Evaluation of partial arytenoidectomy as a treatment for equine laryngeal hemiplegia

The efficacy of partial arytenoidectomy was assessed in 6 Standardbred horses, with surgically induced laryngeal hemiplegia, at rest (Period A) and during exercise at speeds corresponding to maximum heart rate (Period C) and 75% of maximum heart rate (Period B). Peak expiratory and inspiratory airflow rate (PEF and PIF), and expiratory and inspiratory transupper airway pressure (P_UE and P_UI) were measured and expiratory and inspiratory impedance (Z_E and Z_I) were calculated. Simultaneously, tidal breathing flow-volume loops (TBFVL) were acquired using a respiratory function computer. Indices derived from TBFVL included airflow rates at 50 and 25% of tidal volume (EF₅₀, IF₅₀, EF₂₅. and IF₂₅) and the ratios of expiratory to inspiratory flows. Measurements were made before left recurrent laryngeal neurectomy (baseline), 2 weeks after left recurrent laryngeal neurectomy (LRLN) and 16 weeks after left partial arytenoidectomy coupled with bilateral ventriculectomy (ARYT). After LRLN, during exercise Periods B and C, Z₁ and the ratio of EF₅₀/IF₅₀ significantly increased and PIF, IF₅₀ and IF₂₅ significantly decreased from baseline values. At 16 weeks after ARYT, Z₁ returned to baseline values during Periods B and C. Although PIF, IF₅₀, IF₂₅, PEF/PIF, and EF₅₀/IF₅₀ returned to baseline values during Period B, these indices remained significantly different from baseline measurements during Period C. After ARYT, TBFVL shapes from horses during Period C approached that seen at the baseline evaluation. Partial arytenoidectomy improved upper airway function in exercising horses with surgically induced left laryngeal hemiplegia, although qualitative and quantitative evaluation of TBFVLs suggested that some flow limitation remains at near maximal airflow rates. These results indicate that, although the procedure does not completely restore the upper airway to normal, partial arytenoidectomy is a viable treatment option for failed laryngoplasty and arytenoid chondropathy in the horse.     

Impact of four fiber-rich supplements on nutrient digestibility,colostrum production,and farrowing performance in sows

This study aimed to investigate the impact of dietary fiber (DF) sources on sow and litter performance, and apparent total tract digestibility (ATTD) of gross energy (GE) and nutrients. A total of 48 sows were stratified for body weight at mating and randomly assigned to one of four DF sources (mixed fiber [MF], palm kernel expellers [PKE], sugar beet pulp [SBP], or soy hulls [SH]) and fed the diet from mating until farrowing. Within DF treatments, sows were supplemented with one of two extra energy sources (glycerol or sugar dissolved in water), whereas a third group (control) received water from day 108 of gestation until farrowing. The number of total born, live-born, and stillborn pigs; birth time and birth weight of the pigs; farrowing duration; and farrowing assistance (FA) were recorded. Live-born pigs were weighed again at 12 and 24 h after birth to record weight gain, which was used to estimate intake and yield of colostrum. Blood samples were collected once daily from day −3 relative to farrowing until day 1 after farrowing in sows and once from selected pigs right after birth. Fecal samples were collected on day 114 of gestation and colostrum at 0, 12, 24, and 36 h after onset of farrowing. Intake of soluble and insoluble nonstarch polysaccharides (NSP) was greater for SBP (P < 0.001) and PKE (P < 0.001) supplemented sows, respectively, when compared with other groups. Farrowing duration and stillbirth rate were not affected by DF sources, but PKE and SH supplemented sows had greater FA than SBP and MF supplemented sows (P < 0.001). Extra energy supplement did not improve the farrowing performance. Concentration (P = 0.02) and output (P = 0.04) of dry matter in colostrum, and ATTD of GE (P < 0.001) and crude protein (CP; P < 0.001) were lower for PKE supplemented sows than in sows from the remaining groups. Intake of insoluble NSP correlated negatively with ATTD of GE (P < 0.001) and CP (P < 0.001). Concentrations of glucose (P < 0.001), lactate (P < 0.001), CO₂ (P < 0.001), and HCO₃ (P < 0.001) in sows blood were increased with time progress relative to farrowing. Newborn pigs from PKE supplemented sows had greater concentration of lactate (P = 0.02) and lower blood pH (P = 0.02) than the remaining treatments. In conclusion, PKE supplement reduced ATTD of GE and CP, and concentration and output of dry matter in colostrum but increased FA. Results of this experiment indicated that the use of PKE as a fiber source for late gestating sows should be avoided.     

