bluuebunny/crossref_metadata_2025 huggingface dataset:
Patterns of gonadotropin secretion in cyclic Finn ewes selected for and against high ovulation rate
Authors: Haresign W. , Cooper A. C. , Khalid M. , Hanrahan J. P.
Published: September 2010

A comparison of the patterns of LH and FSH secretion was undertaken in lines of Finn sheep selected for and against high ovulation rate. Mean ovulation rate was significantly higher in the high line ewes (mean 4·1) compared with both the control (mean 2·5) and low line (mean 2·7) ewes (P <0·01). The pre-ovulatory LH peak occurred significantly earlier in the high line ewes (mean 52·1 h) compared with both the control (mean 65·0 h) and low line (mean 59·0 h) ewes (P < 0·05). While mean LH pulse frequency and overall mean LH concentrations were both significantly higher during the follicular compared with the luteal phase of the cycle (P < 0·05), there were no consistent relationships between patterns of pulsatile LH secretion and ovulation rate among the three selection lines. Plasma FSH concentrations remained significantly higher over the entire follicular phase of the oestrous cycle in the high line ewes compared with both the control and low line ewes (P < 0·05). It is suggested that the ovulation rate achieved by high line ewes may be causally related to their higher follicular phase FSH concentrations.
The effect of immunoneutralization of PMSG at a gonadotropin-induced oestrus on the duration of ovulation and reproductive performance of sows
Authors: Kirkwood R. N. , Soede N. M. , Dyck G. W. , Thacker P. A.
Published: September 2010

Two experiments were performed to examine the effects of immunoneutralizing PMSG at the onset of oestrus on the reproductive performance of sows. In experiment 1, 12 multiparous sows received 750 i.u. PMSG at weaning and six sozus acted as controls and were injected with saline. At 84 h after PMSG injection, all sows received an injection of 500 i.u. human chorionic gonadotropin (hCG) and six of the PMSG-treated sows also received an injection of 750 i.u. of a monoclonal anti-PMSG serum. The ovaries of all sows were examined by real time ultrasonography at 60-min intervals from 36 to 48 h after hCG injection for evidence of ovulation. In sows observed to ovulate, there was no significant effect of treatment on the interval from hCG injection to the start of ovulation, the duration of ovulation or subsequent litter size. In experiment 2, 253 primiparous sows received injections at weaning of 750 i.u. PMSG (no. = 134), 400 i.u. PMSG plus 200 i.u. hCG (no. = 69) or served as controls (no. = 50). At breeding, 67 of the PMSG-treated sows received an injection of 750 i.u. of monoclonal anti-PMSG serum.

More gonadotropin-treated than control sows were bred by 7 days after weaning (P < 0·05). Farrowing rates were higher in sows receiving the PMSG followed by anti-PMSG and PMSG plus hCG than in controls (P < 0·05), with those receiving PMSG alone being intermediate. There was no effect of treatment on subsequent litter sizes. These data indicate that the reproductive performance of primiparous sows may be improved by gonadotropin administration at the time of weaning. However, there was no advantage to using any particular hormone combination or anti-PMSG.
Growth and carcass traits in pigs after selection for lean tissue growth rate on low and high protein diets
Authors: Stern S. , Lundeheim N. , Andersson K.
Published: September 2010

Two lines of pigs that had been selected for five generations for lean tissue growth rate (LTGR) on a high (HP) or low (LP) protein diet were evaluated on a commercial diet (165 g crude protein per kg diet). The growth characteristics of 534 animals were measured, and carcass data were obtained on 405 animals. Differences between lines were tested for significance taking genetic drift into account. The animals from the HP-line grew faster both before and during the test and were 6·5 days younger at slaughter than the LP-line pigs. The HP-line pigs had a higher lean content (587 v. 558 g/kg) and a thinner backfat layer (17·8 v. 22·7 mm) than the LP-line. LTGR was higher in the HP-line (374 v. 347 g/day). No significant differences between lines were found in meat quality or in the incidence of osteochondrosis in elbow or knee. The realized differences between lines confirm that selection for LTGR on a high protein diet was more effective in improving both leanness and growth rate compared with selection for LTGR on a low protein diet.
Functional and metabolic changes in rabbits undergoing continuous heat stress for 24 days
Authors: Amici A. , Finzi A. , Mastroiacono P. , Nardini M. , Tomassi G.
Published: September 2010

Intensively reared rabbits are particularly sensitive to heat stress. For this reason it is useful to identify reliable stress indicators to evaluate peculiar stress conditions of the breeding environment.

In order to recognize which changes in biochemical and functional measurements can be utilized as stress indicators, three groups of eight New Zealand White rabbits, of 2·8 kg body weight and 11 weeks of age, were kept in individual cages and submitted to different environmental conditions.

Group 1 was located in a climatic chamber at 33·5 (s.e. 0·5)°C and relative humidity 0·62 (s.d. 0·05) and groups 2 and 3 (control) at 18·0 (s.d. 0·5)°C. Group 1 was given ad libitum a commercially pelleted diet, group 2 was pairfed with group 1, and group 3 was given food ad libitum. For all the groups, at days 0, 1, 6, 12 and 24, the following measurements were made: body weight, rectal temperature, food consumption and plasma glucose, cholesterol, urea, triglycerides, uric acid, and glutamate oxalacetate transaminase, glutamate pyruvate transaminase, thiobarbituric acid-reactive substances, vitamin A and vitamin E, SH-groups and total (peroxil) radical-trapping antioxidant parameter (TRAP).

