bluuebunny/crossref_metadata_2025 huggingface dataset:
The effects of forage type and level of concentrate supplementation on food intake, diet digestibility and milk production of crossbred cows (Bos taurus×Bos indicus)
Authors: Khalili H. , Varvikko T. , Crosse S.
Published: September 2010

An experiment was carried out to evaluate the effects of forage type and level of concentrate supplementation on forage intake, diet digestibility and milk production. Twenty-four crossbred cows (Bos taurus×Bos indicus), in early lactation, were allocated to the following six dietary treatments: native grass hay (H) or oat-vetch hay (OV), offered ad libitum, and supplemented with either 0, 2·5 or 5·0 kg per cow per day of a wheat-middling-based concentrate. A four-period, partially balanced, change-over design was used and the treatments were arranged as a 2 × 3 factorial.

The daily dry-matter (DM) intake was 640 g (P < 0·001) higher with cows on (H) diets compared with those on OV diets. However, OV diets were more digestible (0·675 v. 0·566, P < 0·001) resulting in 800 g higher (P < 0·05) daily intake of digestible DM. The daily milk yield was 1·24 kg higher (P < 0·001) for cows on OV diets compared with H diets. Milk fat concentration was higher (P < 0·05), but milk protein concentration was lower (P < 0·001) with H diets. The rates of rumen degradation of DM and nitrogen of OV were higher than of H for all incubation periods; similarly the values of the rate constant of DM and nitrogen were greater for OV than for H.

The daily DM intake increased by 3·72 kg/day (P < 0·001), when the amount of concentrate increased from 0 to 5·0 kg/day, indicating a minor substitution of basal forage by concentrate. The apparent DM digestibilities of the diets were higher when the diets were supplemented with concentrates. The milk yield increased linearly (P < 0·001), when the level of concentrate supplement increased from 0 to 5 kg, resulting in 0·52 kg more milk per day per kg additional concentrate given.
The apparent digestibility of Atriplex barclayana and its effect on nitrogen balance in sheep
Authors: Benjamin R. W. , Oren E. , Katz E. , Becker K.
Published: September 2010

An in vivo digestibility trial was conducted by feeding sheep the leaves, fruits and twigs of Atriplex barclayana in a proportion roughly equivalent to that eaten by sheep grazing freely in Atriplex plantations. Four treatments were imposed on each of four sheep in a 4 × 4 Latin-square experimental design: Atriplex offered alone or with 100, 200 or 300 g/day tapioca meal.

The mean apparent digestibility of the Atriplex dry matter (DM) and organic matter (OM) consumed were 0·59 and 0·56, respectively. Addition of tapioca to the Atriplex in the diet did not improve these digestibility coefficients. The low OM content of 760 g/kg together with its digestibility of 0·56 resulted in the Atriplex having a low metabolizable energy concentration of 6·28 MJ per kg DM. The in vitro apparent DM digestibility of Atriplex was approximately 0·09 higher than the in vivo apparent digestibility.

The mean nitrogen concentration of the Atriplex DM was 16·6 g/kg, and its apparent digestibility 0·73, which was not improved by the addition of tapioca to the diet. Nitrogen retention of the sheep eating only Atriplex was proportionately 0·17 of the nitrogen intake. The addition of 300 g tapioca improved nitrogen retention to 0·27 but was not significantly different from the other treatments.

Water intake and urine excreted were as high as 14 and 12 I/day respectively, for an Atriplex DM intake of about 1300 g/day. During the experiment the sheep only maintained live weight, despite daily intakes of up to 1200 g Atriplex DM and up to 300 g tapioca.
The effect of including Colombian rice polishings in the diet on rumen fermentation in vitro
Authors: Garcia D. Cardenas , Newbold C. J. , Galbraith H. , Topps J. H.
Published: September 2010

The effect of including full-fat Colombian rice polishings, at 250 or 500 g/kg dry matter (DM) or defatted Colombian rice polishings (at 500 g/kg DM) on the fermentation of a basal diet of dried grass and medium-quality hay, in the rumen simulation technique (Rusitec), was investigated. With diets which contained 0, 0·25, 0·50 full-fat or 0·50 defatted, proportions of rice polishing, values for pH were depressed (7·22, 7·19, 7·11, 7·06 (s.e.d. 0·05)) and total volatile fatty acid concentrations were increased (52·8, 52·5, 75·5, 754 (s.e.d. 2·1) mmol/l) at the high levels of inclusion of rice polishings. Concentrations of ammonia (130, 140, 228, 209 (s.e, d. 64) mg/l) and total bacterial numbers (2·32, 2·70, 3·55, 442 (s.e.d. 0·82) × 108 per ml) were elevated by rice polishings inclusion. Numbers of cellulolytic bacteria (2·52, 1·74, 1·84, 2·10 (s.e.d. 0·60) × 106 per ml) and protozoa (19·8, 16·2, 15·8, 22·2 (s.e.d. 1·51) × 103 per ml were depressed (the latter significantly P < 0·01) by the inclusion offull-fat, but not by defatted, rice polishings.
Reproductive performance of purebred and crossbred beef cattle in the tropics of Mexico
Authors: Duarte-Ortuño A. , Thorpe W. , Tewolde A.
Published: September 2010

