bluuebunny/crossref_metadata_2025 huggingface dataset:
The effect of food intake in the rearing period on the reproductive performance of heavy and light gilts from large litters
Authors: Ogle R. B. , Dalin Anne-Marie
Published: September 2010

Sixty crossbred gilts, comprising 15 groups of four littermates from large litters (> 12 pigs) were used. The experiment was designed as a 2 × 2 factorial, with two initial live weights (light (L) or heavy (H)) and either a low (lp) or high (hp) plane of feeding during the rearing period and post mating within each litter group. The hp gilts were significantly heavier (P< 0·001) and had thicker backfat (P< 0·001) than the lp gilts at first oestrus. The Hhp gilts reached puberty 26·4 days earlier than the Hip gilts (P< 0·05). Level of food intake significantly influenced ovulation rates and total embryo numbers, the hp gilts shedding on average 2·4 more ova and having 1·9 more embryos than the lp gilts 28 to 35 days post mating (P< 0·05). However, due to somewhat higher embryonic mortality in the hp gilts, the mean number of live embryos was not significantly higher than for the lp gilts (P< 0·05).
Change in amino acid composition of different protein sources after rumen incubation
Authors: Susmel P. , Stefanon B. , Mills C. R. , Candido Manuela
Published: September 2010

The effective degradability (Dg) of dry matter (DM), nitrogen (N) and amino acids (AA) in soya-bean meal (SBM), fish meal (FM), dried brewers' grains (DBG) and ensiled lucerne (EL) was measured using polyester bags suspended in the rumens of six cows given a basal diet of maize silage, hay and concentrate. Rumen outflow rate was measured using chromium-mordanted SBM.

AA were grouped into essential (EAA), non-essential (NEAA) or branched chain (BrAA). The AA concentration in DM varied from 88 g/kg DM for EL to 566 g/kg for FM. The proportion of determined AA in crude protein (CP) was similar for SBM, FM and DBG and always higher than 0·85. EL had the lowest A A concentration in CP, partly due to the presence of ammonia N (170 g/kg total N).

Methionine always had a higher, and threonine a lower Dg than total AA in all foods. Dg of other AA was generally food dependent.

SBM always had the highest EAA, BrAA, NEAA, mean AA and total N degradability, whilst FM always had the lowest Dg for EAA, BrAA, mean AA and total N, and these values were significantly different in comparison with SBM. The effective Dg of BrAA in DBG was significantly lower than in SBM and significantly higher than in FM. In EL, NEAA and mean AA Dg were significantly lower compared with SBM.

Effective Dg of total AA in SBM and EL was significantly lower than the CP Dg; this difference was not apparent in DBG or FM.

The undegraded fraction of FM and EL had a significantly higher proportion of EAA whilst DBG and EL had a higher proportion of BrAA when compared with the unexposed food. Isoleucine concentration, highest in EL, and lysine and methionine contents, highest in FM, differed significantly between the four protein source residues.

The first limiting AA after rumen incubation, in relation to casein and meat, was always methionine. The essential amino acid index of the food residues post incubation, relative to casein and meat, was lower in SBM, DBG and EL but higher in FM.
Estimates of genetic and phenotypic parameters of growth and carcass traits from closed lines of pigs on restricted feeding
Authors: Gu Y. , Haley C. S. , Thompson R.
Published: September 2010

Data from two selected lines of pigs in closed herds of a breeding company were collected over a 5-year period. The lines were selected for growth rate and leanness and were housed together in the same environment. Animals were performance tested from 35 kg for about 58 days, and were fed individually according to a scale determined by time on test; the boars were more liberally fed than the gilts. At the end of test, average daily gain (ADG) values were calculated and ultrasonic measures were taken of fat depths at the shoulder (SF), loin (LF) and last rib, 4·5 cm (CF) and 8 cm (KF) off the mid line.

Estimates of heritabilities, phenotypic and genetic correlations were obtained from paternal half-sib analyses. All heritability estimates were significantly different from zero and ranged from 0·18 to 0·42 for ADG and from 0·21 to 0·59 for fat depths. The genetic correlations between ADG and fat measurements in boars of the two lines were not significantly different from zero, averaging 0·08; in the gilts they were negative, averaging –0·39.

After long-term selection, appreciable genetic variation remained in the closed lines studied here for growth rate and fat depths. Although sex and feeding level were confounded, it is likely that the genetic correlation between growth rate and fat depth was influenced by the level of feeding and associated with partitioning of energy between lean and fat deposition.
Conformation of twin and quadruplet freemartins
Authors: Donald H. P.
Published: September 2010

1. Observations were made at 2 years of age on 25 freemartins and their castrated brothers. Three of the freemartins belonged to a set of 4-egg quadruplets. For comparison there were 93 normal pregnant twin and single-born heifers and 14 males twin to males.

2. Twelve body measurements on each animal were taken. Averages for each character for 25 single-born Ayrshire heifers and for 10 single-born Friesian heifers were used as standards for comparison with the various groups of twins of like and unlike sex, triplets, and quadruplets.

3. Normal twin heifers were slightly smaller in all respects than the standard. Freemartins were also smaller but more so. The quadruplet freemartins were smaller still, but at 2 years they had the live-weight of normal heifers only 1½ years old. Twin males, whether from like or unlike-sexed pairs, were on average slightly smaller than the standard.

