bluuebunny/crossref_metadata_2025 huggingface dataset:
Genetic variation in reaction time to halothane exposure
Authors: Blasco A. , Webb A. J.
Published: September 2010

The inheritance of the time taken to react to halothane anaesthesia was examined as a possible quantitative measure of penetrance, which might allow the advantage of the halothane gene in lean content to be separated from its disadvantage of stress susceptibility. Restricted maximum-likelihood analyses were conducted on a total of 2207 pigs from 118 sire families in British Landrace and Pietrain-Hampshire lines selected for a high frequency of positive halothane reaction over 6 years. Reaction time averaged 94 s with a CV of 0·53, and was significantly influenced by line, season and live weight, but not sex. Estimated heritabilities averaged 0·07 (s.e. 0·06) and 0·16 (s.e. 0·12) in the two lines respectively, giving a pooled estimate of 0·09 (s.e. 0·05). Due to the high CV, family selection with a heritability of around 0-1 could be expected to give a rapid genetic change in reaction time. It is therefore concluded that selection for slower reaction to halothane could provide a means for reducing the incidence of stress susceptibility while retaining the advantage of the gene in lean content. However, further evidence is required on the correlation of reaction time with stress susceptibility and lean content.
Food intake, milk yield and live-weight gain of dairy cows given increased amounts of calcium-saponified fatty acids of palm acid oil
Authors: Hermansen J. E.
Published: September 2010

A long-term experiment (first 24 weeks of lactation) with Danish Black and White cows and a short-term experiment with Jersey cows (experiment periods of 6 weeks) were carried out. In the long-term experiment, the effect of supplementing a normal dairy ration with 0·5 kg calcium (Ca) soap, 10 kg Ca-soap or 2 kg rolled barley was investigated in two herds, where silage was given ad libitum. The daily intakes of fatty acids in the diets were approximately 625, 1000, 1400 or 650 g respectively. Energy intake increased markedly by the supplementation, but not differently between soap or barley supplementation. The effect on milk production was not consistent in the two herds. In one herd, the soap supplement tended to increase milk fat yield (80 g/day) but not more than the barley supplementation which, in contrast to the fat supplementation, also increased milk protein yield. The effect of the fat was consistent over the first 6 months of lactation. In the other herd, only small differences in milk production were obtained with either supplements. In the short-term experiment carried out in mid lactation, a supplement of 0·8 kg Ca-soap increased daily intake of fatty acids from 730 to 1280 g per cow daily. Total food intake, milk and milk fat yield were not affected by the supplement but milk protein yield and live-weight gain were significantly reduced.
Reproductive performance of purebred and crossbred Zebu cattle under artificial insemination in the Amazon tropics
Authors: Garcia M. , Huanca W. , Echevarria L.
Published: September 2010

Breeding data from 1543 artificial inseminations, performed on 763 purebred and crossbred zebu cattle reared on 73 small farms, in the Amazon basin of Peru from 1980 to 1986, were evaluated. Inseminations were performed during morning hours using Holstein or Brown Swiss frozen semen. The calving to first oestrus and calving to conception intervals, number of services per conception, intervals between services and conception rate were evaluated. A total of 64-4% of first services and 61-4% of conceptions occurred between the middle of the dry season and the middle of the rainy season. Farm effect proved to be the most important source of variation for all reproductive traits. Other important factors influencing the interval from parturition to first service were breed of cow, parity and season of service. Parity influenced the interval from parturition to conception while parity, time of oestrous detection and inseminator influenced conception rate. The long post-partum anoestrous interval was found to be the most important factor limiting reproductive efficiency on small farms involved in the artificial insemination programme. The reproductive performance of the crossbred cattle tended to be better than that of the purebred zebu cattle.
Effect of feeding different levels of fatty acids or calcium soaps of fatty acids on digestion and metabolizable energy in sheep
Authors: Sklan D. , Nagar Lily , Arieli A.
Published: September 2010

Sheep were given diets containing 0, 30, 50 or 90 g/kg added free fatty acids from palm oil or from calcium soaps prepared from the same fatty acids in a three period switch-over design. Addition of free fatty acids to the diet enhanced metabolizable energy (ME) intake when added at 30 and 50 g/kg but not at 90 g/kg. On feeding 90 g/kg free fatty acids, rumen volatile fatty acid levels decreased and acid-detergent fibre and protein digestion was reduced. Calcium soaps of fatty acids enhanced ME intake at all levels added and had no effect on rumen fermentation. Addition of both free fatty acids and calcium soaps of fatty acids enhanced apparent digestibility of total fatty acids and of all fatty acids except stearic acid. The ME of free fatty acids added at 30 g/kg was 35·56 MJ/g and of calcium soaps of palm oil was approximately 33·05 MJ/g.
The influence of pre-slaughter transport and lairage on meat quality in pigs of two genotypes
Authors: Warriss P. D. , Brown S. N. , Bevis E. A. , Kestin S. C.
Published: September 2010

