bluuebunny/crossref_metadata_2025_split huggingface dataset:
Rumen degradation of straw 4. Selection and degradation of morphological components of barley straw by sheep
Authors: Bhargava P. K. , Ørskov E. R. , Walli T. K. 
Published: September 2010

AbstractExperiments were made to study the proportion, chemical composition, and rumen degradability of the morphological components of barley straw (Corgi variety) and to study the selection of these components by sheep. The proportions in the harvested straw dry matter (DM) as leaf blade, leaf sheath, stem and chaff were 128, 314, 500 and 58 g/kg DM, respectively. The different components of straw on analysis proved to have very different concentrations of nitrogen and neutral-detergent cellulase digestibility. The leaf blades had the highest and the stems the lowest values. The degradabilities of DM in the components and in the whole straw were determined by measuring DM loss from samples incubated in nylon bags for various periods in the rumen of sheep. Responses were measured using the mathematical model p = a+b (1–e−ct) where p is DM loss, (a+b) potential degradability, c the rate constant of DM loss and t is the time of incubation. DM losses decreased in the order leaf blades > leaf sheath > whole plant > chaff > stems. Leaf blades also had the highest potential degradability and rate of degradation.In another trial, five sheep were offered unchopped barley straw ad libitum. There were five treatment periods in which sheep were allowed to leave uneaten proportionately 0·2, 0·3, 0·4, 0·5 and 0·7 of the straw on offer for assessing the animal's selection of the morphological components of that straw. The amount of leaf blade in the material consumed increased in largely a linear (P < 0·01) fashion with the amount of excess allowance. The proportion of stem eaten varied conversely. The selection of leaf sheath was less apparent. Little stem was consumed until the proportion of leaf blade in the food available decreased below proportionately 0·4. The practical significance of the study is discussed.
Genetic parameters of test day records of British Holstein-Friesian heifers
Authors: Pander B. L. , Hill W. G. , Thompson R. 
Published: September 2010

AbstractEstimates of genetic parameters for test day records of yields of milk, fat and protein and concentrations of fat and protein were obtained on 47 736 British Holstein-Friesian heifers in 7973 herds, progeny of 40 proven (to improve connectedness) and 707 young sires (comprising about one-fifth of the progeny), using multivariate restricted maximum likelihood methods with a sire model.Heritability estimates for lactation yields of milk, fat and protein and concentrations of fat and protein were 0·49, 0·39, 0·43, 0·63 and 0·47, respectively. Estimates for individual test day records of these traits ranged from 0·27 to 0·43, 0·16 to 0·34, 0·22 to 0·33, 0·11 to 0·48 and 0·21 to 0·43, respectively. Generally, heritability estimates for test day records were lowest at start and highest in mid lactation.Estimates of genetic correlations among yields of a trait on different test days ranged from 0·57 to 0·99, and for fat and protein concentrations from 0·34 to 0·99, the correlations being highest for adjacent tests. Phenotypic correlations were lower than genetic correlations. Genetic correlations of test day records with corresponding lactation traits were high (0·76 to 0·99), being highest in mid lactation.Genetic correlations of test day milk yield with test day yields and concentrations of fat and protein throughout the lactation were similar to those for complete lactation.The high heritabilities of test day yields and their high genetic correlations with complete lactation, except for the first 1 or 2 test days, suggest that lactation performance may be predicted from test days in early and mid lactation.
Effects of genotype and stocking density on post-weaning daily gain and meat production per hectare in cattle
Authors: Mezzadra C. , Escuder J. , Miquel M. C. 
Published: September 2010

