Temperature Fluctuations Accompanying Water Movement through Porous Media

Temperature measurements were made at localized sites in bentonite, kaolinite, and small glass beads during infiltration. The temperature of the medium was observed to rise gradually and then to drop sharply as the infiltrating water approached and reached the measurement site. Temperature fluctuations were observed to be about 9 degrees C for bentonite, 4 degrees C for kaolinite, and 0.1 degrees C for the glass beads.     

In vitro Release of Ovarian Progesterone is Decreased During the Oestrous Cycle and Pregnancy of Swine with Obesity/Leptin Resistance

Previous studies indicate that reproductive prolificacy of obese swine breeds is markedly influenced by embryo losses in early pregnancy. In such period, adequate secretion of progesterone (P4) by the ovary is essential for pregnancy success. This study analyses the luteal functionality during the oestrous cycle and early pregnancy of Iberian sows and Large White x Landrace females, in terms of P4 secretion after in vitro culture of luteal tissue stimulated or not with luteinizing hormone (LH). The secretion of progesterone (expressed in ng/mg of luteal tissue or ng/mgLT) of the corpora lutea of obese Iberian swine was always hampered when compared to lean genotypes, either during early oestrous cycle (110.7 ± 37.8 vs 259.7 ± 10.2 ng/mgLT; p < 0.0001), late oestrous cycle (49.0 ± 3.5 vs 75.92 ± 7.14 ng/mgLT; p < 0.0001) or early pregnancy (38.4 ± 2.1 vs 70.7 ± 5.3 ng/mgLT; p < 0.0001). The differences in basal P4 secretion remained after stimulation with LH. Finally, P4 secretion during early pregnancy of Iberian sows decreased with age and, hence, with obesity features (46.6 ± 4.2 vs 65.5 ± 4.8 ng/mgLT; p < 0.001). In conclusion, the results of the present study provide convincing evidence of a reduced luteal function during oestrous cycle and early pregnancy of sows with obesity/leptin resistance like Iberian sows, which may contribute to the low reproductive efficiency reported in this breed.     

Mycobacterium avium subsp. paratuberculosis infection in wildlife on three deer farms with a history of Johne's disease

Abstract

AIM: To determine the prevalence of Mycobacterium avium subsp. paratuberculosis (Map) infection in wildlife, in pastoral landscapes with a recent history of clinical Johne's disease in livestock.

METHODS: A total of 449 wild mammals and birds from three farms in the South Island of New Zealand with recent histories of clinical Johne's disease in their deer herds were trapped and examined for gross pathological changes in the gastrointestinal tract. Additionally, individual mesenteric lymph nodes from 380 mammals, and segments of gastrointestinal tract from 32 birds were excised, homogenised and cultured for viable Map bacilli. The prevalence of Map infection was then calculated for the various species. Faecal samples from those mammals which had culture-positive tissues were further cultured for the presence of Map.

RESULTS: Gross pathological changes were identified in the gastrointestinal tract of four brushtail possums, one cat, six ferrets, 12 hares, six hedgehogs, three rabbits, one stoat, and one paradise shelduck. Infection with Map in the gastrointestinal tract was confirmed in only three of these cases, one each of brushtail possums, hares and hedgehogs. In contrast, Map infection in the absence of gross pathological changes was frequently recorded in enteric tract tissues of mammals and birds. Among mammals, Map infection was recorded in 18/73 (25%) brushtail possums, 4/23 (17%) cats, 15/42 (36%) hedgehogs and 29/113 (26%) rabbits. Among birds, intestinal tract tissue Map infection was recorded in 3/17 (18%) paradise shelducks. Among 64 of the 74 mammals which had Map culture-positive tissues, 38% (n=5) of hedgehogs and 11% (n=3) of rabbits also had culture-positive faecal samples.

CONCLUSIONS: This study is the first to identify that Map infection can be prevalent in wildlife in New Zealand. There was a high prevalence of Map infection among both scavenging and grazing wild animals. Both mammals and birds are capable of harbouring viable Map organisms in their gastrointestinal tract; further, viable Map was excreted into the environment via faeces by hedgehogs and rabbits.

CLINICAL RELEVANCE: Previous studies overseas have postulated a role of wildlife as reservoirs of Map infection and possible vectors of Johne's disease to livestock. Here, brushtail possums, hedgehogs and rabbits and in particular were identified as potential wildlife hosts for Map infection in NewZealand. This suggests that several wildlife species could contribute to the persistence of Map infection within a wildlife/livestock complex, and potentially, perhaps more importantly, to the spread of infection between farms.     