Follow-up of 100 dogs with acute diarrhoea in a primary care practice

This study aimed to examine the aetiology of acute diarrhoea and the relapse rate in 100 client-owned dogs presented to a first-opinion clinic. History, physical examination, faecal testing and owner questionnaire data were collected at initial presentation (T₀) and at either the time of relapse or at a recheck performed within 3 months. All dogs received treatment according to their clinical signs. Of 96 dogs that completed the study, 37 (38.5%) relapsed during the study period, 21 (21.9%) relapsed within 3 months, and 16 others (16.6%) at 3 months to 1 year after initial examination. Dogs that had undergone a change in housing location within 1 month prior to presentation and dogs <1 year old were significantly more likely to have positive parasitological analyses (P = 0.02 and P = 0.001, respectively). Pica was a risk factor for relapse (P = 0.0002).     

Atrial natriuretic peptide and cardiac troponin I concentrations in healthy Warmblood horses and in Warmblood horses with mitral regurgitation at rest and after exercise

ObjectiveAtrial natriuretic peptide (ANP) and cardiac troponin I (cTnI) serve as biomarkers for increased cardiac pressure/volume loading and for myocardial stress or damage. The objective was to describe the time course of plasma ANP concentrations (Cp_ANP) and plasma cTnI concentrations (Cp_cTnI) in horses with mitral regurgitation (MR) compared to healthy horses at rest and after exercise, and to describe the relationship of Cp_ANP with cardiac dimensions and intracardiac pressures.Animals15 healthy Warmblood horses and 7 Warmblood horses with MR.MethodsCardiac dimensions at rest were measured using echocardiography. All horses underwent standardized treadmill exercise. Biomarker concentrations and intracardiac pressures were measured at rest and after exercise. Hypotheses were tested using statistical methods. The level of significance was P < 0.05.ResultsHorses with MR showed increased left atrial (LA) and left ventricular (LV) dimensions but similar exercise capacity compared to healthy horses. Pulmonary capillary wedge pressures (PCWP) and Cp_ANP increased with exercise. Horses with MR had higher PCWP and higher Cp_ANP at rest and after exercise compared to healthy horses, with the maximum difference in Cp_ANP reached 10 min after exercise. Cp_ANP was significantly related to PCWP and – although inconsistently and only in healthy horses – to echocardiographic indices of LA and LV size and function. Cp_cTnI was low throughout the study in both groups.ConclusionsCp_ANP is increased in horses with MR and is related to LA pressures and to left heart dimensions. MR is not necessarily associated with exercise intolerance and exercise-induced myocardial stress or damage.     

Change in body condition and carcass characteristics of cull ewes fed diets supplemented with rumen bypass fat

Thirty Malpura ewes (>6 years age) distributed into three groups of 10 each were maintained on concentrate supplemented with rumen protected fat at 0 (T₁), 20 (T₂) and 40 (T₃) g kg⁻¹ and chick pea straw for a period of three months. Towards the end of feeding experiment a metabolism trial was conducted on five representative ewes from each treatment. Blood and rumen liquor samples were analyzed at 0 and 90 days of feeding for blood biochemical and rumen metabolites. Five representative ewes were slaughtered at the initiation of the study and all the experimental ewes were slaughtered after termination of the experiment. The gain in weight (kg) and final body condition score was higher (P<0.05) in T₂ and T₃ as compared to T₁. The concentrate intake increased (P<0.05) with bypass fat (RBF) supplementation. The serum glucose and population of spirotrichs and total protozoa in rumen liquour sample increased (P<0.05) with concentrate as well as concentrate with RBF supplementation. Pre-slaughter weight, hot carcass weight, dressing percent, loin eye area, bone percent and carcass fat improved (P<0.05) with RBF supplementation. Composition of Longissimus dorsi muscle also revealed improvement when compared with 0 day composition. The feeding protocol also revealed higher returns by RBF supplementation. It is therefore concluded that RBF supplementation is advantageous in improving body conditions of cull ewes.     