Food consumption of animals exposed to 33·5 °C was strongly reduced in the 1st day (13·6 v. 161·6 glday); a gradual increase until the end of the trial was then observed (98·8 v. 177·3 gl day). Rectal temperature rapidly increased and remained stable and higher than in the control groups all through the trial (P < 0·01). The major changes in the measurements of the heat stressed animals were a significant increase of the plasma level of vitamin E at days 6, 12, 24 (P < 0·05), and a significant reduction of the plasma concentration of SH-groups and TRAP (P < 0·05).

The results suggest an impairment or overload of antioxidant systems after thermal stress, indicating a reduced resistance to biological and environmental stress factors. The results also indicate that some parameters of antioxidant systems can be used to select a significant stress indicator.
An ethical evaluation of animal biotechnology: the case of using clones in dairy cattle breeding
Authors: de Boer I. J. M. , Brom F. W. A. , Vorstenbosch J. M. G.
Published: September 2010

This paper presents an approach for ethical evaluation of biotechnology, which is illustrated by cloning in dairy cattle breeding. The approach for ethical decision-making that was followed, the so-called network model, started with determining fundamental moral principles that together constitute a framework for the detection of ethical issues in a given situation. In terms of human ethics, four fundamental principles have been defined: beneficence, non-maleficence, justice and autonomy. In the context of animal biotechnology, the same four fundamental moral principles as in humans are considered, except that autonomy is replaced by respect for the integrity of the animal. Based on a Dutch advisory committee concerning animal biotechnology, two additional principles were considered: irreversibility and veriflability. For each individual case, moral decision-making means balancing of moral intuitions, moral principles and morally relevant facts. The final outcome on moral acceptability of an action, therefore, will differ among people. The latter is demonstrated using three types of people (the ruler, the steward and the partner/participant). For each type of person, the fundamental attitude toward animals and nature is defined and a possible decision on the application of cloning in dairy cattle breeding is given. The authors' opinion, however, is that the benefits of cloning are relatively small, especially in the long term, whereas the moral drawbacks of cloning are considerable. The authors conclude that other ways of furthering animal husbandry should have priority.
Performance and blood chemistry in lambs following fasting and transport
Authors: Horton G. M. J. , Baldwin J. A. , Emanuele S. M. , Wohlt J. E. , McDowell L. R.
Published: September 2010

Thirty-six 5-month-old Dorset ram lambs (28·7 kg) were used to investigate the effects of fasting and transport on performance and selected blood parameters. Three treatment groups (no. = 12) were: (1) control-food and water, without transport; (2) fasting for 72 h, without transport; and (3) transport in a trailer to a nearby auction-barn, then driven 8 h/day for 3 days without food or water for a total of 72 h. Lambs were given a total mixed diet containing 163 g/kg crude protein throughout the 28-day post-transport period. Both fasted and transported lambs consumed less food than the control group during the first 7 days post treatment (P < 0·05). Water intake was similar for all treatment groups on the 1st day post transport, after which both fasted and transport lambs drank less ivater than control lambs during the following 6 days (P < 0·05). Live-weight loss after the 3-day fast and transport period and subsequent body-weight gain during the 28-day realimentation period differed across all treatment groups (P < 0·05 and P < 0·09; (1) 1% and 305 g, (2) 14·8% and 343 g, and (3) 20·0% and 390 g, respectively, though control lambs had the highest weight gains over the 32-day experimental period. Plasma urea nitrogen was lower in both fasted and transported lambs on days 6, 7 and 11 compared with control lambs (P < 0·05). Plasma glucose concentrations on days 4 and 5 were lower in transported lambs than in fasted lambs, and highest in control lambs (P < 0·05); glucose concentration levels remained lower in both fasted and transported lambs than in control lambs on days 6 and 7 (P < 0·05). Plasma cortisol concentrations were highest in transported lambs during the 3-day transport period and for 2 days immediately following transport (P < 0·05). Effects of the 72 h fast were exacerbated by auction barn activity and subsequent transport, and compensatory gains by fasted and transport lambs were incomplete within the 28-day post transport period.
Mechanical stimulation of rumination in sheep by the intraruminal addition of inert fibre particles
Authors: Campion D. P. , Leek B. F.
Published: September 2010

Inert fibre particles were used in a series of experiments in order to quantify the effects of some physical characteristics of dietary long fibre on rumination. Removal of hay from the diet of hay I concentrate-fed sheep reduced true rumination to zero after a period of 8 days, although pseudorumination, much reduced in duration, persisted. Then by introducing loose, chopped, inert polyethylene particles through a rumen cannula, rumination was restored. When different masses of loose inert polyethylene particles chopped into 10-mm lengths were placed in the rumen, the time spent ruminating was found to be directly proportional to mass of fibre placed in the rumen (P < 0·001). By inserting a fixed mass of particles of different lengths, the optimum length of inert fibre for rumination to occur was found to lie between 7 and 30 mm. Finally, when, in place of loose fibre, a polyethylene fibre ‘pompom’, fixed on a rod, was introduced via the cannula and placed so as to brush different areas of the retkulorumen, it was found that the greatest rumination response was evoked when the pompom was allowed to stimulate mechanically the cranial regions of the retkulorumen (P < 0·05). It is concluded that inert polyethylene fibre mimicked the peripheral excitatory effects of dietary fibre by stimulating mechanoreceptors (epithelial receptors) located in the cranial portions of the retkulorumen. Adding about 50 g of 7 to 30 mm inert fibre caused sheep on low-fibre diets to ruminate normally for over 3 h.
The use of compositional growth curves for assessing the response to dietary lysine by high-lean growth gilts
Authors: Friesen K. G. , Nelssen J. L. , Goodband R. D. , Tokach M. D. , Schinckel A. P. , Einstein M.
Published: September 2010

