Deep seam and minesoil carbon sequestration potential of the South Wales Coalfield, UK

Combustion of coal for energy generation has been a significant contributor to increased concentrations of atmospheric carbon dioxide. It is of interest to evaluate the potential of former coalfields for mitigating these increases by carbon sequestration and to compare different options to achieving this end. Here, carbon sequestration in residual coal seams and through reclamation of spoil tips is compared, and their carbon dioxide storage potential in the South Wales Coalfield estimated. Coal seam sequestration estimates come from an established methodology and consider the total unmined coal resource below 500 m deep with potential for carbon sequestration. The most likely effective deep seam storage capacity is 104.9 Mt carbon dioxide, taking account of reservoir conditions and engineering factors. Whilst many spoil tips in South Wales have been reclaimed, the focus has not been on carbon sequestration potential. Estimates of minesoil restoration sequestration capacity were based on a survey of restored minesoil and vegetation carbon stocks, mainly on sites 20-30 years after restoration; data from this survey were then extrapolated to the coalfield as a whole. Minesoil storage is estimated at 1.5 or 2.5 Mt (+2.2 Mt in tree biomass) carbon dioxide based on average grassland or woodland measurements, respectively; modelled data predicted equilibrium values of 2.9 and 2.6 Mt carbon dioxide respectively in grassland or woodland minesoils. If all sites achieved close to the maximum capacity in their land use class, minesoil storage capacity would increase to 2.1 or 3.9 Mt carbon dioxide, respectively. Combining the best woodland minesoil and standing biomass values, sequestration capacity increases to 7.2 Mt carbon dioxide. The wider social, economic, environmental and regulatory constraints to achieving this sequestration for each approach are discussed. Coal seam sequestration has a much higher capacity but sequestration in mine sites is less costly and has fewer regulatory constraints. Findings indicate a significant combined potential for carbon sequestration in the South Wales Coalfield and highlight challenges in achieving this potential. On a global scale, ex-coalfield sequestration could contribute to broader efforts to mitigate emissions.

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 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.

Peripheral testosterone in boars after administration of hCG, ACTH and testosterone at three ages

Forty-four purebred Yorkshire boars, reared outdoors on concrete, were randomly assigned to one of three age groups (150 +/- 7, 200 +/- or 250 +/- 7 days of age) for the purpose of examining endogenous testosterone concentration in response to one of four exogenously administered treatments. Four boars from each age group were administered either human chorionic gonadotrophin (hCG; 1000 U.S.P. units intravenous), adrenocorticotrophin (ACTH; 100 IU intravenous), or testosterone proprionate (TP; 25 mg intramuscular). The remaining boars served as controls and were given saline (S; 5 ml IV). Blood samples were collected from each boar at -120, -90, -60, -30, and 0 min pre-treatment and at 15, 30, 45, 60, 75, 90, 105, 120, 150, 180, 210, 240, 270, 300, 330, and 360 min post-treatment via an indwelling anterior vena cava catheter. Plasma testosterone was quantified by radioimmunoassay. Within treatment, boars receiving hCG, ACTH or S responded similarly (P>.10) across the three age groups for measured testosterone. Plasma testosterone was elevated (P<.05) by 30 min (4.7 +/- .5 ng/ml; X +/- SEM) and 15 min (5.5 +/- 1.1 ng/ml) post-treatment in boars administered hCG and ACTH, respectively, when compared with the S (1.0 +/- .3 ng/ml) group. Testosterone in hCG treated boars peaked by 90 min (21.8 +/- 1.8 ng/ml) post-treatment, declined slightly until 210 min (18.8 +/- 1.8 ng/ml) post-treatment and increased thereafter. Hormone levels in ACTH treated boars plateaued by 45 min (7.5 +/- 1.4 ng/ml) post-treatment and began to decline by 90 min post-treatment. Plasma testosterone for TP treated boars differed (P<.05) over time among the three age groups. Boars 150 +/- 7 and 200 +/- 7 days of age had an increase in plasma testosterone at 150 and 240 min post-treatment with TP, respectively. Results suggest that the testosterone biosynthetic and secretory capabilities of the boar testes are fully operational by 150 days of age.

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.

Phosphorus in swine. V. Interrelationships of various feedlot performance, serum minerals, structural soundness and bone parameters in barrows, boars and gilts

Daily gain, daily feed intake, feed per unit of gain, serum Ca, serum P, serum Mg, structural soundness scores, foot pad scores, metacarpal breaking force and metacarpal ash values from five Ca P trials with barrows, gilts or boars were subjected by sex in each trial to multivariate analysis of variance. Correlation coefficients were obtained from the residual sums of squares and sum of products; thus, coefficients were corrected for treatment effects. Individual values were used for all comparisons except those involving daily feed and feed/gain, for which pen means were used. High positive correlations were observed between daily gain and daily feed; there was no relationship between daily gain and feed/gain, but daily feed was positively correlated with feed/gain. Serum Ca levels were not highly correlated with daily gain, daily feed or feed/gain. Although all coefficients were less than .5, serum P was positively (P less than .01 or less than .05) related to daily gain. Serum Ca and serum Mg concentrations were unrelated to serum P concentrations, but serum Ca was positively correlated with serum Mg. There was no relationship between daily gain and soundness or pad scores. Although there were some inconsistencies, a positive relationship was observed between daily gain and metacarpal dried weight, and between daily gain and breaking strength. There appeared to be little, if any, relationship between daily feed and feed/gain and bone parameters. Ca, P and Mg were not consistently related to metacarpal dried weight, breaking strength or ash. Dried weight was positively correlated to breaking strength in four trials and to ash in two trials. Breaking strength was correlated to ash in only one trial. These results offer no support for the belief that stronger, denser bones produce more structurally sound animals, because soundness and pad scores were not related to bone parameters.

Glucocorticoid concentrations, corticosteroid binding protein characteristics and reproduction performance of sows and gilts subjected to applied stress during mid-gestation

Two experiments were conducted to evaluate the effects of applied heat (greater than or equal to 28 C) and crowding (less than or equal to .9 m2 floor space/animal) stress for 50 days during mid-gestation on glucocorticoid concentrations, corticosteroid binding globulin (CBG) characteristics and reproductive performance of 20 sows (Exp. 1) and 23 gilts (Exp. 2). Blood as collected via puncture of the anterior vena cava on days -1 and 0 before initiation of treatment and on days 1, 2, 12, 13, 48, 29 and 1, 5, 9 +/- l, 19 +/- 1, 50, 63 +/- 3, 90 +/- 1 after initiation of treatment for sows and gilts. respectively. Plasma glucocorticoids and CBG characteristics were determined by competitive protein binding techniques. Overall mean glucocorticoid concentrations for eight sows and 12 gilts subjected to stress were lower (P less than .05) than those of control animals, CBG binding capacities (CBC) were lower (P less than .05) in treated sows and gilts bled on days 12 and 9 +/- 1 after initiation of stress, respectively. Overall mean CBC and affinity (Ka) of cortisol to bind to the CBG molecule were lowered (P less than .05) in stressed gilts. Other than a reduction (P less than .05) in gestation length observed in stressed crossbred sows, reproductive performance was not affected by stress. When infrequent blood samplings are employed, measurement of CBC may serve as a more precise indicator of a physiological stress response than glucocorticoid concentration.