Two hundred and thirty-nine pigs reared at the Meat and Livestock Commission's Stotfold Pig Development Unit and derived from the four major breeding companies in the UK were slaughtered at 63 kg live weight in an experiment which examined the effect of genotype (Meat-line or White-line), pre-slaughter transport time (1 or 4 h) and lairage time (2 or 21 h) on carcass and meat quality. The pre-slaughter handling was chosen to simulate good commercial procedures and cover the range of transport and lairage times probably experienced by a large proportion of British slaughter pigs. Meatline pigs had higher killing-out proportions and heavier carcasses, with increased cross-sectional area of them. longissimus dorsi. Backfat thickness was similar in the two genotypes. White-line pigs had heavier livers and produced meat which potentially had a lower incidence of PSE. Longer transport time increased live-weight loss. It reduced carcass yield in the White-line but not in the Meat-line pigs. Transport had no major effects on meat quality. Longer lairage, during which the pigs were fed in compliance with the law, resulted in reduced carcass yield but increased liver weight and allowed some repletion of liver glycogen. It also reduced ultimate pH values in them. semimembranosusandm. adductor. There were no important or consistent differences in the way pigs of the two genotypes responded to pre-slaughter handling.
Atrophic rhinitis: the influence of the aerial environment
Authors: Robertson J. F. , Wilson D. , Smith W. J.
Published: September 2010

Infectious atrophic rhinitis is a disease of the upper respiratory tract of pigs, characterized in the live animal by deformation of the snout and conchal atrophy. However, the severity of the disease in pigs on commercial units is highly variable and air quality may be implicated as a significant factor in addition to the recognized pathogens. In this study the aerial environment was monitored in 49 pig buildings on 12 commercial farrowing-finishing units. A total of 1117 pigs from the 12 farms were examined individually at commercial slaughter weight to quantify the severity of conchal atrophy, using snout scoring and morphometric techniques.

A number of significant relationships were shown between environmental variables in the farrowing house and the severity of conchal atrophy. Mean snout score (MSS) and the percentage of snouts from each herd sample with a score of three or more (SS3) were correlated with total bacterial counts (r = 0·78 (P< 0·01) and 0-83 (P< 0·01) respectively), counts of 10 [mi to >15 urn particles (r = 0·67 (P<0·05), 0·73 (P<0·05)) and concentrations of gravimetric dust (r = 0·65 (P<0·05), 0·64 (P<0·05)). Concentrations of ammonia were correlated with SS3 (r = 0·68 (P<0·05)).

Dust in the first-stage weaner houses was again a significant component of the aerial environment associated with the severity of the disease. MSS and SS3 were correlated with counts of 10 urn to >15 μm particles (r = 0·66 (P<0·05), 0·68 (P<0·05)), concentrations of respirable dust (r = 0·67 (P<0·05), 0·63 (P<0·05)), total dust (r = 0·75 (P<0·05), 0·87 (P<0·001)), and gravimetric dust (r = 0·83 (P<0·01), 0·88 (P<0·001)). The results support the theory that the mass or number of particles present as inspirable aerosols, and the presence of large numbers of viable bacteria may compromise the local defence mechanism of the upper respiratory tract in the pig and facilitate colonization by Bordetella bronchiseptica and Pasteurella multocida. Saturation deficit in the second-stage weaner houses was correlated with both mean morphometric index and SS3 (r = 0·860 (P<0·01) and 0·683 (P<0·05) respectively), and volumetric stocking density in the finishing houses was correlated with both MSS and SS3 (r = -0·84 (P<0·01), -0·64 (P<0·05)). It is hypothesized that the severity of the disease may be lessened by reducing the concentrations of dust, microbes and ammonia which may play a significant role in the development of the disease.
Influence of method of forage preservation on fibre and protein digestion in cattle given lucerne, birdsfoot trefoil and sainfoin
Authors: Kraiem K. , Garrett J. E. , Meiske J. C. , Goodrich R. D. , Marten G. C.
Published: September 2010

Six steers, each fitted with a ruminal cannula and T-type duodenal and ileal cannulae, were used to investigate protein and fibre utilization from lucerne, birdsfoot trefoil and sainfoin preserved both as hay and silage. Steers were fed at 2-h intervals during six 12-day periods in an experiment with a 6 × 6 Latin-square design. Animals were fed all-forage diets of six treatments (lucerne hay and silage, birdsfoot trefoil hay and silage, sainfoin hay and silage). Samples were collected from all alimentary sites twice daily during the last 3 days of each period. Acid insoluble ash was used as a solid marker and Cr-ethylene diamine tetra-acetic acid as a liquid marker. Organic matter (OM), hemicellulose (HC) and cellulose (CL) total tract digestibilities of lucerne, birdsfoot trefoil and sainfoin were similar (OM: 599, 608, 580 g/kg; HC: 499, 497, 480 g/kg; CL: 590, 618, 608 g/kg). However, crude protein (CP) digestibilities were lower (P < 0·001) for sainfoin (582 g/kg) than for lucerne (732 g/kg) or birdsfoot trefoil (693 g/kg). Nitrogen (N) flows at the duodenum or ileum were similar among forages despite lower N intake for sainfoin. Presence of tannins in sainfoin may have been responsible for low protein degradation in the rumen, and reduced N digestion in the small intestine. Forage preserved as hay or silage had similar CL, HC and OM digestibilities, while CP digestibility was higher (P < 0·05) for silages.
A comparison of the responses by lactating cows given grass silage to changes in the degradability or quantity of protein offered in the supplement
Authors: Small J. C. , Gordon F. J.
Published: September 2010

Twenty-four lactating British Friesian type cows were used in a four period, partially balanced, changeover design experiment to evaluate eight treatments consisting of four protein sources in the supplement (soya-bean meal, formaldehyde treated soya-bean meal, fish meal and a mixture supplying equal crude protein levels from fish and soya-bean meal (respective degradabilities of total supplement nitrogen (N) were 0·56, 0·37, 0·32 and 0·44), each offered in supplements formulated to contain 150 and 200 g crude protein per kg fresh weight in a 4 × 2 factorial design. All supplements were offered at 8·0 kg/day in addition to ad libitum access to a medium digestibility grass silage (digestible organic matter as proportion of dry matter (DM), 0·66); with a relatively poor quality fermentation (pH, 4·5; ammonia-N proportion of total N, 0·21).

