bluuebunny/crossref_metadata_2025 huggingface dataset:
The dietary requirements of calcium and phosphorus for growing lambs
Authors: Wan Zahari M. , Thompson J. K. , Scott D. , Buchan W.
Published: September 2010

Groups of wether lambs were fed on four concentrate diets, from a live weight (LW) of about 25 kg until they had grown to about 50 kg, when they were killed, minced and analysed. A fifth group was killed at the start of the trial to provide data on their initial composition. The dietary treatments were identical except in their concentrations of calcium (Ca) and phosphorus (P) and supplied, with some approximations: (A) 0·75 times the requirements for Ca and P estimated according to the recommendations of the AFRC Technical Committee on Responses to Nutrients (TCORN, 1990); (B) a close match to the estimated requirements for both elements; (C) 1·5 times the estimated requirements for both elements; (D) 1·5 times the Ca requirement and 0·75 times the P requirement.

The retentions of Ca and P in the lambs were closely similar with diets B and C (6·8 and 7·3 g Ca per kg LW and 4·1 and 4·5 g P per kg LW) and significantly lower with diet A (4·8 g Ca and 3·0 g P per kg LW) and diet D (5·0 g Ca and 2·7 g P per kg LW). Parallel differences in response to diet were evident in the composition of the metacarpi. Plasma Ca and P concentrations showed no significant differences between the dietary treatments A, B and C, but plasma P concentrations were markedly depressed with lambs on diet D and plasma Ca concentrations were elevated in this group. Rumen P concentrations were also markedly lower in lambs on diet D and their food intakes and growth rates were lower than in lambs in other groups. The results indicate that Ca and P retentions were not increased by feeding these elements in excess of their estimated requirements and were reduced when Ca and P or P alone was reduced proportionately to about 0·75 times requirement. The data are in accord with the TCORN recommendations and suggests that they provide a satisfactory basis for defining Ca and P requirements for growing lambs.
Experimental design for comparative digestibility trials with pigs: limitations of Latin squares
Authors: Goedhart P. W.
Published: September 2010

In comparative digestibility trials with growing pigs Latin squares are widely used as experimental designs. In this paper conditions for the application of Latin squares are explicitly stated and checked with real data. Data were collected at the Institute for Livestock Feeding and Nutrition Research in the Netherlands and consisted of digestibility trials run on pigs of 40 to 100 kg live weight. There is strong evidence for a certain form of period × animal interaction in the data. This may seriously affect estimates of treatment effects and results of significance tests. It is concluded that Latin squares are unsuitable for comparative digestibility trials with pigs growing from 40 to 100 kg. When there is no interest in statistical comparison of the diets under study, Latin squares can still be used. Some suggestions for alternative designs are given.
An evaluation of an inoculant of Lactobacillus plantarum as an additive for grass silage for dairy cattle
Authors: Mayne C. S.
Published: September 2010

Herbage from the first regrowth of perennial ryegrass based swards was direct-ensiled following treatment with either an inoculant of Lactobacillus plantarum (Ecosyl, Imperial Chemical Industries pic) at 3·0 1/t, formic acid (850 g/kg) at 2·9 1/t, or no additive (control). During harvesting, alternate loads of inoculant material were treated with an absorbent polymer (ammonium polyacrylamide) at the rate of 1 kg/t herbage and ensiled in separate 100-t capacity silos. The mean dry matter (DM) and water soluble carbohydrate concentrations of herbage used for the four treatments was 157 and 120 g/kg respectively. Lactic acid levels post ensiling increased more rapidly in inoculant-treated herbage than with the other treatments. Formic acid and inoculant-treated silages were well preserved whereas control and inoculant-plus-polymer silages were only moderately well preserved. Losses of DM during ensilage were greater with the formic acid treatment with DM recovery values of 0·78, 0·72, 0·76 and 0·73 for the control, formic acid, inoculant and inoculant-plus-polymer silages respectively. Treatment of herbage with an absorbent polymer prior to ensiling resulted in a proportional reduction in effluent volume of 0·2 whereas formic acid treatment increased effluent flow by 0·28. The silages were evaluated in a changeover design experiment with two periods each of 4 weeks duration, using 24 British Friesian dairy cows. Animals were housed in individual stalls and in addition to the treatment silages, received 5 kg/day of supplement containing 193 g crude protein per kg DM. Silage intakes were increased by proportionately 0·10, 0·14 and 0·05 respectively with the formic acid, inoculant and inoculant-plus-polymer treatments compared with the control. The increased silage intakes with the inoculant treatment were reflected in an increased milk yield of 1·1 kg milk per day whereas formic acid and inoculant-plus-polymer treatments had no significant effect, although formic acid treatment did result in a significant increase in milk fat concentration. There were no major differences between treatments in energy or nitrogen digestibility, when determined on a complete ration basis. In conclusion, a large milk yield response was obtained as a result of treatment of herbage with inoculant prior to ensiling and this resulted from increased silage and hence energy intake. Treatment with formic acid increased silage and energy intake but had no effect on milk energy output.
Selection for rate and efficiency of lean gain in Hereford cattle 1. Selection pressure applied and direct responses
Authors: Mrode R. A. , Smith C. , Thompson R.
Published: September 2010