Trace Mineral Supplementation in the Presence of Antagonists on Growth Performance,Health, and Carcass Characteristics of Transport-Stressed Calves

Crossbred steer calves (n = 64) were used in a 2 × 2 factorial arrangement to evaluate two levels of organic trace minerals and two levels of inorganic trace minerals. Calves were fed 28 d on the ranch in two pens of eight head per treatment before a simulated transport stress. After being loaded, hauled 129 km, unloaded with an overnight stand without feed and water, and reloaded, they were shipped to the Colorado State University (CSU) research feedyard in Fort Collins and placed in 64 individual pens. Calves fed the organic low level and inorganic high level trace minerals gained better (P<0.05) the first 28 d than did calves fed the organic high level or inorganic low level trace minerals. Overall growth performance was not influenced by trace mineral types or levels. Longissimus area was greater (P<0.05) for calves fed the low level organic trace minerals compared with that for calves fed the low level inorganic trace minerals. Eosinophils (d 28) were higher (P<0.05) for calves fed the organic high level trace minerals compared with calves fed inorganic low level trace minerals. Infectious bovine rhinotracheitis (IBR) and parainfluenza (PI₃) titers were not influenced by trace minerals. Red blood cells and packed cell volume were higher (P<0.05) for calves fed low level trace minerals regardless of trace mineral type. Liver Co was increased (P<0.05) at the 28-d sampling when inorganic trace minerals were fed. Liver Co was highest (P<0.05) at the 168- d sampling for calves fed low level inorganic trace minerals followed by calves fed organic high level trace minerals. Liver Fe was lower (P<0.05) in calves at the d-168 sampling when organic trace minerals were fed. Liver Zn was elevated (P<0.05) by d 28 by feeding the inorganic low level trace minerals, and by d-168, liver Zn was higher (P<0.05) for calves fed the low levels of trace minerals. Initial growth performance was maintained by either supplementing organic trace minerals or elevating dietary inorganic trace minerals when confronted with high dietary Fe, S, or Mo.     

Anti-inflammatory response of dietary vitamin E and its effects on pain and joint structures during early stages of surgically induced osteoarthritis in dogs

There is evidence that vitamin E (VE) has anti-inflammatory and analgesic properties in human osteoarthritis (OA). This double-blinded and randomized pilot study used a broad spectrum of clinical and laboratory parameters to investigate whether such beneficial effects could be detected in a canine experimental OA model. Dogs were divided into 2 groups: control (n = 8), which received a placebo, and test group (n = 7), which received 400 IU/animal per day of VE for 55 d, starting the day after transection of the cranial cruciate ligament. Lameness and pain were assessed using a visual analogue scale (VAS), numerical rating scale (NRS), and electrodermal activity (EDA) at day 0, day 28, and day 55. Cartilage and synovial inflammation lesions were assessed. One-side comparison was conducted at an alpha-threshold of 10%. At day 56, dogs were euthanized and concentrations of prostaglandin E₂ (PGE₂), nitrogen oxides (NO_x), and interleukin-1 beta (IL-1β) were measured in synovial fluid. Concentrations of NO_x and PGE₂ in synovial fluid were lower in the test group (P < 0.0001 and P = 0.03, respectively). Values of VAS, NRS, and EDA showed a consistent trend to be lower in the test group than in the control, while statistical significance was reached for VAS at day 55 and for EDA at day 28 (adjusted P = 0.07 in both cases). Histological analyses of cartilage showed a significant reduction in the scores of lesions in the test group. This is the first time that a study in dogs with OA using a supplement with a high dose of vitamin E showed a reduction in inflammation joint markers and histological expression, as well as a trend to improving signs of pain.     