AbstractWith the objective of determining genetic × environmental interaction for beef production under direct grazing conditions, measured as both individual average daily gain (ADG) and per ha (PROD), 160 steers were utilized through 2 years, from two breeds of different growth potential, and four stocking rates (SR) tending to establish different nutritional environments. The breeds were Aberdeen Angus (A) and high-grade Limousin crossbred (L) and the SRs established were 2·25, 2·87, 3-50 and 4·13 steers per ha. The pasture where the steers grazed was Festuca arundinacea. Response variables were analysed by least-squares using a fixed model of year, breed, SR and their two-way interactions. There were highly significant effects (P < 0·01) of the interaction of breed × SR for ADG and PROD. Quadratic and linear regressions (P < 0·01) were adjusted for PROD and ADG on SR respectively using the least-squares means. The proportional superiority of L on A at the lowest SR was 0·27, while at the highest SR the situation was reversed, A gained proportionately 0·32 more weight than L. These results indicated that under limiting conditions of nutrition as generated at the highest SR in this experiment, the small-sized individuals tended to produce meat more efficiently both individually and per ha, the opposite situation being true when nutritional conditions were not restrictive.
Effects of rapid inbreeding and of crossing inbred lines on the growth of linear body dimensions of sheep
Authors: Wiener G. , Lee G. J. , Woolliams J. A. 
Published: September 2010

AbstractSheep of three hill breeds and the crosses among them were closely inbred for four generations to create five levels with inbreeding coefficients 0·0 (F2/O2), 0·25 (I1,), 0·375 (I2), 0·50 (I3), and 0·59 (I4). Inbred females were also mated to unrelated inbred males of the same breed or crossbred type to produce line-crosses (LC). Mating was arranged so that the effects of inbreeding on the individual could be differentiated from maternal inbreeding. A total of 2369 animals were available up to 78 weeks of age and 1062 to the age of 4 years. This study examines the effects on six linear body dimensions and draws comparison with the effects on body weight. There were significant reductions in the size of the body dimensions with increasing inbreeding but the maximum depression was usually at the I2 stage for individual inbreeding and the I3 stage for maternal inbreeding. Most of the linear and many of the non-linear effects of inbreeding of the individual were significant and the effects of maternal inbreeding were also significant in a majority of cases. Inbreeding effects were more marked for relatively late-maturing parts (shoulder and hook widths) than for early-maturing (cannon bone and tibia lengths) with head width and body length intermediate but closer to the early-maturing parts. This was seen separately at each age, and in the effects of advancing age. By 78 weeks of age, the effects of inbreeding of the individual on absolute size had increased with age and by 4 years of age, in spite of a small recovery in size relative to F2/O2, was still greater than in early life. The effects of maternal inbreeding became progressively less with advancing age relative to non-inbreds. The changes with inbreeding could not be explained by dominance effects alone and epistasis is therefore likely also to be involved.
Effect of calving date on lifetime productivity of cows in a winter-calving Aberdeen Angus herd
Authors: Garcia Paloma J. A. , Alberio R. , Miquel M. C. , Grondona M. O. , Carrillo J. , Schiersmann G. 
Published: September 2010

AbstractLifetime productivity of 408 Aberdeen Angus cows from the Estacion Experimental Agropecuaria (EEA) of Balcarce, Argentina, was analysed during the 1972 to 1983 period according to their date of calving. Cows were allocated to two groups: one group of early first calving (Fl) when cows calved within the first 25 days of the calving period; the other, of late first calving (F2) when cows calved after that date. Independently using similar criteria, the effect of date of second calving on lifetime productivity was analysed in the same cows, groups SI and S2. Early first calving cows weaned more kg of calf when their first four calvings were considered than cows of late first calving (659 v. 628 kg). The same tendency was observed when cows were compared according to their second calving date (653 v. 634 kg). Differences in weaning weight between calves from early and late cows were only significant for the first calving (group Fl v. F2) and for first and second calving (group SI v. S2). This fact was a consequence of the shorter initial calving interval for late cows (F2 and S2) so that subsequent ages of their calves at weaning were similar to early cows (Fl and SI). Groups F2 and S2 cows had first and second calving intervals respectively of 351 and 356 days, while groups Fl and SI cows had intervals of 372 and 371 days. It is concluded that the date of the first calving and the high overall reproductive performance of the herd contributed to a high concentration of early calvings and a high productive efficiency.
A note on effect of docking on skin structure and characteristics of the fleece in Rahmani fat-tailed sheep
Authors: Marai I. F. M. , El-Gaafary M. N. , Ahmed B. A. K. 
Published: September 2010

