Fatty acid metabolism and deposition in subcutaneous adipose tissue of pasture- and feedlot-finished cattle.

An experiment was conducted to evaluate the effects of pasture finishing versus feedlot finishing, over time, on fatty acid metabolism in Angus crossbred steers (n = 24). Ruminal fluid, serum, and adipose tissue biopsies were obtained on d 0, 28, 84, and 140. Pasture forages and diet ingredient samples were obtained at 14-d intervals to determine nutritive value and fatty acid composition. The feedlot diet consisted of corn silage, cracked corn grain, soybean meal, and a vitamin and mineral supplement. The pasture-finished steers grazed sequentially on triticale (x Triticosecale rimpaui)/annual ryegrass (Lolium multiflorum), alfalfa (Medicago sativa)/orchardgrass (Dactylis glomerata), and a cool-season grass/legume mixture. The feedlot diet contained an average of 57% of total fatty acids as linoleic acid and 2% as linolenic acid. The pasture forages contained 9% of total fatty acids as linoleic acid and 66% as linolenic acid. Concentrations (% of total fatty acids) of linolenic acid were greater (P < 0.05) in ruminal fluid, serum, and adipose tissue of the pasture-finished steers, compared with the feedlot-finished steers. Concentrations (% of total fatty acids) of cis-9, trans-11 CLA were greater (P < 0.05) in adipose tissue of the pasture-finished steers than feedlot-finished steers. Concentrations of cis-9, trans-11 CLA in adipose tissue declined (P < 0.05) in the feedlot-finished steers from d 0 to 28 to 84. In the pasture-finished steers, concentrations of cis-9, trans-11 CLA in adipose tissue (mg/g of tissue) peaked (P < 0.05) on d 28 and remained elevated (ranged from 9.91 to 12.80 mg/g of tissue) throughout the duration of the study. In the pasture-finished steers, linolenic acid concentrations tended to peak (P = 0.07) on d 28 and remained elevated (ranged from 0.64 to 0.80% of total fatty acids) throughout the study. It appears that only a short time is needed to alter the n-3 and CLA composition of adipose tissue in cattle finished on pasture.

Evaluation of copper sulfate and a copper lysine complex as growth promoters for weanling swine.

Two 5-wk trials using 176 weanling pigs (average initial weight of 8.3 kg and age of 31 d) were conducted to examine the effect of feeding varying levels of dietary Cu from copper sulfate (CuSO4) or a copper lysine complex (CuLys) on performance, mineral stores, serum copper, and serum mitogenic activity. Dietary treatments were 0 (15 mg/kg of Cu in basal diet), 100, 150, or 200 mg/kg of supplemental Cu from CuSO4 or CuLys. Average daily gain and ADFI increased linearly (P < .01) with increasing dietary levels of Cu during wk 1 to 2, 3 to 5, and 1 to 5, with no difference (P > .10) between the Cu sources. Overall gain:feed ratios were not consistently affected by Cu source. Dietary Cu linearly increased liver, kidney (P < .001), and brain (P < .05) concentrations of Cu. In the liver, the linear response to supplemental Cu differed between Cu sources (P < .001); pigs fed 200 mg/kg of Cu from CuLys had the highest concentration of Cu. Serum Cu concentrations increased linearly during wk 1 to 2 (P < .01), 3 to 5, and 1 to 5 (P < .001), with no difference (P > .10) between sources. Serum mitogenic activity increased linearly during wk 1 to 2 and 1 to 5 (P < .05). Growth performance was linearly improved as the dietary level of Cu increased from 15 to 200 mg/kg, with similar responses for both Cu sources. Serum and tissue concentrations of Cu were generally equally affected by the two Cu sources, except liver Cu concentration, which was onefold higher for pigs fed 200 mg/kg of Cu as CuLys.

Forage systems for beef production from conception to slaughter: I. Cow-calf production.