Heat-tolerant versus heat-sensitive Bos taurus cattle: influence of air temperature and breed on the acute phase response to a provocative immune challenge

The difference in the acute phase response of a heat-tolerant and a heat-sensitive Bos taurus breed to a lipopolysaccharide (LPS) challenge when housed at different air temperatures (T_a) was studied. Angus (ANG; heat-sensitive; n = 11; 306 ± 26 kg BW) and Romosinuano (RO; heat-tolerant; n = 10; 313 ± 32 kg BW) heifers were transported from the USDA Agricultural Research Service SubTropical Agricultural Research Station in Florida to the Brody Environmental Chambers at the University of Missouri, Columbia. Heifers were housed in stanchions in 4 temperature-controlled environmental chambers. Initially, T_a in the 4 chambers was cycling at thermoneutrality (TN; 18.5°C–23.5°C) for a 1-wk adjustment period, followed by an increase in 2 of the 4 chambers to cycling heat stress (HS; 24°C–38°C) for 2 wk. On day 19, heifers were fitted with jugular catheters and rectal temperature (RT) recording devices. On day 20, heifers were challenged with LPS (0.5 μg/kg BW; 0 h), sickness behavior scores (SBSs) were recorded, and blood samples were collected at 0.5-h intervals from −2 to 8 h and again at 24 h relative to LPS challenge at 0 h. Serum was isolated and stored at −80°C until analyzed for cortisol and cytokine concentrations. A breed by T_a interaction (P < 0.001) was observed for RT such that the post-LPS average RT in RO heifers housed at TN was lower than the RT of all other treatment groups (P < 0.001), whereas ANG heifers housed at HS had greater post-LPS average RT than all other treatment groups (P < 0.001). In response to LPS, HS increased SBS after LPS in RO heifers compared to RO heifers housed at TN (P < 0.001), whereas HS decreased SBS after LPS in ANG heifers compared to ANG heifers housed at TN (P = 0.014). The cortisol response to LPS was greater in TN than in HS heifers (P < 0.01) and was also greater in RO than in ANG heifers (P = 0.03). A breed by T_a interaction (P < 0.01) was observed for tumor necrosis factor-α (TNF-α) concentration such that HS increased post-LPS serum concentrations of TNF-α in ANG heifers compared to ANG heifers housed at TN (P = 0.041), whereas HS decreased post-LPS concentrations of TNF-α in RO heifers compared to RO heifers housed at TN (P = 0.008). A tendency (P < 0.06) was observed for a breed by T_a interaction for IL-6 concentrations such that RO heifers had greater post-LPS concentrations of IL-6 than ANG heifers when housed at HS (P = 0.020). A breed by T_a interaction was observed for interferon-γ (IFN-γ; P < 0.01) concentrations such that HS decreased post-LPS concentrations of IFN-γ in ANG heifers compared to ANG heifers housed at TN (P < 0.001), and HS increased post-LPS concentrations of IFN-γ in RO heifers compared to RO heifers housed at TN (P = 0.017). These data indicate differences in the acute phase response between the heat-tolerant RO and heat-sensitive ANG heifers under different T_a which may aid in elucidating differences in productivity, disease resistance, and longevity among cattle breeds.     

DNA Fragmentation as an Early Indicator of Extender Efficacy: A Preliminary Study

Evaluation of new potential semen extenders is a field of economic and scientific importance, but assessing motility alone may not be sufficient. The objectives of this study were to examine the effect of oxidative damage by short-term exposure to H₂O₂ on stallion sperm motility and DNA fragmentation and to correlate motility to the percentage of DNA damage as assessed by both terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) and single-cell gel electrophoresis assays. Motility and DNA fragmentation were determined immediately before cooling (0 hour) and at 24 hours postcooling. The addition of H₂O₂ (300 μM) to the extender had no effect on either total or progressive motility (P > .05). DNA fragmentation as determined by both Comet and TUNEL assays did not differ between 0 hour and those cells stored for 24 hours in the absence of H₂O₂ (P > .05). However, the addition of H₂O₂ to the extender plus incubation for 24 hours resulted in greater total Comet length, tail length, and tail moment as well as an increase in percentage of sperm cells with DNA damage detected by TUNEL compared to 0 hour (P < .05). Motility was not correlated with DNA damaged cells detected by TUNEL or Comet assays (P > .05). In conclusion, although both the Comet assay and TUNEL detected significant DNA fragmentation in cells exposed to H₂O_2, there was not a significant or appreciable effect of H₂O₂ on motility. Therefore, motility alone is likely not the best laboratory assay with which to assess cooled extender efficacy.     