The histological characteristics of the skin of docked and undocked fat-tailed sheep were studied at 15-day intervals between birth and 90 days of age, then every 30 days until 180 days and every 3 months until 1 year of age. Data presented in this paper were recorded at birth, 30, 60, 120,180 and 360 days of age. The fleece characteristics were studied at 1·0,1·5 and 2·0 years of age.The skin structure was similar in docked and undocked Rahmani sheep and did not differ from that of other breeds of sheep.The effect of docking was significant at most ages of the study on internal diameter of primary follicles and on the external and internal diameters of secondary and on average diameters of wool follicles (P < 0·05). The effect of docking was highly significant on each of staple length and wool diameter.
Specialised sire and dam lines. III. Choice of the most profitable parental combination when component traits are genetically non-additive
Authors: Moav Rom 
Published: September 2010

When crossbred offspring are used for production of an agricultural commodity profit is a function of three genotypes, that of the sire, the dam and the crossbred offspring. Heterosis in the component traits of profit, in any of the above genotypes, affects profit. Thus only when the final product is a four-way cross can we get crossbred parents plus a crossbred progeny and a full use of the available heterosis.When the contributions of the sire and dam to profit are unequal, there is a justification for the breeding and use of specialised sire and dam lines, even though the component traits may be genetically additive. Multiple crosses (three- and four-way) may improve profit over two-way crosses only when there is heterosis in one or more of the component traits.When profitability is presented as a function of productivity and repro-ductivity, five heterosis factors of the component traits may affect profit. These are: (a) Improved efficiency of production in a crossbred ‘commercial offspring’, (b) Improved viability (a component of reproductivity) in a crossbred ‘commercial offspring’, (c) Improved ‘female fertility’ in a crossbred dam. (d) Improved efficiency of the ‘commercial offspring’ through heterosis for maternal effects in the crossbred dam. (e) Improved male fertility through heterosis in the crossbred sire.When the profit equation is non-linear, the same degree of heterosis as that measured on the component traits may have quite a different effect on profit, depending on the level of performance of the traits. By crosses and backcrosses between the parental lines the location and composition of the heterosis factors may be altered favourably.Graphic and algebraic procedures were outlined for finding sire-dam combinations that maximise profit in the presence of heterosis when a group of genetic stocks is available.
The association between commercial cut-out yield and gross chemical composition in market pigs
Authors: Doornenbal H. , Martin A. H. 
Published: September 2010

In a study of 100 pig carcasses, representing a sample of the pigs used in previously reported work, gross chemical composition of the ham, shoulder, loin, belly and half carcass were determined for one side. Percentage yield (trimmed v. untrimmed) of picnic, butt, ham and loin (PBHL), and certain carcass measurements were recorded on the other side of the carcass. From the covariance analyses, it was concluded that backfat thickness of the carcass alone was of only moderate predictive value for total chemical carcass fat.Carcass protein could, for most purposes, be predicted with satisfactory precision from the percentages of protein in the loin or in the ham, with residual standard deviations of 0·27 and 0·36% respectively.Although percentage yield of lean cuts may be considered satisfactory for commercial evaluation of swine carcasses, it was not an accurate index of the true leanness of a carcass expressed as the percentage of chemically determined protein.Multiple regression equations were computed for predicting the percentage of protein in the carcass and percentage yield of PBHL from conventional carcass measurements. The residual standard deviations for predicting the percentage of protein were 0·49 for the males and 0·42 for the females; for percentage yield of PBHL these were 1·31 and 1·22 respectively. Total backfat thickness was the most important single variable in predictions. Variances among sexes were non-homogeneous for the important traits, with the females in all cases showing the greater variability. The results of regression analysis within sex indicated that, for maximum precision, a separate prediction equation for each sex was required.
Selection practices in dairy herds. 2. Selection patterns in the later lactations
Authors: Hinks C. J. M. 
Published: September 2010