Six year-round, all-forage, three-paddock systems for beef cow-calf production were used to produce five calf crops during a 6-yr period. Forages grazed by cows during spring, summer, and early fall consisted of one paddock of 1) tall fescue (Festuca arundinacea Schreb.)-ladino clover (Trifolium repens L.) or 2) Kentucky blue-grass (Poa pratensis L.)-white clover (Trifolium repens L.). Each of these forage mixtures was combined in a factorial arrangement with two paddocks of either 1) fescue-red clover (Trifolium pratense L.), 2) orchardgrass (Dactylis glomerata L.)-red clover, or 3) orchardgrass-alfalfa (Medicago sativa L.), which were used for hay, creep grazing by calves, and stockpiling for grazing by cows in late fall and winter. Each of the six systems included two replications; each replicate contained 5.8 ha and was grazed by eight Angus cow-calf pairs for a total of 480 cow-calf pairs. Fescue was less than 5% infected with Acremonium coenophialum. Pregnancy rate was 94%. Cows grazing fescue-ladino clover maintained greater (P less than .05) BW than those grazing bluegrass-white clover, and their calves tended (P less than .09) to have slightly greater weaning weights (250 vs 243 kg, respectively). Stockpiled fescue-red clover provided more (P less than .05) grazing days and required less (P less than .05) hay fed to cows than stockpiled orchardgrass plus either red clover or alfalfa. Digestibilities of DM, CP, and ADF, determined with steers, were greater (P less than .05) for the orchardgrass-legume hays than for the fescue-red clover hay. All systems produced satisfactory cattle performance, but fescue-ladino clover combined with fescue-red clover required minimum inputs of harvested feed and maintained excellent stands during 6 yr.

Forage systems for beef production from conception to slaughter: II. Stocker systems.

Fall weaned Angus calves grazed stockpiled 1) tall fescue (Festuca arundinacea Schreb.), 2) tall fescue-red clover (Trifolium pratense L.), or 3) tall fescue-alfalfa (Medicago sativa L.) or were barn-fed, 4) tall fescue hay, 5) orchardgrass (Dactylis glomerata L.)-alfalfa hay, or 6) tall fescue silage from late October to early April during each of 5 yr. Infection of the fescue with Acremonium coenophialum ranged from 0 to 55%. There were two replications each of steers and heifers for each forage system in a completely random design. Each replicate was grazed by three Angus stockers, except for System 1, which was grazed by six stockers, for a total of 420 stockers. Each pasture replicate contained .8 ha (except System 1, which was 1.6 ha), and the stocking rate was one stocker per .27 ha. Fescue hay and silage were harvested each spring for barn-fed systems from the area stockpiled for grazing by cattle in System 1. Nitrogen fertilizer (90 kg/ha) was applied in early spring and again in early August, before stockpiling; no N was applied to stockpiled fescue grown with legumes. Daily gains by calves grazing stockpiled fescue-alfalfa were greater (P less than .01) than by calves grazing stockpiled fescue-red clover or N-fertilized stockpiled fescue (.50, .33, and .34 kg/d, respectively), but fescue-alfalfa calves required more days (P less than .01) of supplemental hay feeding (105, 60, and 36, respectively). Calves fed fescue hay in the barn gained more (P less than .01) than those fed fescue silage.(ABSTRACT TRUNCATED AT 250 WORDS)

Evaluation of a bone biopsy technique for determining the calcium and phosphorus status of swine from weaning to market weight.