4. Percentage deviations of each group mean from standard varied systematically when characters were listed in a pre-determined order based on earliness of maturing. This relation has been summarised for each group by the regression of the percentage deviation on order of maturity, the order beginning with head width, and ending with the widths of hooks, pins, and chest. Each available group differed significantly from the chosen standard in conformation in such a way that the later a character appeared in the order, the less it exceeded, or the more it fell short of the standard.

5. As judged by the size of these regression coefficients, males twin to males showed the greatest difference in conformation from normal single-born females. Males twin to freemartins showed a slightly smaller difference. Freemartins were intermediate but closer to males. Fertile twin females and single-born females differed very little. These relations held at both 2 years of age and a live-weight of 650 lb. (1½ to 1½ years).

6. The quadruplet freemartins were anomalous in having the linear dimensions of immature normal instead of freemartin females of the same weight as if their early maturing body characters had been permanently retarded during slow growth before and after birth.
Lamb survival in two hill flocks
Authors: Purser A. F. , Young G. B.
Published: September 2010

The effects of birth weight, maternal age and parity on survival of single lambs have been studied in a Blackface and a Welsh Mountain flock.

In both flocks the maximum survival rate was found to occur among lambs with birth weights just above the mean. Mortality increased as lambs' birth weight increased or decreased from the optimum, but was especially heavy at the lower extreme of the range of birth weights.

Mortality decreased with age of dam to 14·3% for lambs from 4- to 6-year-old Blackface ewes and to 9·4% for lambs of 3- to 4-year-old Welsh ewes. Ewes having their first lambs gave mortality rates twice as great as for the mature ewes in the same flocks. The lower chances of survival of first born lambs irrespective of dam's age accounts for the apparent trend of mortality with maternal age in the Blackface.

Changes in mortality rates associated with variation in lamb's birth weight and with the age structure of the ewe flock were estimated. Possible means of improvement of survival rate are discussed.
A note on the measurement of ‘eye’ muscle area in beef carcasses
Authors: Bodwell C. E. , Harrington G. , Pomeroy R. W.
Published: September 2010

1. The area of eye muscle cross-section of beef carcasses may be accurately measured by tracing the boundary and measuring the tracing with a planimeter. Taking a single area measurement from each of duplicate tracings increases the accuracy by some 30%. If a planimeter is not available, the area may be estimated by superimposing a grid on the tracing and counting squares; although this method is some 25% less accurate than the planimeter method it is sufficiently repeatable for experimental use.

2. Area estimated by combinations of linear measurements is highly repeatable, but predicts true area with insufficient accuracy for experimental use. The standard error of prediction is about 7% of the mean area. Regression equations relating planimeter area and combinations of measurements for various cuts and animals are given.
The relationship of hogg weight to the subsequent performance of Scottish Blackface ewes
Authors: Purser A. F. , Roberts R. C.
Published: September 2010

The relationship of six-month weight of sheep to their subsequent performance has been studied in a Scottish Blackface flock. The various aspects of performance considered were—live-weight of the ewe at tuppings, mortality and culling rates, fleece weight, lambing and weaning percentages and weight of lamb weaned. The regressions of these characteristics on sixmonth weight all declined with increasing age of the sheep and in any case only tupping weight, fleece weight and weight of lamb weaned had an association which was statistically significant. The results for each year of life of the sheep (up to drafting age at 6½ years) were subsequently combined to show how the total production of a flock of 1,000 ewes was related to the weight of the hoggs.
A report on feeding additional protein to fattening steers implanted with hexoestrol
Authors: Dodsworth T. L.
Published: September 2010

Twenty-four Hereford × Angus × Shorthorn steers, which were 18 months old, were divided at random into four groups of six. There were four treatments, two involving the feeding of supplementary protein and two involving implantation of the steers with hexoestrol, thus:

(1) basic ration, no hexoestrol;

(2) supplementary protein, no hexoestrol;

(3) basic ration, hexoestrol implant;

(4) supplementary protein, hexoestrol implant.

While the hexoestrol implantation produced a significantly higher growth rate, the addition of protein, above the level in the basic ration, had no effect.
The effect of hexoestrol on growth, carcass quality, endocrines and reproductive organs of ram, wether and female lambs
Authors: Preston T. R. , Greenhalgh Isoline , MacLeod N. A.
Published: September 2010

1. Two experiments were made. In Experiment 1, 124 ram, wether and ewe lambs were allocated to four equal groups as they reached a live-weight of 30 lb. Group A received no hexoestrol; group B were implanted with a 15 mg. pellet of hexoestrol and lambs of group C were given a second pellet of 15 mg. 35 days after the first. Group D were implanted with three 5 mg. pellets simultaneously in three different sites. The lambs were creep-fed while running with their dams on pasture and were killed as they reached a live-weight of 95 lb.

In Experiment 2, 20 weaned ram lambs were allocated to a hexoestrol-implant group or a control group as they reached a live-weight of 40 lb. They were fed a pelleted ration indoors and were slaughtered at a live-weight of 110 1b.

