energy intake on lipogenic enzymes. The BCS in which a cow calves, nadir BCS, and the amount of BCS she loses postcalving are associated with milk production, reproduction, and health. Body condition score may also be a valid indicator of animal welfare, but further research is required to determine the effect of BCS and BCS change on how a cow "feels." Although the actual strength of the association may vary, there is relative consistency in the associations among calving and nadir BCS, and BCS change on milk production, postpartum anestrous, the likelihood of a successful pregnancy and days open, the risk of uterine infection, and the risk of metabolic disorders. For many production and health variables, the association with BCS is nonlinear, with an optimum calving BCS of 3.0 to 3.25 (5-point scale); lower calving BCS is associated with reduced production and reproduction, whereas calving BCS >/=3.5 (5-point scale) is associated with a reduction in early lactation dry matter intake and milk production and an increased risk of metabolic disorders. Ongoing research into the automation of body condition scoring suggests that it is a likely candidate to be incorporated into decision support systems in the near future to aid producers in making operational and tactical decisions.

Defining animal welfare - does consistency matter?

Animal welfare has many varied understandings reflecting social concerns for, and the scientific assessments of, the way animals are treated. They range from the absence of suffering, to where the animal is in a state of complete mental and physical health and in harmony with its environment, to an economic or socio-political understanding reflecting human preferences. Animal welfare thus has both empirical (scientific) and moral components. It is suggested that the term should be considered as a judgement to be undertaken by combining varied understandings. Furthermore, it may be more important to acknowledge underlying values and assumptions, both moral and scientific, than to risk excluding valid viewpoints through pursuing a prescriptive definition.

Developing a systematic strategy incorporating ethical , animal welfare and practice principles to guide the genetic improvement of dairy cattle.

People have complex and diverse relationships and interactions with, and expectations of, animals; relationships which are very important. In making sense of this complexity, we draw on our values. The objective of this study was to reflect upon, develop and articulate key values guiding the genetic improvement of dairy cattle. Animal husbandry is guided by the philosophy that while animals serve our needs, we must ensure that their needs are met, and any compromises to those needs justified and minimised. In applying modern technology to the genetic improvement of animals, this philosophy should be enacted through consideration of all the broader goals of agriculture, and the ecology and biology of the farming system. It should also be informed by the differing perspectives of interested parties, including stock handlers, veterinarians, animal welfare groups, consumers, and the public. Monitoring the consequences of technology applications, managing and avoiding any harms, and considering the future of animals and ourselves, should also be part of decision making in this area. Transparent consideration of these principles will help to ensure that any compromises to animal welfare resulting from trait selection are both reasonable and necessary, and that any harms are minimised, thereby helping to safeguard continuation of the important contribution that animal agriculture, and in particular the dairy sector, makes to society.

Gonadotrophin-induced follicle development in red deer hinds during the breeding and non-breeding seasons.

The effect of exogenous equine chorionic gonadotrophin (eCG) and endogenous (GnRH-treatment) gonadotrophins in promoting antral follicle development in red deer hinds was assessed during the breeding and non-breeding seasons. After progesterone pretreatment, hinds received no further treatment, a single injection of 300 iu equine chorionic gonadotrophin or infusion of GnRH (1.0 microg h(-1)) for up to 4 days. Ovaries were recovered (n = 5 per group) at the time of, or 36 h after, progesterone removal. All follicles > or = 2.0 mm in diameter were dissected out, their health status assessed and follicular fluid oestradiol content measured. Granulosa cells were counted and their capacity for oestradiol and cAMP production assessed in vitro. Oestrus, the preovulatory LH surge and ovulation rates were monitored in additional groups of hinds that had been treated identically (n = 5 per group). During the breeding season, all monitored animals ovulated, but five of 15 (one eCG, three GnRH, one progesterone alone) did not exhibit oestrus, and three (all eCG) had luteinized follicles. During seasonal anoestrus, four hinds (all eCG-treated) displayed oestrus, but only two ovulated. Two non-ovulating hinds (one eCG, one progesterone alone) had luteinized follicles. The total number of follicles, or of large (> or = 4 mm) follicles, did not differ significantly between seasons. There were proportionately more healthy follicles during seasonal anoestrus (P < 0.05). Treatment with GnRH, and to a lesser extent eCG, increased the number of oestrogenic follicles and their follicular fluid oestradiol content. In summary, exogenous and endogenous gonadotrophins affected antral follicle development similarly in both the breeding and non-breeding seasons, although the response was variable among animals and often associated with failure of oestrous expression, ovulation and with follicle luteinization.

