bluuebunny/crossref_metadata_2025 huggingface dataset:
A note on the effect of monensin when added to diets high in sodium hydroxide-treated straw given to cattle
Authors: Holzer Z. , Levy D. , Samuel V. , Drori D.
Published: September 2010

Four groups of 12 beef heifers were each given either straw treated with 35 g sodium hydroxide per kg (TS) or untreated straw (US) and were either supplemented with 35 mg monensin per kg (Ms) or not supplemented (Ns). The diet consisted of approximately 0·40 of a concentrate mixture that contained 12·8 MJ metabolizable energy and 243 g crude protein per kg dry matter, and 0·60 straw. Feeding was ad libitum. The average initial weight of the heifers was 207·2 kg and the experiment lasted 86 days.

The average dry matter consumed was 2·3g/kg live weight. Average daily gain (±s.e.) was 505±31·6, 371±33·8, 380±26·2 and 257±32·7g/day for treatment groups TS-Ms, TS-Ns, US-Ms and US-Ns, respectively. These findings indicate that monensin may counteract some ill-effects of diets high in sodium hydroxide-treated straw and thus further research is warranted.
The influence of high food levels in early pregnancy on embryo survival in multiparous sows
Authors: Toplis P. , Ginesi M. F. J. , Wrathall A. E.
Published: September 2010

Thirty-eight multiparous sows were used to ascertain whether a high (4 kg/day), compared with a low (2 kg/day) food level affected early embryonic survival. To avoid any effect on ovulation rate the treatments were imposed 3 days after mating (2 days after presumed ovulation) and continued until the sows were killed 30 days after mating. Sows which were given the high food level gained more than twice as much body weight as those on the low food level, but ovulation rates, embryo numbers, embryo body sizes and embryo survival rates were similar for both feeding levels. It is concluded that, if necessary, multiparous sows may be fed higher than normal food levels in early pregnancy without prejudice to embryonic survival.
Turnips with chemically-treated straw for beef production. 1. The effects on the growth of steers
Authors: Macdearmid A. , Williams P. E. V. , Innes G. M.
Published: September 2010

A growth trial lasting 84 days and digestibility trials were carried out with Hereford × Friesian steers weighing initially 360 kg. Daily dry-matter intakes (kg) of 32 steers offered turnips with blood meal (250 g/day) and straw treated with sodium hydroxide (SP), urea (UP), ammonia (AP) or untreated (CP), and of a further eight steers offered turnips and ammonia-treated straw without a supplement of blood meal (A) were 6·5 (SP), 6·0 (UP), 6·6 (AP), 5·9 (CP) and 6·3 (A); live-weight gains (kg/day) were 0·69, 0·58, 0·60, 0·37 and 0·39 respectively. The non-protein nitrogen intake of steers on treatments SP and CP were matched to those on treatments AP, A and UP by the addition of urea. Coefficients of apparent straw organic matter digestibility were 0·629 (SP), 0·531 (UP), 0·578 (AP), 0·446 (CP) and 0·569 (A). Overall food intakes on all treatments were low initially (88 g/kg W0·73) and declined further to 78 g/kg W0·73. Live-weight gains also were low; those of steers given diets CP and A were lower (P< 0·001) than gains of steers on other treatments.

Improvements in the apparent digestibility of straw were obtained by chemical treatment but all values, except that of the UP group, were low. The supplementation of ammonia-treated straw with blood meal (AP) produced a higher (P< 0·001) growth rate in steers compared with that of steers receiving ammonia-treated straw alone (A). The low mean pH (6·48) and ammonia concentration (9 mg/100 ml) of rumen liquor sampled during the growth trial suggest that the poor growth rates and low food intake of cattle in this trial may be associated with the rapid release of soluble sugars from turnips given only once daily.
The effects of dietary protein concentration on the lactational performance of the rabbit
Authors: Partridge G. G. , Allan S. J.
Published: September 2010

An experiment was performed to examine the effects of feeding four concentrations of crude protein in the diet to lactating rabbits. Diets A, B, C and D contained 173, 181, 224 and 243 g crude protein per kg dry matter respectively. Each diet was offered at one of two feeding levels: H (330 g/day) or L (280 g/day) with three replicates in each of the eight treatment groups. Milk production and nitrogen balance were measured over a 28-day lactation.

Although dry-matter intakes on feeding level H were significantly higher than those on feeding level L the difference diminished as the crude protein concentration decreased. The effect of crude protein intake on doe milk production was estimated therefore by regression analysis with digestible energy intake as a covariate. Both crude protein intake and digestible energy intake alone had significant effects (P < 0·001) on daily milk production and there was also a significant effect (P < 0·05) of crude protein intake after fitting digestible energy intake. Overall the equation was:

Milk production (g/day) =

17·61 + 0·985 crude protein intake (g/day) + 30·3 digestible energy intake (MJ/day).

(±0·448) (±14·8)

The relationship between digested nitrogen and nitrogen output as milk was also examined by regression analysis with digestible energy intake as a covariate. This equation was:

Nitrogen output in milk (g/day) =

0·438 + 0·164 digested nitrogen (g/day) + 0·572 digestible energy intake (MJ/day).