2. Length of teats and weight of the pituitary were significantly increased for all lambs treated with hexoestrol as compared with their controls. Excessive mammary development and one case of rectal prolapse were observed i n treated ewe lambs, while 3 of the treated rams in Experiment 2 had scrotal oedema.

3. The rate of live-weight gain was greater for all hexoestrol-implanted lambs in Experiment 1 but less for the implanted lambs on Experiment 2 as compared with their respective controls. The differences just failed to attain significance at the 5% level.

4. Dressing percentage was significantly reduced by hexoestrol treatment i n Experiment 1. On the other hand treated ram lambs in Experiment 2 had significantly higher dressing percentages and appeared to be fatter than the controls.

5. Weights of testes and seminal vesicles in the ram and of the ovary in the ewe were decreased by hexoestrol treatment. Weights of seminal vesicles in the wether and of oviducts and uterus in the ewe were increased.
Factors influencing average milk yield of herds at two levels of production
Authors: Wiener Gerald
Published: September 2010

An experiment was started in 1950 designed to find out what proportion of the difference in milk yield between herds is genetic in origin. Sixty-five pairs of twins were split at birth equally between farms having high-yielding herds and farms having low-yielding herds. A previous paper on this experiment reported on the growth of the twins, the present paper on milk yield and on management practices in the herds.

Twenty-four pairs of twins survived to complete one lactation and these provide an estimate of 24%±18% for the genetic part of the difference between the herds.

Aspects of rearing of the twins and of management of the herds were examined. Twins in the high-yielding herds were served and calved earlier than those in the low-yielding group but they had a longer interval between service and calving. Differences between average heifer yields and average cow yields were from one-and-a-half to two times greater in the high- than in the low-yielding herd group. There were no obvious quantitative differences in feeding practice between the two groups although differences in body size suggest that twins in the high group were done better. For the age at first service there was a positive rank correlation of 0·30 between body size differences and subsequent differences in first lactation milk yield. There was no single factor of management or environment which appeared to be the cause of the yield difference between the herds.
The effect of partial replacement of groundnut meal by white-fish meal in the diet of early-weaned calves
Authors: Preston T. R. , Ndumbe R. D. , Whitelaw F. G. , Charleson Euphemia B.
Published: September 2010

Comparisons have been made of a calf early-weaning concentrate mixture in which 50% of the total nitrogen was derived from groundnut meal and a similar mixture having 33% of the nitrogen from groundnut and 19% from white-fish meal.

In a feeding trial with 9 pairs of Aberdeen-Angus crossbred calves which were weaned at 3 weeks and then fed ad libitum, those given the ‘groundnut plus fish meal’ ration ate 4% less concentrate and gained 6 lb. more in weight over an 81-day period than their pair mates fed the ‘groundnut’ ration. Neither effect was significant.

There were no differences between the two rations in their digestibility or their ability to promote nitrogen retention when food intake was equalised.
Preliminary studies of eye judgements of the gammons of bacon pigs in relation to dissection data
Authors: Gatherum D. P. , Harrington G. , Pomeroy R. W.
Published: September 2010

1. Attributes desired in the gammons of bacon pigs are discussed, together with the methods whereby they are measured.

2. An experiment is described in which 16 judges made visual assessments of the qualities of the gammons of 10 carcasses of bacon weight from photographs, both of the fresh carcasses and of the cured bacon sides.

3. The judges did not show a high level of agreement in their rankings of the gammons. Although the overall rankings by the panel of the gammons on the fresh carcasses and on the bacon sides were similar, neither ranking was related to the composition or yield of the gammons.

4. The judges showed better agreement in their rankings of photographs of the cut surfaces of these 10 gammons and the cross-sections of the cooked gammons produced from them; in this case their preferences were related to the lean content of the gammons.

5. A second trial in which 25 judges scored 12 actual bacon sides for the quality of their gammons showed an even lower level of agreement between the judges' rankings, and again there was little agreement between the overall rankings of the panel and the results of dissections.
Level of feeding during early life and the subsequent reproductive performance of sows
Authors: Lodge G. A. , McPherson R. M.
Published: September 2010

1. Nine groups of 4 litter-mate Wessex Saddleback gilts were divided on a within-litter basis between 4 treatments so that they were reared from 8 weeks of age to 200 1b. live-weight according to different levels of total feed intake; (a) a high level rising to 8·0 1b. meal per day at 200 1b. live-weight, (b) a medium level approximately 80% of the high, (c) a low level approximately 60% of the high and (d) changing from the low to the medium level between 14 and 16 weeks of age. From 200 1b. live-weight to mating at first heat after reaching 300 1b. all were fed to the medium scale (6·5 1b. meal per day), and all were treated alike during each of 3 pregnancies and lactations.

2. Mean rate of growth from weaning to 100 1b. and from 100 to 200 1b. differed significantly between treatments (P<0·001), and mean efficiency of feed conversion of the low-plane group was significantly poorer than that of the high-plane group (P<0·05) from weaning to 100 1b. live-weight.

3. All gilts, regardless of treatment, reached puberty at approximately the same age (25 weeks), with the result that mean weight at puberty differed markedly between treatments (P<0·001); 116, 154, 189 and 147 1b. for treatments (a) to (d) respectively.

