bluuebunny/crossref_metadata_2025_split huggingface dataset:
Ram-induced reproduction in seasonally anovular Corriedale ewes: MAP doses for oestrous induction, ram percentages and post-mating progestagen supplementation
Authors: Rodríguez Iglesias R. M. , Ciccioli N. H. , Irazoqui H. 
Published: September 2010

AbstractExploiting the ‘ram effect’ is an inexpensive alternative for out-of-season breeding in moderately seasonal breeds. For maximum efficacy in Corriedale sheep, oestrous ewes have to be introduced together with the teaser rams. Successful applications depend upon timely manipulation of the animals to induce oestrus in most ewes and to minimize the likelihood of successfully induced non-pregnant ewes returning to anoestrus during the mating period.In the first of two experiments, the effects of two alternative ram: ewe ratios (1:6 or 1:12) and five different doses (0, 15, 30, 45 or 60 mg) of medroxy-progesterone acetate (MAP) applied in intravaginal sponges for 9 days were assessed on seasonally anovular adult Corriedale ewes. Control ewes (0 MAP) did not receive sponges, but were injected with 20 mg progesterone at ram introduction. A second experiment tested the efficacy of post-oestrus intravaginally applied MAP (30 mg; 7-day treatment starting on days 3 to 6 after oestrus) for improving reproductive variables of successfully induced ewes exposed to entire rams.Proportions of ewes ovulating and ovulation rates (assessed through laparoscopy) did not differ significantly (P > 0·05) in ewes treated with various MAP doses (213/220 = 96·8% and 1·26 (s.e. 0·031) respectively) or injected with progesterone (56/58 = 96·6% and 1·21 (s.e. 0·058) respectively). The MAP content of the sponges did not affect (V > 0·05) the proportion of ewes ovulating (269/278), marked by the rams (197/213), returning to oestrus (81/197) or lambing among those not returning to first oestrus (87/119). More ewes were marked in the groups exposed to a higher ram percentage (79·7 to 70·6%; P < 0·001) but no other reproductive variable was affected by the ram: ewe ratio at ram introduction (P > 0·05). In the second experiment, post oestrus progestagen supplementation reduced the proportion of ewes returning to first oestrus from 27% to 16% (P < 0·05) but failed to improve lambing rate or the number of lambs born per ewe lambing. Thus, MAP doses as low as 0·25 of the commercial formulation (60 mg) induced oestrus in seasonally anovulatory Corriedale ewes exposed to rams and oestrous ewes. Increasing the ram: ewe ratio augmented the proportion of marked ewes but did not affect any other reproductive variable. Supplementing MAP after oestrus did not improve reproductive rate in Corriedale ewes induced to ovulate during the seasonal anoestrus.
Nutrition of draught oxen in semi-arid west Africa. 2. Effect of work on intake, apparent digestibility and rate of passage of food through the gastro-intestinal tract in draught oxen given crop residues
Authors: Fall A. , Pearson R. A. , Lawrence P. R. , Fernández-Rivera S. 
Published: September 2010

AbstractTwo experiments were conducted to investigate the relationships between work and intake and digestion of food by draught oxen given millet stover. In the first experiment, intake of millet stover, water intake, live weight, plasma concentrations of triiodothyronine, thyroxine and urea-nitrogen were measured in 18 animals that worked 0, 2 or 4 h/day in sequence during three 3-week experimental periods. Digestibility and rate of passage of food residues through the digestive tract were measured in a second experiment on 12 animals working either 0, 2-5 or 5 h/day in sequence during three 2-week experimental periods. Feeding behaviour was monitored on six animals working either 0, 2-5 or 5 h/day. Work did not affect intake of millet stover, apparent digestibilities and the rate of passage of digesta through the gastro-intestinal tract. This suggests that the nutrient supply from intake of roughages by ivorking oxen is unlikely to be sufficient to compensate for the extra energy expended during work. Food intake was affected by the quality of the millet stover offered. The level of intake of millet stover ivas proportional to the amount of leaves in the stover. Food intake increased also as work progressed. However, animals mobilized their body reserves to perform work. Animals consumed more water on working days than on days they were at-rest in shade. The heat stress that working animals were subjected to did not appear to interfere with their digestive function.
Responses of Romney sheep to selection for resistance or susceptibility to nematode infection
Authors: Morris C. A. , Vlassoff A. , Bisset S. A. , Baker R. L. , West C. J. , Hurford A. P. 
Published: September 2010

