Efficiency Of Live-weight Gain Research Articles

Effect of rates and extent of ruminal barley grain dry matter and starch disappearance on bloat, liver abscesses, and performance of feedlot steers

The objective was to test the hypothesis that differences in ruminal solubility and degradation of barley grain affects health and rate and efficiency of gain in feedlot steers. Ten barley grains were fed to 200 steer calves (365±27 kg) in diets containing 85.5% barley grain. Overall, 14% of the steers bloated at least once in the experiment and 16% had abscessed livers. Incidences of bloat and liver abscesses did not differ ( P>0.15) between barleys with two- versus six-row head-type morphology. The percentage of animals which bloated at least once was negatively related to the percentage of barley dry matter (DM; r=−0.60; P<0.1) and starch ( r=−0.73; P<0.05) which slowly disappeared in the rumen. Similarly, the percentage of slowly disappearing DM was correlated to the percentage of animals with liver abscesses ( r=−0.82; P<0.01). No differences in DM intake (9.7–10.9 kg per day), daily gain (1.46–1.61 kg per day), kg gain per kg feed DM consumed (0.146–0.157), or carcass characteristics were detected between steers fed the barleys. Dry matter intake, daily gain and feed efficiency of the steers were not related to starch or DM in ground barley which initially washed out of the bags or slowly disappeared in the rumen. Also, rate of disappearance of starch and DM were not related to rate or efficiency of liveweight gain. Daily gain was, however, positively related ( r=0.70; P<0.05) to the percentage of DM which slowly disappeared when rolled grain was incubated in the rumen. Similarly, the estimated degradability of rolled barley in the rumen at a ruminal passage rate of 5% per h was positively related ( r=0.66; P<0.05) to liveweight gain per feed DM consumed. In conclusion, bloat and liver abscesses increased when barley grain was rapidly solubilized and degraded in the rumen. Further, although rate and extent of ruminal disappearance of starch and DM from ground barley grain have important implications with respect to health of cattle, the effect of intrinsic differences in ruminal degradability on rate and efficiency of gain cannot be evaluated in isolation from the effects of grain processing.

Growth and carcass characteristics of three lamb genotypes finished on the same level of feeding

AbstractThis study investigated the efficiency of growth and the carcass characteristics of 24 Greyface (Border Leicester × Scottish Blackface), 24 Texel (12 purebred and 12 Texel × Texel-Greyface) and 24 Rouge (12 purebred and 12 Rouge × Rouge-Greyface) lambs finished on the same level of feeding. The efficiency of live-weight gain (kg/MJ) was higher in Greyface compared with Texel lambs (P&lt; 0·01). The efficiency of empty body-weight gain (kg/MJ) was higher in Greyface (P&lt; 0·01) and Rouge (P&lt; 0·05) compared with Texel lambs. The efficiency of carcass gains (kg/MJ) tended to be higher in Greyface and Rouge compared with Texel lambs (P= 0·07). The efficiency of non-carcass component gains (kg/MJ) was also higher in Greyface compared with Texel lambs (P0·05). Carcass water, protein, lipid and ash gains did not vary significantly between the genotypes, however carcass energy gain tended to be higher in Greyface and Rouge compared with Texel lambs (P= 0·08). The relative proportions of water, protein, lipid and ash in carcass gains did not vary significantly between the genotypes. At the end of the experiment carcass water content was higher in Texel compared with Greyface lambs (P&lt; 0·05) and carcass ash content was lower in Texel compared with Greyface (P&lt; 0·01) and Rouge (P&lt; 0·05) lambs. The concentration of saturated fatty acids was higher in Greyface compared with Rouge lambs (P&lt; 0·001) and higher in Rouge compared with Texel lambs (P&lt; 0·05). Monounsaturated fatty acid concentrations were higher in Rouge compared with Greyface lambs (P&lt; 0·05) and higher in Texel compared with Rouge lambs (P&lt; 0·001). Polyunsaturated fatty acid concentrations were higher in Rouge and Texel compared with Greyface lambs (P&lt; 0·01). The ratio of n-6:n-3 fatty acids was lower in Rouge compared with Greyface lambs (P&lt; 0·05).The efficiency of empty body gain was higher in male compared with female lambs (P&lt; 0·05). Carcass water (P&lt; 0·01) and protein (P&lt; 0·05) gains were higher in male lambs. At the end of the experiment male carcasses contained a higher content of water (P&lt; 0·05), protein (P&lt; 0·01) and ash (P= 0·07), and a lower lipid (P&lt; 0·05) and energy (P&lt; 0·001) content. Carcass lipids from male lambs contained a higher concentration of polyunsaturated fatty acids (P&lt; 0·001) and tended to contain a lower concentration of saturated fatty acids (P = 0·06).