Ultrasound during mid‐gestation: Agreement with physical foetal and placental measurements and use in predicting gestational age in sheep

To determine the effects of poor maternal nutrition and litter size on foetal growth during mid‐gestation, pregnant ewes (n = 82) were fed 100%, 60% or 140% of NRC TDN beginning at day 30.2 ± 0.2 of gestation. Transabdominal ultrasound was performed weekly between day 46.0 ± 0.4 and 86.0 ± 0.7 to monitor foetal heart width (HW), umbilical diameter (UMB), rib width (RW) and placentome outer (OD) and inner diameter (ID). Data were analysed with repeated‐measures using the mixed procedure for effects of maternal diet, litter size and gestation, and equations predictive of gestational age were generated using the regression procedure. To determine the agreement of ultrasound measurement and actual size, ewes (n = 20–21) were euthanized at day 45 or 90 to obtain corresponding postmortem measurements for Bland–Altman analysis. The HW, UMB and placentome OD and ID increased with gestation (p < .0001) but were unaffected by maternal diet or litter size (p ≥ .12). Ultrasound underestimated postmortem measurements of HW (14.8%), UMB (7.3%), placentome OD (4.5%) and ID (37.3%) at day 90 of gestation. Ultrasound underestimated RW at day 45 (7.7%) but overestimated RW (23.8%) at day 90, indicating inconsistent bias when reporting RW by ultrasound. Combining the HW, UMB, RW and placentome OD generated the strongest equation predictive of gestational age (R² = .91). These findings indicate that during mid‐gestation, maternal diet or litter size did not affect HW, UMB or placentome diameters and these factors can be used to estimate gestational age.     

The effect of time between doses on serological response to a recombinant multivalent pilus vaccine against footrot in sheep

SUMMARY The response of sheep to a recombinant multivalent footrot vaccine containing pilus antigens was examined after the administration of two doses of vaccine at Intervals ranging from 2 to 52 weeks. Agglutinating antibody titres were measured 3 weeks after the second vaccination and showed that lengthening of the interdose interval results in higher agglutinin titres. The capability of sheep to mount an increasingly strong immune response as the interval between doses is increased provides an opportunity to maximise the usefulness of vaccination by administering the first dose well before an expected footrot transmission period. This advantage of increasing the interdose interval has not been reported for traditional, whole-cell footrot vaccines, and use of the new pilus vaccine in this manner may improve prospects for disease control. Furthermore, sheep given a third dose either 6 or 12 months after their initial two-dose vaccination program achieved significantly higher titres than those elicited after the second dose, suggesting the likelihood of further improvement in disease control in successive seasons.     

Creatine monohydrate supplemented in swine finishing diets and fresh pork quality: III. Evaluating the cumulative effect of creatine monohydrate and alpha-lipoic acid

The objective of this study was to evaluate short-duration supplementation of alpha-lipoic acid (ALA) and creatine monohydrate (CMH) to improve fresh pork quality. Forty-eight commercial hybrid barrows were blocked by BW and randomly allotted to one of four treatments: 1) no CMH or ALA; 2) supplementation of 24 g of CMH(-1) x pig(-1) x d(-1); 3) supplementation of 600 mg ALA(-1) x pig(-1) x d(-1); or 4) combined CMH and ALA supplements. Twelve pigs per treatment were individually penned with ad libitum access to water and a finishing diet. Treatments were hand-fed to individual pigs daily (divided into three equal doses) for 5 d before slaughter at 113 kg BW in two separate groups of 24 pigs each. Intramuscular pH was recorded at 45 min postmortem and again at 24 h in the ham semimembranosus (SM) and the longissimus muscle (LM) between the 10th and 11th rib. A Meatcheck (SFK Technology, Peosta, IA) conductivity probe was inserted in the same anatomical locations as pH measurement, providing an index value (PY) from 0 to 100 (a higher index value indicates more intact muscle cells and higher water-holding capacity). Color (L, a, b values) measurements were obtained at 24 h postmortem on the ham gluteus medius (GM), SM, and LM. Two 2.54-cm-thick loin chops were removed from the loin for determination of Warner-Bratzler shear force and glycolytic potential. The intact SM and the posterior portion of the boneless loin were vacuum-packaged and stored for 7 d to determine purge loss. Creatine-supplemented pigs had a higher (P = 0.03) PY value in the SM (66.67) at 45 min postmortem than either ALA, singularly (63.50), or in the combined CMH/ALA (62.27) treatments. (A higher PY index indicates superior water-holding capacity.) Lipoic acid supplementation resulted in the highest pH at 45 min (P = 0.029). These results justify further evaluation of the potential positive influence of supplementing alpha-lipoic acid to improve pork quality.     

Influence of Sperm Cell Dose and Post-insemination Backflow on Reproductive Performance of Intrauterine Inseminated Sows

This study was carried out to evaluate the effects of the sperm cell dose and semen backflow on the pregnancy rate and number of embryos of sows inseminated once at 0-24 h before ovulation, using an intrauterine technique. The results were analysed from a total of 211 sows assigned to three groups inseminated with doses of 0.25 x 10(9) (T1), 0.5 x 10(9) (T2) and 1.0 x 10(9) (T3) spermatozoa. Semen backflow was observed in 95% of the females (143/151) evaluated for this purpose. The percentage of semen backflow is close to two-third of the volume and the percentage of sperm is around 15% of the infused sperm dose. Intrauterine insemination can be successfully performed provided that at least 0.5 billion of sperm cell dose is infused at an interval of 0-24 h before ovulation.