bluuebunny/crossref_metadata_2025_split huggingface dataset:
Energy value of dry maize gluten feed in starter, growing or finishing steer diets
Authors: DiCostanzo A. , Chester-Jones H. , Plegge S. D. , Peters T. M. , Meiske J. C. 
Published: September 2010

ABSTRACTThree experiments were conducted to determine the metabolizable energy (ME) concentration of dry maize gluten feed (DMGF) in starter (experiment 1), growing (experiment 2) or finishing (experiment 3) diets for steers. Seventy-two weanling Holstein-Friesian steer calves (initially 52 kg live weight); 32 Aberdeen Angus and 24 Shorthorn steer calves (initially 250 kg live weight) and 32 Aberdeen Angus, 24 Shorthorn and 68 crossbred steers (initially 367 kg live weight) were used in experiments 1, 2 and 3, respectively. In experiment 1, calves were given one of three total mixed rations in which energy and protein ingredients on a dry matter (DM) basis were (g/kg): (1) 590 ground maize grain (MG), 260 rolled oats (RO) and 150 soya-bean meal (SBM); (2) 210 DMGF, 400 MG, 260 RO and 130 SBM; or (3) 440 DMGF, 210 MG, 250 RO and 100 SBM. Daily live-weight gains (LWG) and food-to-gain (F/G) ratios were similar across dietary treatments (P > 0·05). Calves given the diet containing 440 g DMGF per kg had higher DM intakes (DMI) than those given no DMGF (P < 0·05). ME concentration of the diet without DMGF was greater than ME concentrations of diets containing DMGF (P < 0·05). In experiment 2, calves were given one of four diets containing, on a DM basis (g/kg): (1) 800 maize silage (MS) and 200 MG; (2) 800 MS and 200 DMGF; (3) 500 MS and 500 DMGF; or (4) 200 MS and 800 DMGF. LWG and DMI of calves given 500 or 800 g DMGF per kg diets were higher than those of calves given 0 or 200 g DMGF per kg diets (P < 0·05). F/G ratios tended to increase and dietary ME concentrations tended to decrease with increasing content of DMGF in diets. In experiment 3, steers were given one of four diets, which on a DM basis were (g/kg): (1) 850 MG and 150 MS; (2) 300 DMGF, 150 MS and 550 MG; (3) 500 DMGF and 500 MG; or (4) 750 DMGF and 250 MG. LWG was not altered when DMGF replaced MG only or MG and MS (diet 2 v. 1 or diets 3 and 4 v. 1, respectively (P > 0·05)) in the diet. Steers given the 300 or 750 g DMGF per kg diets had higher DMI and lower F/G ratios than those fed diets without DMGF (P < 0·05). ME concentration of the diet without DMGF was greater (P < 0·05) than the ME concentration of 300 or 750 g DMGF per kg diets. ME concentration of DMGF, calculated by regression, was proportionately about 0·9 of the value of MG in all experiments and averaged 11·46 MJ/kg DM.
Circulating concentrations of LH and FSH and pituitary responsiveness to GnRH in intact and ovariectomized suckled beef cows in two levels of body condition
Authors: Wright I. A. , Rhind S. M. , Whyte T. K. , Smith A. J. , McMillen S. R. , Prado R. 
Published: September 2010

ABSTRACTThe effect of body condition on hypothalamic and pituitary function in post-partum suckled beef cows was studied. Thirty-eight Blue-Grey cows were calved at a body condition score of either 2·35 (L) or 2·80 (H), fed to maintain live weight and body condition thereafter and ovariectomized at either 5 or 9 weeks post partum. The H cows had higher LH pulse frequencies before ovariectomy (0·36 v. 0·28 pulses per h; P < 0·05) and 15 days after ovariectomy (0·86 v. 0·72 pulses per h; P < 0·01), indicating a direct effect of body condition on GnRH release from the hypothalamus. Body condition had no effect on the ability of the pituitary to release LH in response to a physiological dose (2·5 u.g) of GnRH in entire or ovariectomized cows at 5 or 9 weeks post partum. The magnitude of the increase in circulating levels of LH following GnRH injection was greater at 9 weeks compared with 5 weeks post partum (2·23 v. 1·73 u.g/1; P < 0·001) in entire cows, but there was no difference between 5 and 9 weeks in ovariectomized cows. Following ovariectomy there was a 2·5-fold increase in LH pulse frequency within 15 days and LH pulse frequency approached 1 pulse per h in all treatments groups. It is concluded that both the hypothalamus and the pituitary are capable of functioning normally by 5 weeks post partum in suckled beef cows, that the pulsatile release of GnRH from the hypothalamus is inhibited, possibly due to a very high sensitivity to oestradiol, and that the sensitivity of the pituitary to the negative feedback effect of oestradiol may decrease with time post partum.
Relationships between secretory patterns of growth hormone, prolactin and body reserves and milk yield in dairy ewes under different photoperiod and feeding conditions
Authors: Bocquier F. , Kann G. , Thériez M. 
Published: September 2010