Records of beef cows on a ranch in south-east Mexico gave 1377 ages at first calving (AFC) and 3932 calving intervals (CI) for the comparison by least-squares analysis of the genetic groups: commercial zebu (CZ), Brahman, other zebu breeds and their zebu crosses (zebu), F, crosses born to zebu dams by Bos taunts or Santa Gertrudis sires, and 3/4 bred zebu and 3/4 Bos taurus. Subsamples of 1090 ages at first calving and 3154 intervals were analysed considering the breed groups: CZ, Brahman, Guzerat, Gyr and Indo-brazil, and the F1 crosses resulting from matings between these zebu breeds, Santa Gertrudis and Charolais as sire breeds and the CZ as the dam breed. Three populations were analysed for each model, the original ranch population and two populations reduced by retrospective culling. The original population had a mean AFC and CI of 1226 and 489 days respectively reduced by the first and second culling by 24 and 37 days and by 62 and 83 days respectively. Repeatability of CI increased from 0·06 to 0·11 and 0·14 respectively.

Genetic group significantly influenced AFC. In the original population F1 heifers had a significantly younger AFC than Brahman and zebu heifers but not significantly younger than the other genetic groups. Heifers with 0·25, 0·75 and 1·00 zebu genes did not have significantly different AFCs. After the retrospective culling only the 3/4 bred zebus were significantly superior to the worst group, the zebus. The effect of breed group was only significant in the original population but generally the same rank order was maintained after the retrospective culling. F, Charolais × CZ heifers had the youngest AFC, a superiority of 67 days over CZ and 92 days over Brahman. Purebred zebus and their F, crosses with CZ did not calve earlier than CZ dams. Genetic group had a highly significant effect on CI. Females with 0·50 and 0·75 Bos taurus genes had shorter CIs than females with 0·75 and 1·00 zebu genes. The superiority was maintained after culling. Breed group had a significant effect in each population. F1 Charolais × CZ dams had the shortest CI. CZ had equivalent or shorter CI than all zebu breeds and their F1 crosses with CZ. Heterosis effects for AFC and CI in the zebu crosses were generally advantageous but small, while the heritabilities for the zebu population were negative for AFC and 0·05, 0·22 and 0·06 for CI in the original and two culled populations respectively.
Rapeseed meal in the diet of pubertal heifers during early pregnancy
Authors: Vincent Isobel C. , Hill R. , Williams H. Ll.
Published: September 2010

The response of Hereford × Friesian heifers to large intakes of two types of high glucosinolate rapeseed meal were studied during two 5-month periods in consecutive years. In year 1, six heifers were given a compound concentrate food containing 250 g/kg extracted rapeseed meal and six control animals were given concentrate containing 210 g/kg soya-bean meal. In year 2, a further six heifers were given concentrate containing 320 g/kg expeller rapeseed meal and six control animals were given the same soya-bean meal compound concentrate. The crude protein (CP): metabolizable energy (ME) ratio of all diets was 14·3 g CP per MJ ME. Barley straw was the only roughage offered.

There were no differences between groups in ovarian activity assessed from plasma progesterone concentrations, nor in behavioural activity around oestrus. The heifers were slaughtered 6 weeks after artificial insemination. Pregnancy rate was proportionally 0·58 (7/12) in the rape-fed and 0·67 (8/12) in the control heifers (P > 0·05). Foetuses from heifers given rapeseed meal were slightly smaller than those from control heifers; the difference was significant in year 2 (P < 0·05).

Thyroid glands of heifers given rapeseed meal showed histological evidence of goitrogenicity but weights of the glands did not reflect this. Plasma thyroxine values were depressed in heifers given rapeseed meal (year 1, P < 0·001; year 2, P < 0·05). Plasma thiocyanate was elevated in rapeseed meal heifers in both years (P < 0·001) compared with values for control animals.
Growth performance and body composition of wether lambs implanted at two different initial live weights with trenbolone acetate combined with oestradiol-17β
Authors: Sulieman A. H. , Galbraith H. , Topps J. H.
Published: September 2010

Thirty-two Border Leicester ♂ × Scottish Blackface ♀ wether lambs, aged about 5 months, were divided into two groups on the basis of live weight, such that group G1 contained the 16 lightest lambs and group G2 the 16 heaviest. Lambs in group G1 were subdivided equally at random either to be sham-implanted controls (Group C1) or to be implanted with 35 mg trenbolone acetate (TBA) + 5 mg oestradiol-17β (OE) (group T1) at 24 kg initial live weight. The lambs in group G2 were also subdivided into two groups (groups C2 and T2), and similarly treated approximately 1 month later at 37 kg initial live weight. The lambs were offered ad libitum a diet containing an estimated 12·5 MJ metabolizable energy (ME) per kg dry matter (DM) and 140 g/kg DM crude protein. Comparisons were made for the main effects of hormonal treatment and initial live weight. Both hormonal treatment and initial live weight gave increases for DM intake, gut fill, empty body weight, carcass weight and, in the half carcass side weight, weights of dissected lean tissue, bone and intermuscular fat and chemically determined DM, crude protein and lipid. Weights of mm. semitendinosus, longissimus dorsi, supraspinatus and gastrocnemius were also increased due to hormonal treatment and in group G2 lambs compared with those in group G1. When expressed as a proportion of carcass side weight, hormonal treatment effects were not significant for individual muscles and dissected carcass lean, bone and fat and chemically determined lipid and ash. Variable effects on other body components were recorded for both treatments in the absence of any significant interactions. The responses to hormonal treatment were essentially similar in groups G1 and G2. The question is raised as to the contribution of the greater food intake in implanted lambs to the maintenance of fatness in these animals.
Effects of body condition at calving and feeding level after calving on LH profiles and the duration of the post-partum anoestrous period in beef cows
Authors: Wright I. A. , Rhind S. M. , Whyte T. K. , Smith A. J.
Published: September 2010