4. Gilts reared on medium and high planes of feeding exhibited oestrus less strongly than those reared on the low-plane, with the result that mean weight at successful mating was significantly greater in these two groups (P<0·05).

5. Four gilts in the low-plane group and one in the high-plane group failed to conceive after repeated matings, but numbers were insufficient to indicate the significance of this.

6. From the original 36 gilts, 27 first litters, 26 second litters and 25 third litters were produced and reared to 8 weeks of age. There was no significant difference between treatment groups in litter size at birth, mean weight of piglets at 3 or 8 weeks of age or total litter weight at weaning.

7. Trouble from temporary collapse of the legs was experienced in all but one gilt of the high-plane group between 6½ and 7½ months of age.
Heritabilities and genetic correlations of egg production and other characters in a White Wyandotte flock
Authors: Hale R. W.
Published: September 2010

Five years' records of unculled White Wyandotte flocks at Hillsborough, Northern Ireland, were analysed to give estimates of heritabilities and of genetic and environmental correlations by two methods. Pooling data for four years and eliminating hatch effects gave heritabilities of 0·28 for eggs laid by survivors to 500 days; 0·61 for weight of pullets at penning; 0·51 for weight of pullets at 8 weeks; 0·18 for days to first egg; and 0·71 for spring egg weight. These are in general agreement with most other published figures, as are most of the genetic correlations. A suggestion of sex-linkage in the genetic correlations between weight at 8 weeks and days to maturity was not supported by other figures from the data. The method of eliminating hatch effects, unexpectedly, gave higher heritability figures where heritability was already moderate or high. It gave numerically greater figures in most genetic correlations, but did not lead to an expected reduction in the environmental correlations. The data were probably inadequate for a rigorous test of the method.
Parentage tests in cattle using erythrocyte antigens and serum transferrins
Authors: Rendel Jan , Gahne Bo
Published: September 2010

Blood grouping was used to investigate 1000 parentage cases in Swedish cattle. The blood samples were tested for 39 antigenic factors belonging to 9 different systems. One of the two possible bulls could be excluded as the sire in about 80% of the complete parentage cases in the Swedish Friesians (SLB) as well as the Swedish Red and White breed (SRB). The additional use of the transferrin systems in 79 of these cases resulted in a considerably increased efficiency. The probability of making exclusions with the aid of the various blood grouping systems was estimated from gene frequency data and showed good agreement with the results actually obtained. In the SRB the combined use of tests for cellular antigens and transferrins is expected to give solutions in about 84% of the complete paternity cases with two possible sires.

The value of using genotypic classifications in the complex blood group systems in parentage tests is discussed. Finally, attention is given to the difficulty encountered in parentage cases involving twin-born animals with erythrocyte admixture.
The nutritive value of grass silage self-fed to fattening cattle
Authors: Kerr J. A. M. , Brown W. O. , Morrison J.
Published: September 2010

1. High and low dry-matter silages were fed to fattening bullocks on the self-feed system giving daily live-weight increases per head per day of 2·6 lb. and 1·7lb. respectively, over a feeding period of 10 weeks.

2. Chemical data on the composition of a low dry-matter silage and high dry-matter silage are presented.

3. Digestibility studies using sheep were carried out to obtain the starch equivalent values of the two types of silage. The starch equivalent of the high dry-matter silage was 12·4 while that of the low dry-matter silage was 9·9. This difference in starch equivalent explains the extra 0·9 lb. per head per day live-weight increase made by the bullocks on the high dry-matter silage.

4. Mineral balances were carried out. The results show that the low dry-matter silage would supply an inadequate amount of calcium for satisfactory production.
The effect of suckling, management and season on sheep milk production as estimated by lamb growth
Authors: Doney J. M. , Munro Joan
Published: September 2010

1. The mean daily live-weight gains of lambs from the 1956–59 flock records were used to estimate the milk yield of ewes during the first six weeks of lactation.

2. The yield was affected by the number of lambs suckled but not by the number born. Ewes rearing twins on the hill gave a higher yield than those rearing singles (145%–155%). Good grazing raised the yield to twice that of ewes rearing singles on the hill.

3. In 3 out of the 4 years the utilised yield was remarkably constant in the case of ewes rearing single lambs, but ewes rearing twins on the hill were more variable. Ewes rearing twins on low ground did not show any significant seasonal differences.

4. From an experiment on 36 ewes it was confirmed that twin-rearing ewes produce more milk than single-rearing ewes in all environments. There was no difference between ewes rearing one lamb whether born as a single or as a twin. Leaving two lambs on the ewe for a few days to establish a high level of milk yield did not benefit the remaining lamb after its twin was removed.
Long continued oestrogen administration to fowls
Authors: Greenwood Alan W.
Published: September 2010

Long continued administration of a substance (dienoestrol diacetate) having oestrogenic properties as a dietary additive to chickens from hatching over a period of 4½ years resulted in:—

(1) an early, transient, hindrance to sexual development in both males and females,

(2) a wide range of individual variation in response to the drug, shown i n the degree of feminisation of the plumage in males, and certain characteristics associated with egg laying in the females,

(3) shell defects and related early embryonic deaths which could be attributed to an interference by the drug with development and differentiation of the oviduct.