Selection of bulls for rate and efficiency of lean gain was studied in a herd of Hereford cattle. There were two selection lines, one selected for lean growth rate (LGR) from birth to 400 days and the other for lean food conversion ratio (LFCR) from 200 to 400 days of age, for a period of 8 years. A control line bred by frozen semen from foundation bulls was also maintained. Generation interval was about 2·4 years and average male selection differentials, per generation were 1·2 and — 1·1 phenotypic standard deviation units for LGR and LFCR respectively.

Genetic parameters and responses to selection were estimated from the deviation of the selected lines from a control line and by restricted maximum likelihood (REML) techniques on the same material. Realized heritabilities were 0·40 (s.e. 0·12) for LGR and 0·40 (s.e. 0·13) for LFCR using the control line. Corresponding estimates from REML were 0·42 (s.e. 0·10) and 0·37 (s.e. 0·14). The estimate of the genetic correlation between LGR and LFCR was about — 0·69 (s.e. 0·12) using REML.

The estimates of direct annual genetic change using deviations from the control were 3·6 (s.e. 1·3) g/day for LGR and — 0·14 (s.e. 0·07) kg food per kg lean gain for LFCR. Corrsponding estimates from REML were similar but more precisely estimated. The correlated responses for LFCR in the LGR line was higher than the direct response for LFCR.
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

Three 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

The 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

Dairy 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

Four 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

The 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

The 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

To 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

The 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

Twenty-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

Two 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

The 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

The 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%
Chemical composition of carcass soft tissues of serially slaughtered Hereford × Friesian, Friesian and Charolais × Friesian steers finished on two diets differing in energy concentration
Authors: Keane M. G. , Allen P. , Connolly J. , O'Ferrall G. J. More
Published: September 2010

The chemical composition of the muscle and fatty carcass tissues of Hereford × Friesian (HE), Friesian (FR) and Charolais × Friesian (CH) steers finished on high (H) (12·6 MJ/kg dry matter) and medium (M) (10·4 MJ/kg dry matter) metabolizable energy (ME) concentration diets and slaughtered at low (L), normal (N) and heavy (W) carcass weights was determined in a 3 × 2 × 3 (no. = 9) factorial experiment. There were also pre-finishing slaughter groups of nine animals of each breed type. Target L, N and W carcass weights were 260, 300 and 340 kg, for HE and FR and 260, 320 and 380 kg, for CH, respectively.

Main effect side soft tissue weights of the finished groups were 128, 125 and 134 (s.e.d. 1·3) kg for HE, FR and CH, 133 and 125 (s.e.d. 1·1) kg for H and M and 108, 129 and 150 (s.e.d. 1·3) kg for L, N and W, respectively. Soft tissue chemical composition was 540, 562 and 590 (s.e.d. 5·0) g/kg moisture, 162, 174 and 181 (s.e.d. 1·7) g/kg protein and 288, 254 and 220 (s.e.d. 6·6) g/kg lipid for HE, FR and CH and 558 and 570 (s.e.d. 4·1) g/kg moisture, 170 and 175 (s.e.d. 1·4) g/kg protein and 262 and 246 (s.e.d. 5·4) g/kg lipid for H and M, respectively. The allometric regression coefficients for moisture, protein and lipid weights on soft tissue weight were 0·65, 0·69 and 206, respectively. The coefficients for moisture and protein weights on muscle and fat weights were < 1·0, whereas for lipid, they were >1·0. The breed differences in soft tissue chemical composition paralleled differences in physical composition. Dietary ME concentration had little effect on the chemical composition of individual tissues. For the M diet, HE, FR and CH were calculated to have similar soft tissue lipid concentrations (250 g/kg) at side soft tissue weights of 113, 125 and 157 kg, respectively. Corresponding side muscle weights at similar muscle lipid concentration (70 g/kg) would be 77, 90 and 108 kg.
Studies on the effects of milking on calf growth and viability and on cow reproductive performance in traditionally managed N'Dama herds
Authors: Agyemang K. , Dwinger R. H. , Grieve A. S. , Little D. A.
Published: September 2010