An experiment was conducted to examine the effects of body condition at calving and feeding level post partum on the duration of the post-partum anoestrous period in beef cows. Forty-seven cows were used in each of 2 years. Cows were fed differentially before calving to achieve two levels of body condition at calving in November and December and were then fed at one of two levels of feeding post partum in a 2 × 2 factorial experiment. At calving, mean body condition scores were 2·85 (F) and 2·23 (T) (P < 0·001) while live weights were 521 kg and 457 kg (P < 0·001) for F and T cows respectively. After calving metabolizable energy intakes were 111 and 118 MJ/day (H) or 56 and 64 MJ/day (L) in years 1 and 2 respectively. The H cows maintained live weight during the first 61 days of lactation while the L cows lost live weight (0·0 v. -1·1 kg/day, P < 0·001). The number of cows still acyclic on 1 May each year was higher (P < 0·01) on the TL treatment (10/24) compared with the other treatment combinations (FH: 2/22; FL: 5/22; TH: 2/24). The effect of level of feeding on the duration of the anoestrous period was significant in the T cows (89 v. 116 days for TH and TL cows respectively; P < 0·01) but not in the F cows (80 v.89 days for the FH and FL cows respectively; P > 0·05). At 3 weeks post partum LH pulse frequency was higher in F than in T cows and tended to be higher in H than in L cows. At 6 and 9 weeks post partum LH pulse frequency was higher in H than L cows. LH pulse amplitude was higher in F than T cows at 3 weeks post partum and tended to be higher at 6 weeks post partum. It is concluded that both body condition at calving and feeding level after calving influence the duration of the post-partum anoestrous period with the effect of feeding level being particularly pronounced in thin cows.
The performance of ewes offered concentrates containing olive by-products in late pregnancy and lactation
Authors: Aguilera J. F. , García M. A. , Molina E.
Published: September 2010

Ewes of the Segureña breed were allocated to groups and were group-fed different diets composed of concentrates and roughage (lucerne hay in experiment 1 and barley straw in experiment 2), in late pregnancy and lactation. The concentrates were formulated with sunflower cake and barley, either alone (control group) or partly replaced with olive cake (OLC) and olive molasses (OLM) in a 5:1 ratio. The OLC was either untreated or was treated with NaOH or ammonia. Concentrates were given to provide proportionately 0·4 and 0·7 of calculated metabolizable energy (ME) requirements in experiments 1 and 2 respectively. In experiment 2 a further group grazed pasture and was given barley at a reduced rate.

In experiment 1, the mean ME intake during late pregnancy (5+1 weeks pre-lambing) for all treatment groups was about 796 kj/kg M0·75 per day and largely exceeded their average energy requirements, whereas it was close to requirements (601 kj/kg M0·75 per day) in experiment 2. During lactation, ME intake was adjusted to the theoretical needs for ewes suckling a single lamb (835 to 870 kj/kg M0·75 per day) and was slightly deficient (990 to 1020 kj/kg M0·75 per day) for ewes with twins, irrespective of both treatment (except the group at pasture) and experiment.

Minor differences in animal performance, attributed to the type of concentrate offered, were found. In pregnancy, alkali treatment of OLC significantly improved live-weight gains (P < 0·01). Live-weight gains of ewes in experiment 2 were lower than those in experiment 1 in accordance with their lower ME intake, the lowest gains being found in the group at pasture (P < 0·05). Weight losses in lactating ewes in experiment 1 were 17 to 100 and 9 to 165 g per ewe per day for ewes suckling single and twin lambs respectively. In experiment 2 ewes with twins gained weight, while those with single lambs showed little weight change, although differences between experiments were too small to attain statistical significance. No differences in barley straw intake by pregnant ewes were found between treatment groups. However, the intake of barley straw by lactating ewes in the groups offered concentrates containing OLC and OLM was significantly higher than that by controls (P < 0·05).

Birth weight of lambs tended to be higher in experiment 2 when ewes consumed less ME during pregnancy, although variations were not statistically significant. The most important cause of growth rate variation was the number of lambs born to a ewe (P < 0·001). The growth rate of lambs in the outdoor group was significantly lower than that of lambs in the indoor groups (P < 0·05).
Optimization of selection for food intake capacity in pigs
Authors: Kanis E. , de Vries A. G.
Published: September 2010

Optimum selection directions for averagead libitumfood intake capacity (FIC) in growing pigs were derived by means of a biological growth model based on the linear/plateau relationship between protein deposition and food intake. Breeding goal traits were minimum fat to protein deposition ratio (R), maximum protein deposition rate (Pdmax) and FIC. The selection index included FIC, daily weight gain (DG), backfat thickness and proportion of lean meat in the carcass of a full-sib.

Selection indexes were developed for three alternative levels of FIC. If FIC was too low to realize Pdmax, the economic weight of FIC was positive and optimal selection emphasis should be mainly on FIC, resulting in a rapid increase of DG. If FIC was higher than necessary to realize Pdmax, the economic weight of FIC was negative, and short-term selection resulted in increase of carcass leanness but decrease of FIC and DG. If FIC was just sufficient to realize Pdmax, selection should be for R and Pdmax. In this third alternative, the gain in FIC should follow the gain in R and Pdmaxin an optimal way and selection should best be carried out with a desired gains index, which results in improvement of DG and carcass leanness.