The birds were maintained throughout the experiment under two contrasting environments ‘natural’ and ‘constant’. In the former group two birds developed tumours (one a typical adenocarcinoma) while four of the ‘constant’ birds had adenocarcinomata on examination post-mortem. The incidence of the condition was much lower than that encountered in a previous experiment and suggested that the oestrogen employed was not of itself a carcinogenic agent.

The primary function of the ovary was apparently unaffected and egg production to normal expected levels in both environments was attained.

The disproportionally high number of hens dying with inspissated yolk i n the oviduct and/or free yolk in the abdomen emphasises the possible effect of oestrogen on oviduct development and activity.

The danger of increasing the ‘load’ of oestrogens to susceptible individuals destined for breeding stock (and not short term administration of oestrogens for growth and ‘finishing’ of birds for slaughter) is referred to, and also its wider application were natural and synthetic oestrogenic substances in the diet to exceed a non-effective level.
Response to selection for multiple births in the Australian Merino: a progress report
Authors: Turner Helen Newton , Hayman R. H. , Triffitt L. K. , Prunster R. W.
Published: September 2010

Results of two-way selection for multiple births are reported, in a flock of Australian Merinos.

Base ewes, selected for having multiple or single births at each of two lambings at 5 and 6 years of age have shown a good repeatability, the T group (multiple-bearers) having averaged 31 more lambs per 100 ewes mated than the O group (single-bearers) for 6 subsequent lambings.

Unselected daughters of the base ewes, now ranging in age from 2 to 6 years, have also shown a difference in lamb drop, those in the T group averaging 21 more per 100 ewes mated. The difference in lamb drop has increased with the age of the daughter ewes, reaching 31 lambs per 100 ewes mated at 6 years of age.

A small group of Merino ewes from a property where selection for multiple births is practised has produced 1·60 lambs per ewe mated at 2 and 3 years of age.

It is suggested that earlier low estimates of heritability for the incidence of multiple births have led to unwarranted pessimism, and that in some circumstances selection for multiple births may be successful.
The evaluation of economically optimal rations for bacon pigs formulated by curve fitting and linear programming techniques
Authors: Dent J. B. , English P. R.
Published: September 2010

Least cost rations for specific rates of growth in the growing and finishing periods were given to pigs slaughtered at 200 lb. live-weight. During the growing period pigs grew very close to the planned rates in spite of the fact that some food was rejected. Pigs given rations for a low growth rate in the growing period grew slightly faster than planned in the finishing period. In the finishing period pigs given rations for the high growth rate grew on average very near to this rate. The pigs given the ration for the low growth rate grew slightly faster than planned. Food conversion efficiency was for all pigs very near to, or slightly better than, that planned. The rations had no adverse effect on carcass quality.
Levels of serum protein and antibodies toBrucella abortusin Finnish Landrace lambs
Authors: Halliday R.
Published: September 2010

The mean concentrations of total serum protein, γ-globulin and antibody were almost identical in groups of Finnish Landrace lambs from litters in which one, two or three, respectively, survived till the 3rd day. Lambs from two litters each with four survivors had considerably lower mean concentrations. Merino × Cheviot and Scottish Blackface lambs examined previously had significantly lower serum protein concentrations than the Finnish lambs and higher antibody levels in single than in twin lambs.
A genetic analysis of 305-day yield in second lactation in Red Danish cattle and Black Pied Danish cattle
Authors: Christensen K. , Sørensen P. , Venge O.
Published: September 2010

The material for the present investigation included approximately 4000 cows in 50 progeny groups from the dual-purpose breeds Red Danish cattle and Black Pied Danish cattle. The main objective was to investigate production in 305 days of second lactation. The characteristics studied were milk yield, butterfat yield and fat content. Analyses of the influence of the four environmental factors, herd average, age at calving, calving interval and calving season, were carried out using least squares. It was shown that age at calving, calving interval and calving season had a curvilinear effect on the yield traits. Herd average yield had a strong linear effect on the yield traits. The reduction in the phenotypic variance due to regression of yield on environmental factors was about 35% for milk and butterfat, and about 18% for fat content.

Heritabilities for yield traits in second lactation as well as phenotypic and genetic correlations between the yield traits in first and second lactation were presented. The coefficients of repeatability for milk and butterfat yield diminished from 0·5 to 0·3 when the data were corrected for the environmental factors.
Digestibility by pigs of the major chemical components of diets high in plant cell-wall constituents
Authors: Farrell D. J.
Published: September 2010

Digestibility of the major chemical components in diets high in plant cell-wall constituents was determined with four pigs. Two were given a commercial pig meal and two were given, in addition, alkali-treated straw (25% of the diet). Dry-matter digestibility of the straw was 32%, and protein excretion in faeces was increased by the addition of straw to the basal diet. Calculations based on microbial protein synthesis per gram of organic matter fermented showed that the additional nitrogen in the faeces may have been almost entirely microbial in origin.