Complementarity of bird-resistant and non-bird-resistant varieties of sorghum stover with cottonseed cake and noug (Guizotia abyssinica) cake when fed to sheep

A study was conducted to examine whether oilseed cakes (cottonseed cake (CSC) or noug (Guizotia abyssinica) cake (NSC)) are complementary to the bird-resistant (BR) and non-bird-resistant (NBR) varieties of sorghum stover and whether sheep select against morphological fractions containing high concentrations of tannins or proanthocyanidins (PA). Either 24 (growth study) or 16 (metabolism study) Ethiopian Menz sheep were used in a randomized complete block design to study the interaction of variety of sorghum stover with type of oilseed cake on feed selection, intake, digestibility, microbial protein synthesis, nitrogen (N) retention and growth. The degradability of the feeds and refusals was also determined. The NBR variety was more degradable than the BR variety during the early hours of incubation. NSC degraded faster, although to a lesser extent than CSC. Stover variety had no effect on ruminal ammonia concentration (RAC) while CSC induced a higher RAC than NSC did. Sheep given the NBR variety had more dust, less heads, less leaf, less sheath and more stem in their ingesta than those fed on the BR variety. It was seen that the sheep discriminated against the stems, since the ratio of stem in ingesta to stem on offer was &lt;1. Since PA are more highly concentrated in the sheath than in any of the other plant fractions, it appears that the choice of the morphological composition of the ingesta by sheep was not determined by PA. Sheep selected a diet which was 2–5% or 5–11% more degradable than the offered or refused feeds, respectively. Relative to NSC, CSC enhanced the intake of N, N bound to neutral detergent fibre (NDF), digestibility and N retention and tended to increase (P&lt;0·06) liveweight gain (LWG) and organic matter (OM) intake but had no effect on microbial protein synthesis. Compared with the NBR variety, the BR variety depressed N digestibility and N retention, had no effect on microbial protein synthesis and on LWG, but depressed the efficiency of LWG by c. 30%. Sheep given the BR+NSC diet had the lowest daily gain but excreted copious amounts of urine, probably in an attempt to eliminate toxic waste substances. Since sorghum is a crop of the semi-arid regions, it is quite likely that, although the bird resistance trait increases crop yield, it has resulted in a feed that is rather less suitable for livestock in this production environment, where water shortages are frequent. In-depth studies on the consequences of water shortage on the utilization of bird-resistant sorghum stover are required.

Porcine somatotropic regulation of thymic weight, thymosin beta 4, and insulin-like growth factors in lean and obese swine.

Experiment 1 involved genetically lean and obese gilts and barrows injected for 42 d with 0, 2, or 4 mg/d of porcine somatotropin (pST; n = 96). Blood was collected at 0, 6, and 24 h after the initial pST injection and thereafter every 2 wk. Experiment 2 involved lean and obese gilts and barrows (n = 48) that were administered implants that released 0, 2, or 4 mg/d of pST for 42 d. Blood was collected at d 0, 7, 14, 28, and 42 of the study. Thymic weights and a final blood sample were collected at the end of the 42-d trial. Thymic weights increased (P < .01) with dose of pST in injected and implanted animals. Thymosin beta 4 increased (P < .05) in a pST dose-dependent manner in injected and implanted animals, but concentrations were increased more in implanted animals. Concentrations of thymosin beta 4 decreased or reached a plateau in gilts but continued to increase in barrows to the end of the trial. Thymosin alpha 1 concentrations were increased (P < .01) in barrows compared with gilts, but the concentrations were not related to dose of pST. Concentrations of pST in injected animals increased (P < .01) within 6 h after injection and had returned to basal concentrations by 24 h after injection. Concentrations of pST in implanted animals were dose-dependent (P < .05) and remained increased throughout the trial. Concentrations of IGF-I and -II were pST-dependent (P < .01) and increased throughout the trial period. Outside of the pST dose relationships, temporal changes in thymosin beta 4 were not highly related to changes in pST, IGF-I, or IGF-II. The pST dose-related increases in thymic weights and thymosin beta 4 concentrations are consistent with pST stimulation of the immune function in conjunction with overall increases of growth and efficiency of live weight gain in swine.