AbstractDivergent breeding lines of Romney sheep, selected as lambs for consistently low or high faecal worm egg count (FEC) following natural multispecific challenge by nematode parasites, have been maintained at Wallaceville Animal Research Centre since 1979. From the start of the trial until 1992, 821 and 736 experimental lambs in lines selected for increased resistance (R) and increased susceptibility (S), respectively, were generated, with the use of 44 different sires. In order to assess genetic responses to selection, FEC and productivity data were analysed using restricted maximum likelihood procedures. By 1988 the two lines had diverged in average loge (FEC+100) by 0·67 log units, and by 1992 divergence had increased to 1·48 log units, representing 2·90 genetic standard deviations of divergence. No significant correlated responses were observed in live weights. However, by 1992 the mean score for breech soiling (dags) in the R line was proportionally 0·41 greater than in the S line (F < 0·001). Yearling fleece weight was proportionally 0·15 greater in S-line than in R-line animals when grazed together under identical levels of challenge (P < 0·001) but the lines did not differ significantly in fleece weight when they were grazed apart. The R line had significantly higher reproductive success than the S line (P < 0·05), as measured by lambs weaned per ewe mated (1·01 v. 0·92, respectively). It is concluded that selective breeding can change the degree of resistance or susceptibility to nematode infection in Romney sheep, and selection for productivity needs to be continued at the same time in any practical breeding programme.
The influence of heat production on voluntary food intake in growing pigs given protein-deficient diets
Authors: Ferguson N. S. , Gous R. M. 
Published: September 2010

AbstractNinety-six entire male Large White XLandrace pigs were assigned at 13 kg to one of six dietary crude protein (P) treatments (230 g/kg (P1), 201 g/kg (P2), 178 g/kg (P3), 151 g/kg (P4), 125 g/kg (P5), 93 g/kg (P6)) and one of four temperatures (T) (no. = 4) (18°C, 22°C, 26°C, 30°C), and were given food ad libitum until slaughter weight of 30 kg. At all temperatures gut fill was a constant proportion of food intake (Fl) (1·56) but this ratio varied with different protein concentrations. Food intake increased with decreasing temperature and with decreasing protein content to a maximum rate on P4 (1·347 kg) whereafter FI declined. There was a linear decrease in average daily gain (ADG) with decreasing protein content while temperature had a significant curvilinear effect on ADG and food conversion ratio (FCR) with maximum ADG (0·680 kg/day) at 26°C. Body protein content decreased as the dietary protein concentration declined below P3 and there was a corresponding increase in lipid content. Temperature had no effect on body protein content but had a significant effect on lipid content. Similar trends occurred in the rate of protein (PR) and lipid (LR) retention with maximum PR (117·1 g/day) attained on PI, P2 and P3. Protein and temperature had a significant effect on total heat loss (THL). Maximum THL occurred in the protein treatment that resulted in pigs consuming maximum FI. The efficiency of protein utilization increased with increasing temperature but the response was dependent on the protein supply. It is concluded that on low protein diets pigs increase their Fl to maintain potential protein growth until a point is reached where the animal can no longer compensate and FI will decline. The extent of the compensation will depend on the amount of heat the animal can lose which in turn is dependent on the environmental temperature.
Relationship of body condition score and live weight with body composition in mature Churra ewes
Authors: Frutos P. , Mantecón A. R. , Giráldez F. J. 
Published: September 2010