Ovarian steroids modulate tumor necrosis factor-α and nitric oxide-regulated prostaglandin secretion by cultured bovine oviductal epithelial cells

Ovarian steroids assure an optimum environment for the final maturation of oocytes, gamete transport, fertilization, and early embryonic development. The aim of experiment 1 was to examine the influence of ovarian steroids on tumor necrosis factor-α (TNF-α)- or nitric oxide (NO)-regulated prostaglandin (PG), and nitrite/nitrate (NO₂/NO₃) secretion by cultured bovine oviductal epithelial cells (BOECs). BOECs were pretreated with 17β-estradiol (E₂; 10⁻⁹ M) and/or progesterone (P₄; 10⁻⁷ M) for 24 h. For the next 24 h, BOECs were treated with TNF-α (10 ng/mL) or spermine nitric oxide complex (NONOate; 10⁻⁵ M). Prostaglandin F_2α and PGE₂ secretion was measured in medium by ELISA. The pretreatment of cells with P₄ (progesterone), E₂ (17 β-estradiol), or E₂/P₄ augmented TNF-α-induced PGF_2α and PGE₂ secretion (P < 0.01). The pretreatment of cells with E₂ or E₂/P₄ increased NONOate-induced PGF_2α and PGE₂ secretion (P < 0.01). TNF-α induced NO₂/NO₃ production by BOECs. The pretreatment of cells with E₂ augmented only TNF-α-induced NO₂/NO₃ production (P < 0.05). The aim of experiment 2 was to examine the influence of TNF-α, NO, and ovarian steroids on the protein content of enzymes specifically involved in PG and NO production, PG synthases, and NO synthases (NOSs). BOECs were treated with TNF-α (10 ng/mL) or NONOate (10⁻⁵ M). TNF-α increased the protein content of PGG/H synthase, PGF synthase, and PGE synthase (P < 0.05) and endothelial and inducible NOSs (P < 0.05). Nitric oxide increased the protein content of PGF synthase, PGE synthase, endothelial NOS, and inducible NOS (P < 0.05). These results show possible linkage between TNF-α and NO, modulated by ovarian steroids, in the regulation of PG synthesis by BOECs that may be important for triggering the process of oviductal contractions.     

Heat-tolerant versus heat-sensitive Bos taurus cattle: influence of air temperature and breed on the metabolic response to a provocative immune challenge

The response of the immune and stress systems have been assessed in response to a lipopolysaccharide (LPS) challenge, yet the role of metabolism in mediating energy requirements during the acute phase response has not been sufficiently studied. This study tested heat-tolerant (Romosinuano [RO]) and heat-sensitive (Angus [ANG]) Bos taurus breeds at different ambient temperatures (T_a) to determine differential metabolic responses to LPS challenge. Twenty-one heifers (ANG: n = 11, 306 ± 26 kg BW; RO: n = 10, 313 ± 32 kg BW) were housed in stanchions in 4 temperature-controlled chambers. Initially, T_a in all 4 chambers was cycling at thermoneutrality (TN; 18.5°C–23.5°C) for a 1-wk adjustment period, followed by an increase in 2 chambers to cycling heat stress (HS; 24°C–38°C) for 2 wk. Five ANG and 5 RO heifers were housed at TN, whereas 6 ANG and 5 RO heifers were housed at HS. On day 19, heifers were fitted with jugular catheters. On day 20, heifers were challenged with LPS (0.5 μg/kg BW; 0 h), and blood samples were collected from −2 to 8 h and at 24 h relative to LPS challenge. Serum was analyzed for glucose, insulin, and NEFA concentrations. In addition, feed intake was measured 3 d before and on the day of the challenge. Feed intake decreased over time (P < 0.001) and was decreased in heifers housed at HS compared with heifers housed at TN (P = 0.013). Glucose concentrations before LPS challenge were greater in RO (P = 0.01) than in ANG heifers and greater in TN-housed heifers (P = 0.02) than in HS heifers. Glucose after LPS challenge initially increased before decreasing below baseline concentrations (P < 0.01) in all heifers. In addition, there was a breed by T_a interaction (P < 0.004), such that HS decreased glucose concentrations in ANG heifers compared with ANG heifers housed at TN (P < 0.001), whereas HS did not affect glucose concentrations after LPS challenge in RO heifers (P = 0.941). Nonesterified fatty acid concentrations before LPS challenge were not affected by breed (P = 0.37) or T_a (P = 0.60). Although NEFA concentration after LPS challenge was unaffected by T_a (P = 0.78), there tended to be a breed by T_a interaction (P = 0.07) such that, when housed at HS, RO heifers had greater serum NEFA concentrations after LPS challenge than ANG heifers (P = 0.009). Insulin concentration before LPS challenge was greater in RO heifers than in ANG heifers (P < 0.01). Insulin after LPS challenge increased (P < 0.01), with RO heifers producing a greater insulin response than ANG heifers (P < 0.01). These data suggest that HS decreases the metabolic response of heat-sensitive ANG heifers in response to LPS challenge, thus providing physiological evidence that may explain differences observed in the acute phase response between heat-sensitive ANG and heat-tolerant RO cattle breeds.     