(±0·068) (±0·294)

The practical implications of feeding high levels of crude protein in the diet to increase milk production and pup weaning weight are discussed.
A note on the growth and food consumption of crossbred lambs of five sire breeds
Authors: Woolliams J. A. , Wiener G.
Published: September 2010

Lambs, 8 weeks of age, the offspring of sires of the Scottish Blackface, East Friesland, Finnish Landrace, Suffolk and Texel breeds mated to Scottish Blackface females as a common maternal breed were fed ad libitum on a concentrate containing barley and fish meal for 14 weeks. Live weight and food intake were measured at intervals of 2 weeks.

Live-weight gain varied between sire breeds, Suffolk crosses having the greatest growth rate and the Blackface lambs the least, but there were no significant differences in their food conversion ratios. Food intakes were compared with those predicted by two methods. When the only criteria for prediction were live weight and the metabolizability of the diet the prediction was poor, whereas very accurate agreement was found when the criteria for prediction included consideration of the changes in energy efficiency with food intake and with maturity.
A note on the theoretical relation between the fractions of maturity of organs and of the whole animal
Authors: Parks J. R.
Published: September 2010

A general parabola constrained to pass through points (0,0) and (1,1) yields a linear one parameter (q) function which can be used to relate the fraction of maturity of organs or masses of tissue to the fraction of maturity of the whole animal. This is an empirical approach. It is often preferable to derive a function from a theory of the phenomenon under study. A theory of feeding and growth of animals is used to derive a non-linear one parameter (k) function which can be used to study the same data to which the linear q-function is applicable. The parameter, k is directly proportional to the fraction of total nutrients consumed by the animal which is allocated to the organ as the animal ages. If the fraction of nutrient allocated remains constant, the parameter k is constant and has the same properties as the parameter q. However there is nothing in the theory which constrains k to be constant, therefore, the q-function is of more general use than the q-function in the study of the relationship of the fraction of maturity of organs to that of the whole animal. Two cases are presented to illustrate this generality.
A comparison of live animal measurements for selecting lean beef sires
Authors: Simm G. , Alxiston J. C. , Sutherland R. A.
Published: September 2010

The value of several live animal measurements for predicting carcass lean content was assessed on 97 Hereford bulls. The bulls were from a series of performance tests extending over a period of 4 years. The measurements made were live weight, ‘Weighband’ estimate of live weight, skin-fold thickness at the 13th rib, anal-fold thickness and Danscanner and Scanogram ultrasonic fat area. All measurements, except anal-fold thickness, showed satisfactory repeatability from one day to the next (0·45 to 1·00). Ultrasonic measurements showed the highest correlations with carcass lean content (0·22 to 0·66; corresponding residual s.d.'s, 13·87 and 26·46 g/kg). The most precise prediction of lean content was achieved with live weight and ultrasonic measurements in a multiple regression. The precision achieved and best anatomical sites for ultrasonic measurement varied with the group of bulls (highest R2 values 0·61 to 0·77; corresponding residual s.d. 's, 25·75 and 22·47 g/kg). The Scanogram machine produced more repeatable results than the Danscanner. When compared on the same animals Scanogram measurements gave slightly more precise prediction of carcass lean content than Danscanner measurements. Over all groups of bulls the two machines produced results of similar accuracy. Accounting for precision of estimating carcass lean content, response to selection for leanness was estimated to be 0·0034 to 0·0049 of the mean per annum for bulls of about 400 or 500 days of age.
An evaluation of tail paint as an aid or alternative to oestrus detection
Authors: Ducker M. J. , Haggett Rosemary A. , Fisher W. J. , Bloomfield Glenys A. , Morant S. V.
Published: September 2010

One hundred Friesian heifers were tail-painted between 14 and 21 days after calving. Once a week the paint strip was renewed if any paint had been removed. Over the whole period of observation the ovulation detection rate by definite signs of oestrus was high (0·79), whilst the proportion of silent ovulations detected by tail paint removal was low (0·10). In addition, tail paint was not removed on 0·28 of the occasions when definite oestrus with ovulation occurred and on 0·26 of the occasions when all the paint was removed it was not associated with any reproductive event. In practice, the critical time for tail paint to be effective is during the service period. Again, tail paint identified fewer (P < 0·001) ovulations than definite signs of oestrus (0·66) and had a significantly higher false positive rate (P < 0·001). Month of calving did not affect these results but the accuracy of tail paint declined as the season progressed (P < 0·001). False positive indications were not associated with individual animal characteristics. In a second trial 43 cows were tail-painted and 43 were not. There was no significant difference in the mean number of days from calving to first insemination or successful pregnancy between the two groups. It is concluded that in these trials tail paint was not an effective or reliable aid or alternative to oestrus detection.
Further studies on the value of liquid skimmed milk as a protein source for growning pigs
Authors: Mitchell K. G. , Partridge I. G. , Barber R. S. , Pittman R. J.
Published: September 2010

1. A trial was carried out with 96 purebred Large White and Landrace pigs to assess the optimum content of skimmed milk in diets given from 20 to 90 kg.