Growth modelling was used to characterize the response to digestible lysine in two experiments (114 gilts in experiment 1 and 96 gilts in experiment 2) from 34 to 72·5 kg and 72·5 to 136 kg, respectively. Maize-soya-bean meal diets were formulated to assure that lysine (5·4 to 10·4 and 5·4 to 9·4 g digestible lysine per kg for experiments 1 and 2, respectively) was the first limiting amino acid. Analysis of variance was used to test linear and quadratic responses in cumulative weight gain on test as digestible lysine increased. A time × digestible lysine interaction (linear, P < 0·001) was detected, indicating that a separate regression equation for each lysine level was necessary. In experiment 1, average daily gain (ADG) and carcass crude protein (CP) accretion were maximized for gilts given 10·4, 9·4 and 8·4 g digestible lysine per kg from 34 to 44 kg, 44 to 54 kg, and 54 to 72·5 kg, respectively. Lipid accretion was minimized for gilts given 7·4 to 8·4 g digestible lysine per kg. In experiment 2, ADG was maximized by feeding 8·4 g/kg from 72·5 to 92·5 kg and 7·4 g/kg from 92·5 to 136 kg. Carcass CP accretion was maximized by feeding 9·4 g digestible lysine per kg, whereas lipid accretion was minimized for gilts given 8·4 g digestible lysine per kg from 72·5 to 136 kg. If feeding graded levels of digestible lysine resulted in parallel lines for protein accretion, mean values would result in accurate data evaluation. However, responses to digestible lysine changed over the feeding period. Therefore, the use of body weight and compositional growth curves offers an approach to more accurately characterize the growing pig's response to increased digestible lysine.
The effect of concentrate type and supplementary lactic acid or soya oil on milk production characteristics in dairy cows offered grass silages of contrasting fermentation type
Authors: Doherty J. G. , Mayne C. S.
Published: September 2010

Sixteen first lactation dairy cows were used in a 2 × 2 × 2 × 2 factorial design experiment. Two silages, an extensively fermented inoculant-treated silage or a restricted fermented, mixed aliphatic carboxylic acid-treated silage were offered with two concentrate types (starch- or fibre-based) and supplementary lactic acid (LA, 0·4 kg/day) or soya oil (SO, 0·41 kg/day). Concentrates containing 180 g crude protein per kg were offered at 6 kg/day. Silage dry-matter intake tended to be higher (P = 0·07) with restricted fermented silage compared with the inoculant silage. Milk fat or protein concentrations were not significantly affected (P > 0·05) by silage fermentation type. LA inclusion had no significant effect (P > 0·05) on animal performance. SO inclusion significantly increased (P < 0-05) milk yield (+ 0·8 kg/day), decreased milk fat concentration and yield (40·2, 32·9 g/kg and 779, 667 g/dayfor - and + SO respectively, P< 0·001) and decreased milk protein concentration (-0·81 g/kg, P < 0·01). A significant concentrate × soya-oil interaction (P<0·01) suggested a greater reduction in milk fat concentration with the SO, starch compared with the SO, fibre combination. Modified acid-detergent fibre (P < 0·01) and neutraldetergent fibre (P < 0·001) apparent digestibility coefficients were significantly lower with starch- compared with fibre-based concentrates. Results suggest that milk production responses to changes in concentrate composition were not influenced by the extent of restriction of the silage fermentation process.
Changes in the coat of cashmere goat kids of two different genotypes from birth to 13 months of age
Authors: Merchant M. , Riach D. J.
Published: September 2010

The development and moulting of the birth and first adult coat of two genotypes of cashmere-bearing goats, a highyielding Siberian (S) and low-yielding Icelandic × Scottish feral (IF), were examined. Samples of fibre from the neck, mid side, belly and rear-leg areas and of mid-side skin were obtained monthly from five male and five female kids of each genotype from birth to 13 months of age. Guard hair and undercoat length, secondary/primary (S/P) skin follicle ratio and the proportion of skin follicles containing a non-growing fibre with a brush end were recorded. S/P ratio reached an asymptote between 4 and 5 months of age and was higher fP < 0·01) in S (10·7) than in IF (6·7) kids. In both genotypes peaks of brush formation in primary follicles occurred between 2 and 4 months and again between 8 and 11 months of age. In contrast to primary follicles, secondary follicles had only a single peak of brush formation occurring at 10 and 8 months of age for S and IF kids respectively. Guard hair moulted from the birthcoat, but there was no loss of undercoat prior to 12 months of age and harvesting of cashmere prior to this time is unnecessary.