There were no significant interactions between source and level of protein on any of the animal performance variables. Source of protein did not influence milk output or milk composition but increasing protein intake significantly increased milk yield (26·0 and 26·7 (s.e. 0·19) for the low and high protein supplements respectively). Blood urea levels were significantly influenced by both protein source and level.

Total diet digestibility and energy and N utilization studies were undertaken with six replicates per treatment and the full data are presented. Neither protein source nor level had any significant effect on DM or energy digestibility. N digestibility was significantly reduced following formaldehyde treatment of soya-bean meal (0·69 v. 0·72 (s.e. 0·01)) and most N utilization variables were influenced by the level of protein intake but not by protein source.
Dietary energy losses of cattle influenced by body type, size, sex and intake
Authors: Anrique R. G. , Thonney M. L. , Ayala H. J.
Published: September 2010

Digestibility (DE) and metabolizability (ME) of a single pelleted diet was examined with growing Angus and Holstein cattle. One hundred and ninety-one individual digestion trials were conducted with bulls, steers and heifers. Food was offered ad libitum or restricted with a daily meal frequency of four. Data were analysed by two covariate models. The first included relative dry matter intake (RDMI) defined as the ratio of DMI to body weight (M0·73). In the second model, covariates were defined by genetic-size scaling; the first covariate scaled DMI by mature weight (A) raised to the power 0·73 (DMI/A0·73) and the second covariate was degree of maturity (μ) defined as body weight divided by A. Model 2 also allowed separation of size and DMI effects. No breed differences were detected. There was a consistent trend for increasing ME and ME/DE from heifers to steers to bulls which was significant between heifers and the average of bulls and steers (575·3 v. 589·3 and 832·8 v. 844·3 J/kJ for ME and ME/DE, respectively). Independent of animal effects, DE, ME and urinary energy (UE) decreased and ME/DE and faecal energy (FE) losses increased as RDMI or DMI/A0·73 increased. Per unit rise in RDMI equivalent to maintenance, the corresponding changes for DE, ME, ME/DE, FE and UE were –33·9, –13·6, 21·3, 34·1 and 9·6 J/kJ, respectively. DE increased 1·5 and ME increased 0·8 J/kJ GE for each 01 unit increase in degree of maturity.
In vitro and in vivo digestibility of soya-bean straw treated with various alkalis
Authors: Felix A. , Hill R. A. , Diarra B.
Published: September 2010

Three trials were conducted to evaluate the effects of treating soya-bean straw with various alkalis plus ensiling on digestibility of various nutrients and on nitrogen retention in ruminants. Soya-bean straw was treated with sodium hydroxide, calcium hydroxide or ammonium hydroxide and ensiled at 650 g/kg moisture. In trial 1, the effects of level and type of alkali on in vitro digestibility of ensiled soya-bean straw were evaluated. Concentrations of alkalis used were 0 (control), 20, 30, 40 and 50 g/kg dry matter. Both in vitro digestibilities of dry matter and organic matter of soya-bean straw were significantly (P < 0·05) increased with alkali treatment at all levels plus ensiling compared with untreated or treated unensiled straw. The 40 g/kg alkali concentration level in combination with ensiling appeared to be the most effective overall. In trial 2, the effects of type of alkali on nutrient digestibility and nitrogen retention in wether lambs were evaluated. Sixteen wether Suffolk lambs were given untreated or alkali-treated (40 g/kg) ensiled soya-bean straw. Treatments were: (1) water-treated straw; (2) NaOH-treated straw: (3) Ca(OH)1-treated straw; and (4) NH4OH-treated straw. Lambs given NH4OH-treated ensiled straw digested the dry matter, organic matter, and crude protein better than those given water-treated ensiled straw (P < 0·05). NH4OH improved nitrogen intake by proportionately 0·181 but not nitrogen retention. For trial 3, eight Angus steers were used. Chopped soya-bean straw was treated with NH4OH and ensiled in Silopress bags. Treatments were: (1) untreated dry straw; (2) water-treated straw; (3) 30 g/kg NH4OH-treated straw; and (4) 40 g/kg NH4OH-treated straw. The trial consisted of a 7-day collection period which was replicated once. Apparent digestibilities of dry matter, crude protein and various fibre constituents were increased by ensiling or ensiling and NH4 OH treatment combinations (P < 0·05). Alkali treatments in combination with ensiling appeared to improve digestibility of soya-bean straw, but ammoniation did not improve nitrogen utilization. Ensiling appeared to have a more significant effect than alkali treatments per se on the degradability of soya-bean straw.
Marker-assisted selection of candidate bulls for progeny testing programmes
Authors: Kashi Y. , Hallerman E. , Soller M.
Published: September 2010

A theoretical analysis of the potential benefits of marker-assisted selection (MAS) of candidate bulls prior to entry into a young sire progeny testing programme was carried out. It is assumed that quantitative trait loci (QTL) affecting milk production have been mapped with respect to known genetic markers, and MAS is based on evaluation of elite sires in order to identify marker alleles in coupling to favourable or unfavourable QTL alleles. Candidate bulls, descendants of the elite sire will then be selected, prior to conventional progeny testing, on the basis of the marker alleles derived from the elite-sire ancestor.