It was shown that, in cases where FIC was higher than necessary to realize Pdmax, selection with a desired gainsindex should be preferred because this was more profitable in the long term. From the model calculations, it followed that future profit from selection of growing pigs for production traits is likely to decline because of the necessity to increase FIC.
Comparison by direct animal calorimetry of the net energy values of an early and a late season growth of herbage
Authors: Corbett J. L. , Langlands J. P. , McDonald I. , Pullar J. D.
Published: September 2010

1. Herbage was harvested from a single pasture in early June and late August of the same year and was preserved by freeze-drying. The June herbage contained more water-soluble carbohydrate than that cut in August but in other respects, including chemical and botanical composition and the apparent digestibility of organic matter and nitrogen, differences between the herbages were small.

2. The June herbage was given to a mature ewe during eight periods each of about 4 weeks' duration, and the August herbage was given during nine periods. The level of feeding varied between periods from about 0·35 to 1·5 times the maintenance level; in addition the fasting metabolism of the sheep was determined on three occasions. Gross energy intakes and the losses of energy in faeces, urine, methane and as heat were measured in each period.

3. The metabolisable energy of the June herbage was utilised more efficiently than that of the August herbage for fattening, and probably for maintenance also. It is suggested that this result stemmed from the difference in soluble carbohydrate content which was lower in the August material. The cellulose of that herbage was digested to a significantly greater extent, a larger proportion of the gross energy was lost as methane, and the ruminai volatile fatty acids, included a significantly lower proportion of propionic acid.
The voluntary intake of food by sheep and cattle in relation to their energy requirements for maintenance
Authors: Blaxter K. L. , Wainman F. W. , Davidson J. L.
Published: September 2010

The voluntary intake and apparent digestibility of three roughages, alone and in mixtures, by six steers and six sheep were studied in 56 individual experiments. The fasting metabolism of each animal was also determined so that maintenance energy needs could be assessed.

No significant differences between the voluntary intakes of roughages by cattle and sheep were found when, for all experiments with each species, voluntary intake (g./kg.W0·73)was regressed on apparent digestibility. Cattle, however, digestedthe same roughagebetter than did sheep and consumed more of it. Despite their higher maintenance needs/kg. W0·73, when given the same roughage cattle thus attained the same relative feeding level (energy apparently digested/energy required for maintenance) as did sheep, there being an indication that sheep were more efficient users of low quality roughages than cattle. Sheep with high maintenance requirements tended to eat more than those with low ones, but no such relationship could be established with cattle.

When fixed amounts of higher quality roughage were given to both steers and sheep which were also given a lower quality roughagead libitum, the total intake of food was in proportion to the voluntary intakes attained when the roughages were given separately.
The use of sample joints in predicting the composition of the pig carcass
Authors: Adam J. L. , Smith W. C.
Published: September 2010

Carcass data from 123 pigs slaughtered at either 120 lb., 200 lb. or 260 lb. live-weight have been analysed to study the relative value of four sample joints in predicting tissue composition in the carcass.

Percentage fat, muscle or bone in all joints was highly correlated (P<0·01) with the corresponding percentage of that tissue in the carcass. The highest correlations and correspondingly lowest residual standard errors were found for the loin, rib and composite loin and ham joints.

Significance tests of the a and b constants in regression equations relating percentage fat, bone and muscle in the joint to that in the carcass showed that only with the rib joint was it legitimate to combine the data from each slaughter weight into ‘overall’ equations.

As pooling the data for the combined loin and ham joint had little effect on the magnitude of the residual standard errors, overall equations relating tissue composition of that joint to the whole are also given. The accuracy of prediction, however, was lower than that obtained with the rib joint.

Application of the pooled regression equations relating carcass and rib joint composition to independent data, obtained by identical techniques, gave promising results.
Genetic parameters of growth between birth and sixteen weeks in Down Cross Sheep
Authors: Bowman J. C. , Broadbent J. S.
Published: September 2010

This paper reports a paternal half sib analysis of data collected over 3 years to estimate additive genetic variance of growth between birth and 16 weeks in crossbred progeny derived from Down rams. The data were divided into two groups and pooled estimates of parameters obtained by two methods. The paternal half sib intra-class correlations varied between 0·017 and 0·057 depending on pooling group and method. It is suggested that such low correlations arise because (a) most of the lambs in the study were still sucking at slaughter, close to 16 weeks of age, and the trait measured is thus largely influenced by maternal milking ability (b) the selection practised in the Down breeds may have been effective and reduced genetic variation and (c) there is considerable inbreeding in the Down breeds.

In further analysis of data from four farms involving rams mated to more than one breed of ewe there was limited evidence of specific combining ability of growth between birth and 16 weeks of age for Welsh ewes compared to ewes of other breeds.
A note on sex differences in muscle properties of pigs with special emphasis on colour
Authors: Kolaczyk S. , Kotik T.
Published: September 2010

Investigations of measurable properties of pig muscle have been carried out in many countries (Scheper, 1962). This note describes the effect of sex on six characteristics of longissimus dorsi muscles, i.e. content of moisture, fat, total nitrogen, expressible moisture, myoglobin, total pigment and colour (light reflectance).
A note on the maintenance requirement of adult conditions
Authors: Butterworth Martyn H.
Published: September 2010

The maintenance requirement for digestible organic matter of adult sheep has been derived by Wood and Capstick (1926) and more recently by Lang-lands, Corbett, McDonald and Pullar (1963) by means of regression analysis of data for feed intake, live-weight and live-weight gain.