Influence of barley silage:concentrate ratio on rate and efficiency of liveweight gain, diet digestibility and carcass characteristics of beef steers

Eighty steers were fed diets with eight ratios of 100:0, 75.1:24.9, 58.3:41.7, 34.4:65.6, 18.9:81.1, 8.0–92.0, 3.7:96.3 or 0:100 barley silage:concentrate on a dry matter (DM) basis. Diets were fed to provide about equal digestible energy (DE) per unit liveweight for 24 wk, then fed to appetite until the steers reached a market weight of about 515 kg. Steers receiving the 100% silage diet were fed for ad libitum intake from week 24 to week 52 (28 wk) and were then fed 100% concentrate diet until they reached market weight. The average daily gain (ADG) of steers fed 100% silage was lower than that of those fed forage and concentrate. Efficiency of DE utilization for liveweight gain increased at a decreasing rate as level of concentrate in the diet increased. Carcass backfat thickness increased with rate of gain. Digestibility of energy, DM, crude protein (CP), and starch exhibited a curvilinear response to increasing levels of concentrate in the diet. The proportion of concentrate in the diet for maximum economic benefit depends on the cost per unit of DE from silage versus that of barley, the efficiency of DE utilization for liveweight gain and time to reach market weight. Key words: Beef cattle, barley, barley silage, forage:concentrate ratio, digestibility

The effect of ruminal escape protein and ambient temperature on the efficiency of utilization of metabolizable energy by lambs1

Forty-eight crossbred lambs (22.5 +/- 2.6 kg average BW) of equal numbers from both sexes were used to observe the effect of protein supplement (none, canola meal, or fish meal) and temperature (21 +/- 1.8 degrees C or 4.7 +/- 1.7 degrees C) on growth and energetic efficiency in a 2 x 3 x 2 factorial experiment. Twelve lambs were slaughtered at the onset of the trial to determine initial body composition. The remaining 36 were fed diets consisting of 50% concentrate and 50% straw at DMI of 77 and 83 g/kg.75 daily in the warm and cold, respectively, for an 85-d period. Daily gains of the control lambs and of those supplemented with canola and fish meal were 80, 94, and 101 g/d, respectively; however, no differences in efficiency of live weight gain could be detected. Apparent digestibilities of DM, GE, OM, and fiber were decreased (P < .05) in response to the cold. Methane production was increased (P < .01) in the cold. Metabolizable energy intake was not increased by exposure to cold, even though DMI was higher (P < .1) in the cold. Cold-treated lambs retained less (P < .01) total energy as well as less (P = .02) fat energy as determined by comparative slaughter. Supplementation with protein increased (P < .05) energy retained as protein; however, it did not affect total energy retained or energetic efficiency. Energy retention estimated from the calorimetry-balance technique was 30 to 80% greater than that estimated from the comparative slaughter technique. It was concluded that methane production in lambs with short fleece was increased when the temperature was reduced from 21 to 5 degrees C and that energetic efficiency was not affected by the concentration or type of protein in the diet.

Effect of divergent selection for weaning weight on liveweight and wool growth responses to feed intake in Merino ewes

During a 6-week experiment, the feed requirements for maintenance of liveweight (LW) by adult Merino ewes were measured in 2 flocks selected over 32 years for divergent weaning weight. Also examined were the net efficiency of LW gain and wool growth in response to change in feed intake, and the ability to digest dietary organic matter. Ewes selected for high weaning weight (W+) were 31% heavier than those selected for low weaning weight (W-) at the start of the experiment. To maintain LW, W+ ewes ate 24% more digestible organic matter (DOM) per day than W- ewes. There were no differences (P&gt;0.2) in the net efficiency of feed use for LW gain. The W+ ewes digested more (P&lt;0.01) dietary organic matter, by 1.8 percentage units, than W- ewes and, consequently, required only 22% more dry feed to maintain their heavier LW. Ewes from the 2 flocks did not differ (P&gt;0.4) in the amount of wool grown, and as W+ ewes were larger, they produced less (P&lt;0.01) wool per kg LW for the same DOM intake.