The secondary follicles of S kids had a longer growing period and fibre length increased at a greater rate than that of IF kids, resulting in more than a two-fold difference in the maximum undercoat length. Assessments to estimate the final weight and proportion of cashmere, made prior to completion of growth of the fleece, are likely to underestimate these parameters for high-yielding goats in comparison with their low-yielding counterparts. However, it is unlikely to alter the ranking, and hence the selection, of animals for retention in the breeding herd.
Rapeseed meal, maize-gluten feed and fish meal as protein supplements for maize silage given to growing/finishing Limousin × Holstein Friesian bulls
Authors: Grundy H. F. , Wheeler K. P. A. , Hardy R.
Published: September 2010

In each of three experiments, 60 Limousin × Holstein Friesian bulls, initially of 191, (s..e. 5·0), 177 (s.e. 5·5) and 210 (s.e. 7·2) kg mean live weight for experiments 1, 2 and 3 respectively, were offered maize silage ad libitum plus one of three barley-based, isonitrogenous compound diets containing 200 g rapeseed meal, 575 g maize-gluten feed or 100 g fish meal per kg fresh weight. Compound diets were given at the rate of 3·0 kg (fresh weight) per head per day up to 320 kg live weight and at 3·3 kg per head per day from 320 kg to 420 kg live weight. In experiment 3, when bulls were taken through to slaughter, the compound diet was further increased to 3·5 kg per head per day from 420 kg live weight to slaughter. Experiments 1 and 2 were conducted over 128 and 194 days, with mean live weights at the end of the experiments of 347 (s.e. 17·2) and 414 (s.e. 24·2) kg respectively. In experiment 3, bulls were slaughtered at 16 months of age at a mean live weight of 544 (s.e. 25·0) kg.

In experiment 1, the fish-meal diet gave the highest rate of daily live-weight gain at 1·34 compared with 1·17 and 1·16 (s.e.d. 0·041) kg for rapeseed-meal and maize-gluten diets, respectively. In experiments 2 and 3, daily gains were similar on all treatments at 1·21, 1·19 and 1·26 (s.e.d. 0·036) kg and 1·06, 1·09 and 1·11 (s.e.d. 0·035) kg for the rapeseed-meal, maize-gluten and fish-meal diets respectively. Total daily dry-matter intakes did not show consistent trends: in experiment 1, intakes were 5·8, 5·6 and 5·8 kg/day, in experiment 2, 6·2, 6·2 and 6·3 kg/day; and in experiment 3, 7·1, 7·3 and 7·1 kg/day for rapeseed-meal, maize-gluten and fish meal, respectively. The higher intakes of dry matter in experiment 3 were due to the greater intakes of maize silage by bulls taken to heavier weights in this experiment.
Effect of energy intake on the performance of different types of pig from 45 to 100 kg body weight. 1. Protein and lipid deposition
Authors: Quiniou N. , Dourmad J.-Y. , Noblet J.
Published: September 2010

Between 45 and 100 kg body weight, Large White castrated males (cLW), and crossbred Pietrain × Large White castrated males fcPP×) and boars (bPP×) were either given food ad libitum in experiment 1 or allocated to four energy levels (0·70, 0·80, 0·90, 1·00 ad libitum) in experiment 2. Daily protein and amino acid supplies were calculated to be non-limiting for growth. Protein (PD) and lipid (LD) deposition rates were measured according to the comparative slaughter technique over the whole experimental period (experiments 1 and 2) and according to the nitrogen and energy balance technique at four stages of growth: 48, 64, 79 and 94 kg mean body weight (experiment 2). Average daily gain increased linearly with metabolizable energy (ME) intake, the slope of the relationship being significantly different between types of pig (from −28 to +36 g per additional MJ ME). Daily PD increased with ME intake above maintenance (MEp) according to a linear-plateau relationship in the three types of pig: the slope was significantly affected by type of pig (from +3·4 to 6·0 g per extra MJ MEp) but not by stage of growth. Daily LD increased linearly with MEp intake; neither the type of pig nor the stage of growth affected its slope (+13-5 g per extra MJ MEp). The LD/PD ratio in the extra body-weight gain associated with increased energy intake was affected only by the type of pig.
The effects of food intake during lactation and post weaning on the reproductive performance and hormone and metabolite concentrations of primiparous sows
Authors: Carroll C. M. , Lynch P. B. , Boland M. P. , Spicer L. J. , Austin F. H. , Leonard N. , Enright W. J. , Roche J. F.
Published: September 2010

The objective of this study was to investigate the effect of low food intake on post-weaning fertility and hormone concentrations in primiparous sows. One hundred and forty primiparous sows (Landrace × Large White) were randomly assigned to one of four treatment groups: (A) restricted to 3 kg food per day during lactation and 2 kg food per day post weaning (no. = 36); (B) restricted to 3 kg food per day during lactation andad libitumfeeding post weaning (no. = 33); (C)ad libitumfeeding throughout with a mean voluntary food intake of 3·7 kg/day during lactation (no. = 36); and (D)ad libitumfeeding throughout with a mean voluntary food intake of 4·9 kg/ day during lactation (no. = 35). Litters were standardized at eight to 10 pigs at 2 days post partum and were weaned at 27·2 (s.e. 0·5) days post partum. After weaning, sows were observed twice daily for signs of oestrus and were mated on the day(s) of standing oestrus. Six sows from each group were fitted with indwelling jugular cannulae 2 days before weaning. Blood samples were collected 1 day before weaning (W−l), 1 day after weaning (W+l) and 4 days after weaning (W+4), and these sows were slaughtered on W+4. Ovaries were recovered, follicles and corpora lutea were counted, and folUcular fluid collected. Sows given food at a restricted level (groups A and B) lost more backfat during lactation than sows given foodad libitum(groups C and D) (P < 0·01). Piglet weaning weights, weaning to conception intervals and the proportion of sows ovulating by W+4 were not significantly different among groups. In sows that did not ovulate, numbers of large follicles were not significantly different among groups but the low food intake (groups A, B and C) sows had more medium-sized follicles than high food intake (group D) sows (P < 0·01). FolUcular fluid concentrations of oestradiol, progesterone and insulin-like growth factor-1 (IGF-1) did not differ among groups (P > 0·05). Plasma non-esterified fatty acids concentrations were greater in groups C and D than in groups A and B on W−l, W+l and W+4. Serum insulin and plasma glucose concentrations were lower in groups C and D than in groups A and B on W−l and W+l, but were similar among groups on W+4. Serum growth hormone concentrations were lower in group D than group A and B on W−l and W+l but not W+4. Concentrations of IGF-1 in serum were greater in groups C and D than groups A and B on W−l and W+l but not W+4. It is concluded that low food intakes during lactation and post weaning affected body condition, serum hormones and metabolites and ovarian function of primiparous sows without dramatically affecting ovarian hormones or reproductive performance.
Selection of Merino sheep for resistance to Haemonchus contortus: genetic variation
Authors: Woolaston R. R. , Piper L. R.
Published: September 2010