Tibia biopsies were taken from 75 live pigs at 4-wk intervals and from 251 slaughtered pigs to evaluate bone biopsy as a procedure for determining Ca/P status in pigs fed 70, 85, 100, 115 and 130% of the NRC (1979) estimated dietary Ca and P percentage requirements from weaning to market. Least squares means and SE of live and slaughter biopsy wet weight, ash weight and dry, fat-free ash percentage (DFF%) were compared at each time in each trial and found not to differ. Diet and time effects on ash weight, ash percentage of wet weight and DFF% of the biopsy core also did not differ greatly between slaughter and live biopsies and generally responded linearly and quadratically (P less than .01) to increasing Ca/P level and time. Biopsy measures were correlated (P less than .05) with third and fourth metacarpal and metatarsal length, bending and shear stress and DFF%. Means for slaughter biopsy DFF% did not differ greatly from the average of third and fourth metacarpal and metatarsal DFF% from slaughter pigs. Means for live and slaughter biopsy DFF% were lower than those for whole bones for the 70 and 85% NRC estimated Ca/P levels, but not for the 100, 115 and 130% NRC levels. Bone biopsy offers potential as a reliable noninvasive procedure for monitoring Ca/P status of swine from weaning to market, but it needs further study for use in Ca/P research in swine.

Calcium and phosphorus requirement of swine from weaning to market weight: I. Development of response curves for performance.

Three trials using 300 pigs were conducted to establish response surfaces for effects of calcium and phosphorus (Ca/P) levels and of time on postweaning pig performance. Five dietary Ca/P levels (70, 85, 100, 115 and 130% of the NRC [1979] estimated dietary Ca and P requirements) were fed from weaning to market weight. Twelve replicates, each consisting of five pigs, were used across the three trials, and one pig per replicate was slaughtered every 4 wk following the start of the trials. Efficiency of feed utilization (G:F) was insensitive to diet within the range of Ca/P levels used, whereas ADG and average daily feed intake (ADFI) were linearly (P less than .01) and quadratically (p less than .01) related to both diet and weigh period. Asymptotic models relating continuous effects of total Ca + P intake (average grams per day of Ca + P) relative to the NRC estimated Ca + P intake and days on test at the midpoint of each weigh period were fitted to the data and used to derive response surfaces for ADG and ADFI. Ninety, ninety-five and ninety-eight percent of maximum ADG, ADFI and G:F also were determined; 98% of maximum ADG was reached with a Ca and P intake of 99.8% of NRC Ca/P estimates, whereas Ca and P intakes of 95.3 and 83.5% of NRC estimates were required to produce 98% of maximum ADFI and G:F, respectively.

Calcium and phosphorus requirement of swine from weaning to market weight: II. Development of response curves for bone criteria and comparison of bending and shear bone testing.

Three trials involving 251 crossbred pigs were conducted to establish response surfaces for effects of Ca/P levels (70, 85, 100, 115 and 130% of NRC [1979] estimated requirements) and time (weaning to market) on bone criteria and to compare bending and shear bone testing. Nine replicates, each consisting of five pigs, were used over the three trials. One pig per replicate was slaughtered every 4 wk following the start of the trials. Third metacarpals and metatarsals (3M) and fourth metacarpals and metatarsals (4M) were collected at slaughter; the bone length, bending or shear stress, and dry, fat-free ash percentage (DFF%) were determined. Most bone criteria increased (P less than .01) at a decreasing rate (P less than .05) in response to increasing dietary Ca/P intake and increased linearly (P less than .01) with time on test, although bone length and stress increased at a decreasing rate with time on test. Asymptotic models relating continuous effects of total Ca + P intake ratio (CAP; expressed as a percentage of NRC) and number of days on test before slaughter to bone measurements were fit to least squares slaughter time by diet means. Bone length and DFF% reached 98% maximum at or near 100% the NRC estimated CAP level; however, to reach 98% of maximum bone shear and breaking stress higher CAP levels were required. Shear testing of bones was more desirable than bend testing as a method of determining bone strength due to reduced variability, better discrimination of Ca/P and time effects and ease of calculation.

Effects of ewe breed and management system on efficiency of lamb production: II. Lamb growth, survival and carcass characteristics.