Evaluation of British Friesian, Canadian Holstein and beef breed × British Friesian steers slaughtered over a commercial range of fatness from 16-month and 24-month beef production systems 1. Live-weight gain and efficiency of food utilization

ABSTRACTThe live-weight gain (LWG) and efficiency of food utilization of purebred British Friesian and Canadian Holstein steers and of crossbred steers out of British Friesian dams by Charolais, Hereford, Limousin, Lincoln Red, Simmental, South Devon and Sussex sires were examined in two beef production systems. One was similar to the commercial 18-month grass/cereal system (16-month) and the other to a commercial 2-year system (24-month). The cattle were serially slaughtered at three levels of fatness covering the commercial range and determined by the use of the Scanogram ultrasonic machine. The trial extended over 4 years and involved a total of 650 cattle. Data for the two production systems were analysed separately. Changes in growth performance were examined relative to estimated carcass subcutaneous fat content (g/kg; SFC) and sire breed crosses compared at the mean fatness level within system: 65 g/kg SFe for 16-month and 74 g/kg SFe for 24-month.Sire breed differences were not detected (P &gt; 0·05) in the regressions on SFe of age and live weight at slaughter, overall daily LWG and overall efficiency of weight gain. Pooled within sire breed, live at slaughter and age at slaughter increased by 2·5 kg and 2·8 days (16-month) and 2·2 kg and 2·1 days (24-month) for each g/kg increase in SFe.Charolais crosses and Canadian Holsteins were heaviest at equal SFC in both systems, but the latter were 63 days older (16-month) and 42 days older (24-month): Hereford, Lincoln Red and Sussex crosses were lightest and among the youngest in both systems.Sire breed crosses differed significantly in daily LWG: Charolais crosses grew fastest in both systems; the relative growth rate of other sire breed crosses was less consistent between the two although the Hereford crosses and British Friesians grew slowly in both systems. Overall efficiency of LWG (g gain per kg digestible organic matter intake) ranged from 164 to 205 (16-month) and 146 to 171 (24-month). Canadian Holsteins and British Friesians had the lowest efficiency of LWG in both systems of production; differences between the other breeds were not statistically significant (P &gt; 0·05).

The response of the muscles of weanling Large White × Landrace pigs to methionine and palm-oil supplementation to cassava flour-soya-bean meal diet

It was observed in a recently concluded study (O. O. BalogunandB. L. Fetuga, unpublished data) that methionine and palm-oil supplementation to a cassava flour-soya-bean meal diet encouraged satisfactory growth, efficiency of live-weight gain, nitrogen retention and carcass quality of weanling pigs. Our earlier reports (Balogun &amp; Fetuga, 1981; Balogun, Fetuga &amp; Oyenuga, 1982) also indicated that the muscles of pigs responded differently to dietary methionine and lysine and that the quantitative requirements of these amino acids for maximum development of the muscles were at variance with the methionine or lysine requirements for maximum growth performance and nitrogen retention.

Effets de l'adjonction d'huile de maïs à un régime alimentaire pour veaux de boucherie : I. Conséquences zootechniques

Eighty young male calves (French Friesian breed) were used to determine linoleic acid [C18 : 2 (n-6)] requirements and were allocated to one of the four following regimens : Group (1) : milk substitute diet without soya lecithin (diet A) containing 2.6 % of lipids as linoleic acid ; Group (2) : same diet but with soya lecithin (diet B) including 3.5 % of lipids as linoleic acid ; Group (3) : same diet as in group 2 (diet B) but additionally, 5 ml of com oil were given on each morning feeding starting day 63 after the beginning of the experiment ; Group (4) : same diet as in group 3 but 5 ml of com oil were given starting on day 6. Both rate and efficiency of live-weight gain were improved by additionnal com oil. This increase was only significant (p &lt; 0,05) in group 3. There were no significant differences between groups for any of the carcass characteristics studied. Before 55 days of age, polyinsaturated fatty acids requirements were met by both diets (with or without soya lecithin) which delivered approximately 1.2 to 1.6 % of total energy as linoleic acid. For calves older thas 2 months, linoleic acid requirements seemed to be within 1.8-2.1 % of total energy. Addition of 5 ml of com oil to diet B starting on day 6 (group 4) induced an excess of linoleic acid and thus reduced the mean growth rate of the individuals.