2. Pigs on treatment 1 (control) received a barley and soya bean diet providing 12·9 MJ digestible energy per kg and 161 g crude protein per kg until they reached 54 kg and 144 g crude protein per kg thereafter. Those on treatments 2 to 4 received 3·5, 4·5 and 5·75 1 skimmed milk per day, respectively, from 28 kg live weight, after a gradual increase from 2·0 I/day at 20 kg; this was given with a basal barley diet which provided 12·9 MJ digestible energy per kg and 111 g crude protein per kg. All diets were given according to scales to permit all pigs equal daily intakes of digestible energy. Treatments 1 and 2 were approximately isonitrogenous.

3. In order of treatment, average daily gains (g) were 658, 712, 743 and 737 (s.e. of difference, 15) and food: gain ratios were 3·06, 2·73, 2·63 and 2·60 (s.e. of difference, 0·05). There were no important treatment effects on linear carcass measurements.

4. It appeared that lysine supply was a major determinant of the results obtained.

5. The greatest daily gains were achieved when a minimum of 4·5 1 of skimmed milk was given daily with the basal diet; this approximates to an average skimmed milk: meal ratio of 2·8 I/kg.
A note on the comparison of two dissection methods used routinely in britain for beef carcass evaluation
Authors: Wood J. D. , Bayntun J. A. , Kempster A. J.
Published: September 2010

The dissection methods used at the ARC Meat Research Institute, Langford (MRI) and by the Meat and Livestock Commission (MLC) for beef carcass evaluation were compared.

When account was taken of small differences in the way tissues are defined in the two methods, they gave essentially the same results for the important aspects of carcass composition. Twenty carcasses with 60 to 120 g subcutaneous fat per kg side weight were selected from those in the serial slaughter phase of the MLC's beef breed evaluation programme. The cattle had been slaughtered and dressed at a commercial abattoir on the same site as the MLC's Central Carcass Evaluation Unit, Blisworth. The left sides were dissected by the MLC and the right sides at the MRI after being taken there as quarters (which resulted in a greater evaporative weight loss). Mean values for lean, bone, intermuscular fat and subcutaneous fat (as g/kg in the side) did not differ significantly between the methods and the slopes of the regressions of MRI on MLC proportionate composition values were not significantly different from 1·0.
A selection index for dairy cows
Authors: Hill W. G. , Swanson G. J. T.
Published: September 2010

The rationale for a method of computing selection indices for dairy cows is outlined. It uses predicted transmitting abilities of sires from a best linear unbiased prediction or similar method of evaluation together with mean transmitting abilities (cow indices) of dams to estimate herd genetic levels. Indices for individual cows are computed using deviations from those of contemporaries in the herd of her sire's transmitting ability, her dam's index and her own production in each lactation.

The method is being used in the UK, cow indices being expressed as transmitting abilities relative to the same fixed genetic base as for sire evaluation.
Factors affecting maintenance requirements of beef cows
Authors: Russel A. J. F. , Wright I. A.
Published: September 2010

The maintenance energy requirements of 29 Hereford × Friesian and 27 Blue Grey (White Shorthorn × Galloway) cows each offered one of six levels of feeding supplying between 0·5 and 1·2 likely maintenance requirements for 56 days were estimated, from regressions of daily live-weight change on energy intake, as the energy intake corresponding to zero live-weight change.

There were no effects of level of intake on diet digestibility or of genotype on maintenance requirements.

Maintenance requirements (M, MJ metabolizable energy per day) were shown to be determined by both live weight (LW, kg) and body condition score (C) according to the relationship: M = 0·147LW – 0·016C.LW.

The estimates derived are compared with other published values and the hypothesis is advanced that maintenance requirements are likely to be more closely related to body protein mass than to body weight.

The dietary energy equivalent of 1 kg loss of live weight is calculated to be 26·7 MJ and it is estimated that in non-lactating cows body tissue is used for maintenance with an efficiency of 0·77.
A note on reproductive performance and plasma progesterone level during early pregnancy of Scottish Blackface and Cheviot ewes in relation to body condition and level of nutrition prior to mating
Authors: Rhind S. M. , Gunn R. G. , Doney J. M.
Published: September 2010

Seventy-nine Scottish Blackface and 79 North × South Country Cheviot ewes were fed to increase their mean condition score by 0·5 over periods of either 4 (M/H group) or 8 (I group) weeks prior to mating. Thereafter, they were fed a live-weight maintenance ration until they were slaughtered at 50 to 65 days after mating. Reproductive tracts were recovered, corpora lutea counted and embryos counted and examined. Plasma progesterone levels were monitored at selected times after mating. The proportion of ewes in each treatment group that were pregnant at the time of slaughter was similar (0·75 to 0·83) but there was evidence of differences in the pattern of reproductive failure with treatment. The proportion of non-pregnant ewes which had apparently been pregnant initially was 0·55 in the M/H group compared with only 0·27 in the I group. Circulating progesterone levels were not affected by premating nutritional treatments but differed with breed.
The effects of frequency of feeding on milk production of dairy cattle: an analysis of published results
Authors: Gibson J. P.
Published: September 2010