Selection procedure has been examined in Friesian and Ayrshire populations of dairy cattle in an attempt to determine the extent to which the relatively simple selection process in the first lactation was modified by the effects of age, by the incomplete repeatability of milk yield, and by the availability of production information from more than one lactation.As a result of a greater intensity of selection for milk yield in the lower yielding herds, effective selection for yield was maintained at the later cullings despite increased wastage for reasons other than yield in the ageing population.The high yielding animals that were selected by farmers in early life continued to outlive and to outyield their lower yielding first lactation contemporaries, notwithstanding a small amount of evidence that the heaviest yielding group were severely culled in the second lactation, mostly for reasons beyond the farmers' control. There was also some evidence that a high first lactation yield predisposed the animal to disposal for reasons other than yield in later life.Survival at any particular culling was primarily determined by the milk yield in the previous lactation. In this respect, the culling after each lactation appeared to be independent of previous selection decisions, and the individual animal had to demonstrate its merit repeatedly to survive—earlier merit did not compensate for a subsequent failure.
The nutrition of the early-weaned calf. X. The effect of replacement of fish meal with either urea or ammonium acetate on growth rate and nitrogen retention in calves fed ad libitum
Authors: Kay M. , MacLeod N. A. , McKiddie G. , Philip Euphemia B. 
Published: September 2010

1. A growth trial and nitrogen balance studies were carried out on 32 early-weaned calves fed on a basal diet containing fish meal or diets in which the fish meal nitrogen was partially replaced by urea or ammonium acetate or totally replaced by urea.2. Growth rate and feed conversion efficiency were highest on the fish meal diet and fell as urea replaced the fish meal.3. Rumen ammonia levels and urinary nitrogen excretion were highest, and nitrogen retention lowest, in the calves receiving the diet in which fish meal nitrogen was completely replaced by urea nitrogen.
Feed intake of grazing cattle. V. A further study of the influence of pasture restriction combined with supplementary feeding on production per animal and per acre
Authors: Holmes W. , Curran M. K. 
Published: September 2010

This paper reports the second of two experiments which examined the possibility of improving pasture utilisation by restricting grazing and giving cows a supplement of concentrates. Two treatments (A and B) were continuously imposed, each on a group of 10 adult Ayrshire cows, for about 4 months. Cows received either pasture alone allocated daily by electric fence (B), or half this area of pasture plus 3 Ib. cubed concentrates per 10 lb. milk (A).Herbage intakes were estimated by grass cutting techniques and also by faecal index methods, and animal performance was recorded. Over the whole experiment the two treatments gave similar levels of production per animal. Significant differences in milk yield and live-weight gain were detected only in periods 1 and 4, respectively, when the intended restriction was not completely achieved. While production per acre of grass was doubled by treatment a about 4,000 lb. grain was considered necessary to replace one acre of grazing.The results are discussed in relation to the previous experiment. They suggest that the method of replacing half the normal grazing with barley or other concentrated feeds could be usefully employed to alleviate pasture shortage in parts of the grazing season and might therefore facilitate the maintenance of a high stocking rate.
Influence of rumen ciliate protozoa on conversion of food and growth rate in early-weaned zebu calves
Authors: Osman H. El-Sayed , Akkada A. R.Abou , Agabawi K. A. 
Published: September 2010

SUMMARYThe ruminal activity, daily live-weight gain and feed conversion efficiency of zebu calves inoculated with whole rumen contents from a mature cow were compared with those of calves maintained under the same conditions except that they were ciliate-free and isolated from other ruminants.A thriving mixed population of ciliate protozoa became established in the rumen of calves two weeks after inoculation.Entodiniumwas the first genus to appear and was followed byIsotricha, Polyplastron, Ophryoscolex, DiplodiniumandDasytricha.The ruminal volatile fatty acid and ammonia concentrations in the inoculated calves showed a pronounced rise above the values found in the uninoculated controls.The inoculated calves grew faster and had a higher feed conversion efficiency than the uninoculated controls.
Taste responses of calves to various concentrations of different salts
Authors: Mehren M. J. , Church D. C. 
Published: September 2010