ABSTRACTDairy ewes (Prealpes breed) were subjected to differential photoperiod treatments: either long (15·5 light (L): 8·5 dark (D) or short (8·5 L: 15·5 D). Treatments started 15 days before lambing and continued until the 5th week of lactation. After lambing the 22 ewes of each photoperiodic treatment were divided in two groups and fed on either a high or low plane (19 v. 10·5 MJ/day and 370 v. 237 g crude protein per day). Milk yield was not affected by photoperiod but significantly modified by feeding levels (1154 v. 789 ml/day). Protein content of the milk was reduced under long days (—4·9 g/1) compared with short days, while no effect was observed for fat content. Body chemical composition changes, estimated by the deuterium oxide (heavy water) dilution technique between weeks 1 and 4, were affected by both treatments, with a significant interaction between photoperiod and diet for body protein changes: under short days lipid and protein changes were closely related while under long days they were independent.Blood samples were taken on day 23 of lactation from six ewes per group, every 30 min from 07.30 to 15.30 h for growth hormone (GH) and prolactin (PRL) measurements. The timing of GH and PRL pulses were different, but there was evidence that secretory patterns of each hormone were synchronized across ewes within the four treatments. Long photoperiod increased plasma PRL baseline rather than pulse amplitude, with no effect of diet. Undernutrition mainly increased GH pulse amplitude rather than baseline concentration, with no significant effects of photoperiod.High spontaneous concentrations of GH were associated with body lipid mobilization (R2 = 0·51) and were also involved in the control of protein changes (R2 = 0·71). These results indicate that GH (and PRL) are involved in nutrient partitioning in the lactating ewe.
The effect of variation in dietary calcium supply on the phosphorus requirements of growing lambs
Authors: Rajaratne A. A. J. , Scott D. , Thompson J. K. , Buchan W. , Pennie K. 
Published: September 2010

ABSTRACTFour groups of eight lambs (four male + four female) of about 25 kg live weight were given a concentrate diet which was supplemented with either calcium (Ca) or Ca and phosphorus (P). The levels of Ca and P in the diets were set in relation to estimated requirements (R) as determined by the Technical Committee on Response to Nutrients (TCORN, 1990) and the four treatments were as follows: treatment A Ca and P = 1R; treatment B Ca = 2R P = 1R; treatment C Ca = 4R P = 1R; treatment D Ca = 4R P = 2R.At about 50 kg live weight the lambs were slaughtered and their body composition was determined.The composition of their gains was also determined using information obtained from a fifth group of lambs killed at the start of the trial. There were significant treatment effects in relation to body mineral composition with Ca and P levels being higher in lambs on treatments C and D compared with those on treatments A and B. Magnesium levels were also higher in lambs on treatment D. Lambs on treatments A and B grew at the same rate (0·t25 kg/day) and retained Ca and P in relation to live-weight gain at rates close to those on which TCORN (1990) based their estimates of requirements. Lambs on treatments C and D, however, retained these minerals at somewhat higher rates though this improvement in mineralization was accompanied by a slight reduction in growth rate and in some lambs on these treatments there were health problems due to the formation of kidney stones.The levels of Ca and P recommended by TCORN (1990) for lambs are adequate for normal growth and mineralization. Some improvement in mineralization may be achieved by feeding these minerals at above recommended levels but this improvement would appear to be at the expense of a reduction in growth rate and an increased risk of urolith formation.
The effect of different pasture management strategies during the weaning-to-mating period on reproductive performance of Greyface ewes
Authors: Gunn R. G. , Doney J. M. , Agnew R. D. M. , Smith W. F. , Sim D. A. 
Published: September 2010