Automated feeding systems for dairy cows offer the benefits of ‘little and often’ feeding. Published data were collected and analysed to establish the extent of such benefits. Twenty-three publications reporting the results of 35 experiments were examined. Several statistically significant positive responses indicated that milk fat concentration, and to a lesser extent yield of milk, could sometimes be increased by increasing the feeding frequency. However, for ail experiments the average proportional increases (± s.e.) in milk fat concentration and milk yield were fairly small at 7·3 (± 3·3) % and 2·7 (± 1·3) %, respectively. The responses of milk fat concentration and milk yield were apparently correlated (r= 0·43, s.e. = 0·20), and the mean proportional response of milk fat yield was 8·3 (± 3·1) %. There was no evidence that milk protein concentration, lactose concentration or changes in body weight were affected by changes in feeding frequency. Increases in food intake were sufficient to explain some, but not all, instances of increased milk fat production. All statistically significant responses to increased feeding frequency occurred when the milk fat concentration was originally depressed, milk fat depression generally being due to feeding pelleted or highly concentrated diets. Increases in milk fat concentration through increased feeding frequency were generally insufficient to bring the milk fat concentration up to a commercially acceptable level. All statistically significant responses were observed on moving from one or two to three or more meals per day, but the possibility of further responses beyond four meals per day could not be ruled out. It was concluded that cows producing milk of commercially acceptable milk fat concentrations were unlikely to benefit from increased feeding frequency.
The effect of nutrition on the reproductive performance of first-litter sows 2. Protein and energy intakes during lactation
Authors: King R. H. , Williams I. H.
Published: September 2010

A factorial experiment involving high (53·1 to 59·5 MJ) and low (25·4 to 27·1 MJ) daily intakes of digestible energy, and high (550 to 745 g) and low (302 to 318 g) daily intakes of crude protein during lactation, was conducted with 68 first-litter sows. Average lactation length was 32 days, and average backfat changes during lactation were +0·3, −1·4, −7·2 and −5·4 mm for the high energy/high protein, high energy/low protein, low energy/high protein and low energy/low protein combinations, respectively. The corresponding mean live-weight losses during lactation were 3·9, 32·5, 29·8 and 35·8 kg. Within 8 days of weaning, more sows receiving high intakes of both energy and protein during lactation exhibited oestrus (0·88 v. 0·53, x2 = 6·7, P < 0·01) than sows whose energy and/or protein intake throughout lactation had been restricted. Nitrogen balances of sows were determined between 18 and 22 days after farrowing. Sows receiving high intakes of both energy and protein during lactation were in positive nitrogen balance, whereas the nitrogen balances of sows on the other three dietary treatments during lactation were similar to each other but negative. Ovulation rate, subsequent litter size and embryo mortality were not significantly affected by energy or protein intake during lactation.
Amino acid requirements of growing pigs 5. The interaction between isoleucine and leucine
Authors: Taylor S. J. , Cole D. J. A. , Lewis D.
Published: September 2010

Thirty-two female growing pigs (25 to 55 kg live weight) were subjected to four dietary treatments combining two levels of isoleucine and two levels of leucine to investigate the effects of leucine supply on the requirement for isoleucine.

Results for daily live-weight gain, food conversion efficiency and carcass quality judged by ham dissection indicated that 3·8 g isoleucine per kg diet was marginally adequate for the growing pig in diets containing 13·4 g leucine per kg. An interaction between dietary leucine and isoleucine was demonstrated. Increasing the dietary leucine concentration to 20·4 g/kg clearly resulted in a deficiency of isoleucine in the basal diet, as daily gain, food conversion efficiency and carcass quality were significantly improved by increasing the isoleucine concentration from 3·8 g to 4·5 g/kg diet. Dietary leucine concentration did not influence performance at the higher level of isoleucine supply. Changes in plasma urea and amino acid concentrations confirmed the findings from the growth experiment of the interaction between isoleucine, leucine and valine.
Amino acid nutrition of the lactating sow: limitation by indispensable amino acids
Authors: Wilkinson R. , Cole D. J. A. , Lewis D.
Published: September 2010

In the first of two experiments of 6 × 6 Latin-square design a diet of barley, soya bean meal and fish meal, known to give an adequate lysine intake (56 g/day) at the level of feeding adopted, was diluted with maize starch to give crude protein intakes ranging between 448 and 923 g/day but with the lysine intake held constant by using synthetic lysine in the diets. The diets were given to sows suckling ten piglets between days 12 and 30 of lactation. Dietary amino acid adequacy was assessed by changes in plasma urea, urinary urea, urinary nitrogen and plasma amino acid concentrations. The dietary amino acid supply became limiting with a protein intake of approximately 730 g/day. In the second experiment, a diet of similar composition was used with varying additions of synthetic threonine, methionine, isoleucine and tryptophan: the control diet contained all the synthetic amino acids added, the basal diet none and the other diets were formed by adding groups of three out of the four synthetic amino acids. On the basis of some of the variables studied, it was concluded that, for this diet, threonine was the limiting amino acid after lysine.
Comparison of two methods for evaluating reproductive development in prepubertal gilts
Authors: Deligeorgis S. G. , English P. R. , Lodge G. A. , Foxcroft G. R.
Published: September 2010