As data from digestibility trials carried out both in Trinidad and Venezuela were available, similar equations were derived for adult male sheep under tropical conditions. Groups of six adult male sheep were housed individually and total collections of faeces and urine were made for periods of 10 days after preliminary periods of 7 or 10 days. The quantity of forage offered was generally that which the individual sheep would eat without leaving a large residue. The results obtained in these trials and a more detailed description of the methods used have been described elsewhere (Butterworth, 1963; 1965). In all, 178 sets of data were used. Each set for an individual animal consisted of daily intake of digestible organic matter (D), the mean (W) of initial and final body weights, and daily change in weight (G) all in lb. Values of D and G were means obtained from the results for the 10-dayperiod. The value of G was subject to high error in determination as periods were short and measurement of weight change in ruminant animals over short periods is most unreliable (see for example, Lush, Christensen, Wilson and Black, 1928; Whiteman, Chambers, Loggins, Pope and Stephens, 1954). Mean values and ranges of the values were as follows: D=0·96 lb. (0·46–1·87 lb.), W=84·2 lb. (56·0–149·0 lb.) and G=0·02 lb. (-0·5-+0·5 lb.). The digestibility coefficients for the dry matter of the various forages used ranged from 47·3 to 68·0%.
A note on heritability of live-weight-for-age in Israel-Friesian dairy bull calves and its genetic correlation with milk production
Authors: Soller M. , Shilo A. , Bar-Anan R.
Published: September 2010

The design and evaluation of breeding programmes for live-weight-for-age (LFA) in dairy cattle requires estimates of the heritability and the additive genetic and residual components of variance for this trait, and also of its genetic correlation with milk production. A number of estimates of these parameters are available (summarised recently by Langelet, 1963; Mason, 1964; and Nichols and White, 1964). They are, however, generally based on rather limited data, on data from cows rather than bull-calves, or on data from dual purpose cattle. In this note estimates of the variance components and heritability for LFA in dairy cattle bull calves, and of the genetic correlation between bull calf LFA and milk production will be presented.
A comparison of the live-weight changes, nitrogen retention and carcass composition of pregnant and non-pregnant gilts
Authors: Elsley F. W. H. , Anderson D. M. , McDonald I. , MacPherson R. M. , Smart R.
Published: September 2010

1. Twelve gilts, six pregnant and six non-pregnant, were each given a daily ration of 2.2 kg. for a 110-day period.

2. Live-weight gain during this period was 53 kg. for the pregnant animals compared with 23 kg. for the non-pregnant animals.

3. Apparent digestibility of nitrogen and dry matter and the energy of digested feed did not differ significantly between the pregnant and non-pregnant animals.

4. Daily nitrogen retention was on average 9·2% higher for the pregnant animals, the difference between the two groups becoming progressively greater during the trial.

5. Highly significant differences were found in pre-slaughter live-weight, weight of reproductive tract and weight of mammary region. The difference in the weight of free draining blood was also significant. No difference was found in the weight of alimentary tract, visceral organs, head or decapitated carcass.

6. The carcasses of the pregnant animals contained less subcutaneous fat plus skin and more intermuscular fat plus muscle than those of the non-pregnant animals. The weights of bone did not differ.
Analysis of production records from a lowland sheep flock. I. Lamb mortality and growth to 16 weeks
Authors: Bichard Maurice , Cooper M. McG.
Published: September 2010

An analysis has been made of the reproductive performance of a breeding flock of Clun Forest ewes in Northumberland. Data are based upon 941 breeding females and 75 males. The average lambing percentages were 43·9 115·4 and 137·7 for ewes aged 1, 2 and over 2 years. Total lamb mortality to 3 or 6 weeks of age was 23·7% for lambs from 1-year-old dams, 16·6% from 2-year-olds, and 12·9% from older ewes. Mortality for all ages of dams was 12·1 % for single lambs, 15·0% for twins and 34·0% for triplets. Birth weight was strongly associated with survival within all birth types and maternal ages.

Analyses of weights at birth, 21, 42 and 112 days showed that much of the observed variation in lamb weight was associated with age of dam and type of birth and rearing. Single lambs and those from mature dams were significantly the heaviest. The effect of age of dam on lamb weight decreased sharply from birth to weaning, whereas the type of birth and rearing was the major influence at 21 and 42 days, and was still important at 112 days.

The mean weights of all lambs adjusted by least squares analysis to the basis of male twins from 3-year-old dams were 9·2, 19·7, 30·6 and 62·7 Ib. at the four ages. Four- and 5-year-old ewes reared the heaviest lambs. Interactions between the effects studied were significant both within and between years and accounted for from 7 to 10% of the total variation. A single set of general correction factors at each age was shown, on average, to account for 80–90 % of the variation between subclasses within years and may have applicability to comparable flocks.
The effect of superovulation on fertilisation and embryonic survival in the pig
Authors: Hunter R. H. F.
Published: September 2010

1. Thirty-one gilts were injected subcutaneously with 1,500 i.u. PMS on Day 15 of the cycle, and inseminated on the morning of the 2nd day of oestrus.