An animal model was used to estimate heritabilities of faecal egg count (FEC) and packed cell volume decline (PCVD) in lines of Merinos selected for divergent levels of resistance to Haemonchus contortus. The estimated heritability of FEC was 0·23 (s.e. 0·03) and of PCVD was 0·21 (s.e. 0·03). A cube root transformation was found to be effective in normalizing FEC data and reducing the range of within selection line-birth year variances from 118-fold to 10-fold. Transforming FEC data increased the heritability estimate to 0·29 (s.e. 0·03) and reduced selection bias due to heterogeneity of variance, but the further step of pre-adjusting the transformed data to a common variance had only a trivial effect. Heritability estimates for FEC in years with high means and variances were similar, as were estimates for transformed FEC. The estimated genetic correlations between measurements in years with high and low means and variabilities were 0·77 to 0·91.

PCVD and pre-adjusted transformed FEC had a phenotypic correlation of 0·48. Estimates for the genetic correlation ranged from 0·76 in the decreased resistance line to 1·00 in the increased resistance line and 0·87 with pooled data. Other effects on resistance included birth type and dam age, with twins and progeny of maiden dams being more resistant than their cohorts. Sex effects were unimportant for FEC but males had higher PCVD than females in most, but not all, years. Younger animals had higher FEC and PCVD than older animals. Maternal genetic effects were found to be unimportant, as were the effects of low levels of inbreeding.
Breeding season and ovulation rate in ewes treated with long days in spring followed by a melatonin implant and exposure to a ram
Authors: Sweeney T. , O'Callaghan D.
Published: September 2010

While the onset of the breeding season in ewes can be advanced up to 7 weeks following exposure to long days (44 days) before lambing, a melatonin implant from lambing and exposure to a ram from the summer solstice, this advance is reduced by the absence of a ram. The aim of this experiment was to determine if earlier exposure to the ram and/or exposure to more long days before lambing would further advance the onset of the breeding season. A further aim was to compare the ovulation rate and duration of the breeding season between ewes with a normal and advanced onset of the breeding season due to this treatment regime. Pregnant ewes lambing in mid March were allocated to treatments as follows: (1) controls, maintained on natural photoperiod; (2) 44 LD + mel, exposed to 44 long days (18L: 6D; LD) before lambing followed by a 700-mg melatonin implant after lambing; (3) 90 LD + mel, as in treatment 2, but exposed to 90 LD before lambing; (4) 90 LD + mel + ram, as in treatment 3, including continuous exposure to a vasectomized ram from 10 April. Reproductive state was assessed from serum progesterone concentrations in blood collected at 3- to 4-day intervals from 10 April and ovulation rate was determined during the luteal phase of the first five oestrous cycles in control ewes and ewes exposed to 90 LD + mel + ram. Ewes exposed to 90 LD + mel + ram commenced the breeding season 10 weeks earlier (median date 25 July, range 28 days;P< 0·001) than controls (median date 8 October, range 68 days). Overall, the onset of the breeding season was not advanced in ewes given 44 or 90 LD + mel in the absence of a ram, but a biphasic response was evident, with 40 to 50% of ewes beginning the breeding season at the same time as ewes on 90 LD + mel + ram. Ovulation rate was similar between control ewes and ewes exposed to 90 LD + mel + ram (P > 0·05). The duration of the breeding season was longer in ewes exposed to 90 LD + mel + ram (210 (s.e. 15) days;P< 0·002) than in control ewes (158 (s.e. 10) days), with no difference in date of the end of the breeding season (P > 0·05). Exposure of ewes to 90 LD before lambing in March, followed by a melatonin implant and exposure to the ram from 10 April advanced the onset and extended the duration of the breeding season without an overall effect on ovulation rate. The ram is an important component of this signal sequence.
The effect of GnRH analogue (buserelin) treatment on day 12 post mating on ovarian structure and plasma progesterone and oestradiol concentration in ewes
Authors: Beck N. F. G. , Jones M. , Davies B. , Mann G. E. , Peters A. R.
Published: September 2010