Variation in antral follicle development during the follicular phase of the oestrous cycle in red deer (Cervus elaphus) hinds.

The aim of this study was to quantify antral follicle populations in cyclic red deer hinds and to monitor follicle development leading to ovulation. Oestrus was synchronized with exogenous progesterone and ovaries were recovered approximately 0, 12, 24 or 36 h (follicular phase) or 10 days (luteal phase) after progesterone withdrawal (n = 5 per group). All follicles > or = 2 mm in diameter were dissected out, health status was assessed, follicular fluid oestradiol content was measured, granulosa cells were harvested and their capacity for oestradiol and cAMP production was determined. The time of oestrus and the preovulatory LH surge were monitored in five control hinds. Deer ovaries contained 26.6 +/- 3.45 (mean +/- SEM) follicles > or = 2 mm in diameter (range 4-81), with at least one large antral follicle (diameter: 8.3 +/- 0.38 mm) per hind. There was a strong correlation between follicle size and granulosa cell population (r(2) = 0.676). Approximately half (50.7%) of the follicles were classified as healthy, with the percentage classified as atretic decreasing with increasing follicle size. Neither the total number of antral follicles nor their size distribution differed significantly among groups. There were significantly more (P < 0.05) healthy follicles at 24 h after progesterone withdrawal than at 0 h, when large oestrogenic follicles had fewer granulosa cells, lower follicular fluid oestradiol concentrations and lower aromatase activity (P < 0.05) than did those from other groups. In summary, antral follicle development in red deer is similar to that in other monovulatory ruminants, and at least one large follicle is present at all stages of the oestrous cycle.

Role of ovarian failure in reproductive senescence in aged red deer (Cervus elaphus) hinds.

Physiological and endocrine factors associated with reproductive senescence were assessed in a group of 19 ageing red deer hinds. Reproductive success, defined as the percentage of hinds weaning a calf successfully, decreased gradually from 89% at 6-7 years of age to 50% at 17 years, and subsequently decreased markedly; only one hind reared a calf at 19-20 years of age. When the 12 surviving hinds were approaching 21 years of age, they were compared with ten mature 7-year-old females over the onset of the breeding season. All hinds were subsequently killed, the reproductive tracts were recovered and antral (>/= 2 mm in diameter) and preantral follicle populations were determined by dissection (n = 7 hinds per age group) or stereological analysis (n = 2 ovaries per age group), respectively. Cyclical ovarian activity (plasma progesterone) was evident in fewer aged hinds compared with mature hinds (3/12 versus 10/10, P < 0.001) and mean plasma LH concentrations were higher in aged animals than in mature animals (0.57 +/- 0.05 and 0.20 +/- 0.05 ng ml(-1), P < 0.001). Mean uterine (44.2 +/- 4.5 and 75.4 +/- 4.2 g; P < 0.001) and ovarian masses (0.88 +/- 0.11 and 1.52 +/- 0.12 g; P < 0.001) were lower in the aged hinds, which also had fewer antral follicles than did mature hinds (0.89 +/- 0.35 and 23.5 +/- 4.5 follicles per hind, respectively; P < 0.001). Only one primordial follicle was observed in one of the ovaries of the aged hinds, compared with 7000-21 000 in the ovaries of mature hinds. The high gonadotrophin concentrations, paucity of primordial and antral follicles and failure of ovulation indicate collectively that waning reproductive performance after 17 years of age is primarily due to ovarian failure.

Genetic influences on reproduction of female red deer (Cervus elaphus) (1) seasonal luteal cyclicity.