2. Twenty of the animals were killed 1 to 4 days after insemination to study fertilisation, and the remaining eleven were killed on the 25th day of pregnancy to study embryonic survival.

3. All animals exhibited normal oestrous behaviour, only two of them failing to return to oestrus by Day 19 of the cycle. Treatment with PMS shortened the follicular phase of the cycle in nearly all instances.

4. Eighteen of the twenty animals in which eggs were studied were fertile and within these 84·2% of the eggs examined were undergoing normal development, 2·1% were fragmenting, 4·0% were polyspermic and 7·8% were primary oocytes. Ten unpenetrated secondary oocytes (1·9%) were also recovered.

5. Of the eleven animals in which embryonic survival was studied, only eight were pregnant at autopsy; the remaining three had 35 to 44 corpora albicantia, but no embryonic remains could be detected in the uterus.

6. The average ovulation rate in the eight pregnant animals was 35·4, with a range of 13 to 48. However, the average number of normal embryos was 17·0, with a range of 7 to 28.

7. The percentage survival of normal embryos varied from 26% to 83%. Embryonic survival was better at ovulation rates below that of the mean (35·4); an abnormally large or complete loss of embryos occurred at ovulation rates higher than 36.

8. Despite the range in percentage survival, the number of normal embryos found at the 25th day of pregnancy in five of the gilts was considerably above that found in untreated gilts.
The time taken by cows to eat concentrates
Authors: Jones Cathy G. , Maddever Kathleen D. , Court Doris L. , Phillips Mary
Published: September 2010

The investigation was designed to measure the time taken to eat concentrate foods and to determine whether the type and quantity of food, the age of the cow, the length of time between feeds and the eating habits of the cow influence consumption rate.

The data indicate that the main factor affecting eating time is the quantity eaten. Within the range of 2 to 8 Ib., the larger the ration the faster the rate of eating. Further, the data show that up to 20 Ib. of concentrates can be consumed per cow per day in a parlour without any check in the faster rate of eating recorded when the higher levels of concentrates are offered.

The type of concentrate is also important: cubes are eaten faster than meal. There are considerable variations between cows in the time taken to eat.

The results of this investigation did not show any obvious effects on the time of eating of breed of cows, position of manger, nor of the length of interval between bulky and concentrate rations.

Graphs relating the eating times of cows with the times available for eating in parlours are shown, and these can be used for reference on farms in parlour planning.
The protein requirement of the ruminant calf. II. Further studies on the effect of protein content of the concentrate mixture on the performance of calves weaned at an early age
Authors: Stobo I. J. F. , Roy J. H. B. , Gaston Helen J.
Published: September 2010

1. Eighty-four Friesian heifer calves were used in two experiments (Experiments 4 and 5) to study the protein requirement of the ruminant calf to 12 weeks of age. The calves were weaned at 5 weeks of age and given a concentrate containing one of several protein levels, together with hay and water.

2. In Experiment 4, the effect of changing the protein content of the concentrates at 8 weeks of age under ad libitum feeding conditions was studied. A concentrate containing 20·6% crude protein (air-dry basis) tended to promote more rapid weight gains in calves to 8 weeks than a similar concentrate with 12·1% crude protein. Following the change in diet at 8 weeks, both groups of calves given the low-protein diet gained weight at similar rates in the period 8–12 weeks, irrespective of the protein level to 8 weeks. During the period 8–12 weeks calves given the high-protein diet, after receiving a low-protein diet to 8 weeks, tended to gain weight at a faster rate than those given the high-protein concentrate throughout. After adjustment for differences between treatment groups in mean concentrate consumption and mean live-weight at 8 weeks, the live-weight gain from 8 to 12 weeks was significantly greater in calves given the high-protein diet after 8 weeks.

3. In Experiment 5, a significantly lower growth rate was obtained when concentrate intake was restricted to a maximum of 2 kg./day than when given ad libitum. Calves given the concentrates containing 15·9% or 20·6% crude protein gained weight significantly faster than those given the concentrate containing 12·1% crude protein, at both levels of feeding, after live-weight gain was adjusted for differences between treatment groups in mean food consumption and live-weight at 1 week.

4. It is concluded that no advantage is obtained by giving a concentrate containing more than 15·9% protein to Friesian heifer calves weaned at 5 weeks of age. The results indicate clearly the importance of an adequate supply of energy in the diet of the ruminant calf if maximum live-weight gain is to be achieved.
Lamb survival, growth and fleece production in relation to birthcoat type among Welsh Mountain sheep
Authors: Purser A. F. , Karam H. A.
Published: September 2010

Data on 2,055 Welsh Mountain lambs showing wide variation in birthcoat type were used to study the association of birthcoat type with lamb survival and subsequent performance. Each lamb was assigned to one of six grades on the basis of its distribution of halo hair.

Lamb mortality up to weaning was associated with birthcoat type though the effect was significant only in the deaths of live-born lambs before 14 days of age. During this period fine birthcoated lambs showed the highest losses with a mortality rate of 13% compared with rates up to 5% for intermediate and hairy birthcoat lambs. The lowest overall mortality rates occurred among lambs with intermediate birthcoats.

Growth of 669 surviving ewe lambs did not show any significant correlation with birthcoat grade at any stage up to 18 months of age. However, the carcass weights and dressing-out percentages of 570 wether lambs were significantly higher among fine birthcoat lambs.