SUMMARYExperiments were conducted to observe the taste responses of male and female calves to various levels of sodium salts, chloride solutions, and trace minerals. Animals were penned individually and given a completely pelleted ration ad libitum. Trace mineralized salt was freely available.Using water as a basis for determination, a non-discrimination zone was established. This zone represented an intake ranging from 63 to 37%. Preference threshold was set at 80% of intake, while the rejection threshold was set at 20% of intake. Responses were determined by expressing the intake of the test solution as a percentage of the total intake during the test period. Responses at a given chemical concentration were measured during two 8-hr periods.Taste response observations were made on the following: 0·02, 0·08, 0·32 or 1·25% sodium chloride (NaCl), sodium sulphate (Na2SO4), sodium bicarbonate (NaHCO3), sodium carbonate, monobasic sodium phosphate (NaH2PO4), dibasic sodium phosphate (Na2HPO4), ammonium chloride, potassium chloride, calcium chloride, magnesium chloride, and manganese chloride. In addition, observations were made when 0·02, 0·08, 0·32 or 1·25% NaHCO3, Na2SO4, or Na2HPO4 were offered in opposition to equal concentrations of NaCl. The responses to 5, 10, 20, 40 and 60 p.p.m. concentrations of cupric chloride, zinc chloride, molybdenum trioxide and cobaltous chloride were observed also.
Chemical processing of wheat straw and cotton by-products for fattening cattle. 1. Performance of animals receiving the wet material shortly after treatment
Authors: Levy D. , Holzer Z. , Neumark H. , Folman Y. 
Published: September 2010

SUMMARYTwo fibrous roughages, wheat straw and cotton hulls, were treated with 0, 40 and 80 g sodium hydroxide (NaOH)/kg roughage, applied in amounts of water calculated to bring the roughages to moisture contents of 30 and 60%. The effects of these factors on the nutritive values of the two roughages were examined using a 2 × 3 × 2 factorial design.Digestibility trials,in vitroandin vivo, and a 9-mo feeding trial were carried out with the roughages soon after treatment. Concentrates were limited to 6 kg/head per day throughout the animal experiments and roughages were offeredad libitum.Neutral detergent fibre decreased by 7·8 and 13·5% with the 40 and 80 g application rates of NaOH respectively.The treatment of both roughages with NaOH increased considerably theirin vitrodry matter digestibility and total solubles after enzyme treatment, the increases being related to the rate of application of NaOH. Digestibilityin vivowas improved only by the 40 g NaOH treatment.Treatment with NaOH reduced the voluntary intake of both roughages. Only the 80 g/kg treatment had a positive effect on rate of live- and carcass-weight gain. On the other hand, NaOH improved very significantly the efficiency of conversion of metabolizable energy into live and carcass weight and increased significantly the degree of fatness of the animals. These results indicate a marked improvement in the nutritional value of both roughages due to NaOH treatment. The reason for the small response in rate of gain may be explained by a shortage of protein owing to a possible reduction in its digestibility. Cotton hulls excelled wheat straw in almost every respect. Animals on NaOH-treated cotton hulls bloated chronically unless some long straw was given. Moisture level had practically no effect on performance.The effects of the treatments on rumen or blood constituents were small.
The effects of selection on sex differences in pre-weaning growth in beef cattle
Authors: Hopkins I. R. 
Published: September 2010

SUMMARYPre-weaning growth data from 3822 calves reared in 11 Victorian herds were analysed. The results suggested that the superiority of males (bulls) over castrated males (steers) in pre-weaning growth was due, at least partly, to the early castration of poorly growing male calves, i.e. to the effects of early selection. The extent of this selection bias was further examined using results from similar studies and from experiments in which bulls and steers were selected without bias. These studies strongly supported the view that the superiority of bulls over steers was primarily due to selection and not to sex effects. If sex did influence the bull-steer difference it was of no statistical or practical importance.In the Victorian data, the ratio of bulls to steers was higher in subclasses in which average growth rates were higher. When selection effects are correlated in this way with other environmental effects such as age of dam effects further biases may arise in estimation of those effects and hence in individual or mass selection.The results indicated, therefore, that unless bulls and steers are treated as one sex biases can arise in both individual selection and progeny selection.