Lamb growth, survival and carcass characteristics were compared for progeny of either 1/2-Suffolk, 1/2-Rambouillet (Western) ewes or 1/2-Suffolk, 1/4-Rambouillet, 1/4-Finnsheep (1/4-Finn) ewes produced over 3 yr in three different management systems. System 1 lambs were born in late fall and fed to slaughter on a concentrate diet. System 2 lambs were born in January and February and grazed pure stands of alfalfa or ladino clover after weaning. System 3 lambs were born in March and April and remained with their dams on native bluegrass-white clover pasture throughout the grazing season. Lambs were slaughtered as males reached 55 kg and as females reached 50 kg. One-half of the males in System 1 were left intact; all males in Systems 2 and 3 were castrated. Lamb survival did not differ among systems. Lambs from yearling 1/4-Finn ewes had higher survival rates than lambs from yearling Western ewes, but at older ewe ages, progeny of the ewe groups did not differ in survival. Lambs in System 1 grew fastest (mean lifetime gains of 310 +/- 4 g/d) and were youngest at slaughter (156 +/- 3 d), and lambs in System 3 were oldest at slaughter (234 +/- 2 d). System 2 lambs differed considerably among years in growth rate and slaughter age (mean slaughter ages of 191, 230 and 193 d across years), primarily in response to differences in rainfall. Lifetime gains and slaughter ages of lambs did not differ between ewe breeds. Ram lambs grew 15% faster than wethers and were leaner. Differences among systems in carcass traits were small. System 1 lambs tended to be fattest and System 2 lambs leanest. Progeny of 1/4-Finn ewes had higher subjective scores for carcass fatness (e.g., feathering, flank fatness) and conformation but did not differ from progeny of Western ewes in objective measures of fatness (e.g., backfat, yield grade).

Effects of feeding restricted energy and elevated calcium and phosphorus during growth on gait characteristics of culled sows and those surviving three parities.

Crossbred gilts (n = 288) were weaned at 4 to 5 wk of age and retained through three parities. They were used to determine the effects of feeding restricted energy (ad libitum vs 75% ad libitum) and elevated calcium-phosphorus levels (100 vs 150% of the dietary percentage suggested by NRC, 1979) from weaning to 100 kg of body weight on subsequent sow gait characteristics obtained from 16-mm motion pictures. After 100 kg, all females were fed and managed similarly throughout breeding, gestation and lactation. At 50 and 100 kg body weight and 21 d after weaning, females were filmed from the side and rear as they walked on a treadmill (traveling at the rate of .90 cm/s with zero slope) using two 16-mm Arriflex cameras. Objective measurements were taken from the film by projecting it on a reverse screen. Visual appraisal of structural soundness were scored subjectively for each female at each time period. The front foot pastern angle was correlated positively with structural soundness scores, suggesting that sows with smaller angles (more sloping) were given more desirable soundness scores. Early dietary energy and Ca-P levels did not influence number of sows completing three parities or culled for various reasons, front and hind pastern angles, the angles at the hock and carpal joint or rear view measurements, but sows fed ad libitum to 100 kg had a larger frame size even after three parities. Sows that survived three parities tended to have larger body capacity (girth diameter and width across hams) and smaller front and bind pastern angles and angles of the carpal joint and hock at maximum flex than did culled sows. Structural soundness scores did not differ between culled and surviving sows.

Influence of two supplemental vitamin E levels and weaning age on performance, humoral antibody production and serum cortisol levels of pigs.

Three trials using 156 Yorkshire x Hampshire x Duroc crossbred pigs (avg initial wt, 7.9 kg) were conducted to evaluate the effects of two supplemental dietary vitamin E (11 vs 220 IU/kg of diet) and weaning age (21, 28 or 35 d) on performance and immunocompetence of pigs. Supplemental vitamin E (220 IU/kg of diet) increased (P less than .01) serum concentrations of vitamin E for all weaning ages compared with pigs fed 11 IU of vitamin E/kg of diet. However, supplemental vitamin E did not affect performance, serum cortisol concentration or the primary and secondary antibody response to sheep red blood cells. As weaning age increased, weekly ADG and avg daily feed intake increased linearly (P less than .01). Cortisol levels decreased during the 1st wk following weaning and then increased linearly (P less than .01) over time; pigs weaned at 35 d of age had higher (P less than .01) cortisol values initially and over time than pigs weaned at 21 and 28 d. Pigs weaned at 35 d had a higher (P less than .01) primary response to sheep red blood cells than pigs weaned at 21 and 28 d of age, but this effect was not observed for the secondary response. There were no interactive effects (P greater than .10) of dietary vitamin E level and weaning age. In summary, the highest level of supplemental vitamin E increased serum vitamin E concentration but did not affect performance, cortisol levels or one test of the immune response, antibody titers to red blood cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Supplemental biotin for swine. I. Influence on feedlot performance, plasma biotin and toe lesions in developing gilts.