In a second experiment, ground lucerne was progressively introduced into the diet in substitution for commercial pig meal. There was no obvious associative effect on the digestibility of the chemical components examined. Apparent digestibility of dry matter of the all-lucerne diet was 53%.
Relation of concentration of growth hormone in blood plasma to growth rate and carcass characteristics in the pig
Authors: Chappel R. J. , Dunkin A. C.
Published: September 2010

1. Pig growth hormone (PGH) concentrations were measured in plasma samples from piglets of 3–4 to 7–8 weeks of age.

2. Plasma PGH concentrations decreased significantly with age. No difference was observed between the hormone concentrations of gilts and barrows.

3. Correlation coefficients were calculated between mean plasma growth hormone concentration over a 4-week period and several carcass characteristics and measures of growth rate. Plasma PGH over this period showed significant negative correlations with several measures of carcass backfat thickness at bacon weight. In barrows only, PGH concentrations showed a significant direct correlation with relative growth rate from 3 to 7 weeks.
Nutritional evaluation of wheat. 2. The sequence of limiting amino acids in wheats of different protein content as determined with growing rats
Authors: Ivan M. , Farrell D. J.
Published: September 2010

1. Weanling male rats were used in three experiments to evaluate the sequence of limiting amino acids for maximum growth with diets based on wheats containing 10, 13 or 17% crude protein (N×5·71).

2. Lysine was the first-limiting, threonine the second-limiting, and valine or methionine the third- or fourth-limiting amino acid for growth rate and feed-conversion ratio of rats offered the diet based on wheat containing 10% crude protein. A further four amino acids (isoleucine, histidine, tryptophan and tyrosine) were limiting for feed-conversion ratio only.

3. For the diet based on wheat containing 13% crude protein the sequence of limiting amino acids was lysine, threonine and methionine.

4. Only lysine was limiting in the diet based on wheat containing 17% crude protein.

5. Plasma-free amino-acid concentrations were found to be a valuable criterion for prediction of the first-limiting amino acid in diets.

6. Improvement of growth and feed-conversion ratio was observed with diets based on wheat containing 17 or 13% crude protein when the limiting amino acids were supplemented to provide the recommended allowance. Further improvement in feed-conversion ratio was obtained when lysine and threonine were provided in excess of the recommended allowances.

7. There was a lysine-threonine interaction affecting growth rate and feed-conversion ratio, and a lysine-me.thionine interaction affecting feed-conversion ratio.
Protein levels in diets for European pigs in the tropics. 2. The effect of lysine and methionine supplementation on the protein requirement of growing pigs
Authors: Fetuga B. L. , Babatunde G. M. , Oyenuga V. A.
Published: September 2010

One hundred and twenty-eight Landrace and Large White pigs were allocated on the basis of sex, litter origin and initial weight to one of 16 treatments made up of four basal 16, 18, 20 and 22% protein diets, each supplemented with either 0·00,0·05,0·10 or 0·15% synthetic L-lysine; methionine was added to meet the levels earlier found to be optimal. All diets had a common energy level of 3740 kcal/kg DE and pigs were fed from 8 to 50 kg live weight.

Growth rate and feed efficiency improved as the protein levels were increased from 16 up to 20%. Only the 16 and 18% protein diets showed significant responses to additional lysine. Best overall gains and efficiency of gain was achieved on the diet with 20% protein and total dietary lysine and methionine+cystine levels of 1·17 and 0·66% respectively. Carcass leanness increased and fatness decreased as protein and lysine levels were increased, being best at the highest level (1·41%) of lysine studied.

Nitrogen retention indicated slightly lower protein and lysine requirement, efficiency of utilization being best on the 18% protein diet with added 0·15% lysine, giving a total dietary lysine level of 1·1% at the equalized methionine and cystine level of 0·66%.

It is indicated that diets providing between 18 and 20% protein in the diet, provided proper amino acid balance is maintained, would be optimal for pigs between 8 and 50 kg live weight.
A note on dried grass as a component of concentrate mixtures for lactating dairy cows
Authors: McIlmoyle W. A. , Murdoch J. C. , Gordon F. J.
Published: September 2010

Twenty-four cows were used in a randomized block, continuous feeding trial to examine the effects of including 0, 25 or 50% of dried grass in a concentrate given to cows receiving grass silage ad libitum. The concentrates also contained barley, and soya bean meal to maintain the crude protein content at 16%, and were given at the rate of 0·4 kg/kg of milk. The treatments were imposed for a 6-week period after a preliminary feeding period of 4 weeks. At the beginning of the experiment the cows had, on average, calved 39 days previously. The mean intakes of silage dry matter were 7·60, 8·28 and 8·39 kg/day with the concentrates containing 0, 25 and 50% dried grass, respectively, and were significantly greater when dried grass was included in the concentrate. The mean milk yields of 200, 18·2 and 19·6 kg/day for the three treatments respectively were not significantly different. Body-weight change and milk composition were not significantly different between treatments.
Milk production from silage and concentrates containing varying proportions of dried grass and cereals
Authors: Gordon F. J.
Published: September 2010