Effect of pre- and post-pubertal castration on Piemontese male calves: I. Live and slaughtering performances

To evaluate the effect of different age of castration on live and slaughtering performances in Piemontese males a study was carried out on 24 cattle divided in 3 groups: EC—early castrated (5th month of age), LC—late castrated (13th month) and IM—intact males, reared under the same environmental condition until the same fattening degree, then slaughtered at 18 month of age. The animals were fed at the same energy and protein level. Live weight was recorded monthly and 18 linear body measurements were recorded at 18th month of age. Live performances and slaughtering data were recorded or calculated. Differences were found in live weight (higher in IM than EC and LC; P < 0.01), buttock girth, chest girth (both higher in IM than EC; P < 0.05) and shin girth (higher in IM and LC than EC; P < 0.05). The average daily weight gain was higher in IM compared to EC and LC (P < 0.01). The carcass weight was higher in IM than EC and LC (P < 0.01). Little differences were found between EC, LC and IM in some anatomical parts weights. No differences were pointed out in the dressing percentage. Castration of Piemontese bulls at 13th month of age do not improve live and slaughtering performances compared to animals castrated at 5 month of age, even if the LC linear body measurements are more similar to the IM than EC.     

Reference intervals for transthoracic echocardiography in the American Staffordshire Terrier

This study reports the echocardiographic reference intervals in the American Staffordshire Terrier (AST). The echocardiographic variables obtained in 57 healthy adult AST were compared with published data from the general canine population and other breeds. In the AST, the left ventricular volumes were lower than values reported in Boxers and Dobermans (P<0.0001), but higher than in small breeds (P<0.0001). The left ventricular ejection fraction was higher than Boxers and Dobermans (P<0.0001), but lower than small breed dogs (P=0.027). The aortic peak velocity values were similar to Boxers (P=0.55) but higher than the general canine population (P<0.0001). The reference intervals presented in this study are clinically useful for an accurate echocardiographic interpretation and screening in the AST.     

Reproductive responses of rabbit does to a supplemental lighting program

The objective was to investigate whether the productivity of rabbit does can be improved, when natural photoperiod is decreasing, by adopting a supplemental lighting program. Three experiments were conducted involving two groups: control, submitted to the natural decreasing photoperiod, and supplemented with a lighting program which provided 14 h light/24 h beginning at 10 weeks of age. In the first experiment, 20 nulliparous does, 10 from each group, were euthanized 8 h after being presented to a buck; the overall number of follicles, whose diameter exceeded 1 mm, was determined macroscopically. The right ovaries were collected, histologically analyzed, and electronically measured. In the second experiment, 30 nulliparous does, 15 from each group, were presented to a buck (day 1). Receptive does were euthanized on day 8 to evaluate embryonic survival (number of normal embryos/ovulation rate). In the third experiment, 48 nulliparous does, 24 from each group, were followed from the first presentation to the buck until the weaning of the first litter. The effect of treatment on reproductive and body weight traits of does, and litter performance traits, at birth and weaning, was evaluated. The average number of follicles whose diameter exceeded 1 mm was higher in the treatment group (12.05±1.07 vs. 8.63±1.00, P=0.037). Receptive does of the treatment group had heavier ovaries relative to those of the control group (790±59 vs. 470±64 mg, P=0.004), whereas no treatment difference regarding this trait was found for non-receptive ones. Treatment had a favorable effect on pregnancy rate of total exposed and of receptive does (80.0% vs. 33.3%, P=0.01, and 92.3% vs. 50.0%, P=0.02, respectively). The number of underdeveloped embryos was lower (0.067±0.380 vs. 2.500±0.455, P=0.004), embryonic survival up to day 8, and uterus weight was higher in the treatment group (0.839±0.075 vs. 0.534±0.087, P=0.033 and 13.83±0.72 vs. 10.99±0.84, P=0.037, respectively). Number of presentations tended to be lower (1.32±0.17 vs. 1.75±0.16, P=0.077) and adjusted litter size in the first reproductive cycle tended to be higher (7.09±0.89 vs. 5.22±0.68, P=0.091) in the treatment group relative to the control group. A supplemental lighting program providing 14 h light/24 h favors reproductive performance of primiparous does; its application may be recommended to increase productivity when natural photoperiod is decreasing.     