AbstractThirty-five mature Churra ewes, ranging in live weight from 30·3 to 52·6 kg and in body condition score from 1·25 to 4·00 were used to study the relationship between body condition score (BCS), live weight (LW) and body composition and fat distribution in ewes of this breed, which is one of the major sheep breeds of northern Spain. The procedure at slaughter and at subsequent dissection was designed to partition each body into two components, carcass and ‘non-carcass’. Right side carcasses and ‘non-carcass’ components were used to analyse the chemical composition. From the left side of the lumbar region a joint was cut and dissected into muscle, bone, subcutaneous and intermuscular fat. According to the results obtained, omental fat represented the highest proportion of total internal fat regardless of the level of fatness. Distribution of internal fat was similar to that observed in other milk production breeds. Regressions on LW explained more of the variation than those on BCS for individual internal fat depots and chemically determined ‘non-carcass’ fat. The prediction of total body fat afforded by LW was better than that provided by BCS. The subcutaneous and intermuscular fat depots in the lumbar joint were well correlated with BCS, carcass fat and total fat in the body, validating the use of this region for assessing BCS in Churra ewes. Nevertheless, the correlation coefficient with the omental depot was not statistically significant. The results of this study suggest that BCS was not as accurate for estimating body composition and fat depots in mature Churra ewes as has been shown previously in other breeds. The single most effective prediction index was LW. However, the utilization of both BCS and LW together provided more accurate estimations.
The effect of the introduction of the Thoka gene for fecundity on lamb production from Cheviot ewes
Authors: Russel A. J. F. , Alexieva S. A. , Elston D. A. 
Published: September 2010

AbstractA flock of Cheviot ewes carrying the Thoka gene for fecundity was established in southern Scotland through the importation of frozen semen from two Icelandic rams. Ewes considered to be probable carriers of the Thoka gene were identified on the basis of measurements of ovulation rate as juveniles at 1·5 years of age and again as adults. Analysis of 3 years' records of 8926 Cheviot lambings and lambings of 351 Icelandic × Cheviot ewes considered to be probable carriers showed that fecundity increased with age in both genotypes, the number of lambs born per ewe mated being 1·07, 1·19, 1·31 and 1·41 in the Cheviots and 1·55, 1·74, 2·33 and 2·30 in the Icelandic-Cheviot crosses at first to fourth lambings respectively. The apparent effect of the crossbreeding on fecundity thus also increased with age, values at first to fourth lambings being 0·48, 0·55, 1·02 and 0·89 lambs per ewe mated, giving a weighted mean value of 0·61 (1·20 v. 1·81 lambs per ewe mated in Cheviot and Icelandic × Cheviot ewes respectively). There was a positive effect of the proportion of Icelandic ancestry on the number of lambs born per ewe mated and thus the observed increases in fecundity, although attributed principally to the effects of the Thoka gene, are also due in part to other genetic factors introduced from the Icelandic sheep in the crossbreeding programme. Lamb mortality to 6 weeks of age was only marginally higher in Icelandic × Cheviots (0·10) than in Cheviots (0·08). The increase in fecundity was achieved without an excessive proportion of large litters (<0·02 of probable carriers gave birth to quadruplets). The results demonstrate that the introduction of the Thoka gene to breeds such as the Cheviot can increase fecundity and hence the potential for more efficient lamb production.
The effect of nutrition on fibre growth in the alpaca
Authors: Russel A. J. F. , Redden H. L. 
Published: September 2010

AbstractTwelve adult male alpacas were given either 0·67 (low) or 2·0 (high) × assumed maintenance requirements for a period of 6 weeks after which time each was transferred to the alternative level of nutrition for a further 6 weeks. Fibre samples were taken from two 10-cm2 areas on the mid-side position of each animal at 2, 6, 8 and 12 weeks, and measurements of fibre weight, yield (clean fibre weight/raw fibre weight), fibre diameter and fibre length made on the samples collected at weeks 6 and 12. The higher level of feeding resulted in higher clean fibre weight (low = 0·42 (s.e. 0·03); high = 0·53 (s.e. 0·04)mg/cm2 per day, P < 0·001) and fibre growth rate (low = 186 (s.e. 10); high = 223 (s.e. 14) yon/day, P < 0·05). Changes in yield (low = 0·917 (s.e. 0·006); high = 0·929 (s.e. 0·009)) and mean fibre diameter (low = 31·4 (s.e. 1·9); high = 32·1 (s.e. 1.6) \xm) were not statistically significant. Calculations showed that the increased weight of fibre attributed to the higher level of nutrition could be explained in terms of the observed increases in fibre-length and diameter but that, unlike the sheep in which the ratio fibre length: diameter remains relatively constant under varying nutritional regimes, the effect of nutrition in the alpaca has a proportionally larger effect on fibre length than on fibre diameter.
Predicting the effects of animal variation on growth and food intake in growing pigs using simulation modelling
Authors: Ferguson N. S. , Gous R. M. , Emmans G. C. 
Published: September 2010