This study compared the onset and duration of the breeding season of female red deer (Cervus elaphus scoticus) and its hybrids with either wapiti (Cervus elaphus nelsoni) or Père David's (PD) deer (Elaphurus davidianus). In Trial 1 (1995), adult red deer (n=9), F1 hybrid wapiti x red deer (n=6) and maternal backcross hybrid PD deer x red deer (i.e., 14 PD; n=9) were maintained together in the presence of a vasectomised red deer stag for 12 months. They were blood-sampled daily or three times weekly so that concentration profiles of plasma progesterone could be used to identify the initiation, duration and cessation of luteal events. There was clear evidence of luteal cyclicity between April and September, with the transition into breeding associated with an apparent silent ovulation and short-lived corpus luteum (i.e., 6-12 days) in every hind. A significant genotype effect occurred in the mean time to first oestrus (P<0.05), with wapiti hybrids and 14 PD hybrids being 9 and 5 days earlier than red deer. Between six and nine oestrous cycles were exhibited by each hind, with no difference in mean cycle length (19.5-19.6 days) between genotypes (P0.10). The overall length of the breeding season was significantly longer for wapiti hybrids (143 days) than for either red deer (130 days) and 14 PD hybrids (132 days, P<0.05). In Trial 2 (1998), adult red deer (n=5), 14 PD hybrids (n=5) and F(1) PD x red deer hybrid (n=5) hinds were maintained together from mid-February (late anoestrus) to early May, in the presence of a fertile red deer stag from 1 April. Thrice-weekly blood sampling yielded plasma progesterone profiles indicative of the onset of the breeding season. Again, there was a significant genotype effect on the mean time to first oestrus (P<0. 05), with F(1) PD hybrids and 14 PD hybrids being 13 and 5 days earlier than red deer. However, conception dates were influenced by the timing of stag joining, and were not significantly different between genotypes. The results indicate genetic effects on reproductive seasonality. However, seasonality observed for PD x red deer hybrids more closely approximated that of red deer than PD deer.

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.

Comparison of seasonal changes in reproductive parameters of adult male European fallow deer (Dama dama dama) and hybrid Mesopotamian x European fallow deer (D. d. mesopotamica x D. d. dama).

In a study, aimed at comparing seasonal reproductive development of European fallow deer (Dama dama dama) with Mesopotamian (D. d. mesopotamico) x European F1 hybrids, five adult males of each genotype, which had been raised together since birth, were maintained as a bachelor group. Morphometric (body weight, neck circumference and testis diameter), endocrine (plasma testosterone concentrations) and seminal (ejaculate volume, spermatozoa per ejaculate and spermatozoa motility) parameters were recorded at fortnightly or monthly intervals for a 15-month period, and antler status was noted daily during the general periods of casting and velvet stripping. In addition, two bucks of each genotype were blood sampled via indwelling jugular catheters every 30 min for 24-h periods on five occasions (2-3 months intervals) during the year, and plasma was analysed for concentrations of testosterone and LH. Parameter profiles of the two genotypes were compared by global and time series ante-dependence covariance analysis to investigate overall profile similarity and the seasonal nature of any observed differences. Plasma hormone profiles from high-frequency blood sampling were subjected to PULSAR analysis to determine pulse frequency and amplitude. Throughout the study hybrid males were approximately 30% heavier than European males. However, both genotypes exhibited dramatic but parallel patterns of body weight change (global P = 0.054). Neck circumference was correlated with body weight throughout (P < 0.05), with similar regression slopes between the genotypes at any sampling time (P > 0.10). Covariance adjustment to a common initial body weight was performed to eliminate the effects of large body weight differences on muscle hypertrophy and regression. While profiles of corrected neck circumference were significantly different at the global level (P < 0.01), analysis by time revealed differences occurring only during the latter period of muscular regression in spring. However, profiles of other parameters, including testis diameter, plasma testosterone concentrations, spermatozoa per ejaculate and percentage motile spermatozoa, exhibited significant displacement between genotypes (global P < 0.05) evident as 2-4 weeks advancement in the sexual development (late summer/autumn) and quiescence (spring) phases for hybrid males relative to European males. Furthermore, mean dates of antler casting and velvet stripping were significantly earlier by 2-3 weeks for hybrid males than European males (P < 0.05). High frequency blood sampling revealed markedly seasonal patterns of secretion of testosterone and LH, with hybrid males exhibiting an apparent earlier onset of high-amplitude testosterone 'surges' in February (late summer) compared to those occurring in April (autumn) for European males. When viewed collectively, the data indicate strongly that the Mesopotamian influence is evident in the earlier attainment of sexual development and fertility in late summer and autumn, and earlier onset of sexual quiescence in spring. This is in accord with anecdotal information on earlier reproductive patterns in purebred Mesopotamian fallow deer.

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

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

Luteolytic potency of a prostaglandin analogue at different stages of the oestrous cycle in red deer (Cervus elaphus) hinds.

