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Low-grade inflammation precedes the development of obesity-related metabolic disorders in humans, but whether the same is true in the horse is not known. The objective of this study was to examine the effects of weight gain and diet on the inflammatory state of horses as determined by serum concentrations of tumour necrosis factor-α (TNF), an inflammatory cytokine. Fifteen mature Thoroughbred geldings with an initial body weight (BW) of 519±12 kg and body condition score (BCS) of 4.3±0.1 were fed a diet of hay plus a concentrate that was either high in non-structural carbohydrates (NSC) (i.e. starch and sugar), similar to those commercially available (CON) or one that had the energy source replaced with fat and fibre (FAT) for 32 weeks. Weight gain was achieved by feeding an additional 20 Mcal/day in excess of digestible energy maintenance requirements and resulted in a final BW of 608±12 kg and BCS of 6.9±0.1. Horses were exercised twice daily at a walk during the weight gain period. Horses were assessed bi-weekly for BW and BCS. Serum TNF was analysed from blood samples collected at 4-week intervals. Although treatment groups began the study with similar mean serum TNF concentrations, 12 weeks of FAT feeding promoted a decrease in circulating TNF that was maintained throughout the study with the exception of weeks 20 and 32. For either diet, there were no linear correlations between serum TNF concentration and BCS when horses increased in BCS from four to seven. The higher level of TNF observed in horses fed the CON diet indicates an increase in some level of systemic inflammation that was independent of their weight gain from a moderately thin to fleshy condition. The influence of diet on serum TNF concentrations should be investigated in horses fed to maintain body condition.

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A study was conducted to determine whether direct-fed microbials (DFM) could be used to increase digestibility and minimize the risk of acidosis associated with feeding an increase in the amount of starch fed to horses. Fifteen mature Thoroughbred geldings were randomly assigned to 1 of 3 treatments in a 3 x 3 Latin square design balanced for carryover effects. Within each 26-d period, horses were offered grass hay + low-starch concentrate (LS; 1.2 g of starch x kg of BW(-1) x meal(-1)) from d 1 to 13 and then were abruptly changed to hay + high-starch concentrate (HS; 2.4 g of starch.kg of BW(-1)x meal(-1)) on d 14 continuing through d 26. The DFM treatments were offered in concentrate pellets at a target dosage of 10(8) cfu/(50 kg of BW x d) as follows: no DFM (CON; control), Lactobacillus acidophilus (LAC1; single-species DFM), or a mixture of L. acidophilus, Lactobacillus casei, Bifidobacterium bifidum, and Enterococcus faecium (LAC4; multiple-species DFM). Total feces were collected over 72 h from d 11 to 13 (LS; low dietary starch collection), from d 15 to 17 (AC; abrupt change in dietary starch collection), and at the end of each experimental period, from d 24 to 26 (HS; high dietary starch collection). Data collected consisted of total DM intake and fecal output, fecal pH, fecal acetate and propionate concentrations, and viable numbers of DFM in the feed. With the exception of Fe digestibility, there were no starch x DFM interactions. There was an effect of starch level (P 0.10). Horses supplemented with LAC4 had increased ether extract (P < 0.05) and a tendency for decreased Na (P < 0.10) digestibilities compared with CON horses. All DFM-supplemented horses had increased Cu (P < 0.05) and Fe and numerically increased Zn digestibilities compared with CON horses. Fecal pH decreased (P < 0.05), and fecal propionate concentration increased (P < 0.05) as dietary starch content changed from LS to HS. There was a tendency for elevated fecal pH (P < 0.10) in LAC1 horses compared with CON horses. These results confirm that increasing starch in the equine diet can enhance nutrient digestibility of the diet. Supplementing equine diets with either a single or mixed strain direct-fed lactic acid bacteria had limited effects on nutrient digestibility or on reducing the risk of acidosis associated with feeding high-starch concentrates to horses. The potential response of DFM supplementation should be evaluated when a more acute acidotic state is induced in horses than in the current study.

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We previously reported that broilers fed n-methyl-D,L-aspartate (NMA) exhibited enhanced feed conversion efficiency and decreased percentage of fat in carcasses. In this experiment, growth performance and backfat thickness were evaluated in barrows fed NMA. Poland China x Yorkshire barrows weighing 68.8 +/- 1.7 kg (mean +/- SE) were allowed ad libitum access to feed containing NMA at levels of either 0 (n = 7), 100 (n = 6), 200 (n = 8), or 300 (n = 8) mg/kg for 36 d. Barrows were slaughtered at 99.5 +/- 2.3 kg BW. There was no effect (P > 0.1) of NMA on ADG or feed consumption. Gain:feed ratio decreased (P < 0.03) in a linear fashion with increasing level of NMA. There was a cubic effect (P < 0.05) of NMA treatment on first-rib backfat thickness. In response to graded levels of NMA, backfat thickness at the 10th rib (P < 0.08) and last rib (P < 0.03) increased in a linear fashion. The NMA had no effect (P > 0.1) on backfat thickness measured at the lumbar vertebra or longissimus muscle area measured at the 10th rib interface. The percentage of lean in the carcass decreased in a linear fashion (P < 0.05) in response to increasing levels of NMA in the diet. In summary, NMA had an overall negative effect on growth performance and carcass yield characteristics in barrows. The dichotomous effects of NMA on feed efficiency and body composition in poultry and swine warrants further scrutiny.