Three trials, utilizing a total of 240 crossbred gilts, were conducted to study the influence of 0 (NB) or 220 (SB) microgram supplemental biotin/kg of diet on feedlot performance, plasma biotin and development of toe lesions in developing gilts. Corn-soybean meal diets were fed from weaning to 92 kg body weight. Gilts were housed on expanded-metal floors to 50 kg body weight and on partially slatted concrete floors until completion of the trials. Feedlot performance, hair and structural soundness scores were not different (P greater than .10) between NB and SB gilts. Plasma biotin (PB) levels were elevated (P less than .01) when supplemental biotin was included in the diet. Gilts consuming SB diets had fewer (P less than .01) toe lesions/gilt and lower (P less than .01) toe lesion severity scores/gilt compared with gilts fed NB diets. Heel-horn erosion and heel cracks were the most frequent toe lesions observed. Fewer gilts (P less than .01) developed side-wall toe cracks when fed SB diets. Supplemental biotin reduced the frequency of individual toes containing heel-horn erosion (P less than .10), heel cracks (P less than .05) and side-wall toe cracks (P less than .05) with the severity of these lesions not affected (P greater than .10) by supplemental biotin. These results suggest that biotin levels in corn-soybean meal diets are adequate for feedlot performance, and that supplemental biotin can improve hoof integrity, but will not prevent toe lesions.

Supplemental biotin for swine. II. Influence of supplementation to corn- and wheat-based diets on reproductive performance and various biochemical criteria of sows during four parities.

Data from 116 females previously fed a corn-soybean basal diet with 0 or 220 micrograms supplemental biotin/kg during growth and development were used to study the influence of 0 (NB) or 440 (SB) micrograms of supplemental biotin/kg to corn-(C) or wheat-(W) based diets for gilts and sows housed in total confinement. Reproductive performance through four parities (total of 245 litters) and various sow and pig biochemical criteria were evaluated. Females fed W diets were older (P less than .07) at first estrus, farrowed litters that were lighter weight (P less than .01) at birth and that contained fewer (P less than .05) total and live pigs compared with females fed C diets. Biotin supplementation did not significantly influence (P greater than .10) farrowing and lactation performance; however, after the first parity, total and live pigs/litter at farrowing tended to be larger for SB females. Conception rate at first estrus postpartum was increased (P less than .07) by 9% and the average weaning to estrus interval was reduced (P less than .05) from 14.5 to 10.2 d with SB. Biotin supplementation increased (P less than .001) the biotin content of sow plasma, milk and liver, while sow liver pyruvate carboxylase activity was not altered (P greater than .10). Pigs farrowed by SB females had three- and fivefold higher (P less than .001) levels of plasma biotin at birth and 14 d of age, respectively; however, liver biotin levels at birth were not different (P greater than .10) for pigs from NB and SB females.(ABSTRACT TRUNCATED AT 250 WORDS)

Supplemental biotin for swine. III. Influence of supplementation to corn- and wheat-based diets on the incidence and severity of toe lesions, hair and skin characteristics and structural soundness of sows housed in confinement during four parities.