The luteolytic effect of the prostaglandin F2 alpha analogue, cloprostenol, was investigated in red deer by monitoring concentrations of plasma progesterone, the induction of oestrus and ovulation, and fertility. Oestrus was synchronized in 48 adult hinds by intravaginal delivery of exogenous progesterone for 12 days and i.m. injection of 250 iu pregnant mares' serum gonadotrophin at progesterone withdrawal. A single i.m. dose of 500 micrograms cloprostenol was administered at day 4, 6, 8, 10, 12, 14 or 16 of the subsequent oestrous cycle (n = 6 hinds per treatment; day 0 = oestrus). Six other hinds were monitored by intensive collection of blood samples between day 16 and day 19 to define changes in plasma progesterone concentrations during spontaneous luteolysis. Samples of jugular blood, collected every second day throughout the study and every 6 h for 78 h from the time of administration of cloprostenol, were analysed for plasma concentrations of progesterone and LH. Oestrus was detected by continuous observation during the period of intensive collection of blood samples and all hinds were subjected to transrectal ultrasonography to assess pregnancy status. On the basis of changes in plasma progesterone concentrations, cloprostenol induced complete luteolysis in all hinds treated on days 8-16 and in five of six hinds treated on day 6. Oestrus, ovulation and conception occurred in 25 (69%), 28 (78%) and 25 (69%), respectively, of hinds treated on days 6-16 inclusive (n = 36). Luteolysis was incomplete in all hinds treated on day 4, and none of the animals exhibited oestrus or ovulated; luteolysis was incomplete for one hind treated on day 6.(ABSTRACT TRUNCATED AT 250 WORDS)

Relationship between the onset of oestrus, the preovulatory surge in luteinizing hormone and ovulation following oestrous synchronization and superovulation of farmed red deer (Cervus elaphus).

The timing of ovulation relative to the onset of oestrus and the preovulatory surge in luteinizing hormone (LH) was studied in red deer following treatments to synchronize oestrus and induce either a monovulatory or superovulatory response. Mature hinds (n = 36) were allocated randomly to two mating groups (n = 16 + 20), with respective treatments staggered by 4 weeks during the 1990 rut (March-April). Each hind was treated with an intravaginal controlled internal drug releasing (CIDR)-type S device for 14 days. Treatments to induce a monovulatory response included CIDR device alone (treatment A; n = 4 + 8) and additional injection of 200 iu pregnant mares' serum gonadotrophin (PMSG) at device removal (treatment B; n = 4 + 4). Treatments to induce a superovulatory response included injections of 200 iu PMSG and 0.5 units ovine follicle-stimulating hormone (FSH) at about time of removal of CIDR devices (treatment C; n = 4 + 4) and further treatment with gonadotrophin-releasing hormone (GnRH) analogue 18 h after removal of CIDR devices (treatment D; n = 4 + 4). The hinds were run with crayon-harnessed stags from insertion of CIDR devices (12 March or 9 April) and blood samples were taken every second day to determine plasma progesterone. Further blood samples were collected for determination of plasma LH and progesterone via indwelling jugular cannulae every 2 h for 72 h from removal of CIDR devices. Hinds were allocated randomly to an initial ovarian examination by laparoscopy at either 16 or 20 h (A and B), or 12 or 16 h (C and D) after the onset of oestrus, with laparoscopy repeated at intervals of 8 h until either ovulation was recorded (A and B), or for four successive occasions (C and D). All hinds received cloprostenol injections 15 days after device removal. A total of 28 hinds (78%) exhibited oestrus and a preovulatory LH surge, with mean (+/- SEM) times to onset of oestrus of 44.6 +/- 1.0 h (A; n = 7), 37.4 +/- 2.0 h (B; n = 7), 16.3 +/- 1.7 h (C; n = 6) or 14.0 +/- 1.7 h (D; n = 8). Failure to exhibit oestrus or LH surge was most prevalent among hinds in treatment A early in the rut.(ABSTRACT TRUNCATED AT 400 WORDS)

Temporal relationship between the onset of oestrus, the preovulatory LH surge and ovulation in farmed fallow deer, Dama dama.

A study was conducted to determine the timing of ovulation relative to the onset of oestrus and the preovulatory LH surge in fallow deer. Mature fallow does were randomly allocated to two treatments (N = 10 per treatment) designed to synchronize oestrus on or about 17 May. Does assigned to Group 1 (prostaglandin-induced oestrus) each initially received single intravaginal CIDR [Controlled Internal Drug Release] devices for 13 days followed by an i.m. injection of 750 mg cloprostenol on Day 12 (15 May) of the subsequent luteal cycle. Does assigned to Group 2 (progesterone-induced oestrus) each received CIDR devices for 13 days, with withdrawal occurring on 15 May. All does were run with crayon-harnessed bucks (10:1 ratio) from the start of synchronization (18:00 h 15 May). Ten does (5 per group) were blood sampled via indwelling jugular cannulae every 2 h for 72 h from cloprostenol injection or CIDR device withdrawal and the plasma was analysed for concentrations of progesterone and LH by radioimmunoassay. Does within each treatment were randomly allocated to an ovarian examination time of 12, 16, 20 or 24 h after the onset of oestrus. Laparoscopy was repeated at 12-h intervals until ovulation was recorded. The ovaries of does failing to exhibit oestrus were examined 72 and 86 h after cloprostenol injection or CIDR device withdrawal. A total of 17 does were observed to exhibit oestrus at a mean (+/- s.e.m.) interval from treatment of 44.6 +/- 3.6 h for Group 1 (N = 9) and 34.1 +/- 2.5 h for Group 2 (N = 8).(ABSTRACT TRUNCATED AT 250 WORDS)