The analysis considers recombination between marker and QTL, the difficulty of tracing specific marker alleles from sire to progeny, and the expectation that MAS, in practice, will be implemented in the grandsons, rather than in the sons of elite sires. It is shown that MAS of candidate bulls, based on the use of a single diallelic marker in linkage to a QTL will have only a negligible effect on the rate of genetic progress. Increases of 15 to 20% in the rate of genetic gain, however, can be obtained by the use of single polyallelic markers, and increases of 20 to 30% can be obtained by utilizing haplotypes of diallelic or polyallelic markers.
Lameness in dairy cattle and the type of concentrate given
Authors: Kelly E. F. , Leaver J. D.
Published: September 2010

A concentrate containing ground barley, soya-bean meal and fish meal was compared with one containing dried molassed sugar-beet pellets, dried distillers' grains and fish meal, in its influence on lameness in housed dairy cattle. Two groups of 24 cows were offered the diets in a 60:40 concentrate dry matter: grass silage dry matter ratio during weeks 3 to 26 of lactation. The same daily amounts of metabolizable energy and crude protein were offered to the two groups. The barley-based concentrate diet significantly increased locomotion score (indicating poorer locomotion), and the number and duration of clinical cases of lameness, compared with the sugar-beet concentrate diet. Hoof growth, wear, shape and hardness were not significantly affected by the diets. There were 16/24 cows with a locomotion score of 3 or over (1 to 5 scale) for an average of 7·3 weeks on the barley concentrate compared with 10/24 cows for 3·7 weeks on the sugar-beet concentrate. There was no significant difference between treatments in milk production or live-weight gain.
A note on fertilization and embryo production in superovulated cattle with various levels of subcutaneous fat tissue
Authors: Bielanski A. , Yadav B. R.
Published: September 2010

One hundred and five Holstein cattle, with a mean body weight of 668 kg, were superovulated using a total dose of 18 mg FSH. Five animals did not have corpora lutea (CL). No ova or embryos were recovered from 12 of the 100 animals which had CL. A total of 810 ova/embryos were collected from the remaining 88 animals and 432 of these were of transferable quality. The mean (range) measurements for subcutaneous fat deposition in samples taken at slaughter from the back, rump and ventral abdominal wall were 14 mm (3 to 34), 7 mm (0·7 to 33) and 7 mm (0·8 to 32), respectively. The number of transferable embryos and fertilized ova decreased as fat levels increased, but the differences between the groups were not significant (P > 0·05). There was a positive relationship between the number of CL and (a) the number of fertilized ova, and (b) the number of transferable embryos (r = 0·53, P < 0·001 and r = 0·48, P < 0·001). The correlation between the number of fertilized embryos and the number of transferable embryos was r = 0·91, P < 0·001.
The effect of milk substitute input during calfhood on the lifetime performance of beef cattle
Authors: Steen R. W. J.
Published: September 2010

Three randomized-block experiments involving 87 British Friesian, 18 Simmental × Friesian and 18 Hereford × Friesian, artificially reared calves (mean initial live weight 47 kg and age 9 days), were carried out to examine the effects of the quantity of milk substitute consumed on the lifetime performance of beef cattle. The three treatments were (1) 400 g milk powder per head daily, weaned at 42 days of age (2) ad libitum intake of milk powder, weaned at 42 days and (3) ad libitum intake of milk powder, weaned at 60 days. All calves were individually penned and fed until after weaning; those on treatment 1 were bucket fed twice daily, while those on treatments 2 and 3 sucked the milk from 25·1 containers through artificial teats. They were offered a pelleted, barley/soya-bean meal concentrate (197 g crude protein per kg dry matter (DM)) ad libitum from purchase until intake reached a maximum of 2·7 kg per head daily, and well preserved grass silage ad libitum from 6 weeks of age. Three commercial, skimmed milk-based, acidified milk substitutes (242 and 187 g crude protein and oil per kg respectively) were used. Intakes of milk substitute, concentrate DM and silage DM per calf to 12 weeks of age for treatments 1 to 3 respectively were as follows: 13·0, 39·7 and 54·8 (s.e. 1·67) kg; 88, 73 and 58 (s.e. 1·5) kg and 9·4, 10·6 and 11·2 (s.e. 0·23) kg. Live-weight gains to 12 weeks of age and carcass weights adjusted to 19 months of age were 0·71, 0·82 and 0·84 (s.e. 0·026) kg/day and 335, 340 and 341 (s.e. 3·8) kg. It is concluded that increasing the input of milk substitute above 400 g per head daily until 6 weeks of age produced only a small and uneconomic increase in the lifetime performance of beef cattle.
The effect of level of nutrition prior to mating on the reproductive performance of ewes of two welsh breeds in different levels of body condition
Authors: Gunn R. G. , Maxwell T. J. , Sim D. A. , Jones J. R. , James M. E.
Published: September 2010