The influence of supplementing 0 (NB) or 440 (SB) micrograms biotin/kg to corn- or wheat-based diets on toe lesions, hair characteristics and structural soundness in 116 crossbred female swine was studied from selection (100 kg) until completion of four parities. Gilts that had been previously fed corn-soybean meal diets with 0 or 220 micrograms supplemental biotin/kg diet during growth and development, remained on either the biotin unsupplemented or supplemented diet. Females were housed in buildings containing partially slatted and solid concrete floors. Toe, hair and soundness evaluations were made at a mean age of 240, 521, 732, 916 and 1,090 d. Type of grain fed did not influence (P greater than .10) any response criteria evaluated. Six types of toe lesions were observed across all dietary treatments and varied in severity from minor to very severe. The percentage of females with heel cracks, heel-horn junction cracks and side-wall horn cracks was reduced (P less than .01) when females were fed SB diets. Females fed SB diets had fewer (P less than .001) total lesions, heel cracks, heel-horn junction cracks, side-wall horn cracks and white-line horn cracks (P less than .03) compared with females consuming NB diets. In general, biotin supplementation was more effective in reducing the number and percentage of toe lesions in multiparous sows compared with gilts and primiparous sows. Biotin supplementation increased (P less than .001) the number of hairs/cm2 skin and improved (P less than .001) hair scores. Histological evaluation and soundness scores were not affected (P greater than .10) by level of biotin fed.(ABSTRACT TRUNCATED AT 250 WORDS)

Restricted energy intake and elevated calcium and phosphorus intake for boars during growth. II. Foot and leg measurements and toe and soundness scores.

Boars were assigned at 5 wk of age in a 2 X 2 factorial arrangement to two energy (ad libitum and 75% of ad libitum) and two Ca and P levels (100 and 150% of the National Research Council daily recommended amounts) to determine the effect of reduced growth rate and elevated Ca and P intake on foot and leg measurements, pad and horn incidence and severity of lesions, and structural soundness. There were 20 boars/treatment; 15 boars from each treatment were necropsied at 10 +/- 2-d intervals from 80 to 220 d of age (45 to 185 d on test), with the remaining five boars in each treatment being necropsied at 220 d of age. Feet and leg measurements were taken and toe pads and horns were scored initially and after 78 and 131 d on when necropsied. Boars remaining after 130 d on test were scored for overall structural soundness. Toe size and circumference and length of limbs increased as boars grew, with larger values for ad libitum-fed compared with limit-fed boars when observed at a constant age. However, when these values were corrected for body weight, the effect of energy was generally removed and, in some cases, reversed. Limit-fed boars appeared to have fewer pad and horn lesions, but the effects were inconsistent. In general, Ca and P levels had little or no effect on toe and limb sizes and pad and horn lesion scores, whether or not the values were expressed on a constant age or corrected body weight basis. A comparison of inside and outside toes on the front and hind feet revealed that outside toes were larger than inside toes, with the magnitude of the difference much larger for the hind foot than for the front foot. The hind inside toes had fewer pad and horn lesions. Structural soundness scores were more desirable in ad libitum-fed compared with limit-fed boars; but, elevated Ca and P levels had no effect. Thus, these data do not support a hypothesis that structural soundness can be improved by reducing the growth rate of developing boars or by feeding an elevated level of Ca and P.

Restricted energy intake and elevated calcium and phosphorus intake for gilts during growth. IV. Characterization of metacarpal, metatarsal, femur, humerus and turbinate bones of sows during three parities.

