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.

Sambar deer (Cervus unicolor) x red deer (C. elaphus) interspecies hybrids.

The artificial insemination of 400 red deer hinds with sambar deer semen resulted in 31 pregnancies at day 40 (24 at day 100) and the birth of four calves. Only one female calf was born alive. The artificial insemination of 10 sambar deer hinds with red deer semen resulted in five pregnancies at day 40, of which none went to term. Gel electrophoresis of three blood proteins confirmed the live calf as the first documented sambar deer x red deer hydrid. G-banded karyotypes were consistent with the calf (2n = 62; six unpaired and one paired metacentric autosomes) being the offspring of a red deer dam (2n = 68; single pair of metacentric autosomes) and a sambar deer sire (2n = 56; seven pairs of metacentric autosomes).

Seasonal patterns of luteal cyclicity in young red deer (Cervus elaphus) and sambar deer (Cervus unicolor).

Seasonal onset of pubertal ovulation and incidence of luteal cyclicity was assessed from plasma progesterone profiles over 15 months for tame red deer (n = 7) and sambar deer (n = 7) hinds. Seasonal responses to photoperiod were determined from plasma prolactin profiles. All red deer attained puberty at 17-18 months of age in May-June and expressed 3-6 luteal cycles of length 20.0+/-10.4 days (mean+/-s.e.m.) over 52-102 days. Six sambar deer attained puberty at 7-19 months of age, between August and December. Duration of luteal cyclicity was variable. While one animal remained continuously cyclic for 13 months, most entered anoestrus between November and February. The mean length of the luteal cycle was 17.2+/-0.3 days. While red deer exhibited strongly seasonal patterns of prolactin secretion, sambar deer showed no such seasonal trends. The data collectively indicate that young sambar hinds at temperate latitudes exhibit loosely defined patterns of reproductive seasonality that are 4-6 months out of phase with those of red deer, although some individuals may be non-seasonal. Failure to express seasonal patterns of prolactin secretion indicates that sambar deer may not perceive photoperiodic cues to the same extent as do red deer.

The effect of growth rate and ultimate pH on meat quality of lambs.

Entire male Romney lambs (n = 60) were grown slowly (67 g/day) and slaughtered at 14 months of age at an anticipated carcass weight of 18 kg. Another group of ram lambs (n = 15) from the same genetic background (born 7 months later) were grown rapidly (162 g/day) for 7 months and slaughtered at the same time and at a similar carcass weight. Preslaughter shearing (20 days prior to slaughter) and swim washing (3 times) were variously imposed upon the 14-month old lambs to give them a graded preslaughter stress. The lambs were head-only electrically stunned and slaughtered. Dressed carcasses were electrically stimulated at 20 min post mortem for 90 s at 14·3 pulses/s, 1·8-2 A and 1130 V peak, then held at 12°C for 2 h and frozen so that the deep leg reached -4°C in 12 h. The ultimate pH was measured for the longissimus dorsi, and loin samples were assessed by tenderometer and a sensory panel. The groups with the greatest stresses imposed had the highest ultimate pH. The most tender meat came either from carcasses with an ultimate high pH greater than 6·3 or from young lambs with an ultimate pH from 5·5-5·7. While 7-month old lambs were slightly more tender than the 14-month old lambs of iso pH, the 14-month old lambs of high pH were the most tender. This suggests that age-related connective tissue effects were minimal for the loin. The shear force values and taste panel tenderness scores were linearly related. When the shear force and panellists' tenderness scores were expressed in relation to ultimate pH, there was a decreased acceptance of meat with a moderate ultimate pH between 5·8 and 6·0. Panel texture assessments showed a less clearly defined, but statistically significant decrease in acceptance at pH 5·8-6·0. Other sensory attributes of flavour, juiciness and aroma were uniform across the whole ultimate pH spectrum.

Changes in blood content and histology during growth of antlers in red deer (Cervus elaphus) and their relationship to plasma testosterone levels.

Antlers were removed sequentially from 18 mature red deer stags between 28 and 112 days after casting of the previous hard antlers and the blood volume determined and structure investigated histologically. One antler from each stag was removed during the growth phase, the other at velvet shedding. Antler blood volume increased linearly, with increasing antler weight at a rate of 194 ml/kg between 28 and 91 days after casting but subsequently declined rapidly. A zone of mineralisation occurred between 5 and 10 cm below the antler tip until 91 days but was subsequently markedly reduced in size and replaced by bone. Between 91 and 112 days growth slowed and a rapid increase in formation of compact cortical bone occurred in the periphery of the whole antler. These changes were associated with increasing circulating levels of testosterone.

A cytogenetic study of eight human melanoma cell lines.

Eight cell lines established originally at the Queensland Institute of Medical Research from human malignant melanoma explants have been studied by means of cytogenetic techniques. All showed abnormalities characteristic for each individual line and consisting of marker chromosomes and of changes in ploidy due to the addition of extra copies of normal chromosomes. Repeat cultures of some lines after one or two years contained most of the markers which had characterized the original samples; additional chromosome abnormalities were also found. An anlysis of the break points concerned in the production of markers showed preferential involvement of chromosomes 1 and 5, with a prevalence of centromeric breaks on No. 1. These findings add further weight to the evidence suggesting that changes in chromosome 1 may be of special significance in the pathogenesis of some solid tumours.

Contamination of human melanoma cell lines by mouse L cells.

Five of 8 cell lines from human melanomas originally established elsewhere were found to consist exclusively of mouse cells when examined in our laboratory some months after their receipt. Cytogenetic studies, including G- and C-banding, showed that the mouse cells in all cultures had originated from a single cell line, identified as the L-line. Contamination probably occurred, one year before its discovery, in a laboratory where L cells and human melanoma cells were briefly kept in the same incubator.