The effects of high-low (HL) and low-high (LH) patterns of nutrition during the 5 weeks prior to a synchronized mating were studied on the reproductive performance of 115 Welsh Mountain and 114 Brecknock Cheviot ewes in a range of body condition at the start of treatment. For 2 months prior to treatment imposition, ewes were grazed in a systematic way at different stocking rates on different sward heights to obtain a range of body condition scores. Target score groupings were 2·00 to 2·25, 2·50 to 2·75 and 3·00 to 3·25 and although scores of 1·50 to 3·25 were obtained, most lay in the 2·00 to 2·75 range. Two treatment groups, balanced for live weight and body condition score, received high and low levels of nutrition for 16 days from mid October, achieved, respectively, by a low stocking rate on a sward with a high surface height plus ad libitum concentrate and a high stocking rate on a sward with a low surface height plus 200 g hay per head per day. Treatments were then reversed for the 17 days prior to mating. Live-weight and body condition-score changes were recorded and reproductive performance at first mating was measured from counts of corpora lutea and viable embryos at slaughter either at return to service or at 4 weeks after first mating. There were no differences due to nutritional pattern in live weight or body condition score at mating. The LH treatment significantly increased the rates of ovulation, conception, multiple ova survival and potential lambing per ewe pregnant and per ewe mated in the Welsh Mountain breed but significantly increased only the rates of ovulation and potential lambing per ewe pregnant in the Brecknock Cheviot breed compared with the HL treatment. The relatively poorer response in the latter breed was partially due to a lower ovulation rate potential coupled with non-significantly lower rates of conception and survival of single-shed ova associated with the LH treatment. Much of this relatively poorer reproductive performance in the Brecknock Cheviot breed was in ewes with body condition scores 3= 2·75. Reproductive performance increased with increasing body condition at the start of treatment over the range of scores =≤ 2·25 to 2·50 in both breeds and, while continuing to improve in scores above 2·50 in the Welsh Mountain breed, in the Brecknock Cheviot breed it started to decline. Ewes with a body condition score of 2·50 in both breeds showed the greatest response in potential lambing rate to the LH treatment.
The effects of food protein content on the performance of pigs previously given foods with low or moderate protein contents
Authors: Kyriazakis I. , Stamataris C. , Emmans G. C. , Whittemore C. T.
Published: September 2010

An experiment was conducted to study the ability of the pig to recover from the effects of a period on a food deficient in crude protein (CP). Forty young pigs were given free and continuous access to foods with either 150 (L) or 252 (M) g CP per kg in period 1 of the experiment, from 6·3 kg to 13·4 and 12·3 kg live weight respectively. These live weights were expected to give equal lipid-free empty body weights. In period 2, four males and four females from each of the period 1 treatments were given access to either M or a food with 377 g CP per kg (H) to a live weight of 30 kg, when the 32 pigs were killed.

Pigs on L took 11 (s.e. 0·6) days longer to complete period 1, and had, at the end of this period, 0·20 (s.e. 0·03) kg less protein and 1·20 (s.e. 0·06) kg more lipid in their bodies than the M pigs, at a common ash weight. In period 2, pigs from L grew at a faster rate (750v.633 (s.e.d. 20) g/day), ate food at the same rate (1115v.1085 (s.e.d. 35) g/day) and converted food more efficiently (0·676v.0·585 (s.e.d. 0·016) g gain per g food) than those from M. At 30·3 kg live weight the pigs from L had corrected their protein deficit relative to ash and reduced their fatness, so that they had the same protein: ash ratio and only 0·47 (s.e. 0·12) kg more lipid in their bodies than those from M. This was the result of a higher rate of gain of protein and water, a lower rate of lipid gain and similar rate of ash gain by the pigs from L than those from M. In the first 7 days of period 2 the pigs from L gained weight at 1·4 times the rate of those from M. In the final 7 days there was no significant effect of period 1 treatment on growth rate. The pigs from L given food H in period 2 were more efficient than those given M in period 2 (food conversion efficiency (FCE) values of 0·884 and 0·791 respectively; s.e.d. 0·027), but this difference was reversed in the final 7 days (FCE values of 0·521 and 0·603 respectively). t I is concluded from these results that a period of eating a food of low protein content produces a reduced protein: ash and an increased lipid: ash ratio in the body and reduced growth rate and efficiency. When subsequently pigs are given a food of sufficiently high protein content, the protein: ash and lipid: ash ratios return to normal. The repletion of labile protein reserves, with their associated water, leads to a substantial increase in the rate of live-weight gain. The lower lipid content of the gain leads to a high efficiency. The duration of these effects depends on the protein content of the food given.
Differences in the composition and tissue distribution of pig carcasses due to selection and feeding level
Authors: Godfrey N. W. , Frapple P. G. , Paterson A. M. , Payne H. G.
Published: September 2010

A total of 96 Large White weaner pigs, comprising equal numbers of entire males and females, and of controls and eighth generation index-selected genotypes, were fed ad libitum until 40 kg live weight. From 40 kg until slaughter at 85 kg live weight pigs within genotype and sex groups were fed either ad libitum or 2·2 times maintenance. The left sides of the carcasses were divided into shoulder, middle and ham portions and the middles further divided into eye, wedge and belly dorso-ventral portions. Tissue dissection was performed on all portions separately.

Selected pigs yielded proportionately 0·15 less fat, 0·08 more muscle, a smaller muscle: bone ratio and 4·05 mm less P2 backfat depth than the controls. When the data were adjusted to the same mean P2 fat depth, the carcasses of selected pigs had 0·07 less fat and 0·03 more muscle. There were no appreciable differences between the genotypes in cranio-caudal tissue distribution. However, there were differences in dorso-ventral tissue distribution since the middles of selected pigs had proportionately and absolutely more of each tissue in the belly. There was no evidence that selection against fat at the P2 site had caused any increase in fat lateral to the m. longissimus.