AbstractAll pig nutrition models to date predict growth responses of either an individual animal or the average animal of a given population over time. Translating the predicted nutrient requirements from the average animal to the population introduces a number of errors as the cause-and-effect response of the average animal is different from the population response. To overcome the problem of estimating the requirements for a given population using models it is necessary to simulate a number of individuals representative of a population and then average these results. This approach however, requires a knowledge of those animal characteristics that vary between individuals and the nature of their distribution. In this paper a scaled growth rate constant (B*), protein weight at maturity (Pm) and the ratio of lipid to protein at maturity (LPRm) are the parameters used to define an individual animal. As no data existed from which the nature of the distribution of B*, Pm and LPRm can be estimated for pigs of different strains and sexes, and due to the impracticality of determining this variability by experimentation, a simulation model was used to estimate the variations within each parameter. In addition this paper quantifies the subsequent effects these distributions have on the genetic variability of average daily gains (ADG) and daily food intake (TI) over a live-weight range of 25 to 90 kg. Comparisons were made between the genetic variation determined by modelling and those published in the literature. The results indicated coefficients of variation for B*, Pm and LPRm of 0·01, 0·05 and 0·10, respectively. An increase in the variability of all three parameters resulted in an increase in the variation in ADG whilst only an increase in the variation of B* and LPRm affected the distribution of FI.
Selection of farm animals for non-linear traits and profit
Authors: Meuwissen T. H. E. , Goddard M. E. 
Published: September 2010

AbstractAccording to animal breeding theory, profit after, say, 10 generations of selection is maximized when the usually non-linear profit function is approximated by a linear breeding goal where the linearization is at the population mean in generation 10 and the linear breeding goal is subsequently predicted by a linear index for which the animals are selected. The prediction of the population mean at generation 10 requires linear relationships among the traits that constitute the non-linear profit, because otherwise this prediction becomes very complicated.A non-linear index is proposed that simply estimates the non-linear goal H =f(u) by Ĥ =f(û), where u = vector of genetic values for the traits and u is its (BLUP) estimate. This non-linear index does not require predictions of (future) population means and does not require linearly related traits.To test these indices a simple meat production example was constructed where the non-linearity between the traits was due to the competition between weight and probability of survival for the same resources from food intake. In the model selection for weight and, in particular, for weight over costs (mainly food) led to reduced profits due to large reductions of survival rates. Although, the example was oversimplified, this should provide a warning for the use of oversimplified breeding goals, e.g. fitness traits may reduce by more than expected from base population genetic parameters.When probability of survival and weight were measured, a non-linear index of these non-linear traits gave the greatest genetic gains. Failure to update genetic parameters each generation severely reduced genetic gain and, if linear indices were used, it was also important to update the economic weights. When probability of survival was measured, profit could be calculated on each animal and included as a trait in the calculation of estimated breeding value. This yielded high genetic gain and did not require updating of genetic parameters or economic weights.
The effect of melatonin treatment in combination with progestagen pessaries on reproductive performance of ewes during the anoestrous period
Authors: Laliotis V. , Vosniakou A. , Lymberopoulos A. , Doney J. M. , Kouimtzis S. 
Published: September 2010

AbstractThe objective of this study was to compare the effects of melatonin implants combined with intravaginal, progestagen-impregnated pessaries with the conventional treatment of progestagen pessaries followed by pregnant mare serum gonadatrophin (PMSG) on the reproductive performance of ewes during the anoestrous period.A commercial flock of 179 seasonally anoestrous Chios crossbred ewes was used. The ewes within the flock were randomly allocated to one of two groups. Ewes of group MP (melatonin + pessaries) received melatonin implants on 20 March (50 days before the target breeding date of 10 May) and were treated with intravaginal progestagen pessaries 35 days later (25 April). Ewes of group PP (pessaries + PMSG) were also treated with pessaries on 25 April. After 14 days the pessaries were removed from both groups and 500 i.u. PMSG was injected (i.m.) into ewes of group PP only. Fertile rams were introduced into both groups 24 h after sponge removal. Pregnancy rate and litter size were determined by ultrasound scanning 80 days after ram introduction.Pregnancy rate at first oestrus was significantly higher in group MP than in group PP (57 v. 40%, P < 0·05). The overall conception rate during two oestrous cycles was significantly higher in group MP than in group PP (78 v. 59%, P < 0·02). The groups did not differ significantly in the mean number of foetuses per pregnant ewe that conceived during the first or second oestrus after pessary removal (1·78 and 1·87, respectively). The total number of foetuses per treated ewe was higher in group MP than in group PP (1·39 v. 1·10) as a consequence of the difference in pregnancy rate.
Differences in microbial fermentation of barley straw induced by its treatment with anhydrous ammonia
Authors: Fondevila M. , Muñoz G. , Castrillo C. , Vicente F. , Martín-Orúe S. M. 
Published: September 2010