Twenty-eight lactating cows were used in an experiment of changeover design with four periods to evaluate concentrates containing 0, 16, 32, 49, 65, 81 and 97% dried grass. The dry matter of the dried grass was 63% digestible. The concentrates also contained barley, together with groundnut meal to equalize their protein content at approximately 16-5% of dry matter. All animals had grass silage ad libitum and all concentrates were given at the rate of 0·4 kg/kg milk. Milk yield, milk composition and liveweight change were not affected by including dried grass in the concentrate. No significant effect of concentrate on silage intake was obtained. Ration digestibility and nitrogen utilization were measured with four animals per treatment. The digestibility of dry matter, organic matter and nitrogen was not reduced by increasing the proportion of dried grass in the concentrate. The efficiency of utilization of apparently digested nitrogen for total productive purposes (body retention and milk nitrogen) was also not affected by the proportion of dried grass.
Nutritional evaluation of wheat 4. Effects of supplementation with amino acids and protein of diets based on wheats containing 10% and 17% crude protein on the performance of growing pigs
Authors: Ivan M. , Farrell D. J. , Edey T. N.
Published: September 2010

1. The effects of supplementing diets containing 10% or 17% crude protein wheat, vitamins and minerals with the limiting amino acids were studied with growing Large White x Landrace pigs. Performance was measured in terms of growth rate, feed conversion, carcass measurements, plasma-free amino acid concentrations, digestibility of dry matter, nitrogen and gross energy, nitrogen retention and metabolizable energy.

2. With diets based on wheat containing 17% crude protein, a lysine supplement gave a slightly higher growth rate and a slightly lower feed conversion ratio than when fish meal and meat meal was the supplement.

3. With diets based on wheat containing 10% crude protein, performance was significantly poorer when the diet was supplemented with the four most limiting amino acids (lysine, threonine, valine, methionine) than with fish meal and meat meal. Meat meal and soya bean meal appeared to be a good source of the limiting amino acids, other than lysine, when added to a diet based on wheat containing 10% crude protein.

4. Eye-muscle area was lower and backfat thickness greater when diets based on wheat containing 10% crude protein were unsupplemented or supplemented with lysine than when they were supplemented with protein or with the four most limiting amino acids. However, no significant differences in backfat thickness were obtained between similar comparisons when the wheat contained 17% crude protein.
Studies in sow reproduction 4. The effect of level of feeding in lactation and during the interval from weaning to remating on the subsequent reproductive performance of the early-weaned sow
Authors: Varley M. A. , Cole D. J. A.
Published: September 2010

Seventy-five enzootic pneumonia-free female pigs (sows) were allocated at random to one of five treatment groups. Four of these groups were weaned following a 10-day lactation period and were fed either 2 or 4 kg per day in lactation and either 2 or 4 kg per day from weaning to remating, such that the patterns of feeding for the four groups in the two periods were: 4 kg, 4 kg (HH); 4 kg, 2 kg (HL); 2 kg, 4 kg (LH) and 2 kg, 2 kg (LL). A fifth treatment group (control) was weaned following a 42-day lactation period and was fed up to 6·3 kg/day, depending on litter size and 2·7 kg/day from weaning to remating. Level of feeding for the four early-weaned groups in both lactation and in the interval from weaning to remating significantly (P < 0·001) affected the weight changes of the sows during these periods. The interval from weaning to oestrus for the early-weaned sows (8·2 days) was significantly (P < 0·001) greater than for the control sows (4·5 days), but this interval was not affected by level of feeding either in lactation or in the remating period for the early-weaned sows. Litter size at the subsequent farrowing for the early-weaned sows (9·3 piglets) was significantly (P < 0·001) less than litter size for the control sows (12·0 piglets). Level of feeding in lactation or in the weaning to remating period had no effect on subsequent litter size of the early-weaned sows.
A note on sperm survival in relation to chloride content in bull semen
Authors: Sharma D. P. , Ludwick T. M.
Published: September 2010

Semen samples from 19 bulls were added to solutions of NaCl having chloride concentrations of 10, 15, 17, 18, 19 and 20 g/1, and were examined continuously for motility until motility had ceased or 5 hr had elapsed. At chloride concentrations of 10 and 15 g/1 some motility was always present after 5 hr. At 19 and 20 g/1 sperm motility stopped abruptly. At 17 g/1 mean survival time was 2·55 hr. In four bulls which had chloride concentrations in semen of over 2·80 mg/ml, sperm survival time was significantly lower than the average for the other semen samples which had chloride contents between 1 -40 and 2·25 mg/ml. A larger study would be needed, however, to establish whether survival of bull sperm is related to the chloride content of the semen at the time of ejaculation.
Reproduction in the gilt 3. The effect of exogenous oestrogen on the attainment of puberty and subsequent reproductive performance
Authors: Hughes P. E. , Cole D. J. A.
Published: September 2010

Ten Landrace × (Landrace × Large White) young female pigs were allocated to each of four treatments. The experiment was arranged as a 2 × 2 factorial design, the variables being oestradiol benzoate v. ethyl oleate and boar v. visual testing. The oestradiol benzoate (or ethyl oleate) was administered at 140 days of age, the treatment consisting of six injections, over a 3-day period, of 0·5 ml of either ethyl oleate or a solution of 0·4 mg/ml β-oestradiol-3-benzoate in ethyl oleate. Subsequently the gilts were either inspected visually each day or taken to a vasectomized boar for oestrus detection. All gilts were mated at the second oestrous period, and slaughtered on the 20th day of gestation. Those gilts receiving exogenous oestrogen attained puberty significantly earlier (P<0·01) than the control gilts. Of the 20 gilts treated with oestrogen, 12 (60%) attained puberty within 5 days of the start of treatment. No significant difference was found between boar testing and visual testing, although receptivity to mating appeared to be lower for visually tested gilts. There are no significant differences between treatments in ovulation rate, conception rate or embryo survival.
The effects of reducing the water intake of lactating dairy cows by 40% for 3 weeks
Authors: Little W. , Sansom B. F. , Manston R. , Allen W. M.
Published: September 2010