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The efficacy of PG 600 (400 IU PMSG and 200 IU hCG) for accelerating the onset of estrus was determined for sows weaned during the summer. Yorkshire sows (average parity = 4.6), nursing 8.6 +/- 0.2 pigs (mean +/- SEM) were weaned after 27.7 +/- 0.4 d of lactation and were treated intramuscularly with either PG 600 (n = 35) or with 0.9% saline (n = 35). Sows were checked for estrus once daily in the presence of a mature boar. Treatment with PG 600 increased (P < 0.05) the percentage of sows in estrus within 7 d after weaning (97.1 vs 82.9%). Relative to controls, sows given PG 600 expressed estrus sooner (3.8 +/- 0.1 d vs 4.5 +/- 0.1 d; P < 0.01). Sows exhibiting estrus within 7 d after treatments were artificially inseminated 0 and 24 h after first exhibiting estrus. The percentage of inseminated sows that farrowed tended to be higher (P < 0.07) for control than for PG 600-treated sows (96.6 vs 82.3%). The number of pigs born live was similar (P > 0.1) for sows treated with PG 600 and with saline, and was 12.7 +/- 0.6 and 11.7 +/- 0.7, respectively. Pigs farrowed by saline-treated sows, however, tended to be heavier (P < 0.09) than pigs farrowed by sows treated with PG 600 (1.49 +/- 0.06 kg vs 1.34 +/- 0.06 kg). In summary, PG 600 accelerated the onset of estrus in sows weaned during the summer. Sows mated during the induced estrus, however, tended to have a lower farrowing rate and farrowed lighter pigs than control sows inseminated during a natural estrus occurring within 7 d after weaning.

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Gravid Yorkshire sows assigned to one of three pen sizes on d 109 of gestation, were continuously observed for 72 h before parturition. Pens included a 2.1- x .7-m rectangular farrowing crate (n = 6), a small, square pen 2.1 x 2.1 m (n = 5), and a large, square pen 4.2 x 4.2 m (n = 5). Body positions were recorded at 30-s intervals. Other behaviors were recorded using the one-zero method of sampling at 1-min intervals. Sows became more active as they approached farrowing. They stood, sat, lay with legs under, changed positions, drank, urinated, defecated, rooted the floor and pipes, mouthed the waterer and pipes, and pawed the floor more (P < .05) during the 24 h before the birth of the first pig than during the previous 2 d. Position changes, rooting the floor, and pawing frequency peaked during the 6 h preceding parturition and show promise as predictors of parturition. During the 24 h preceding the birth of the first pig, farrowing crate sows stood, rooted the floor, and pawed less and sat, lay, and changed positions more than sows in either pen (P < .05). No differences (P > .05) among pens were noted for lying with legs under or out, eating, drinking, urinating, defecating, rooting the pipes, mouthing the pipes. or mouthing the waterer. Pipe biting and other behaviors commonly thought to be caused by confinement stress occurred in all three pen sizes and seem to be components of nest-building, expressed inappropriately, in a barren environment.

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Four experiments were conducted to determine mechanisms by which n-methyl-d,l-aspartate (NMA) increases serum concentrations of growth hormone (GH). Blood samples were collected from barrows every 15 min for 2 h (Exp. 1, 2, and 3) or 3 h (Exp. 4) immediately before and immediately after i.v. treatments. In Exp. 1, barrows (n = 4/treatment) received either .9% saline or 1.25, 2.5, or 5 mg of NMA/kg of BW. The change in circulating GH concentrations was greater (P < .05) for barrows receiving 2.5 mg (by 883%) or 5.0 mg of NMA/kg of BW (by 1,095%) than for those injected with saline. In Exp. 2, barrows (n = 4/treatment) received NMA (2.5 mg/kg of BW) or injections of 1.25 mg of the pure d or pure 1 isomers of NMA/kg of BW. Growth hormone concentrations increased by 177% (P < .025) after NMA treatment and by 245% (P < .01) after injection of the pure d isomer of NMA. The pure 1 isomer of NMA had no effect (P > .1) on GH concentrations. In Exp. 3, barrows received NMA (2.5 mg/kg of BW) 10 min after i.m. injection of saline (n = 7) or ketamine hydrochloride ( n = 8; 19.9 mg/kg of BW), an n-methyl-d-aspartate (NMDA) receptor antagonist. The NMA increased (P < .01) GH concentrations by 289% in saline-pretreated barrows but had no effect (P > .1) on barrows pretreated with ketamine hydrochloride. In Exp. 4, barrows (n = 4/treatment) received NMA 3 h after i.v. pretreatment with antisera to GH-releasing factor (GRF; 154 mL) or no pretreatment. Serum GH concentrations increased by 166% (P < .05) after injection of NMA in barrows receiving no pretreatment. The NMA had no effect (P > .1) on GH concentrations in barrows receiving antisera to GRF. Our results support the concept that NMDA stimulates GRF, and hence GH secretion, by activating an NMDA receptor.