The effects of milking on the overall productivity of N'Dama cattle kept under village conditions were studied using three groups of cows during a 27-month period. One group of 46 cows in 16 herds in Nioro Jattaba village was not milked for human consumption and their calves had access to all of their milk (group 1). Another group of 46 cows in the same herds was partially milked for human use once a day while the calves had access to the residual milk (group 2), the normal husbandry practice in this village. A third group of 70 cows in six herds, managed similarly in a similar production environment in the nearby village of Keneba, was milked twice daily with the residual milk for their calves, the normal husbandry in this village. A mean extraction of 296 (s.d. 110·7) kg milk per cow occurred in group 2 during a lactation period of 517 days while the figure for group 3 was 450 (s.d. 177·7) kg per cow over 430 days. At the end of the observation period, calf mortality to 12 months averaged 6% and was similar in all groups. Calf weights at 12 months in group 1 (98·1 kg) exceeded that of groups 2 and 3 by proportionately 0·26 and 0·38 (P < 0·001) respectively. Mean calving rate was 53% in groups 1 and 2, and 72% in group 3. Post-partum body-weight losses were most severe in group 1, followed in order by groups 2 and 3. A herd productivity index (incorporating calf weight, live weight equivalent of milk extracted for human use, cow and calf viability and calving rate) was 100·7 kg calf weight per 100 kg metabolic weight of cow per year for group 1, 110·2 for group 2 and 166·1 kg for group 3. These values suggest that recommendations to small-holder farmers for enhancing livestock productivity should include strategies to improve milk yields in general rather than advocating no milk extraction or changing the milking regime currently practised.
Some factors related to the voluntary intake of silage by individual dairy cows housed as a group during two winter-feeding periods
Authors: Little W. , Manston R. , Wilkinson J. I. D. , Tarrant M. E.
Published: September 2010

The consumption of grass silage by each individual cow in a group housed during two consecutive winter-feeding periods was continuously recorded. During the first winter, one of two concentrates, containing high starch or high fibre, were offered on a sliding scale and half the cows were injected with bovine somatotropin (bST). During the second winter, one of two concentrates, containing high or low rumen-undegradable protein were offered at a flat rate ivith two-thirds of the cows receiving bST. The cows injected with bST had significantly greater yields of milk but their consumption of silage was similar to that of cows not treated with bST. The type of concentrate offered had no significant effect on silage consumption. Although there were significant variations in the consumption of silage from day to day, there were highly significant variations in consumption attributable to individual cows. This individuality of intake persisted in a consistent manner throughout a feeding period and could not be explained on the basis of milk production, body weight, age or parity. In 24 of the cows which were used in both years, their individual intakes for the two periods were significantly correlated. The possibility that this individuality may be of economic importance is discussed.
A note on plasma cholecystokinin concentration in dairy cows
Authors: Furuse M. , Yang S. I. , Choi Y. H. , Kawamura N. , Takahashi A. , Okumura J.
Published: September 2010

Changes in plasma cholecystokinin (CCK) levels after feeding were investigated in dairy cows. Three HolsteinFriesian lactating cows given concentrates at 06.00 and 13.00 h and hay at 16.30 h were used. Blood samples were taken from the jugular vein from 0 (before feeding, 13.00 h) to 6 h at 1-h intervals. The immunoreactivity of CCK was expressed in terms of the CCK-8 equivalent. The plasma concentration of CCK was not changed over the experimental period. This result might be reflected by the continuous flow of digesta from the rumen.
Effect of hyperketonaemia, feeding frequency and intake of concentrate and energy on milk yield in dairy cows
Authors: Gustafsson A. H. , Andersson L. , Emanuelson U.
Published: September 2010