Twenty-one pairs of litter sister gilts of similar live weight were selected at 150 days of age and one member of each pair was allocated randomly to the following treatments at approximately 170 days (80 kg live weight): 1. stimulation by mature boar; or 2. an intramuscular injection of oestradiol benzoate. The two groups were fed to appetite and slaughtered at approximately 180 days of age. Examination at slaughter indicated greater ovarian and uterine development in response to oestradiol relative to boar treatment (P < 0·01). The results indicate that oestradiol treatment of gilts followed by post-slaughter examination of the reproductive tract is a sensitive method for evaluating the effects of prior treatments on reproductive development. Significant family and pre-weaning growth effects on reproductive development were also evident on both evaluation methods.
Genetic effects on maternal performance and litter pre-weaning and post-weaning traits in rabbits
Authors: Lukefahr S. , Hohenboken W. D. , Cheeke P. R. , Patton N. M.
Published: September 2010

Abstrtact

Flemish Giant (FG) and New Zealand White (NZW) purebreds and terminal crossbreds (TX) (Flemish Giant sires × Florida White-New Zealand White dams) were evaluated during a 10-month period for maternal and litter pre-weaning and post-weaning performance. For the doe traits studied, teat number was greatest and litter interval was shortest, while body weight at breeding age (154 days), litter weight at 21 days and day 1 to 21 food intake were lowest for crossbred does. These traits were similar for pure doe groups, with the exception of body weight, for which FG does were heavier. For the preweaning litter traits examined (no. = 101 litters), litter size born was smallest in the TX group (the purebred groups being similar) and was largest at weaning (28 days) for NZW. Proportion of kits born alive was lowest in FG litters, while the NZW and TX groups were comparable. Litter and average birth and weaning weights, litter daily gain, and doe and litter food intake (1 to 28 days) were all highest in FG litters and lowest in TX litters. Repeatability estimates (t) were low (t < 0·05) for litter size and birth weight traits, and were moderate to high (0·18 < t < 0·58) for the remaining maternally influenced characters. For the post-weaning litter traits studied (no. = 86 litters), NZW litters were larger in number and heavier at market age (56 days), and consumed more food from 28 to 56 days than FG and TX litters. Purebred FG litters, however, had heavier average market weights per rabbit, while purebred NZW and TX litters were similar. Mortality due to respiratory disease was higher in FG litters than in NZW and TX litters. Total mortality incidence was lowest in the TX group.
The effect of winter food level on compensatory growth of weaned, suckled calves grazed at two sward heights
Authors: Wright I. A. , Russel A. J. F. , Hunter E. A.
Published: September 2010

Two experiments were conducted with weaned, suckled calves to investigate the effect of feeding level during the post-weaning winter on their subsequent performance when continuously grazed on pasture maintained at two sward heights. Low, medium and high levels of winter feeding resulted in winter live-weight gains of 0·31, 0·58 and 0·79 (s.e. 0·027) kg/day (P < 0·001) during the 152-day winter in experiment 1 and 0·44, 0·69 and 0·84 (s.e. 0·029) kg/day (P < 0·001) for 189 days in experiment 2. During summer (93 days in experiment 1 and 87 days in experiment 2) there was a significant effect of winter food level on performance when live-weight gains were 1·10, 1·02, 0·87 and 1·35, 1·23 and 1·19 (s.e. 0·060) kg/day for the low, medium and high winter food levels on the short and tall swards respectively in experiment 1 (P < 0·01) and 0·86, 0·66, 0·51 and 1·26, 1·18 and 0·91 (s.e. 0090) kg/day in experiment 2 (P < 0·001). The cattle showing compensatory growth had higher herbage intakes and it is postulated that this occurred because of a negative association between body fat and herbage intake. Sward height had a large positive effect on herbage intake and live-weight gain and it is concluded that for maximum intake on ryegrass swards, herbage height should be at least 8 cm. Lower levels of winter live-weight gain delayed the time to slaughter, but allowed cattle to achieve heavier carcass weights at a fixed level of fatness.

It is concluded that there is no single optimum winter food level for weaned, suckled calves but that the choice will depend upon several factors, including availability of winter and summer food resources, the length of the winter feeding period, the desired date of slaughter and type of carcass to be produced.
Relationship of components of the body among mature cows as related to size, lactation potential and possible effects on productivity
Authors: Jenkins T. G. , Ferrell C. L. , Cundiff L. V.
Published: September 2010

Attributes of lactation and weight of components of the empty body were analysed to evaluate relationships between performance potential of various breeds or breed crosses and the proportion of empty-body components relative to slaughter weight. Differences in major internal organs attributable to breed, breed cross, level of food intake, mature body size and milk production potential were observed. Milk yield was positively related to proportion of lung tissue, tended to be positively related to head and liver tissues but was negatively related to the proportion of warm carcass. As estimated from a three breed diallel, significant additive breed direct effects were observed for several empty-body components. In general, heterosis tended to be non-significant for all proportions of body components with the exception of proportion of head, fore and hind feet and lung tissue. Breed crosses characterized as having greater potential for mature weight were heavier at slaughter and had a greater proportion of structural components such as head, hide and fore and hind feet. Differences among visceral organs associated with production potential for size and milk production are discussed relative to the possible effect on basal energy expenditure and the effect these differences may have on the energy requirements for a cow/calf livestock enterprise.
Rumen degradation of straw 1. Untreated and ammonia-treated barley, oat and wheat straw varieties and triticale straw
Authors: Tuah A. K. , Lufadeju E. , Ørskov E. R. , Blackett G. A.
Published: September 2010