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Prepubertal Yorkshire gilts, 189 d of age and 96 kg body weight (BW), were used to determine the effects of intravenous injections of N-methyl-D,L-aspartate (NMA) on circulating concentrations of luteinizing hormone (LH) and growth hormone (GH). In Experiment 1, blood was sampled from four gilts every 15 min for 2 hr on four consecutive days. One hour after the initiation of sampling on each day, gilts received either vehicle (0.9% saline solution) or 1.25, 2.5, or 5 mg of NMA/kg BW as per a 4 x 4 latin square arrangement of treatments. There was no effect of treatment (P > 0.1) on concentrations of LH in serum. However, relative to vehicle-treated animals, gilts administered 2.5 mg of NMA/kg BW had elevated (1,120%; P < 0.05) circulating levels of GH. In Experiment 2, samples were collected from 15 gilts at 15-min intervals for 1 hr before and 1 hr after NMA (10 mg/kg BW; n = 8) or vehicle (n = 7). NMA increased serum concentrations of both LH (by 80%; P < 0.05) and GH (by 700%; P < 0.01). We suggest that LH and GH secretion in gilts was enhanced by treatment with NMA.

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This study evaluated the effects of diets containing varying amounts of Ca on milk composition and litter characteristics of sows. Yorkshire sows were fed one of the following diets: low Ca (.38%; n = 5), standard Ca (.75%; n = 5), or high Ca (1.12%; n = 4). Diets were fed from d 42 of gestation to d 42 of lactation. Milk was collected on d 7 +/- 1, 21 +/- 1, and 42 +/- 1 of lactation. Lactose was greater (6.4%, P < .05) in milk from sows fed low Ca than in those fed standard (5.5%) or high (5.8%) Ca, but only on d 7 of lactation. No treatment effect or time x treatment interaction was detected for total protein or casein concentrations. Calcium increased (P < .05) over time irrespective of treatment. There was an increase (P < .05) in ADG on d 7 in pigs from high-fed (.28 kg) and low-fed sows (.20 kg) compared with those from standard-fed sows (.13 kg). In conclusion, body Ca is so physiologically regulated that minor dietary alterations have little overall effect on milk composition. Alterations in ADG for pigs, especially from sows fed high Ca, warrant further investigation.

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A microcomputer-photocell system to record, summarize and transfer data on the postural changes of crate-confined sows was developed. The system uses an infrared photocell system mounted on farrowing crates to detect changes in sow body postures prior to parturition. When a sow breaks the infrared beam by standing or sitting, the lack of reflection back to the photocell activates a relay. The relays are connected to an input/output card inside the primary ("host") microcomputer. A second microcomputer, at a location remote to the animal facility, and the host computer both are equipped with multi-tasking operating systems. The host computer uses a data acquisition program written in BASIC to record posture changes, the sow's identifying number, date and time. Both computers are equipped with communications software so that the host computer can transfer data to the remove location while continuing to collect data. Either computer can be used to summarize, graph and examine the accumulated data. Knowledge of periparturient activity patterns allows the observer to predict farrowing time and to determine whether farrowing has begun without being present in the farrowing facility.