Fine birthcoats were also associated with better quality fleece grades, 86% giving rise to kemp-free fleeces with short fine fibres, while 92% of hairy birthcoats gave rise to kempy fleeces with coarser fibres.
An analysis of pre-weaning deaths in rabbits with special emphasis on enteritis and pneumonia. II. Genetic sources of variation
Authors: Rollins W. C. , Casady R. B.
Published: September 2010

Heritability estimates of death from enteritis or pneumonia, the two major causes of pre-weaning death at the U.S. Rabbit Experiment Station, Fontana, California, have been estimated. The data consisted of 15,329 observations made at the station from 1946 to 1961.

From birth to 14 days of age the death rate over the years increased from 0·2 to 6·1% During the period from 15 days to 56 days of age (weaning) the enteritis death rate was quite constant over the years (7·5%) while that of enteritis or pneumonia increased from 8·3% to 13·2%.

Heritability of death from enteritis or pneumonia for the period 15 to 56 days of age was estimated on the basis of paternal half sib analysis to be 0·12 ± 0·02. Based on an analysis of differences between dams within sires the corresponding estimate was 0·58 ± 0·05. The difference between the two estimates was attributed to maternal and non-additive genetic effects.

The genetic correlation between the two diseases under discussion was estimated to be 0·66 and 0middot;57 on the basis of differences among sires and among dams within sires respectively.

Breeding plans are suggested on the basis of the parameters estimated.
The effect of dietary energy content on the voluntary intake of pigs
Authors: Owen J. B. , Ridgman W. J.
Published: September 2010

1. An experiment to investigate the effect of dietary energy concentration on the voluntary intake and growth of pigs from 27·2 to 118·0 kg. (60 to 260 lb.) live-weight is described and the results discussed.

2. From 27·2 to 50·0 kg. live-weight energy intake was substantially restricted and growth retarded by diets of low energy concentration but from 50·0 to 118·0 kg. there was little difference between diets in either energy intake or growth because daily food intake of the low energy diets was increased.

3. Effects of diet on carcass quality as measured by full dissection were small except that killing-out percentage was lower on one of the low energy diets.

4. It is concluded that limited differences in the energy concentration and palatability of ingredients are unimportant in formulating pelleted diets for self-fed pigs.
Factors affecting voluntary feed intake in pigs. II. The effect of two levels of crude fibre in the diet on the intake and performance of fattening pigs
Authors: Cole D. J. A. , Duckworth J. E. , Holmes W.
Published: September 2010

1. Voluntary feed intake, performance and carcass quality were studied with 20 individually housed pigs given isocaloric diets (2,770 kcal/kg. DM) containing either 8·9 % or 12·9 % crude fibre in the dry matter over the period of growth from 45 to 91 kg. live-weight.

2. There were no significant differences between diets in voluntary feed intake, rate of gain or carcass quality.

3. Apparent digestibility coefficients and rates of passage of the diets were determined in eight castrated male pigs. Rates of passage were not significantly affected by diet or live-weight when determined at 57 and 82 kg. live-weight.
Studies on the nutrition of ruminants. II. The effect of level of crude fibre in maize-based rations on the carcass composition of Friesian steers
Authors: Swan H. , Lamming G. E.
Published: September 2010

Three groups of eight yearling Friesian steers were fed on pelleted diets containing ground barley straw, maize and soya bean meal, the percentages of straw in the diets being 10, 30 and 50 (treatments 1, 2 and 3). The crude protein level was adjusted to 12% in all diets on an air-dried basis.

Daily live-weight gain for treatment 2 was 7% greater than for treatment 1, and 12% greater than for treatment 3. Voluntary feed intake was also greater in treatment 2, by 16% when compared with treatment 1 and 4% when compared with treatment 3. The efficiency of feed conversion decreased by 10% for each 20% increase in dietary straw level.

Weight loss during lairage was greater on treatment 3, as were total gut fill and omasum weight. The bone content of carcasses was similar for all treatments; carcass lean was increased in treatment 2. Carcass and channel fat was severely depressed in treatment 3.

The results are discussed in relation to dietary effects on carcass composition.
Partition of nitrogen in the urine of African sheep given a variety of low-protein diets
Authors: Topps J. H. , Elliott R.C.
Published: September 2010

1. Sixteen foods, made up with differing proportions of roughage and concentrates and ranging in crude protein content from approximately 2·6% to 10·0%, were each offeredad libitumto Blackhead Persian wether sheep. The nitrogen balance of the sheep and the distribution of nitrogen in the urine were measured.

2. Urinary nitrogen excretion decreased with the digestible nitrogen intake. There was a highly significant (P< 0·01) positive correlation between either excretion of urea or of allantoin and digestible nitrogen intake.

3. The amount of creatinine excreted varied little with diet but was directly related to the body weight of the sheep.

4. For 8 diets, hippurate excretion by the sheep was directly related (P<0·01) to intake of digestible nitrogen, while a significant (P<0·05) positive correlation between the same measures was found for the other 8 diets.

5. It is suggested that with certain types of diets the excretion of either nitrogen, urea or allantoin in the urine may be useful indicators of digestible nitrogen intake of low-protein diets by sheep.
Protein levels in practical diets for bacon pigs
Authors: Rickaby C. D.
Published: September 2010

1. The performance and profitability of growing-fattening bacon pigs on two diets, A and B, were compared in farm-scale trials at five centres involving a total of 94 pigs. Diet A contained normal amounts of white-fish meal, middlings and barley meal. Diet B was a cheap low-protein diet containing 90–95% barley meal and no wheat offals.