The effects of acetone concentration in milk, feeding frequency, and intake of concentrates and energy in total diet on milk yield were studied in 38624 lactations from 474 herds during 3 years. Herd-related data on feeding factors were collected once per indoor feeding period. Milk acetone concentrations higher than 0·40 mmol/l were deemed to denote hyperketonaemia, whether subclinical or clinical. The lactation curves of ketotic cows had an abnormal shape, with an inverted peak in early lactation. Most of the reduction in milk yield took place during the first 100 days of lactation with an estimated loss of proportionately 0·085 (acetone concentration ≤0·40v.>2·00 mmol/l). The loss in 200-day milk yield was estimated to 328 kg 40 g/kg fat-corrected milk (FCM) at an overall mean of 5056 kg. If a herd's performance is monitored by lactation curves, a low peak — and hence an apparently high persistency – can indicate a ketosis problem. More frequent feeding of concentrates was correlated with a proportionately 0·033 to 0·074 higher milk yield in multiparous cows, but inconsistent between years. A more variable proportional response (−0·035 to 0·131) was observed in primiparous cows depending on interactions with, for example, breed. A greater total energy supply, including a larger amount of concentrate (maximum in lactation), was correlated with a higher milk yield, about 0·06 kg FCM per day per MJ metabolizable energy and 0·5 kg FCM per day per kg concentrate, respectively. However, increased feeding of concentrates at calving (parity 1) and 15 days after calving (multiparous cows) was correlated with decreased milk yield, by about −0–3 and −0–5 kg FCM per day per kg concentrate, respectively.
Influence of pen rearing system and stocking density on post-weaning performance of two breed types of rabbits
Authors: Hamilton H. H. , Lukefahr S. D.
Published: September 2010

Effects of alternative pen rearing system, stocking density, breed-type and their interactions on post-weaning rabbit performance were investigated in a replicated experiment. Californian purebred and terminal crossbred weanlings (no. = 502) were randomized amongst four pen treatments: CSD = conventional wire pen (61 × 76 × 46 cm) stocked with five rabbits; PSD = iron framed, wire-fitted, pen (76 × 244 × 46 cm) stocked with 20 rabbits; PDD = pen stocked with 40 rabbits, and PTD = pen stocked with 60 rabbits. Pen traits measured were average daily food intake (Fl), food efficiency (FE), survival rate (SR), and final weight uniformity (CV). Individual traits were initial (IW) and final (FW) weights and average daily gain (ADG) over 6 weeks.

In CSD v. PSD pen trait comparisons, FI was increased (P < 0·05), and numerically poorer FE and greater CV were detected (P > 0·05) in CSD; however, SR means were similar. Non-significant differences were observed in the PSD v. (PDD + PTD)/2 contrast (P > 0·05). For PDD v. PTD, pen FE was numerically better in the former but CV was greater (P > 0·05). Individual FW and ADG were increased (P < 0·05) in PSD v. (PDD + PTD)/2 groups; no other significant contrast differences were observed. Breed-type (B) × pen treatment (P) interaction was not significant (P > 0·05) for IW, ADG and FW; and individual sire/B × P interaction accounted for proportionately less than 0·05 of the total random variation. These results suggest the commercial potential of large pen rearing of rabbits.
Relationships between egg size, body weight and pelvic dimensions in turkeys
Authors: Hocking P. M.
Published: September 2010

Females of four strains of commercial turkeys, including one large strain with a characteristically high rate of oviducal prolapse, were given food either ad libitum or controlled to reach proportionately 0·8 or 0·6 of the body weight of birds fed ad libitum at 24 weeks of age. Two pens of five turkeys from each treatment were photostimulated at 24 and 30 weeks of age. Each turkey was autopsied after it had laid its first egg. The relationships between egg weight and body weight, and between the weight of abdominal fat, diameter of the vent and distance between the pubic bones and egg weight were studied by regression analysis. Egg weight was a function of body weight raised to the power 0·29 which was significantly different from the allometric relationship for Galliform species of 0·64. There was no evidence that differences existed in the quantity of abdominal fat which could impede oviposition and contribute to oviducal prolapse. There were strain differences in the diameter of the vent and distance between the pubic bones in relation to egg weight but the smallest and largest strains were similar. It was concluded that artificial selection had changed the species relationship between egg weight and body mass and that the susceptibility to oviducal prolapse in sire line turkeys was probably physiological in origin.
The effects of quantity and duration of milk feeding on the intake of concentrates and growth of castrated male Saanen kids to slaughter
Authors: Yan T. , Cook J. E. , Gibb M. J. , Ivings W. E. , Treacher T. T.
Published: September 2010

To examine the possibility of reducing milk substitute costs in artificial rearing of goat kids, 36 castrated male Saanen kids at 2 days of age were randomly allocated across six treatments in a 2×3 factorial design experiment. Milk substitute was provided for the kids over a period of 28 or 39 days, and daily levels of milk substitute dry matter (DM) intake were 0·140,0·176 or 0·272 kg.