ABSTRACTThe effects on reproductive performance of different strategies of pasture management designed to conserve herbage in situ during the late growing season for use during the pre-mating and mating period were studied in three experiments over 3 years with Greyface ewes. Two experiments with 341 ewes compared set-stocking of pasture at 12 ewes per ha on two initial levels of herbage mass with a conservation strategy which left half of the area ungrazed and grazed the other half of the area at 24 ewes per ha from late August until mid October (2 weeks before the start of mating) after which the total area was grazed at 12 ewes per ha. In a third experiment with 124 ewes, the conservation strategy left a quarter of the area ungrazed and varied stocking rate to a minimum of 12 ewes per ha to maintain two initial levels of herbage mass on the other three-quarters of the area and then compared set-stocking at six ewes per ha on this area with set-stocking at 18 ewes per ha on the previously ungrazed quarter of the area during the pre-mating and mating period.Initial levels of herbage mass were within the range of 2000 to 2100 kg dry matter (DM) per ha (7 cm sward height; high) and 1500 to 1700 kg DM per ha (4 to 5 cm; low). Mean herbage accumulation rates between August and October were estimated to be 25 and 44 kg DM per ha per day in the first two experiments. Initial live weight and body condition score also varied considerably between years and subsequent response was influenced by herbage growth rate. Where mean ewe body condition was within the score 2·75 to 3·00, range over the mating period and herbage mass on set-stocked areas was not higher than 2200 kg DM per ha (8 cm sward height) in the pre-mating period or not lower than 1300 kg DM per ha (3·5 cm) at about 3 weeks after mating, the strategy of management did not influence reproductive performance in terms of the number of lambs born. Within these limits, however, reproductive performance was positively related to herbage mass in late August (low = 1·60, high = 1·94).When herbage mass fell below the 1300 kg DM per ha level before or during mating, reproductive performance was improved by a herbage-conservation strategy which maintained ewe body-condition score within the 2·75 to 3·00 range. When herbage mass and growth rate were high, reproductive performance was also improved by a herbage-conservation strategy which restricted the development of excessive body condition before mating by avoiding the increase in barrenness shown to derive from very high levels of body condition.
Estimates of genetic and phenotypic parameters for growth traits of D'Man lambs
Authors: Boujenane I. , Kerfal M. 
Published: September 2010

ABSTRACTThe heritability of growth traits from birth to 6 months of age and the genetic and phenotypic correlations among them were determined from paternal half-sib analyses of 1689 records of D'man lambs. Heritability estimates were 0·34 (s.e. 0·08), 0·23 (s.e. 0·06), 0·52 (s.e. 0·10) and 0·43 (s.e. 0·09) for weights at birth, 30 days, 90 days and 180 days, respectively. Heritabilities for average daily gains from birth to 30 days and from 30 to 90 days were estimated to be 0·12 (s.e. 0·05) and 0·56 (s.e. 0·11), respectively. Genetic and phenotypic correlations among growth traits were all positive and of high magnitude. The former estimates varied from 0·66 to 0·98, the latter estimates ranged from 0·23 to 0·92. Selection for high weight at 90 days would be expected to have large effect on other growth traits as a result of their large positive genetic correlations.
Diet selection in pigs: choices made by growing pigs given foods of different protein concentrations
Authors: Kyriazakis I. , Emmans G. C. , Whittemore C. T. 
Published: September 2010

ABSTRACTTo test the proposition that growing pigs, when given a choice between two foods, are able to select a diet that meets their requirements, and to investigate the rules of diet selection, four foods (L, A, B and H) with similar energy yields, but different concentrations of crude protein (CP) (125, 174, 213 and 267 g CP per kg fresh food respectively) were formulated. The four foods were offeredad libitumeither singly, or as a two-way choice using all the six possible pairs, to 40 individually caged pigs from 12 to 30 kg live weight. On the single foods the rate of food intake fell from 1001 to 971 to 961 to 868 (s.e.d. 40) g/day (F < 0·05) as the protein concentration of the foods increased from L to H; the growth rate followed an opposite trend (492, 627, 743 and 693 (s.e.d. 31) g/day respectively;P< 0·01). When the pigs had to select between two foods limiting in protein (L and A) the less limiting one was preferred (710 (s.e. 200) g A per kg total food intake; the protein concentration of the selected diet was 160 (s.e. 10) g CP per kg). On the choice between B and H (a choice between a food with protein concentration close to requirements and a food with protein excess) the lower food was markedly preferred (928 (s.e. 4) g B per kg total food intake; the protein concentration of the selected diet was 218 (s.e. 1) g CP per kg). When the animals were given a choice between two foods, a combination of which was non-limiting (pairs LB, LH, AB and AH), the protein concentrations of the selected diets were not different between treatments (208, 204, 202 and 205 (s.e.d. 13) g CP per kg respectively) and they also declined systematically with time and weight. The growth rate of the animals on these pairs were 752, 768, 769 and 763 (s.e.d. 54) g/day (P > 0·05), which were not significantly different from the highest growth rate achieved on a single food. The results suggest that pigs, when given a choice between a suitable pair of foods, are able to choose a balanced diet and to change its composition to reflect their changing requirements. The choice-feeding method may well be useful as an effective and economic way of estimating and meeting requirements, and of measuring the growth potential of pigs.
A note on melatonin-treated red deer stags advancing the onset of the calving season in hinds
Authors: Fisher M. W. , Fennessy P. F. 
Published: September 2010