Food restriction increased carcass muscle by 0·10 and decreased fat by 0·17, but had no effect on muscle: bone ratio or cranio-caudal or dorso-ventral tissue distribution. At the same carcass side weight and P2 fat depth, restricted feeding decreased fat by 0·10 and increased muscle by 0·06 in the carcass side.

It is concluded that carcasses of the selected pigs would be undervalued relative to the controls due to less fat and more muscle at the same weight and P2 fat depth. Also, restriction on food intake can cause carcasses to be undervalued relative to feeding ad libitum.
Prediction of gross energy content of ewe milk
Authors: Šebek L. B. J. , Everts H.
Published: September 2010

The interpretation of the results of feeding trials with lactating ewes and their sucking lambs can be improved considerably when milk energy production is known. The determination of gross energy (GE) however is time consuming and expensive. Therefore an equation to predict GE from milk constituents would be helpful.

Using multiple regression analysis a GE-prediction equation was derived with milk samples mainly from crossbred ewes. The concentrations of milk constituents were determined by infrared spectrometry (calibrated with cow milk). Fat concentration ranged between 43·8 and 125·0 g/kg, protein concentration between 32·4 and 53·1 g/kg and lactose concentration between 38·9 and 52·9 g/kg. GE (adiabatic bomb calorimetry) of the samples under consideration ranged between 3500 to 6800 kj/kg.

The following equation, including fat (f), protein (p) and lactose (I), is recommended and predicts GE as kj/kg fresh milk using constituents in g/kg fresh milk:

GE = 41·94 × f + 15·85 × p + 21·41 ×l (residual s.d. = 92, adj.R2 = 0·98).

This equation has, in the GE range 4500 kj to 6000 kj, an almost constant confidence interval with an average of ±25 kJ and an almost constant prediction interval, with an average of ±87 kJ. In the period until weaning it would appear justified to use the derived equation regardless of stage of lactation. The equation is valid for milk samples from sheep breeds with relatively high fat and low protein contents and where milk constituents have been determined by cow milk calibrated infrared spectrometry.
The influence of an inoculant/enzyme preparation as an additive for grass silage offered in combination with three levels of concentrate supplementation on performance of lactating dairy cows
Authors: Smith E. J. , Henderson A. R. , Oldham J. D. , Whitaker D. A. , Aitchison K. , Anderson D. H. , Kelly J. M.
Published: September 2010

Three silages were prepared from the primary growth of a predominantly perennial ryegrass sward (dry matter (DM) 175 g/kg; crude protein 142 g/kg DM; water-soluble carbohydrates (WSC) 243 g/kg DM). Herbage was wilted for 24 h and then treated with either an inoculant/enzyme preparation (Lactobacillus plantarum, Streptococcus faecium and Pediococcus acidilactici), formic acid applied at 4·2 lit (Add F, BP Chemicals) or no additive. Time series analysis of laboratory silages revealed that different patterns of fermentation had been achieved: formic acid treatment resulted in high levels of residual WSC and low levels of lactic acid, indicative of an inhibited fermentation, whilst treatment with the inoculant/enzyme preparation resulted in high levels of lactic acid with a low level of residual sugars, as expected with an enhanced fermentation. Analysis of the material ‘as fed’ showed that losses in the WSC content of the formic acid-treated silage had occurred in the clamp. Secondary fermentation of lactic to acetic acid was apparent in the untreated silage, but not in the inoculant/enzyme-treated silage. Digestibility, as determined using Greyface wether lambs, was marginally higher for both additive treatments when compared with the untreated silage. An evaluation of the silages for milk production was carried out at three levels of concentrate supplementation using 18 Ayrshire × British Friesian cows in a replicated 3×3 Latin-square design experiment. Treatment with formic acid resulted in significantly higher DM intakes, but this was not reflected in milk energy output. Cows offered the inoculant/enzyme-treated silage partitioned energy away from milk production toward body tissue deposition (average milk yields 19·9, 19·9 and 15·2 kg/day, and weight gain 0·26, 0·38 and 0·81 kg/day for the untreated, formic acid and inoculant/enzyme-treated silages respectively). The reason for this is not clear, but it is postulated that microbial capture of degraded nitrogen may have been impaired with the inoculant/enzyme-treated silage, resulting in an imbalance in metabolizable protein: metabolizable energy.
A note on the microencapsulation of pancreatic protease for protection against gastric digestion
Authors: Lin C. W. , Lee T. G.
Published: September 2010

Zeolite, cellulose acetate phthalate (CAP) and maize starch were used as the coating materials for encapsulating pancreatic protease, which was proposed as an additive to enhance the food efficiency and growth rate of weanling pigs. In this study, microcapsules were formed by the process of coacervation in liquid paraffin media, where the deposition time was in the range of 20 to 60 min, and the concentrations of CAP, zeolite and maize starch were 20, 40 and 120 g/kg respectively. Hardening by n-hexane was achieved with 15 min of stirring. Microcapsules generated by this method were 20 to 30 mesh in diameter. They were stable for at least 3 h in simulated gastric conditions (pH 3·97), but disintegrated rapidly under simulated intestinal conditions (pH 6·82).
The effects of dietary fibre and starch concentrations on the response by dairy cows to body condition at calving
Authors: Garnsworthy P. C. , Jones G. P.
Published: September 2010