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To investigate control of parturition time, 154 sows farrowing 220 litters at three locations were treated with altrenogest and Lutalyse (PG). The four treatment groups were: 1) no treatment (control group); 2) an im injection of 15 mg of PG at 1000 on d 111, 112 or 113 of gestation (d 0 = first day of estrus and gestation); 3) altrenogest (20 mg X sow-1 X d-1) fed twice daily for 4 d starting on d 109, 110 or 111; and 4) altrenogest and an injection of PG at 1000 on the day after the last feeding of altrenogest. Control sows at the University of Delaware (UD), University of Maryland (UM) and USDA, Beltsville Agricultural Research Center (BARC) had mean gestation lengths of 113.5, 114.2 and 115.7 d and live pigs/litter were 10.5, 11.0 and 7.4, respectively. Altrenogest started by d 110 prevented unscheduled early farrowing and increased (P less than .01) gestation length by 1.7 and 1.1 d, respectively, at UD and UM, but had not effect at BARC. The time from PG to parturition was 24.3, 22.6 and 34.4 h, respectively, at UD, UM and BARC. More sows at UD and UM farrowed between 0700 and 1700 on the expected day of parturition after injection of PG (59.3%) than with no PG (20.7%; P less than .05). The high incidence of small litters (less than six pigs) from sows inseminated with frozen semen at BARC resulted in negative correlations of live pigs/litter with gestation length (r = -.533, P = .0001) and with time from PG injection to birth of first pig (r = -.425, P = .017); these correlations were not significant at UD and UM where only natural service was used.(ABSTRACT TRUNCATED AT 250 WORDS)

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Forty female and ten male pigs were used to study the effect of carbadox on reproductive performance when included in the diet at a level of 55 mg/kg from one week of age through approximately 60 kg body weight. Five replicates, each consisting of eight females and a pair of littermate boars, all crossfostered, were used. One boar reared on medicated feed and another on an unmedicated diet, were bred to two groups of four littermates. One female in each pair had been fed the medicated diet, and the other the unmedicated diet. The same breeding scheme was carried out for two parities. The following observations were made: length of estrous cycle, weaning-to-estrus interval; conception rate; age and weight at first estrus, at breeding, at 109 days of gestation, at farrowing and after farrowing; gestation length; and litter size and weights at birth and 28 days. The results showed that carbadox had no apparent effect on reproductive performance.

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Ten Yorkshire gilts were fed either 1.36 or .45 kg of a gestation diet per day from day 85 of gestation to farrowing for determination of the effect of feed restriction during late gestation on reproductive performance. All gilts consumed 1.36 kg/day from day of breeding to day 85. Feeding level of affected (P < .001) gestation weight during the experimental period such that the restricted gilts lost 3.2 kg while control gilts gained 15.0 kilograms. Gestation period tended to be shorter (115.4 vs 113.6 days) and total litter weight tended to be lower (10.6 vs 8.6 kg) in the restricted group although the differences were not statistically significant. Litter size was similar (9.6 vs 9.4 pigs/litter). Restriction of gestation feed significantly reduced individual piglet birth weight (1.1 vs .9 kg), liver weight (32.9 vs 26.0 g) and skeletal muscle weights (8.9 vs 7.1 and 2.1 vs 1.6 g for the longissimus and semitendinosus muscles, respectively). Piglets born to restricted dams also had reduced liver and muscle glycogen concentrations (15.1 vs 13.9, 10.1 vs 9.4 and 9.9 vs 9.4 g/100 g of wet tissue for the liver and longissimus and semitendinosus muscles, respectively), lower (P < .05) blood pH (7.31 vs 7.23) and higher (P < .01) blood lactate levels (43.8 vs 71.3 mg/100 ml).

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Proximate composition of individuals from four litters of newborn and six whole litters of 10-day-old purebred Landrace piglets from primiparous and multiparous dams was determined. A dramatic increase in ether extract percentage occurred during the first 10 postpartum days as moisture and ash percentages decreased and protein increased. Average values for newborn and 10-day-old piglets, respectively were: weight 1.39 +/- .26 and 3.07 +/- .57 kg, moisture 79.17 +/- .96 and 70.51 +/- 1.36%; ether extract, .55 +/- .17 and 9.92 +/- 1.46%; protein 12.07 +/- .73 and 14.90 +/- .38% and ash, 4.63 +/- .40 and 3.44 +/- .31%. Although variation in proximate composition was small at birth, within as well as between-litter differences were observed. Carcasses of the heavier newborn piglets had lower moisture and higher protein percentages. Variation in the proximate composition of 10-day-old piglets was greater and accounted for, in part, by within and between-litter differences, plus in the case of moisture and ether extract percentages, differences in 10-day gain. Average values for three 10-day-old, slow-growing piglets were birth weight, 1.39 kg; 10-day weight, 2.13 kg; 10-day gain, .74 kg; moisture 75.49%; ether extract, 3.43%; protein, 15.34%; and ash, 4.37%. Although these piglets had a slow growth rate, their ether extract percentages increased by sixfold over the average value found for newborn piglets.

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Breastfeeding is said to be the ideal form of infant nutrition, but promoting it is thought to be difficult. The results of this study show that success is more likely when breastfeeding and skin-to-skin contact begin in the delivery room. The procedure is simple and the contact period need to be of only 15-20 minutes duration. The primiparas in this study seemed contented, happy or excited with the experience. Possibly it is most beneficial to those mothers who have not asked to hold their infants at birth.

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