Increasing the level of milk substitute offered had no significant effect on intake of concentrate up to weaning, but did significantly reduce the total intake of concentrate through to slaughter. Weaning after 39 days, as opposed to 28 days, also significantly reduced the total intake of concentrates. However, there was no difference when the same total quantity of milk substitute was consumed over different periods. Increasing the daily intake of milk substitute significantly increased daily live-weight gain to weaning, but tended to increase the time taken by kids to regain their weaning weight following cessation of milk substitute intake. However, milk substitute level and weaning age did not significantly affect overall daily live-weight gain or the length of time taken to reach 28 kg.

Eight additional kids were slaughtered at 2 days of age to develop regression equations relating initial body composition to live weight. These relationships were similar to others published for 2-day-old Saanen kids. Treatments had no significant effect on overall rates of fat, crude protein, water, ash and energy gain or on final body composition, carcass weight or carcass composition when kids were slaughtered at a live weight of 28 kg. These data suggest that savings in milk substitute may be achieved by reducing the weaning age and/or the daily intake level.
Follicle populations, ovulation rates and profiles of gonadotropins, inhibin and insulin-like growth factor-1 of heifers actively immunized against androstenedione and inhibin, separately or in combination
Authors: Rhind S. M. , Schemm S. R. , Schanbacher B. D.
Published: September 2010

Four groups of 20 Simmental cross heifers were actively immunized against human serum albumin (control, (C), androstenedione (A), a 30 amino acid synthetic fragment of porcine inhibin alpha (I) or A and I in combination (AI). At the time of the third and final antigen injection and again 2 weeks later, all animals were injected with synthetic prostaglandin F2α (PG) to synchronize oestrus. Concentrations of LH, FSH, insulin-like growth factor-1 (IGF-1) and inhibin (C and A heifers only) in serum samples collected twice daily during 3 days before the second PG injection and at 15-min intervals from 24 to 32 h after PG injection were determined. Two weeks later, all heifers were administered PG and ovariectomized 24 h later. Ovarian follicles were dissected from the stroma, measured and cultured in medium 199 for 2h at 37°C. Numbers of small (3·0 to 7·9 mm diameter) and large (>8·0 mm diameter) follicles were not significantly altered by any of the immunization treatments. Intrafollicular concentrations and secretion rates of oestradiol, testosterone, progesterone and inhibin, determined in vitro, were not affected by immunization. Intrafollicular IGF-1 concentrations were not affected; this hormone was not detectable in the culture medium. Intrafollicular concentrations of oestrogen and testosterone and secretion rates of all three steroids were greater (P < 0·05) in animals which had regressing corpora lutea at the time of ovariectomy. Of the animals that had dominant follicles, one of 17, one of 13, four of 19 and six of 15 in the C, A, I and AI groups, respectively, had two or more. Only the difference between AI and C cows in the incidence of dominant follicles was statistically significant (P < 0·05). Mean circulating concentrations of LH, and inhibin (C and A groups only) and mean LH pulse frequency and pulse amplitude were unaffected by treatment but FSH concentrations were higher in A (P < 0·001) and lower in AI and I heifers (P < 0·001) compared with C animals while IGF-1 concentrations were lower in A heifers (P < 0·001) and higher in AI heifers (P < 0·05) compared with C heifers. It is concluded that immunization against inhibin, either alone or in combination with immunization against androstenedione increased the incidence of multiple dominant follicles in heifers but did not increase their ovulation rate.
A comparison of body components of indigenous Saudi sheep breeds related to relative mature size and growth rate
Authors: Gaili E. S. E.
Published: September 2010

Six male lambs from each of Najdi, Azvassi and Hejazi breeds of sheep were given the same diet and serially slaughtered at 3, 6, 9 and 12 months of age. Slaughter and growth data including estimates of body maturity were collected. Allometeric growth coefficients were obtained for body components and breed differences in the proportions of the components at the same degree of body maturity or groivth rate were computed.

The live weight of lambs slaughtered at 6, 9 and 12 months of age differed between the breeds. Awassi lambs were less mature than Najdi or Hejazi lambs at slaughter. Hejazi lambs grew (relative to their mature size) faster than lambs of the other two breeds. The allometric regression coefficients of body components were similar1 in the breeds except those of the head, skin and genital organs.

Body composition of the breeds was reasonably similar at the same degree of body maturity or growth rate except skin and feet proportions were higher in Awassi and Najdi lambs, respectively, than in the other two breeds. Thus the three breeds conform to the scaling rules relating growth characteristics to mature size.