An investigation was conducted into the effect of buserelin treatment on day 12 post mating on ovarian function and plasma progesterone and oestradiol-17 ji concentration in ewes. Changes in ovarian structures were determined, at laparoscopy or after slaughter, 48 h after treatment in 38 control and 41 ewes given an injection of 4 jig buserelin on day 12 post mating (day 0 = day of oestrus). Ovulation rate was higher in buserelin treated (2·76) than in control (1·87) ewes (P < 0·05). Moreover, 41 of the 113 corpora lutea observed in the buserelin group were the result of ovulations that had occurred within 48 h post treatment, compared with two of 71 in the controls (P < 0·05). Blood samples were collected from 10 ewes in each treatment group for hormone analysis. Mean progesterone concentrations tended to be higher, in samples collected from 2 to 6h post treatment, in the buserelin group (4·31 (s.e. 1·32) p.g/1) compared with the control group (3·71 (s.e. 1·44) fig/l. Furthermore, overall mean oestradiol concentrations were lower, during days 13, 14 and 15 post mating, in buserelin treated (0·72 (s.e. 0·26) ngfl) than in control (0·94 (s.e. 0·50) ng/l) ewes (P < 0·05). The results of this study indicate that buserelin treatment on day 12 post mating changes ovarian function.
Adaptation of whole animal energy metabolism to undernutrition in ewes: influence of time and posture
Authors: Ortigues I. , Vermorel M.
Published: September 2010

The effects of undernutrition and of the duration of undernutrition on changes in whole animal energy metabolism and on spontaneous physical activity were studied in adult, non-lactating, non-pregnant ewes. Animals were first given food at 338 kj metabolizable energy (ME) per day per kg live weight 0·75 (LW0·75), (M). Intake was then reduced by half (0·5M) during 7 weeks. Diet apparent digestibility decreased slightly with undernutrition. Rate of LW loss remained constant throughout the whole 0·5M period. Heat production (HP) declined by proportionately 0·18 within the 1st week at 0·5M and by another 0·05 in the following weeks. These latter changes were directly related to LW loss, since HP scaled to metabolic LW remained unchanged over the whole 0·5M period. Time spent standing decreased with undernutrition from proportionately 0·42 at M to 0·33 at 0·5M as a result of a reduction in the average duration of individual standing periods at all hours of the day except in a few hours preceeding feeding times. Energy cost of standing could not be dissociated from the energy cost of eating; these overall costs were not clearly modified by undernutrition but varied with time post prandially. Standing cost alone was estimated at 10 J/min per kg LW. Efficiency of ME utilization for maintenance (km) was calculated at 0·71, and ME requirements for maintenance (MEm) at 338 kj/day per kg LW0'75. No adaptation was noted with the duration of undernutrition. Accounting for the behavioural adaptation tended to increase km to 0·74 but MEm remained unchanged, suggesting that the behavioural changes observed with undernutrition were not sufficient to significantly modify whole animal energy metabolism.
The effect of housing and food restriction during winter on growth of male red deer calves
Authors: Webster J. R. , Corson I. D. , Suttie J. M.
Published: September 2010

Low winter growth is a characteristic of male red deer and is caused, in part by a combination of reduced appetite and higher energy expenditure due to cold weather. This study aimed to determine whether housing during winter would reduce energy expenditure and increase the growth rate of male red deer calves. An additional aim was to investigate whether food restriction in winter would be compensated for by increased spring growth. In each of two consecutive years, 80 calves were randomly allocated to eight groups (no. = 10) comprising two replicates of four treatments during winter. Groups were housed inside (I) or outside (O) and given food either ad libitum (AL) or restricted (R) to maintain live weight. Winter treatments (southern hemisphere) ran from 22 May to 25 August (year 1) and from 5 June to 5 September (year 2). During these periods, animals were weighed weekly and group food intake recorded daily. At the end of winter animals were moved outside onto pasture and weighed monthly until the end of spring (27 November, year 1 and 7 December, year 2). In year 2 weighing continued during summer, until 4 April. The animals were slaughtered on 28 November and 18 January (year 1) and 5 April (year 2). The effect of housing on live-weight gain (LWG) and dry-matter intake (DM1) in AL groups was not significant in either year. However in R groups, O had a higher DMI than I in both years (P < 0·05) and a higher LWG than I in year 1 (P < 0·05). LWG was loiver in R than in AL groups in winter in year 1 (P < 0·05) and year 2 (P < 0·001) and live weight was lower in R than in AL groups at the end of winter in both years. Live weight was still lower in R than in AL groups at the end of spring in both years (P < 0·01). In year 2, this live-weight difference was not significant by the end of summer. Hot carcass weight (HCW) was greater in AL animals than R animals (P < 0·05) and dressing proportion was higher in R than in AL (P < 0·05) in year 1. GR (an index of body fatness) was greater (P < 0·05) in O than I in year 1 and was greater (P < 0·05) in AL than in R animals in year 2. Differences in GR between treatments were not significant in either year, with HCW as a covariate.