The effect of early nutrition on subsequent bone development was studied using gilts that had previously been fed ad libitum or 75% ad libitum intake and 100 or 150% National Research Council-recommended daily Ca and P from weaning to 100 kg. During the three-parity reproductive study, sows were fed a 14% protein diet. Metacarpals and metatarsals were taken from sows culled due to lameness or failure to breed and from sows after completing three parities. Femur and humerus articular cartilage and turbinates were described at necropsy. Metacarpals and metatarsals were heavier and tended to have thicker walls when sows were previously fed ad libitum or fed 150% Ca and P. Energy intake produced the greater response. Metacarpal breaking strength was greatest for sows previously fed ad libitum. Metatarsals were not affected by energy intake. Stiffness, Young's modulus of elasticity (YME) and flexural modulus for metacarpals and metatarsals were not affected by energy intake. Previously fed Ca and P intakes did not affect any of the mechanical bone characteristics. Metacarpals were heavier, had a greater breaking strength, were more elastic and exhibited slightly less resistance to bending than the metatarsals. The ether extract, ash, Ca and P content and the Ca:P ratio of metacarpals and metatarsals were not affected by previously fed energy or Ca and P intakes. The ether extract content tended to decrease and the ash, Ca and P content tended to increase with age. Articular cartilage and turbinate scores were not influenced by previously fed energy or Ca and P intakes. The YME and flexural modulus were the only bone characteristics that were even poorly correlated (average r = .25) with soundness scores, suggesting that high values result in poorer soundness scores. Energy and Ca and P intakes during growth and development had only minimal effects on bone characteristics and no apparent effect on structural soundness and longevity of sows kept for three parities.

Restricted energy and elevated calcium and phosphorus intake for boars during growth. 1. Feedlot performance and bone characteristics.

Eighty crossbred boars were utilized in a 2 X 2 factorial arrangement of two energy levels (ad libitum and 75% ad libitum) and two Ca/P levels (100 and 150% of National Research Council daily requirement) to determine the effect of varying growth rate and Ca/P intake on performance and bone characteristics throughout the growth phase. Boars were fed the diets beginning postweaning at 5 wk of age and continuing until necropsy at 10 +/- 2-d intervals between 80 and 220 d of age, inclusive. Body weight of limit-fed boars was 72% that of ad libitum-fed boars. Daily gain and feed per gain ratio favored boars fed the 150% Ca/P levels. Although limit-feeding enhanced the development of longer, thicker and heavier metacarpals earlier in the growth period (between 80 and 150 d of age), there was little difference between limit-fed and ad libitum-fed boars at 220 d of age when values were corrected for differences in body weight. Mechanical bone characteristics, which were greater for ad libitum-fed than for limit-fed boars at the same age, were not different when values were corrected for body weight. Boars fed 150% Ca/P levels had heavier and thicker walled metacarpals that had greater bone strength than boars fed 100% Ca/P levels, with the magnitude of the difference not as great at 220 d of age and when values were corrected for body weight. Generally, boars fed the ad libitum-150% Ca/P diet had the heaviest and strongest bones. Ether extract, ash and Ca and P content of ash were generally higher for ad libitum-fed vs limit-fed and 150 vs 100% Ca/P diets at 80 and 150 d of age, but were not different at 220 d. Metacarpal weight, size, thickness, strength and ash content increased with age with a small decline in the rate of increase. Ether extract decreased with age. There was a very small increase in the Ca content of ash and a very small decrease in the P content with age, resulting in a slightly wider Ca:P ratio in older boars.

Restricted energy intake and elevated calcium and phosphorus intake for gilts during growth. III. Characterization of feet and limbs and soundness scores of sows during three parities.

Gilts that had previously been fed ad libitum or 75% ad libitum intake and 100 or 150% National Research Council recommended daily Ca and P from weaning to 100 kg were used in a reproductive study in which a 14% protein diet was fed. Foot and leg measurements, subjective toe scores and structural soundness scores were taken at each of three parities, 21 d postweaning. Sows previously ad libitum-fed generally had larger front toes than limit-fed sows; whereas, hind toes were larger for sows previously fed 150% Ca and P levels than sows fed 100% Ca and P. Sows previously fed the ad libitum-150% Ca and P diet had the largest toes. Front inside toes were larger than hind inside toes, but the reverse was observed for front and hind outside toes, with the magnitude of the difference between the inside and outside toes greater for the hind foot. Toe size increased over parities with the greatest increase from parity 2 to 3. Incidence and severity of toe pad and horn scores were generally unaffected by previously fed energy and Ca and P levels and were not correlated to toe size. Hind feet exhibited a larger number of lesions than front feet and outside toes exhibited a larger number of lesions than inside toes, with the hind outside toe exhibiting the greatest number of lesions. In general, incidence and severity of toe lesions decreased or were unchanged from parity 1 to 3. Structural soundness scores were unaffected by previously fed energy or Ca and P levels, but were quadratically affected by parity, with a small increase (poorer) from parity 1 to 2 and a large improvement from parity 2 to 3. Soundness scores were not related to any of the feet or leg measurements and characteristics. Restricting growth rate and feeding elevated Ca and P levels during growth had no effect on incidence and severity of lesions on the toes and overall structural soundness of sows kept for three parities.