AbstractThe effect of ammonia treatment of straw on both the rumen environment and the extent of its microbial fermentation was studied. Four rumen cannulated sheep were randomly given 700 g/day of untreated straw plus urea (US), ammonia-treated straw (TS) and alfalfa hay (AH) in a change-over design with three periods. Rumen pH was lower and ammonia-nitrogen and total volatile fatty acid (VFA) concentrations were higher (P < 0·001) with AH than with US or TS. With the straw diets, TS promoted a lower pH than US (P < 0·05), but differences were less than 0·3 units and the mean pH was never below 6·5. There were no differences between the straw diets in ammonia-nitrogen or VFA concentration (P > 0·05). When untreated barley straw (BS) and treated straw (TS) were incubated in situ disappearance of dry matter (dDM) at 12, 24 and 48 h (P < 0·01) and neutral-detergent fibre (dNDF) at 48 h (P < 0·001) were higher with TS. In vitro incubation showed a higher gas production with TS only after 36 h (P < 0·05) whereas gas from BS fermentation was higher up to 14 h (P < 0·05). Among diets, dDM, dNDF and gas production with US were numerically higher than with TS or AH throughout, although few significant differences were observed, except for a higher dDM at 12 (P < 0·01) and 24 (P < 0·10) h and a higher dNDF at 12 h (P < 0·10). Particle-associated enzymes were extracted from BS and TS incubated in the rumen for 4, 8, 22 and 24 h. Results ofxylanase and cellulase activities support those of straw incubation, with a drop between 4 and 8 h in TS diet. The concentration of residual phenolics per unit of incubated straws after 12 and 24 h show that phenolics release to the media was higher with the TS diet. Daily changes of phenolic concentration into rumen liquid was also higher with TS than with US (P < 0·001). The increased release of straw phenolics by ammoniation reduced the potential for rumen degradation of straw, mainly in the first hours of the fermentation period.
Parity influences the utilization of exogenous glucose in suckler anoestrous Charolais beef cows
Authors: Ponter A. A. , Grimard B. , Humblot P. , Novak N. , Khireddine B. , Sauvant D. , Thibier M. , Mialot J.-P. 
Published: September 2010

AbstractThis work was designed to study the influence of parity (multiparous (MP, no. = 9) or primiparous (PP, no. = 10)) and feeding level (control diet (CD; 1·00) or restricted diet (RD; proportionately 0·70 of requirements) in a 2×2 factorial design on the utilization of exogenous glucose in the suckler anoestrous Charolais beef cow. Lack of ovarian activity was confirmed by low circulating progesterone concentrations measured in weekly blood samples taken after parturition. An injection of glucose (1·5 mmol/kg live weight) lasting 20 min was given 30 days and 50 days post partum. Blood samples were collected before and for 120 min after the start of the injection and plasma insulin, glucose, non-esterified fatty acids (NEFA), β-hydroxybutyrate and urea were measured. Although plasma glucose concentrations were not significantly different between treatment groups in the period immediately after the injection of glucose, CD PP animals had higher plasma insulin levels than CD MP animals (at 25 min: 596·4, 283·8, 435·1 and 309·6 pmol/l,P< 0·05 for groups PP CD, MP CD, PP RD and MP RD respectively). Plasma NEFA concentrations were initially higher in the RD groups compared with the CD groups but were reduced by the glucose injection (P < 0·001). However, the PP RD cows took longer to respond to the exogenous glucose compared with the MP RD cows (at 25 min: PP RD: 133·2 and MP RD: 57·5 eq/l,P< 0·05). In conclusion, suckler anoestrous PP cows appear to require higher plasma insulin levels than MP cows to metabolize exogenous glucose and underfed PP cows were slower to reduce plasma NEFA after glucose injection than underfed MP cows.