In conclusion, housing calves given food ad libitum during winter did not reduce DMI or increase growth rate. When normal growth rates were prevented by restricting food intake, housing lowered DMI requirement, although such a situation is unlikely to be a useful farm management practice as recovery from the growth check was slow. Annual variations in climate may determine both the food savings made by housing and the extent of compensatory growth of food-restricted animals in spring.
Effect of the β-adrenergic agonist cimaterol and dietary protein level on fat young sheep given diets containing submaintenance levels of dietary energy
Authors: Galbraith H. , Minassie B. , Scaife J. R.
Published: September 2010

Thirty Suffolk cross wether sheep aged about 12 months and weighing 57 kg on average were used. They had been given previously a high energy diet to produce a fat body condition and average condition score of 3·7. Animals were allocated to an initial slaughter group (IS) or to four dietary treatment groups (UL, UH, CL and CH) based on sugar-beet feed (L) or white-fish meal (H) supplemented with chopped straw and pelleted, without (UL and UH) or with (CL and CH) the β-adrenergic agonist cimaterol, to provide an estimated 20 g (L) or 130 g (H) rumen undegradable protein per kg dry matter (DM). The sheep were offered 0·3 kg of the appropriate pelleted diet in addition to 200 to 400 g of chopped barley straw to provide proportionately 0·7 of the estimated metabolizable energy requirement for maintenance and, where appropriate, 2·5 mg cimaterol per day. Comparisons were made for the main effects of dietary protein intake and cimaterol and interactions between dietary protein and cimaterol.

The animals on dietary treatments were slaughtered after 49 days. The animals exhibited variable reductions in live weight and weights of carcass and non-carcass components in comparison with the IS group and in response to restricted dietary energy intake. The only effect due to the elevated dietary protein provision was a smaller loss in live weight compared with the low protein diet. In contrast, compared with responses recorded in its absence, treatment with cimaterol resulted in significantly greater values for weights of cold carcass, cross-sectional area o/m. longissimus dorsi and weights of DM, crude protein and ash in the carcass with significantly smaller weights for raw fleece. In comparison with the IS group, significantly smaller changes due to cimaterol were recorded for the weights of carcass crude protein and ash. Cimaterol treatment significantly increased the weight loss of fat in the carcass and in the perirenal and retroperitoneal, but not omental, depots as components of fleece-free non-carcass fat which was also significantly reduced in total. Interactions suggested that losses in carcass weight and DM in the presence of cimaterol were less and gains in carcass protein and ash greater, on the high than on the low protein diet. The results suggest that under conditions of energy undernutrition cimaterol may induce smaller losses or larger gains in carcass but not non-carcass, crude protein at the expense of fat depletion in carcass and non-carcass fat depots.
An association of haemoglobin protein (HBB) with ovulation rate in Cambridge sheep
Authors: Glazko V. I. , Owen J. B. , Dewi I. Ap , Axford R. F. E.
Published: September 2010

Blood from 106 females (1 to 7 years old) of the Cambridge flock at the University of Wales, Bangor was analysed for 21 protein systems. Of the 11 polymorphic systems, haemoglobin protein (HBB) was found to be significantly associated with ovulation rate as measured by mean ovulation rate for all records per ewe. Mean ovulation rate for the HBB AA genotype was 1·25 ovulations higher than for the AB and BB genotypes(P < 0·001).The results suggest that a gene segregating in this breed is different from the Booroola (FecB) gene and that lambs of either sex can be screened at a young age for a major difference in ovulation rate.
Evaluation of the efficiency of alternative selection schemes and breeding objectives in dairy sheep of Greece
Authors: Kominakis A. , Nitter G. , Fewson D. , Rogdakis E.
Published: September 2010

The genetic and economic efficiency of alternative selection schemes and breeding objectives for the Karagouniki dairy sheep in Greece was investigated by model calculations. Criteria of efficiency were the annual genetic gain for the aggregate breeding value, the profit per ewe in the population and the annual selection responses for single traits. The introduction of a two-tier selection scheme, where the recorded ewes are separated into a nucleus and a pre-nucleus, was found superior in both genetic and economic terms for a breeding objective comprising the traits milk yield and number of lambs weaned per ewe per annum. Highest rates for annual genetic gain and selection responses were obtained when the nucleus size was proportionately 0·05 of the population (200 000 ewes), the size of the test matings 0·50 to 0·60 of the size of the pre-nucleus unit (0·10 of the population) and the number of daughters per test ram 40. Opening the nucleus to replacement ewes from the lower tier did not affect positively the annual genetic gain and the selection responses. Furthermore, a breeding objective comprising the traits fat yield and number of lambs weaned per ewe and per annum was found very efficient in both genetic and economic terms while selection on growth and carcass traits did not seem to be justified.
Estimating the metabolizable energy requirement for pregnancy in sheep
Authors: Hutchings N. J.
Published: September 2010

A model is developed in which the metabolizable energy (ME) requirement for growth and maintenance of the foetus, uterus and udder are described explicitly for sheep. The efficiency of the use of ME for the growth of the products of conception (kp) is assumed to be the same as that for growth in non-pregnant animals. Using the results from the model to calculate the efficiency of the use of ME for conceptus growth (kc) in the conventional manner yields values with a similar magnitude and similar variation with food quality as those estimated experimentally. It is concluded that separately accounting for the growth and maintenance of the foetus, uterus and udder is preferable in models but unnecessary in feeding standards.
The effect of different concentrations of protein and fat in milk replacers on protein utilization in kid goats
Authors: Sampelayo M. R. Sanz , Mariscal I. Ruiz , Extremera F. Gil , Boza J.
Published: September 2010

The efficiency of utilization of protein for retention was analysed in pre-ruminant kid goats of the Granadina breed. Sixty male kids were used. Six were slaughtered at birth and the remaining 54 were offered different protein and fat intakes using nine different milk replacers. The protein concentrations were 200, 240 and 280g/kg dry matter (DM) and those of fat were 200, 240 and 280 g/kg DM. Animals were maintained on experiment until they were 60 days old. All were slaughtered on day 61. Nitrogen (N) balance trials were performed during the last 8 days of the 1st and 2nd months. Body composition of the animals slaughtered at birth and at 61 days were determined. Rates of energy retained as protein and as fat were determined (kJ/kg M0·75 per day) and the corresponding rates of metabolizable energy intake as protein and as fat (kJ/kg M0·75 per day) estimated.