The dry-matter degradation of 19 varieties of barley, 14 varieties of wheat, 11 varieties of oats and one variety of triticale straws, both untreated and ammonia treated were studied using the nylon-bag technique. There were significant differences between the untreated varieties of all the types of cereal straw studied with respect to dry-matter loss (DML) values. When the barley and wheat straws were treated with ammonia, the differences between the varieties were also significant although ammonia treatment tended to improve those with lower values to a greater extent than those with higher values. There were also significant differences between the DML values of the oat straws when they were treated with ammonia but only after 48-h incubation. There was a significant negative relationship between the 48-h DML values of the untreated oat straws and the improvement in the DML values with ammonia treatment (r = −0·65; P < 0·05). Grain yield, straw length and nitrogen concentration had no significant relationship with the DML values of the untreated straws. Barley and oat straws had generally higher DML than the wheat and triticale straws.
The effect of frequency of feeding milk replacer to pre-ruminant calves on respiratory quotient and the efficiency of food utilization
Authors: Williams P. E. V. , Fallon R. J. , Brockway J. M. , Innes G. M. , Brewer A. C.
Published: September 2010

Thirty-four British Friesian bull calves were used in experiments to identify diurnal patterns of respiratory quotient (RQ), as an indicator of substrate utilization and to measure energy balance when the same daily amount of milk replacer was given on either 1, 2, 4 or 6 occasions. Each calf spent two 4-day periods in an open-circuit respiration chamber followed immediately, in selected calves, by an 8-day period in a metabolism crate, period 1 starting when calves were 12 days of age and period 2 at 28 days of age. The amount of milk replacer given daily was 32 and 48 g/kg M0·75during periods 1 and 2 respectively.

Neither rate of live-weight gain nor the energy balance of the calves was affected by frequency of feeding. However, raising the frequency of feeding from one to four times daily significantly affected the pattern of RQ. Reduced feeding frequency tended to raise the mean maximum and lower the mean minimum values of RQ; reducing the frequency of feeding significantly increased the range in RQ (F < 0·01).

The apparent dry-matter digestibility of the milk replacer was higher in 36-day-old than in 20-day-old calves (0·93v.0·88; s.e.d. 0·011,P< 0·01). The effect was mainly due to an increase in the digestibility of fat (0·82v.0·73; s.e.d. 0·019). In 20-day-old calves, there was a linear increase in fat digestibility with increased frequency of feeding (P< 0·01) rising from 0·67 in calves given milk once daily to 0·85 when milk was given in six meals.

The results suggest that calves given milk replacer once daily (at a level of intake of 32 rising to 48 g milk powder per kg M0·75) do not pass through a diurnal period of severe nutrient deprivation and that raising frequency of feeding would do little to improve efficiency of energy utilization.
The effect of feeding period and trenbolone acetate on the potential of culled dairy cows for beef production
Authors: Garnsworthy P. C. , Cole D. J. A. , Grantley-Smith M. , Jones D. W. , Peters A. R.
Published: September 2010

Sixty-four Friesian/Holstein cows culled from dairy herds were selected for uniformity and general health. They were allocated to five groups of 12 on the basis of body condition and live weight excluding the two cows at each extreme. These four cows indicated the range of condition and live weight in the sample and were slaughtered at the beginning of the trial with one group of 12 cows. Of the remaining four groups, two were implanted with 300 mg trenbolone acetate (Finaplix, Hoechst) and two used as unimplanted controls; one implanted group and one control group were slaughtered after 60 days and the remaining cows after 100 days. All cows were individually fed to appetite on a pelleted diet of 500 g dried lucerne and 500 g barley per kg. After slaughter the left side of each carcass was cut into primal joints and then separated into fat, lean and bone.

Implantation resulted in greater live-weight gains to 60 days (1·35 v. 112 kg/day, P > 0·05) and to 100 days (1·31 v. 0·92 kg/day, P < 0·01), greater lean meat production and an increase in the lean proportion of carcasses.

Feeding cows for 100 days rather than for 60 days led to higher slaughter weights but daily live-weight gain decreased and food intake increased progressively between 60 and 100 days. Carcasses from cows slaughtered at 100 days had significantly higher lean, fat and bone weights (P < 0·01) but as a proportion of side weight only the fat proportion of the carcass was significantly increased (P < 0·05).

It was concluded that the supplementary feeding of cull cows produced heavier carcasses but at these high rates of gain increased yield was at the expense of proportionately more fat in the carca?.s. This problem was partially countered by implantation with trenbelone acetate.
Predicted and realized responses to selection for an index of bone length and body weight in Scottish Blackface sheep 1. Responses in the index and component traits
Authors: Atkins K. D. , Thompson R.
Published: September 2010

A selection experiment with Scottish Blackface sheep was used to compare predicted and realized responses to selection. Three closed lines, of approximate annual size of 270 ewes and 10 rams, were maintained between 1956 and 1974, in which selection was at random, or for high and low values of an index of cannon-bone length at 8 weeks of age adjusted for body weight at the same age. An unselected base flock (1954-55) and the randomly selected line were used to estimate base population parameters, while the selected lines were used to estimate realized responses to selection.