An experiment was conducted to examine the effects of dietary fibre and starch levels on the response to condition score at calving. Fifty-two cows were used over two winter feeding periods, with 24 and 28 different cows in each. Twelve weeks before their expected calving date, cows were paired and the level of feeding adjusted to attain mean condition scores at calving of 2·0 (T) and 3·5 (F) within pairs. At calving, pairs of cows were allocated to treatment HF or LF, giving four groups in total. Each day for the first 16 weeks of lactation, all cows were offered 10 kg dairy concentrate containing either high-fibre/low-starch (FHF and THF), or low-fibre/high-starch (FLF and TLF), 2 kg sugar-beet pulp and hay ad libitum. Two cows from each group were used to determine apparent digestibility of the whole diet each year, using chromium III oxide as a faecal marker. Eight steers were used to determine the degradabilities of dry matter, nitrogen and fibre in the two concentrates and to provide rumen fluid samples for volatile fatty acid determination.
Covariance matrices for growth traits of Australian Polled Hereford cattle
Authors: Meyer K.
Published: September 2010

Estimates of covariance components due to direct and maternal effects among birth, weaning, yearling and final weight for Australian Polled Herefords were obtained by restricted maximum likelihood fitting an animal model. Data were obtained from commercial herds participating in the National Beef Recording Scheme and an across-herd genetic evaluation service. Analyses were carried out considering nine subsets of data, each comprising at least 3000 weaning, 1000 yearling and 500 final weight records which yielded a total of 30 506,17 105 and 9486 records for the three weights, respectively. Estimates of variances and genetic parameters varied considerably between data sets. Both genetic and permanent environmental effects were found to affect all traits except final weights significantly, with maternal environmental effects explaining proportionately more than 0·20 of the total variation in weaning weight. Estimates of the direct-maternal genetic correlation were consistently negative and moderate to strong, ranging from -0·34 to -0·82 for weaning weight. Maternal correlations between weaning and yearling weights were close to unity. Estimates of the direct genetic correlations among the three later weights were 0·8 or larger. Problems with this kind of analysis are discussed.
A comparison of gas production during incubation with rumen contents in vitro and nylon bag degradability as predictors of the apparent digestibility in vivo and the voluntary intake of hays
Authors: Khazaal K. , Dentinho M. T. , Ribeiro J. M. , Ørskov E. R.
Published: September 2010

Ten hays harvested at three stages (early bloom MB, mid bloom MB or in seed) made from lucerne (Medicago sativaj, sweet clover (Melilotus segetalis), Persian clover (Trifolium resupinatum) and pre-bloom (PB) Italian ryegrass (Lolium multiflorum var.), were offered ad libitum to four Merino male sheep and daily intake (g dry matter (DM) per kg M0·75) and DM apparent digestibility (DMD) were measured. In sacco DM degradation (g per 100 g DM), gas production (ml per 200 mg DM), in vitro digestibility and fibre composition (g/kg DM) of the hays were also studied. Gas production or DM degradation were calculated at 6, 12, 24, 48, 72 or 96 h and their kinetics were described using the equation p = a + b(1 - e-ct). Intake and in vivo DMD of the hays were variable (P < 0·01). Lucerne EB and Persian clover (all stages) had the highest nutritive value, whereas sweet clover (all stages) had the lowest. Apart from neutral-detergent fibre, which was only related to intake (r = -0·68; P < 0·05), chemical components and in vitro digestibility were poorly (P > 0·05) related to animal performance. Between 12 and 96 h incubation, intake and in vivo DMD were better related to DM degradation (r = 0·79 to 0·83; r = 0·61 to 0·77) than to gas production (r = 0·73 to 0·80; r = 0·58 to 0·78). Prediction of intake and in vivo DMD from the (a + b) values did not provide a great advantage over using some of the static values of gas production or DM degradation.

Multiple regression using separated kinetics of degradation resulted in highest accuracy for predicting intake and apparent digestibility from gas production (R2 = 0·63; R2 = 0·78) and nylon bag degradability (R2 = 0·77; R2 = 0·89). It was concluded that the gas test has good potentiality as it was capable of predicting not only apparent digestibility, but also intake to a level close to that of the nylon bag technique.
The use of degradation characteristics of browse plants to predict intake and digestibility by goats
Authors: Kibont A. , Ørskov E. R.
Published: September 2010