Embryo Transfer in Anovulatory Recipient Mares Treated with Estradiol Benzoate and Long-Acting Progesterone

This study aimed to prepare anovulatory mares in anestrus or in the transitional period as embryo recipients. Ninety embryo-recipient mares were divided into two groups (G). G1 (n = 45) comprised animals in anestrus or in the transitional period; these animals were treated for 3 days (D) with 5, 3, and 2 mg of estradiol benzoate (intramuscular) on D0 (day of the donor's ovulation), D1, and D2 (after ovulation), respectively, followed by weekly application of 400 mg of long-acting progesterone (intramuscular) from D3 after ovulation (donor) until the 120th day of gestation. G2 (n = 45) comprised mares with normal estrous cycles. Plasma levels of progesterone (P₄) were measured on days D1, D2, D8, and D14. Sixty percent of the animals in G1 and 71.1% in G2 (P > .05) completed the pregnancy. On D8, there was no difference in P₄ levels between G1 and G2 animals, but there was a difference in P₄ levels on D14 (P < .05). It was concluded that anovulatory mares in anestrus or in the transitional period could be used as embryo recipients. The protocol was efficient and also considered an appropriate alternative to prepare the uterine environment for embryo transfer; long-acting progesterone administration kept P₄ levels high enough to maintain pregnancy until the 120th day and provided recipients during the time of the year when fewer mares were cycling and ovulating.     

Environmental Exposures and Airway Inflammation in Young Thoroughbred Horses

Background

Inflammatory airway disease (IAD) in horses is a widespread, performance‐limiting syndrome believed to develop in response to inhaled irritants in the barn environment.

Objectives

To evaluate changes in bronchoalveolar lavage fluid (BALF) cytology and exposure to particulates, endotoxin, and ammonia during horses'' first month in training.

Animals

Forty‐nine client‐owned 12‐ to 36‐month‐old Thoroughbred horses entering race training.

Methods

In this prospective cohort study, a convenience sample of horses was assigned to be fed hay from a net (n = 16), whereas the remaining horses were fed hay from the ground (n = 33). BALF was collected at enrollment and after 14 and 28 days in training. Respirable particulate, inhalable particulate, respirable endotoxin, and ammonia concentrations were measured at the breathing zone of each horse weekly.

Results

Median respirable particulates were significantly higher when horses were fed from hay nets than when fed hay from the ground (hay net 0.28 mg/m³, no hay net 0.055 mg/m³, P < .001). Likewise, inhalable particulate (hay net 8.3 mg/m³, no hay net 3.3 mg/m³, P = .0064) and respirable endotoxin (hay net 173.4 EU/m³, no hay net 59.2 EU/m³, P = .018) exposures were significantly higher when horses were fed from hay nets. Feeding hay from a net resulted in significantly higher BALF eosinophil proportions over time (P < .001). BALF eosinophils were significantly related to respirable particulate exposure (14 days in training r _s = 0.37, P = .012, 28 days in training, r _s = 0.38, P = .017).

Conclusions and Clinical Importance

Pulmonary eosinophilic inflammation develops in response to respirable particulate exposure in young Thoroughbreds, indicating a potential hypersensitivity to inhaled particulate allergens.