Heritabilities and genetic correlations were obtained in the unselected lines from a variety of collateral and ancestral relationships. The important components of phenotypic variance were estimated and likely responses to selection predicted for the index and its two component traits. Realized responses to selection were estimated from the regression of response on selection differential. The expected variance-covariance matrix of observed responses was included in generalized least-squares estimates of these regressions.

The realized heritability of the index under selection, estimated from the divergence of selected lines, was 0·52 (s.e. 0·02). After allowing for the expected reduction in heritability arising from linkage disequilibrium, this was very similar to the base population estimate of 0·56 (s.e. 0·04). The responses in the component traits of the index were also very close to those expected from base population parameters
Flat v. step feeding of medium or high levels of concentrates for dairy cows
Authors: Poole D. A.
Published: September 2010

A system of feeding concentrates at a flat rate was compared with a step system in which the rate was reduced every 6 weeks. Each system was evaluated at either medium or high level concentrates. There were two trials involving 40 British Friesian cows for weeks 3 to 20 of lactation. The flat rate treatments were 71 (medium) and 9·3 kg dry matter (DM) per day (high) and corresponding step allocations were 8·8, 7·1 and 5·4 kg DM per day or 11·7, 9·3 and 7·0 kg DM per day. Silage was given to appetite. In trial 1 this was lucerne silage of moderate quality (metabolizable energy (ME) = 8·9 MJ/kg DM) and in trial 2 high quality grass silage (ME = 11·1 MJ/kg DM) was used.

In the comparison between systems of concentrate allocation, food intakes, milk production and live-weight change were similar in each trial. In the comparison between medium or high levels of concentrates, silage DM intakes were similar in trial 1 (7·1 v. 7·0 kg/day) but not in trial 2 (9·8 v. 8·7 kg·day, P < 0·05), and milk yields were lower in trial 1 (19·0 v. 21·4 kg/day, P < 0·001) but not in trial 2 (24·1 v. 25·2 kg/day). Milk composition was similar for medium and high concentrate intakes in both trials. Cows given the medium level of concentrates had higher live-weight losses than those given the high level in trial 1 (–58 v. –24 kg, P < 0·01) and trial 2 (–22 v. –kg). When concentrates were given at the medium level with moderate quality silage several cows had acetonaemia. Also, this feeding combination, especially when concentrates were given at a flat rate, reduced the proportion of cows which conceived within a limited breeding period.
Iron-induced copper deficiency in calves: dose-response relationships and interactions with molybdenum and sulphur
Authors: Bremner I. , Humphries W. R. , Phillippo M. , Walker M. J. , Morrice P. C.
Published: September 2010

The effects of dietary supplements of iron, molybdenum and sulphur on copper metabolism in calves were examined. In one experiment, 27 castrated male pre-ruminant Friesian calves were given a milk-substitute ration containing 0·9, 4·5 or 9 mmol iron per kg dry matter for 8 weeks. The iron supplements had no effect on liver copper retention. When 24 of these calves were then given a diet based on barley grains and barley straw containing 0, 4·5, 9 or 13·5 mmols iron per kg for up to 24 weeks, liver and plasma copper concentrations were greatly reduced in all iron-supplemented animals but no clinical signs of copper deficiency developed. Reduction in the dietary sulphur concentration from 88 o t 47 mmol/kg after 12 weeks did not prevent the iron-induced reduction in liver copper concentrations n i animals given 9 or 13·5 mmol iron per kg. Plasma copper concentrations increased in all iron-treated calves given the low-sulphur diets, except in animals given 13·5 mmol iron per kg. The results indicate that iron is a potent antagonist of copper metabolism in weaned calves and that its effects are probably independent of dietary sulphur supply.

In a second experiment 20 Hereford × Friesian female calves were given diets with supplements of 2·7 mmol iron and 20 μmol molybdenum per kg, separately and together, for 41 weeks. Both supplements reduced liver and plasma copper concentrations but only in the molybdenum-treated animals were live-weight gains reduced. The rate of decline in liver and plasma copper concentrations tended to be greatest in animals given both supplements, indicating that additive action of these antagonists is possible.
Responses of lactating sows to food level
Authors: Eastham P. R. , Smith W. C. , Whittemore C. T. , Phillips P.
Published: September 2010

Eighty crossbred sows, following a standard feeding regime in pregnancy, received daily either 2·0, 3·5. 5·0 or 6·5 kg diet containing 130 g digestible crude protein, 8·0 g lysine and 13·1 MJ digestible energy per kg over a 28-day lactation to produce variation in body fatness and live weight. Sows on the highest level of feeding gained 13 kg and lost some 3 mm backfat between farrowing and weaning; corresponding changes on the lowest level of feeding were –31 kg and –9 mm backfat. Live weight of the litter at weaning was positively related to sow daily food allowance in lactation, but the major benefit of increasing lactation food allowance was in reducing the rate of maternal body weight and fatty tissue loss. These effects were described by the regression equations: maternal live-weight change in lactation (kg/day) = —1·7+0·34 lactation food intake (kg/day); maternal backfat change in lactation (mm LJSP2) = —0·40+0·05 lactation food intake fkg/day). Sows ingesting less food in lactation catabolized proportionately more body tissue to maintain milk yield and piglet growth, although they achieved this imperfectly, having lighter litters at weaning. Calculation of an overall net balance, taking into account the need subsequently to replenish tissues catabolized in lactation and ensuring efficient rebreeding of the sow, favoured a lactation feeding strategy towards ad libitum.
Somatomedin C in dairy cows related to energy and protein supply and to milk production
Authors: Ronge H. , Blum J. , Clement C. , Jans F. , Leuenberger H. , Binder H.
Published: September 2010