Twenty-five male goats weighing 16 (s.e. 1-5) kg and aged 15 months were used to measure the dry matter (DM) intake of five browse species namely Acacia albida, Tamarindus indica, Etanda africana, Anogeissus leiocarpus and Sterculia setigera in a growth trial lasting 16 weeks. This was followed by a digestion trial with five goats in a 5 × 5 Latin square with 10 days adaptation and a 5-day measurement period. The degradation characteristics of the browse were measured by incubating samples in nylon bags for 6, 24, 48 and 96 h in the rumens of three sheep fitted with rumen cannulae and given hay plus grass nuts. The exponential model P = a +b(l — ect) was fitted to the data. Rumen fluid from the sheep was also used as an inoculum to incubate the samples in vitro for 3, 6,12, 24, 48, 72 and 96 h. Nylon bag degradability results were compared with in vivo results and in vitro gas production. The mean DM intakes, apparent digestible DM intakes and growth rates were 0·60, 0·62, 0·55, 0·53 and 0·65 kg/day, 0·43, 0·43, 0·35, 0·34 and 0·49 kg/day and 55, 60, 49, 42 and 62 glday for A. albida, T. indica, E. africana, A. leiocarpus and S. setigera respectively. Using the degradation characteristics A, B and c in a multiple regression analysis, the correlation coefficients with DM intake, apparent DM digestibility, apparent digestible DM intake and growth rate were 0·99, 0·88, 0·92 and 0·99 respectively. The inclusion of a lag phase (L) instead of A in the regression analysis improved the prediction of apparent DM digestibility and apparent digestible DM intake. The correlation coefficients between DM loss in nylon bags and in vitro gas production at 6, 24 and 48 h incubation were 0·84, 0·83 and 0·90 respectively. The results indicate that it may be possible to predict DM and apparent digestible DM intakes of browse by goats from the rumen degradation characteristics.
Performance of British Saanen, Boer × British Saanen and Anglo-Nubian castrated male kids from 8 weeks to slaughter at 28, 33 or 38 kg live weight
Authors: Gibb M. J. , Cook J. E. , Treacher T. T.
Published: September 2010

The performance of British Saanen, Boer × British Saanen and Anglo-Nubian kids from weaning to slaughter at 28, 33 or 38 kg live weight (LW) was examined in a 3 × 3 factorial experiment. Kids were reared on a concentrate and hay ration, after weaning at 8 weeks of age. Intakes were measured individually. At slaughter, carcasses and body fractions were weighed, left half-carcasses were dissected into muscle, fat and bone, and the carcass and non-carcass fractions were analysed chemically. There ivas no significant effect of breed type on mean daily intakes, but there was a significant breed-type effect on mean daily LW gains in the order British Saanen > Boer × British Saanen > Anglo-Nubian kids. Compared with the pure British Saanen kids, the Anglo-Nubian kids produced heavier carcasses yielding more muscle and less subcutaneous and intermuscular fat at each slaughter weight. By contrast, the Boer × British Saanen carcasses contained proportionately more fat, mainly intermuscular fat, than the British Saanen when slaughtered at 28 or 33 kg LW. When taken on to slaughter at 38 kg LW, the Boer × British Saanen kids showed little further increase in fat deposition at the internal and intermuscular sites compared with the British Saanens, resulting in carcasses with slightly more subcutaneous fat but lower overall carcass fat content.
The effects of plane of nutrition and slaughter weight on the performance and carcass composition of continental beef bulls given high forage diets
Authors: Patterson D. C. , Moore C. A. , Steen R. W. J.
Published: September 2010

Bulls (½ Blonde d'Aquitaine ⅜ Charolais) were used in a 2 × 3 factorial design experiment with two planes of nutrition in the finishing period and three slaughter weights. High and low planes of nutrition were based on diets with similar forage to concentrate ratio (0·40 of dry matter (DM)) offered ad libitum or at 0·78 of ad libitum DM intake at equal live weight respectively. The target slaughter live weights were 550, 625 and 700 kg. Twelve bulls were taken to each slaughter point and an additional five animals were killed as a pre-experimental slaughter group. Mean initial live weight was 412 (s.e. 5·3) kg at a mean age of 342 (s.e. 2·5) days. No significant interactions were found between the main factors. For the high and low planes, live-weight and estimated carcass gains were 1251 and 989 (s.e. 47·7), and 816 and 668 (s.e. 35·3) g/day respectively, the reduction in gains being similar to the proportional degree of nutritional restriction. Plane of nutrition had no effect on live-weight or carcass gain per unit of energy intake. The low plane of nutrition produced significant decreases in body cavity fat depots, subcutaneous fat in the sample joint and increased the proportions of both saleable beef and high-priced joints in the carcass.

With increase in slaughter weight, energy intake per unit of live weight0·75 and rates of both live-weight and carcass gain tended to decline. The dressing proportions were 583,579 and 609 (s.e. 9·1) g/kg for the slaughter live weights of 550, 625 and 700 kg. Carcass conformation improved while fat depots in the body cavity and estimated concentration of separable fat in the carcass increased with increase in slaughter weight, and both estimated lean and bone concentrations decreased. Forequarter as a proportion of total side tended to increase with increase in slaughter weight. Slaughter weight had no effect on concentration of saleable meat or ultimate pH of carcass muscle. It is concluded that bulls of this genotype can be taken to high slaughter weights on diets having a relatively high proportion of forage as grass silage, with high rates of growth and acceptable carcass leanness.
A note on the effects of breed, stage of lactation and pregnancy status on milk composition of rabbits
Authors: El-Sayiad GH. A. , Habeeb A. A. M. , El-Maghawry A. M.
Published: September 2010

Forty-five New Zealand White and 35 Californian doe rabbits, 8 months old and in the third parity of their 1st year of production were used in this study. Thirty-five does were concurrently pregnant and lactating, the remaining 45 does were non-pregnant. Milk samples were collected in colostrum and at the 7th, 14th, 21st, 28th and 35th days of lactation. Neither breed nor pregnancy status affected the does milk composition except for total phosphorus which was significantly lower (P < 0·05) in the pregnant does' milk. However the major components of milk except lactose, were significantly affected by stage of lactation. Both moisture: total solids and calcium: phosphorus ratios were the same (2:1) throughout the lactation. The ratio between retinol concentration in colostrum and in the 5th week was about 10:1. Specific gravity was significantly (P < 0·05) correlated with protein, lactose (positive) and fat (negative).