Restricted energy intake and elevated calcium and phosphorus intake for gilts during growth. II. Gait characteristics analyzed from 16-mm motion picture photography.

Three groups of 96 crossbred gilts were weaned at 4 to 5 wk of age (average initial weight, 7.2 kg) and assigned to four dietary treatments in a 2 X 2 factorial arrangement of treatments (ad libitum vs 75% ad libitum and 100 vs 150% of NRC daily Ca and P). The effects of dietary treatments on the gait characteristics of gilts were analyzed by 16-mm motion picture photography. At approximately 50 and 100 kg body weight (periods 1 and 2, respectively), pigs were photographed walking on a treadmill, and gait characteristics were measured from the motion picture film. Ad libitum-fed gilts were longer, taller, wider and deeper when compared with restricted-fed gilts on an equal age basis, but not when compared on an equal weight basis. Other side view and rear view measurements were inconsistently affected by energy level (ad libitum vs restricted) at the two time periods, and all measurements were unaffected by Ca and P level. Analysis of the side and rear view characteristics over time generally revealed undesirable changes (P less than .01) from 59 to 100 kg. Both left and right hock-joint deviation increased (P less than .01) from period 1 to period 2, when expressed on an equal weight basis, suggesting the development of joint weakness. The hind pastern angle and the angle at the hock-joint also increased with time (P less than .01), suggesting development of post-leggedness as pigs increased in age and weight. Correlation coefficients among the various photographic characteristics and structural soundness scores were generally very low. Long-term effects of the dietary treatments on structural development are under study.

Restricted energy intake and elevated calcium and phosphorus intake for gilts during growth. I. Feedlot performance and foot and leg measurements and scores during growth.

Three groups of 96 crossbred gilts each were weaned at 4 to 5 wk of age (avg wt, 7.2 kg) and assigned to four treatments in a 2 X 2 factorial arrangement (ad libitum vs 75% of ad libitum energy intake and 100 vs 150% of NRC-recommended daily Ca and P). The effects on feedlot performance and on foot and leg scores and measurements were examined at approximately 50 and 100 kg body weight. Also, pigs were subjectively scored for overall structural soundness at the same weights. Limit-fed gilts consumed 78.1% as much feed as gilts fed ad libitum. Average daily gain of the limit-fed gilts was 86.7% that of the gilts fed ad libitum (P less than .01), and feed/gain was nonsignificantly improved by 8.4% for limit-fed gilts. The feeding of 150% of NRC-recommended levels of Ca and P resulted in a 5% increase (P less than .05) in daily gain, but daily feed intake and feed/unit of gain were not significantly affected. At the same age, almost all foot and leg measurements were larger for gilts fed ad libitum than for limit-fed gilts. However, when the values were adjusted for body weight, there was little or no measureable effect of energy intake. Elevated Ca and P levels had minimal effects, with only a trend toward larger measurements for gilts fed 150% of NRC-recommended daily Ca and P levels. Foot and leg measurements increased from 50 to 100 kg and were larger for the outside toes than for the inside toes for both front and hind feet. Energy intake and elevated Ca and P levels had little effect on the incidence and severity of toe lesions. The incidence of pad and horn lesions increased over time and was much greater on the outside toes on the front and hind feet. Restricted feeding and increased Ca and P levels did not improve overall structural soundness.