Somatomedin C and other hormones, as well as blood metabolites, were measured during the dry period and during lactation in dairy cows, given different amounts of energy and protein, to study metabolic and endocrine adaptations. Somatomedin C, specifically measured by radioimmunoassay after separation from its binding protein, did not exhibit typical diurnal variations, in contrast to somatotropin and insulin, which increased particularly after concentrate intake. Somatomedin C markedly decreased at parturition and reached lowest values around the peak of lactation, while levels of somatotropin, nonesterified fatty acids and ketone bodies were high and those of glucose, insulin, thyroxine and triiodothyronine were low. Thereafter somatomedin C values slowly increased up to the 12th week of lactation and remained elevated. Low energy and protein balances were characterized by particularly low somatomedin C concentrations. An additional protein deficit at peak lactation, when cows were already provided with low amounts of energy, did not further decrease somatomedin C levels. However, when high amounts of energy were given in the form of starch or crystalline fat, somatomedin C increased. Overall, there was a positive correlation of somatomedin C primarily with energy, but also with protein balances and a negative correlation with milk yield. Conversely, somatotropin increased markedly after parturition and was positively correlated with milk production and negatively with protein and energy balances. Thus, somatomedin C levels were paradoxically low in the presence of high circulating somatotropin. Insulin most closely paralleled somatomedin C levels. Therefore the anabolic state of metabolism at the end of pregnancy was characterized by high somatomedin C and insulin and relatively low somatotropin, whereas the catabolic state of early lactation was characterized by high somatotropin, low somatomedin C, insulin and thyroid hormones.
The influence of concentrate amount on locomotion and clinical lameness in dairy cattle
Authors: Manson F. J. , Leaver J. D.
Published: September 2010

An experiment with two groups of 24 cows during weeks 3 to 22 of lactation examined the influence of 7 (L) or 11 (H) kg concentrates per day on the prevalence of lameness. Grass silage was offeredad libitum. The cows were scored on a 1 to 5 scale for their locomotion on a weekly basis (1 = normal locomotion; 5 = severely lame). Cows scoring 3 or more were considered to be clinically lame. This allowed the prevalence of lameness, its severity and duration to be measured and statistically analysed. There were significantly more observations of lameness in the H cows than the L cows (0·077 and 0·021 observations per cow week) and the severity and duration of lameness incidents were significantly greater. The major causes of lameness were solar problems in the hind feet. The prevalence declined in both treatments as lactation progressed. The predisposing causes of the higher incidence in treatment H could have been the higher concentrate: forage ratio, the greater daily metabolizable energy intake or the greater daily crude protein intake. For treatments L and H, mean milk yields were 20·5, 23·7 kg/day; milk fat 41·7, 39·0 g/kg; milk protein 31·4, 32·0 g/kg; live-weight change -0·12, +0·11 kg/day; and condition score 2·04, 2·18.
Effects of oestradiol-17β or zeranol with or without trenbolone acetate on live-weight gain, carcass composition and zeranol residues in steers on an 18-month beef system
Authors: Southgate J. R. , Peters A. R. , Dixon S. N.
Published: September 2010

A comparison of anabolic treatment regimes was made in 761 autumn-born Friesian steers on 14 farms. Prior to turn-out for grazing at 6 months of age and approximately 180 kg live weight, steers were weighed and divided into three equal-weight groups. Group 1 received silastic implants containing 45 mg oestradiol-17β. Group 2 received 36 mg zeranol and group 3 were untreated controls. All steers were weighed at intervals of approximately 3 months (i.e. mid summer, yarding at autumn, mid winter and pre-slaughter) and group 2 steers received a further 36 mg zeranol at the second, third and fourth weighing. At the third weighing half the cattle in each of the treatment groups 1 and 2 received 300 mg trenbolone acetate. Also at the third weighing, group 3 (controls) were subdivided into three equal-weight groups, the first of which received 45 mg oestradiol-17β and 300 mg trenbolone acetate and the second 36 mg zeranol and 300 mg trenbolone acetate. The third subgroup remained as untreated controls.

From 10 farms a 25% sample close to group mean weight at mid winter were slaughtered on the same day and subjectively assessed for subcutaneous fat score and conformation on 15-point scales. The left thin flank was separated into tissues. Samples of lean fat, liver and kidney were analysed for zeranol residues. All implant treatments resulted in higher live-weight gain, heavier slaughter weights and earlier slaughter. Trenbolone increased daily gain only during the first 3 months after treatment. Implanted carcasses were heavier both in the fore- and hindquarter but trenbolone also produced heavier forequarters. Carcasses from treated steers had more subcutaneous fat, less perinephric and retroperitoneal fat and less intermuscular fat in the thin-flank joint. Zeranol residues in implanted steers were not significantly higher than controls except in the kidney, but even these were significantly below accepted tolerance levels.