1. The voluntary water intakes of eight housed lactating cows were measured. Four of them were subsequently deprived of 40% of this water intake for three weeks. Feed consumption, milk yield and quality, water, Na and K balances, and serum and urine osmolalities were measured. The cows were weighed weekly and their pulse, respiration and rumination rates and rectal temperatures were measured daily.

2. In deprived cows there was a decrease in the mean intake of dry matter by 24% and in milk yield by 16%. These changes were apparent after 24 h, but subsequently there were no further changes. Faecal water was reduced significantly and the percentage faecal dry matter increased significantly. Urine osmolality increased but the reduction in urine volume was not statistically significant.

3. Concentrations of urea and Na in serum and serum osmolality were significantly higher in deprived cows throughout the experimental period and increased slightly but significantly each day from the time the deprived animals were last offered water to appetite.

4. The deprived cows lost weight during the 1st week of deprivation but showed no further change until rehydration, after which normal body weight was regained within 4 days. The deprived cows had consistently lower mean rates of respiration and rumination than the control cows throughout the period of deprivation but they showed no signs of distress.
The effect of systems of grassland management and winter feeding on the productivity of an 18-month grass-cereal beef system
Authors: Moran J. B. , Holmes W.
Published: September 2010

Experiments in two successive years with 24 cattle compared a six-paddock grazing system with a simpler two-field system. In each system the whole area was cut for conservation once during the season. The two systems were stocked each at 3·9 or 6·5 cattle/ha. In the following winters the cattle were offered grass silage (1974) or dried lucerne pellets (1975) ad libitum with two levels of barley.

Daily gains on pasture were depressed by the higher stocking rate but there was no difference between grazing systems. The yield of conserved grass was least on the high stocking rate two-field system. The estimated output of utilized metabolizable energy per hectare was highest on the high stocking rate paddock grazing system but the output from the low stocking rate two-field system was almost as high. It was concluded that the latter system was valuable in many practical situations. Cattle that had been grazed at low stocking rates finished earlier in winter. There was some evidence of winter compensation in cattle weight gain on diets with dried lucerne pellets but not on grass silage diets.
A note on the effect of continuous contact with ewes showing regular oestrus and of post-weaning growth rate on the sexual activity of Corriedale rams
Authors: Winfield C. G. , Makin A. W.
Published: September 2010

Thirty-six Corriedale rams were weaned at 3 months of age and subjected to four treatments until 2½ years of age. The treatments consisted of two levels of nutrition, with rams on the high level of nutrition being maintained approximately 15% heavier than those on the low level, and two levels of sexual experience. Sexually experienced rams were kept throughout with ewes that were infertile but showed regular oestrus and inexperienced rams were reared in monosexual groups isolated from females except during periodic mating tests. These 2-h tests were carried out at intervals of 3 to 4 months commencing when the rams were 6 months old. Up to 17 months of age there were no significant differences between treatment groups in the development of ability to serve ewes, except that low nutrition reduced the number of rams which had served ewes at 10 months of age. Between 17 and 28 months of age, rams kept with ewes tended to achieve more serves per test during the breeding season than rams kept without ewes.
The effect of concentrate-to-forage ratio on the milk-yield response to supplementary protein
Authors: Mayne C. S. , Gordon F. J.
Published: September 2010

Twenty-four British Friesian dairy cattle in their first lactation were used in a change-over design experiment with four periods, each of 4 weeks duration. The aim of the experiment was to examine the effects of varying both concentrate crude-protein concentration and the proportions of concentrates and grass silage in the diet on milk yield and composition. Twelve treatments were examined in a 3 × 4 factorial arrangement. Concentrates containing four levels of crude protein (CP), ranging from 120 to 206 g/kg fresh weight were offered in diets containing either 400, 500 or 600 g concentrates per kg dry-matter (DM) intake. The grass silage offered as the basal forage had a DM concentration of 214 g/kg and a digestible organic matter concentration of 682 g/kg DM.

Milk yields (kg/day) for cows offered diets containing 400, 500 and 600 g concentrates per kg DM were 17·2, 18·1 and 18·3 respectively; and 17·4, 17·6, 18·0 and 18·4 for cows offered diets with concentrates containing 120, 147, 176 and 206 g CP per kg fresh weight respectively (pooled s.e. 0·13). Increasing either the proportion of concentrates in the diet or the CP concentration of the concentrates did not significantly affect milk fat concentration, but did increase milk protein concentration.

There was a trend towards a greater milk-yield response to protein supplementation with low- rather than high-concentrate diets, although it appears that this trend may only be apparent in situations where total food intake is restricted.