Copper deficiency: a study of prophylaxis and the interaction with cobalt therapy in lambs on improved hill pastures

ABSTRACTAn experiment was conducted with 84 suckling Scottish Blackface twin lambs on an improved hill pasture with a history of cobalt deficiency and molybdenum/sulphur-induced copper deficiency. The dams of 13 pairs of twins were treated with 90 mg copper at parturition (Cue) and one member of each pair was given a cobalt bullet (Co + ). One member of each of a further 29 pairs was treated periodically with 5 to 15mg copper to maintain plasma copper concentrations &gt;0·6mg/l (Cu+) while their siblings received no supplementary copper (Cu). Fourteen of these pairs also received a cobalt bullet (Co + ). Lambs not treated with cobalt are designated Co−.The Cue treatment increased milk copper concentrations, but only for a short time, and resulted in transitory increases in lamb plasma copper concentrations and rate of live-weight gain. At the end of the grazing phase, at approximately 20 weeks of age, Cu+ lambs had gained 0-28 kg more weight than Cue lambs and 158 kg more than Cue lambs, and had higher liver copper concentrations. Cu+ and Cue lambs had heavier and fatter empty bodies and carcasses than Cu− lambs. The cobalt treatment produced no effects at this stage.Fifty-four of the lambs were housed and given dried grass pellets ad libitum. After 83 days liver copper concentrations were higher in Co− than Co+ lambs, and in Cu+ than in Cu− and Cue lambs. The copper treatments had no effect on rate or efficiency of live-weight gain, but Co− lambs gained weight more quickly and more efficiently than Co+ lambs.

New Zealand-grown and -processed rapeseed (cv. Tower) meal as a protein supplement for growing pigs

Abstract Sixty–four Landrace × Large White pigs were fed 8 diets based on barley and meat and bone meal from 20 to 80 kg live weight. Two of the diets contained either blood meal (BM) or fish meal (FM) as the supplementary protein source, and served as controls. In the other 6 diets ‘Tower’ rapeseed meal (RSM) with and without additional lysine (0.15%) replaced all or half of the FM and BM. Over the live-weight range 20–40 kg pig performance on the diets containing a combination of RSM and either FM or BM was similar to that on the control diets. Addition of lysine to the diet with RSM as the protein supplement improved the rate and efficiency of live-weight gain. Similar dietary treatment differences in performance were recorded over the overall live-weight range (20–80 kg), but they were not significant. The supplementary protein source did not influence carcass measurements, but dressing percentage tended to be lower on diets containing RSM.

Analysis of some factors which affect the productivity of beef cows and of their calves in a marginal rainfall area of Rhodesia. 4. The growth and efficiency of live-weight gain of weaned and sucking calves at different ages

ABSTRACTThe growth and efficiency of live-weight gain of 36 calves confined in pens was studied between 30 and 210 days of age. They were weaned individually at 30, 90 or 150 days old and offered one of three solid foods which contained 200, 300 or 400 g milled roughage/kg both before and after weaning. From 30 to 90 days and from 90 to 150 days weaned calves consumed more (P&lt;0·001) solid food than sucking calves. During both these periods sucking calves consumed more (P&lt; 0·001 and P&lt;0·05 during the first and second periods respectively) metabolizable energy (ME), gained more (P&lt;0·01) body weight and also gained more body weight/MJ ME consumed than weaned calves. Composition of solid food had little effect on calf performance.The combined efficiency (kg calf weight gain/MJ ME consumed by cow and calf unit) was higher (P&lt;0·001) for suckling cows and calves than for weaned cows and calves between 30 and 90 days. Between 90 and 150 days, weaning had no effect on combined efficiency.Eight similar calves which were reared by their dams on veld until 210 days of age were heavier at 90 (P&lt; 0·001) and 150 (P&lt;0·05) days than penned calves which had been given concentrates ad libitum since weaning at 30 days. The body weights of these two groups were similar at 210 days.