2. The average crude protein contents of the diets were: diet A, weaner meal 17·2%, fattener meal 14·1% and diet B 14·8% and 12·1% respectively.

3. The pigs on diet A had a daily live-weight gain 1·26 lb. and a food conversion ratio of 3·38 lb.; corresponding figures for the pigs on diet B were 1·22 lb. and 3·49 lb.

The food costs of the pigs on diet B were lower by 10s. 10d. per pig; although the grading of these pigs was slightly poorer, the ultimate profit was 7s. 10d. greater per pig than for diet A.

4. At a sixth centre, decorticated groundnut meal was used in diet B instead of soya bean meal; this had a marked adverse effect on the performance of the pigs and the profit was 18s. 3d. less per pig than for diet A.
A note on the use of back rasher ratios as predictors of lean percentage in pigs of bacon weight
Authors: Smith W. C. , Tonks H. M. , Lawrence N.
Published: September 2010

A Quality characteristic of the bacon side is the fat to lean ratio of the rashers obtained from it. Although this measurement has received attention in carcass evaluation (Pearson, Bratzler, Hoefer, Price, Magee and Deans, 1956; Lucas and Mitchell, 1962; Jonsson, 1963), unlike many others its accuracy as a predictor of lean content of the carcass has not been established. On this basis it was considered worth while to undertake an analysis of the method.
Acclimatisation of Scottish Blackface sheep to cold. 1. Rectal temperature responses
Authors: Slee J. , Sykes A. R.
Published: September 2010

Closely shorn Scottish Blackface female sheep aged 9–14 months, half on high plane and half on low plane nutrition, were subjected, in climate chambers, to two short acute cold exposures down to – 20° C. The exposures were separated by a period of two weeks in either a thermoneutral environment ( + 30° C.) or a subcritical environment ( + 8° C.). Thirty-seven out of 40 sheep showed a greater resistance to body cooling at the second exposure. The mean rates of fall of rectal temperature (in° C. per 100 min. exposure) were 0·42 at the first exposure and 0·22 at the second exposure. One group of sheep showed virtually complete resistance to cooling at second exposure under the specific test conditions used. The highly significant increase in cooling resistance was taken as a measure of acclimatisation.

The main conclusions were as follows:

1. Blackface sheep could acclimatise to cold as a result of one acute exposure to cold lasting about 8 hours.

2. Acclimatisation was slightly greater amongst sheep kept at a subcritical temperature (+8° C.) between acute exposures.

3. Additional data suggested that some acclimatisation resulted from 2 weeks prior exposure to +8° C. alone; but none was induced by 2 weeks prior habituation to the climate chamber environment at + 30° C.

4. Sheep on high plane nutrition showed greater initial cold resistance and slightly greater ability to acclimatise than those on low plane nutrition.

5. Cold resistance was more closely related to recent weight gain than to absolute body weight.

6. There was great individual variation in initial cold resistance and in ability to acclimatise.

7. Sheep kept at + 8° C. between acute cold exposures maintained significantly lower rectal temperatures than those kept at +30° C.
The effect of inbreeding on feed consumption and utilisation by sheep
Authors: Doney J. M.
Published: September 2010

Twelve inbred (coefficient of inbreeding 25%) and 12 outbred, singlereared, Scottish Blackface castrated male lambs were taken at six months of age from amongst the progeny of three rams. They were housed and fed individually on a pelleted diet in three separate phases. In the first two phases restricted amounts were offered. These were calculated to produce, firstly, a small rate of live-weight gain and, secondly, a small rate of live-weight loss. In the third phase feed was offered to maximum voluntary intake during 2 two-hour periods daily.

On restricted intakes there were no significant differences between the groups. In the third phase the outbred sheep consumed 17% more feed than the inbred group and the daily rates of live-weight gain and wool growth were 33% and 27% higher, respectively. Since the inbred lambs were smaller, the voluntary intake per unit live-weight did not differ significantly between groups.

The estimated requirements of feed for maintenance (20·1 ± 0·4 and 21·9±0·6 g./kg. live-weight, respectively, for the outbred and inbred groups) differed significantly. There were no apparent differences in the estimated efficiency of conversion of available surplus feed to body tissue or wool growth.
The relationship between live weight of ewe at mating and weight of newborn lamb
Authors: Donald H. P. , Russell W. S.
Published: September 2010

Regression of litter weight of newborn lambs on the live weight of ewes at mating has been estimated from data on 15 breeds after conversion of group means of ewes and lambs to natural logarithms. Regression coefficients were estimated to be 0·721 for single lambs, 0·741 for twins and 0·773 for triplets. These values are not signi-ficantly different from each other. Data from ewes with single lambs and from ewes with twins are consistent with the hypothesis that litter weight at birth as a proportion of ewe weight at mating tends to dechne as ewe weight rises from small to large breeds. In a breed with ewes averaging 25 kg the expected birth weight of singles is 9·6% and of twins 15·2%, of ewe weight. For a breed with ewes of 100 kg the corresponding weights would be 6·5% and 10·6% of ewe weight. Since the estimated regression coefficient and the coefficient in the expression for metabolic weight (0·730) are alike, the regression equations can be interpreted as showing that single lambs were 22·6% and twin pairs 36·1% of ewes' metabolic weight.