ABSTRACTThe effects of treating adult red deer hinds nutritional demands to coincide better with and stags with exogenous melatonin on the food production on improved pastures. One calving season in hinds were evaluated in a 2 such method has been the administration of × 2 factorial experiment. Treated stags were implanted with melatonin monthly beginning in December and hinds post calving in January, Melatonin advanced the timing of rutting behaviour in both treated stags. Calving date was significantly influenced by melatonin treatment of hinds (a mean 10-day advancement; P < 0·01) or stags (12-day advancement; P < 0·001). The interaction of hind and stag treatments was not significant, however treatment of both sexes resulted in the greatest advancement in mean calving date (21 days; P < 0·001). These results indicate that treatment of red deer hinds or stags with exogenous melatonin can result in an earlier calving season and suggest seasonally advanced stags can stimulate earlier breeding activity in hinds.
The effect of cimaterol and oestradiol-17β alone or combined on growth and body composition of wether lambs
Authors: Galbraith H. , Hatendi P. R. , Alderson E. M. , Scaife J. R. 
Published: September 2010

ABSTRACTTwenty-four Finn ♂ × Dorset Down ♀ wether lambs about 10 weeks and weighing on average 18 kg were allocated to treatment groups as follows: untreated controls (U); 15 mg oestradiol-17β (OE) implanted subcutaneously (O); cimaterol (2 mg/kg dry matter (DM)) in the diet (C); and 15 mg OE implant + cimaterol (2 mg/kg DM in the diet) (OC). The lambs were offered a diet, restricted to 38 g/kg live weight (LW), and which contained an estimated 12·5 MJ metabolizable energy and 137 g crude protein per kg DM for the experimental period of 62 or 63 days. Comparisons were made for the main effects of OE and cimaterol and also interactions between OE and cimaterol. Treatment with OE, on average, resulted in greater LW gain, DM intake, empty body weight (EBW), body length and chest depth, weight of shoulder and loin joints and carcass crude protein, but had no effect on fat deposition in carcass or depots. As a proportion of EBW, the weights of the pituitary gland and accessory vesicular glands were increased, as was teat length in lambs treated with OE. Cimaterol treatment, on average, increased LW gain, EBW, killing-out ratio, carcass weight and its weight of crude protein and, unlike OE, decreased the weight of the pituitary gland as a proportion of EBW and reduced the weight and proportion of fat in the carcass and perirenal and retroperitoneal depots. Increases in the cross-sectional area of m. longissimus dorsi and in the weight of selected major and minor commercial joints were also obtained in cimaterol-treated lambs. The presence of significant interactions indicated that there was incomplete or no additivity between the effects of cimaterol and OE for LW gain, cross-sectional area of m. longissimus dorsi and weights of carcass and carcass crude protein, omental fat and of certain of the dissected joints. These results suggest either that the mechanisms of action of oestradiol-17β and cimaterol are not independent or that they are affected by similar metabolic or physiological processes which limit the ability of castrated male sheep to exhibit a positive response.
Sucrose as an energy source for growing pigs: digestible energy content and energy utilization
Authors: Beech S. A. , Elliott R. , Batterham E. S. 
Published: September 2010