A note on the comparative growth performance of pigs sired by Piétrain × Hampshire, Hampshire × Large White and Large White boars

ABSTRACTThe performance of progeny sired by Piétrain × Hampshire, Hampshire × Large White and Large White boars was compared over the live-weight range 28 to 65 kg. Feeding was twice daily to ‘appetite’ up to a maximum of 2·27 kg meal/day. Breed of boar did not influence rate or efficiency of live-weight gain, mid-line or internal fat depths nor muscle quality. Progeny of Pietrain × Hampshire and Hampshire × Large White sires, compared with those of Large White boars, had higher killing-out percentages (1·4 and 1·2 units) and larger eye muscles in cross-section (19·3 and 11·6%). Significant but small breed differences were noted in joint proportions of the carcass.

The feeding value to sheep of ‘Grasslands Tama’ Westerwolds ryegrass, ‘Grasslands Paroa’ Italian ryegrass, and ‘Grasslands Ruanui’ perennial ryegrass under rotational grazing management

Abstract The relative feeding value of ‘Grasslands Tama’ Westerwolds rycgrass and ‘Grasslands Paroa’ Italian ryegrass was 115 compared with 100 for ‘Grasslands Ruanui’ perennial ryegrass. There was no difference between the ryegrass cultivars in gross efficiency of live-weight gain, and the diflcrcnces in feeding value were attributed to the lower organic-matter intake of Ruanui. The feed-to-faeces ratio technique was more satisfactory under rotational grazing (C.Y. 8.6%) than under set-stocking (C.V. 12.4%) in detecting small differences in organic-matter intake. This technique was considered to be more reliable than a herbage cutting technique in estimating intake.

A note on the comparative performance of pigs sired by Pietrain/Hampshire and Large White boars

SUMMARYTwo Pietrain/Hampshire crossbred males and two Large White males were mated in equal numbers to 24 Large White females. Breed of sire did not affect litter size or total weight at birth or weaning. After weaning, on ad libitum feeding over the live-weight range 25 to 88 kg, the crossbred pigs grew more slowly to slaughter (5%) but with equal efficiency of live-weight gain. Crossbreds had higher carcass yields (3%) shorter carcasses (3%) and larger ‘eye-muscle’ areas (18%). Fat depths, joint proportions and cut-out values were not affected. The ‘eye-muscles’ of crossbreds were paler in colour and had a lower water-binding capacity than those of the purebreds, but pH1 values and transmission percentages did not differ.

A note on the performance, carcass and muscle quality characteristics of pigs sired by Poland China and Large White boars

SUMMARYTwo Poland China boars were mated with 12 Large White females and two Large White boars were used on the same number of females of similar background. In the post-weaning period a trial was conducted to compare the performance of purebred and crossbred progeny given a grower's diet on an ad libitum scale of feeding over the live-weight range 28 to 66 kg. Breed of boar did not influence litter size nor total litter weight at either birth or weaning. Poland China crosses compared with Large Whites grew more slowly to slaughter (10 %) but with equal efficiency of live-weight gain. Cross-breds had higher carcass yields (4 %), shorter (3 %) and deeper (2 %) carcasses, lower depths of mid-line and internal fat (11 %) and larger eye-muscle areas (22%). Breed of boar had little influence on joint proportions and no effect on carcass cut-out value. The eye muscles of crossbred carcasses were paler in colour and had higher transmission values but drip loss from the meat was not different.