Once the relationships between the rates ofN retained and those of digestible N ingested had been established, it was evident that by increasing the protein content of the diet the efficiency of protein retention was decreased. In contrast, increasing the fat content of the milk replacer increased the efficiency of protein retention. The latter effect was noted for the milk replacers containing the high and medium levels of protein but not for those that contained the lowest level of protein, indicating that the level of protein was then the limiting factor. Having recorded this protein-sparing effect of the fat, the results obtained from the slaughter trials were used to develop generalized equations expressing the rates of energy retention in the form of protein or fat as a function of the rates of metabolizable energy intake achieved as both protein and fat. From the analysis of these equations conclusions are drawn about the variable contribution to protein retention in these animals of energy ingested as fat. This contribution depended on the energy intake achieved both in the form of protein and in the form of fat.
The effect of protein source on lameness and solear lesion formation in dairy cattle
Authors: Offer J. E. , Logue D. N. , Roberts D. J.
Published: September 2010

Two groups of 16 cubicle-housed Holstein-Friesian cattle from weeks 3 to 27 of lactation were offered either a proprietary protein supplement of animal origin (P) or soya-bean meal (S) as the protein source in the concentrate in a continuous design experiment. Concentrates were offered mixed with grass silage as complete diets to give a forage: concentrate ratio of 41: 59 and a crude protein content of 213 and 210 g/kg dry matter (DM) and a metabolizable energy content (MJ/kg DM) of 11·9 and 12·0 for P and S respectively. There was no significant difference due to diet for mean locomotion score (1·75 v. 1·66 (s.e. 0·15)), prevalence (0·1 v. 0·09 per cow per week) or incidence of lameness (0·04 v. 0·04) for P and S respectively. Similarly there was no effect on hoof growth, wear, hardness or conformation. Sole haemorrhages, indicative of subclinical laminitis, were observed throughout the experiment but were most severe at approximately 16 weeks after calving. Levels of heel erosion remained constant throughout. There was no significant effect of treatment on either heel or sole lesion formation. No significant differences were observed between treatments for milk yield, live weight, condition score or blood metabolites. The conclusions from this study were that source of dietary protein has no effect on dairy cow lameness or the development of sole lesions indicative of subclinical laminitis.
An evaluation of food intake, digestive physiology and live-weight changes in N'dama and Gobra Zebu bulls following experimental Trypanosoma congolense infection
Authors: Akinbamijo O. O. , Bennison J. J. , Romney D. L. , Wassink G. J. , Jaitner J. , Clifford D. J. , Dempfle L.
Published: September 2010

The effects of experimental Trypanosoma congolense infection on the digestive physiology and nutrient utilization in Gobra zebu and N'Dama cattle were examined in a 16-week trial. A pair-feeding procedure permitted examination of the effects of both food intake and trypanosomosis infection. Twenty Gobra and 16 N'dama bulls aged between 1 and 2 years were paired on a live-weight basis within each breed. One of each pair was chosen at random to serve as an uninfected control while the other was inoculated intradermally with 104 T. congolense in mice blood in the 6th week of the experiment. Packed cell volume and parasitaemia data were collected weekly throughout the trial. Total dry-matter intake (TDMI) and live-weight changes were measured weekly in all animals during the 16-week trial. Rate of passage (RoP) and dry matter digestibility were evaluated before and after infection.

While infection significantly depressed TDMI in both breeds (P < 0·05), neither infection nor breed affected the RoP and the apparent digestibility of the dry matter. Significant changes in live weight attributable solely to the infection were observed in both breeds. Loss of body weight was more severe (P < 0·05) in infected Gobra bulls compared with N'dama bulls possibly implying a superior efficiency of nutrient utilization by the N'dama during infection. In the course of the trial, one N'dama and three Gobra bulls that presented severe clinical symptoms of trypanosomosis were treated and withdrawn from the experiment along with their pair-fed controls.

In conclusion, the RoP and the digestive efficiency were not affected by infection and breed differences. Also, the trypanotolerance mechanism does not seem to be affected by anorexia but rather by the ability to conserve body reserves during infection.
Skeletal muscle glucose transporter (GLUT-4) protein is decreased in lactating goats
Authors: Balage M. , Hocquette J. F. , Graulet B. , Ferre P. , Grizard J.
Published: September 2010

Lactation in goats is associated with an insulin resistance manifested by an impairment of the ability of insulin maximally to stimulate skeletal muscle glucose utilization. The mechanism responsible for this modification is unknown. Therefore an investigation was made of the insulin-sensitive glucose transporter (GLUT-4) in three skeletal muscles from six lactating (peak of lactation) and six non-lactating goats. GLUT-4 protein content was assessed in crude membrane preparations and Triton X-100 extracts by Western-blot analysis. Lactation resulted in a decrease in GLUT-4 protein content. This decrease was more pronounced in oxidoglycolytic muscles (proportionately -0·40 to -0·60 in m. tensor fasciae latae and longissimus dorsi) than in oxidative muscles (-0·20 in masseter). Down-regulation of the insulin-sensitive glucose transporter (GLUT-4) expression in skeletal muscles from lactating goats may be responsible for the decrease in insulin responsiveness of glucose utilization previously observed in vivo.