ABSTRACTTwo experiments were conducted to determine the effect of including sucrose in diets on energy utilization by growing pigs. In the first experiment, the digestible energy (DE) content of sucrose was determined as 15·6 MJ/kg, indicating that gross energy was 0·96 digested. In the second experiment, iso-energetic diets were used to determine the effects of sucrose on growth and nutrient utilization. Sucrose was used to replace wheat gradually in four iso-energetic diets (15 MJ DE, 0·75 g lysine per MJ DE for pigs from 20 to 50 kg live weight and 15·1 MJ DE, 0·67 g lysine per MJ DE for pigs from 50 to 80 kg live weight). Pigs were fed ad libitum. Food intake (P < 0·01) and carcass daily gain (P < 0·05) increased with sucrose inclusion, independently of the level of sucrose in the diet. Food conversion ratio of male (boar) pigs on a carcass basis was unaffected by sucrose inclusion but increased with female pigs (P < 0·01). Killing-out proportion increased linearly with sucrose inclusion (P < 0·01). Sucrose inclusion improved energy retention (P < 0·05) and increased fat deposition (P < 0·05) but protein deposition was not affected. The weight of the full viscera (P < 0·01), empty digestive tract (P < 0·05), stomach (P < 0·01) and large intestine (P < 0·05) decreased with increasing sucrose inclusion. Sucrose did not affect blood triglycerides or cholesterol concentration (P > 0·05). Sucrose inclusion decreased the crude fibre and crude protein content of the diet and energy utilization was improved. Differences in gut fill indicated that sucrose-based diets were rapidly digested and absorbed.
The use of increased female reproductive rates in dairy cattle breeding schemes
Authors: Meuwissen T. H. E. 
Published: September 2010

ABSTRACTThe effect of increased female reproductive rates on selection response, on efficiency of progeny testing and on the openness of the nucleus was investigated in open nucleus breeding plans. Conventional progeny testing plans and closed nucleus plans are special classes of open nucleus plans. In the open nucleus plans, generation intervals and selection across tiers were optimized. The number of offspring per elite dam was varied from 1 to 41, progeny testing of young bulls in the female base population was varied from 0 to 100 test records and the size of the nucleus was varied from 250 to 2000 young bulls born per year. Also efficiency of selection was varied: efficient selection in T(heoretical)-schemes and less efficient selection in P(ractical)-schemes. Especially, selection of base parents was less efficient i n P-schemes.The deterministic prediction model took account of variance reduction due to selection and reduction of selection differentials due to correlations between estimated breeding values of relatives (order statistics). For closed nucleus plans, the results of the model were verified with Monte Carlo simulation results.By increasing female reproductive rates, genetic gain increased by a factor 0·08 and 0·16 for the T- and P-schemes respectively. The nuclei in P-schemes were less open, due to the less efficient selection in the female base population. Schemes that were less open benefited more from increased female reproductive rates because selection differentials in small nuclei increased more than those in large base populations. The optimal open nucleus plan became less open with increasing female reproduction. Generally, progeny testing of bulls reduced genetic gain (by up to a factor 0·1) but it also reduced inbreeding rates. Progeny testing was more efficient in schemes that were less open: in P-schemes with 41 offspring per dam, progeny testing increased genetic gain. With many offspring per dam there were fewer full-sib families, causing lower selection differentials due to order statistics effects. This effect could be prevented by increasing the size of the nucleus.
The importance of family sizes in adult multiple ovulation and embryo transfer (MOET) nucleus breeding schemes in dairy cattle
Authors: Ruane J. 
Published: September 2010

ABSTRACTThe importance of family sizes in adult multiple ovulation and embryo transfer (MOET) nucleus schemes with discrete generations of single trait selection was examined using Monte Carlo simulation. Two areas were investigated. Firstly, the number of sons and daughters per dam was varied in schemes using hierarchical mating designs. With four or eight sires and 32 dams selected, increasing the number of sons per dam from one up to four achieved 1 to 8% higher rates of response but at the expense of increased variation in response and 10 to 56% higher rates of inbreeding. With four or eight sires and 16, 32 or 64 dams selected, the number of daughters was set to two, four or eight (with one son per dam in each case). For schemes transferring equal numbers of embryos, responses were lower with two daughters per dam but were fairly similar with four or eight daughters per dam while inbreeding rates increased as fewer sires and dams were selected. Secondly, the effects of variation in family sizes due to biological factors and chance were investigated with eight sires and 32 dams selected and with hierarchical or factorial (two or four sires per dam) mating designs. When all selected cows yielded embryos, changes in family sizes due to differences in sex ratios, in survival rates of embryos to selection and to variation in the number of embryos per donor reduced response by 1 to 4%. However, when 20% or 33% of the superovulated females yielded no embryos, thus requiring the use of genetically inferior replacements, response was reduced by a further 9 to 13%