Influence of Breed and Plane of Nutrition on Performance of Dairy, Dual-Purpose and Beef Steers. II. From 180 Days of Age to Slaughter

In two trials a total of 186 Holstein, Jersey, Milking Shorthorn, Angus and Hereford steers were fed from 180 days of age to slaughter at an estimated 55 to 60% of mature bull weight of the breed or to 27 months of age if individuals had not reached prescribed weight. Prior to 180 days of age the steers had been reared at two levels of nutrition. From 180 days to slaughter three diets were used: (1) 75% concentrate, (2) all hay with equal parts alflafa and timothy, or (3) a sequence of all hay for most of the period followed by the concentrate diet. Rate and efficiency of live weight gain on all diets and for both Phase I treatments were highest for the Holsteins followed in order by the Milking Shorthorns, beef breeds (Angus and Hereford) and Jerseys. Efficiency of lean production in relation to caloric intake followed the pattern of live weight gain efficiency. Efficiency of fat production and total caloric efficiency was highest for the beef breeds. Beef steers produced fatter carcasses which graded higher by usual U.S. standards. Palatability and tenderness evaluation of cooked meat ranked the Jerseys and beef breeds highest followed by Holsteins and Milking Shorthorns. The concentrate diet produced fatter carcasses than the hay or combination diets. Carryover effects of low Phase I nutrition levels resulted in more rapid and efficient live weight gains.

High level cereal diets for the growing/finishing pig. IV. A comparison at two slaughter weights (120 and 200 lb) of diets containing high levels of maize, sorghum, wheat and barley

Summary:Seventy-two (thirty-six hogs and thirty-six gilts) Large White type weaner pigs were individually and restrictedly fed four diets (as wet mashes) containing high levels (85% in the starter diets and 90% in the finisher diets) of either maize, sorghum, wheat or barley. Thirty-six pigs (nine per treatment) were slaughtered at 120 lb (54 kg approximately) live weight at the end of the period in which the starter diets were fed and the remaining thirty-six at 200 lb (90 kg approximately) live weight at the end of the period in which the finisher diets were fed.In the starter period the growth rates and food conversion efficiencies of the pigs fed the barley- and wheat-based diets were similar but taken together were slightly superior to those of the pigs fed the maize- and sorghum-based diets. Based on determined digestible energy values the caloric efficiency of live-weight growth was significantly better for the barley-based diet than for all other diets. At a slaughter weight of 120 lb the killing out percentage of the pigs fed the maize diet was significantly higher than that of the pigs fed the barley and wheat diets. Iodine numbers of inner and outer backfats were significantly higher in pigs fed maize than in those fed sorghum and wheat and in those fed barley compared with those fed wheat. There were no other differences in carcass measurements or in the percentages of lean, fat and bone dissected from the carcasses. However, the pigs fed barley had (1) significantly smaller middle regions and (2) as percentages of the total tissue within the body, significantly less fat in the middle region but significantly more fat in the shoulder region, than did any of the other pigs.In the finisher period the pigs fed the barley- and wheat-based diets grew significantly faster and converted their food and digestible energy of that food significantly more efficiently than did the pigs fed maize and sorghum. The caloric efficiency of live-weight gain was also significantly greater for the barley-fed pigs compared with those fed wheat. When slaughtered at 200 lb live weight, with the exception of backfat iodine numbers, where identical differences to those recorded at 120 lb were found, there were no significant differences in carcass measurements. On dissection the barley-fed pigs had significantly more lean and significantly less fat in the carcass than did any of the other pigs.

The influence of dietary concentration of calcium and phosphorus on their retention in the body of the growing pig

SUMMARYThree gilts and three castrated males weighing 23 kg live weight were given four semi-synthetic diets containing increasing amounts of Ca and P. The Ca and P contents (% dry basis) and Ca:P ratios for the four diets were A, 0·30, 0·38, 1:1·27; B, 0·58, 0·68, 1:1·17; C, 0·94, 1·13, l:l·20; D, 1·16, 1·47, 1:1·27. Each animal was slaughtered at 41 kg live weight and the whole body contents of Ca and P determined. Six pigs were slaughtered at 23 kg live weight and their bodies also analysed for Ca and P contents. Dietary concentration of Ca and P did not influence rate or efficiency of live weight gain nor carcass characteristics. Net retention of Ca and P increased with increasing dietary concentration of these elements. Analyses of isolated femurs suggested that optimal mineralization of the bone was associated with a net retention of 8·2 g Ca/kg live weight gain. The data were used to calculate a value of 32·9 mg/kg live weight/day for the endogenous loss of Ca in pigs of 23–41 kg body weight. The values have been used to compute a mineral requirement of dietary calcium which is in excellent agreement with that derived from estimates in the literature.