Superovulation and embryo recovery in Red deer (Cervus elaphus ) hinds.

In two experiments, Red deer hinds were synchronized with intravaginal progesterone and were given 4 d of treatment (3 d before progesterone withdrawal and 1 d after) with an ovine follicle stimulating hormone (FSH) preparation which had a claimed low level of luteinizing hormone (LH) contamination. In Experiment 1, 12 hinds received one of four FSH levels by osmotic minipump. Hinds were run with fertile stags, and laparotomy and embryo recovery were performed 9 d after progesterone withdrawal. The ovulation rates (mean of three hinds per dosage) were 1.0, 2.0, 4.3 and 15.3 (number of corpora lutea counted) for estimated daily dosages rates of 0.036, 0.071, 0.11 and 0.14 units FSH preparation/day; the response to the increasing dosage was exponential (P<0.01). The recovery rate of ova on flushing was 38% (24 63 ), with all recovered ova being fertilized and of transferable quality. In Experiment 2, performed later in the breeding season, eight hinds received 0.14 units FSH/day either by minipump or by intramuscular injection. The mean ovulation rates were 3.0 and 11.0 (a significant difference, P<0.01), respectively, with a recovery rate of 72% (34 47 ), and with only 18 34 ova considered to be of transferable quality. The recovery rate in Experiment 2 was significantly higher than that in Experiment 1 (P<0.001). Overall, the results were better than those previously recorded for red deer, perhaps a function of both the FSH preparation used and an improved progesterone profile in estrus synchronization.

Effects of cranial cervical ganglionectomy and castration of male lambs. II. 24 hour plasma profiles of luteinizing hormone, testosterone and prolactin.

Male lambs were utilized in an experiment designed to evaluate the effects of cranial cervical ganglionectomy (GX), castration and age on hormone secretion profiles. Blood plasma samples were collected at hourly intervals for 24 hours from 24 lambs aged 101 days and 20 lambs aged 277 days, then assayed for concentrations of luteinizing hormone (LH), testosterone and prolactin. At both ages pulsatile secretion of LH and testosterone was confirmed, but no circadian rhythm of LH testosterone or prolactin secretion was detected. Castration elevated LH levels significantly at both ages. GX and its interaction with castration had no effect on LH secretion at 101 days, but at 277 days these factors were significant, largely due to elevated levels being recorded from GX castrates. GX did not affect testosterone levels in entire animals at either age, while plasma from castrates contained no detectable testosterone. GX reduced prolactin concentrations at 101 days of age (summer) but elevated them at 277 days of age (winter). Castration and the interaction of castration with GX had no significant influence on plasma prolactin levels at either age. This study confirmed that the pineal gland of sheep is involved in the regulation of prolactin secretion, and probably influences LH secretion as well.

Effects of cranial cervical ganglionectomy and castration of male lambs. III. Hormonal responses following administration to gonadotrophin releasing hormone (GnRH).

Entire and castrate male lambs, which were cranial cervical ganglionectomized (GX) or untreated, were utilized in a study of responses to intravenous GnRH; 24 animals were treated at both 101 and 277 days of age. GX caused a reduction in basal LH concentrations of both wethers and rams at the first sampling, but increased pre-injection levels of this hormone in 277 day old wethers. Basal LH levels of castrates were substantially higher than those of entires, but GX had no significant influence on pretreatment testosterone secretion in rams. GnRH treatment elevated plasma LH levels in all animals, while in entires increases in testosterone concentrations also occurred. Castration significantly increased peak LH levels together with total LH output. At neither age were the LH or testosterone reponses influenced significantly by GX, nor was the interaction of castration and GX significant for LH response data. The major effect of age at GnRH treatment was that markedly higher testosterone responses were recorded from the older rams.