A survey on the use of rugs in Australian horses

The practice of horse rugging has important implications for horse welfare and performance, but in Australia, rugging practices have not been properly documented. The objective of this study was to obtain an understanding of Australian horse rugging practices. An online survey reviewed the management of 2659 Australian horses over 12 months. Of the reported horses a total of 84.8% were rugged, although most owners (69.5%) indicated that they were unsure whether horses needed to be rugged at all. Rugging was felt by 59.8% of owners to be a requirement for horses in competition. Riding and competition were significantly associated with the use of rugs. Nearly all respondents (89.0%) felt that ‘over-rugging’ was a concern. However, 4.8% of owners would use up to 4 rugs at any one time on their horse and 21.4% of horses were still rugged in temperatures above 20°C in Australia. Many Australian horse owners (42.8%) also believe that horses feel cold if they are not rugged. Anthropomorphism when it comes to rugging horses cannot be justified as the horse has a much wider thermoneutral zone (TNZ) than humans. Australian climate, owner opinions, equestrian discipline and whether a horse is used for riding influence Australian horse rugging practices. However, current practices are based on limited available research and are not necessarily to the benefit of the horse. The major limitation was that the survey likely attracted respondents who are interested in the topic creating a self-selection bias.     

Regulation by gonadal steroids of estrogen and progesterone receptors along the reproductive tract in female lambs.

The regulation of estrogen and progesterone receptor (ER, PR) expression by estradiol (E2) and progesterone (P4) in the oviduct, uterus and cervix of female lambs was studied. The animals received three intramuscular injections of E2, P4 or vehicle with an interval of 24 h and they were slaugthered 24 h after the third injection. Determinations of ER and PR were performed by binding assays and mRNAs of ER alpha and PR by solution hybridization. High levels of ER and PR in both cervix and oviduct were found in the female lamb, differing from other mammalian species. No significant effects by either E2 or P4 treatment on ER and PR levels in the cervix and oviduct could be observed. E2 treatment increased the mRNA levels of ERa and PR more than 3-fold in the cervix, while P4 treatment increased the mRNA levels of ERa and PR in the uterus. The results show differential effects of gonadal steroids on sex steroid receptor expression along the reproductive tract in female lambs, suggesting that steroid target tissues can modulate responses to the same circulating levels of steroid hormones.     

Screening Capsicum species of different origins for high temperature tolerance by in vitro pollen germination and pollen tube length

Successful fruit set depends on several reproductive processes including pollen germination and tube growth processes. An experiment was conducted to determine the effects of temperature on pollen germination characteristics and to identify species/genotypic differences in Capsicum using the cumulative temperature response index (CTRI) concept. Pollen was collected from plants of seven genotypes from five Capsicum species, adapted to various parts of the world and grown outdoors in large pots. The pollen was subjected to in vitro temperatures ranging from 15 to 50 °C at 5 °C intervals. Pollen germination and tube lengths were recorded for all species after 24 h of incubation at the respective treatments. Species/genotypes differed significantly for in vitro pollen germination percentage and pollen tube length with mean values of 78% and 734 μm, respectively. The mean cardinal temperatures (T_min, T_opt, and T_max) averaged over genotypes, were 15.2, 30.7, and 41.8 °C for pollen germination and 12.2, 31.2, and 40.4 °C for pollen tube growth. The CTRI of each species/genotype calculated as the sum of eight relative individual stress response values, such as maximum pollen germination, maximum pollen tube length; T_min, T_opt, and T_max temperatures of pollen germination, and pollen tube lengths, identified species tolerance to high temperatures. Capsicum annum cv. Mex Serrano from Mexico was identified as tolerant, C. chacoense cv. 1312 and C. spp. cv. Cobanero from Argentina and Guatemala, respectively as intermediate and C. frutescens cv. Early Spring Giant from China, C. annum cv. Long Green from South Korea, C. spp. cv. NM89C130 and C. pubescens cv. 90002 from Guatemala as sensitive to high temperatures. The tolerant species/genotypes can be used in breeding programs to develop new genotypes that can withstand high temperature conditions both in the present climate and particularly in a future warmer climate.     

Follow-up of mercury levels in fish,human hair and urine in the Madeira and Tapajós basins,Amazon, Brazil

Informal economy of gold mining has contaminated some important river basins in Amazon. Follow-up studies on critical compartments showed some areas with high Hg levels in fish as well as in human hair samples. Average Hg in piscivorous fish in the Madeira river itself was 846 ppb (N=284) with a maximum of 3921 ppb. Mercury in fish from non polluted areas in this basin shows high variability, even for single species. A seasonal variation in Hg content was observed, with higher values at the end of the dry season. In the upper Tapajós basin comparable values were found for fish but with a definite decreasing trend downstream. Average value for piscivorous fish in the whole Tapajós basin is 482 ppb (N=122) with a maximum value of 3770 ppb. Hair Hg was higher in fishing villages in the Tapajós (average: 17 ppm; with N=432 and maximum value of 176 ppm) than in the Madeira (average: 9 ppm; N=169; maximum 71 ppm), and data from some areas of the Tapajós suggest a decrease with time. Mercury was much higher in urine of goldshop workers in Santarém (low Tapajós) than in Alta Floresta (high Tapajbs) and show a decreasing trend in both cases, probably related to the significant decline in gold mining activities during the study period (1986–1994).     

Effects of Pre‐Weaning Energy Substitutions on Post‐Weaning Follicle Development,Steroid Hormones and Subsequent Litter Size in Primiparous Sows

The present study investigated the effects of pre‐weaning energy substitutions on follicular development, endocrine characteristics and subsequent litter size in primiparous sows. Sows were fed a standard lactation diet (14.1 DE MJ/kg) and then allocated to a Control (C, n = 24), Fat (F, n = 23), Sugar (S, n = 23) or post‐weaning Regumate (positive control; R, n = 22) treatment at 9 days before weaning of the C, F and S treatments. During the treatment period (8 days), 1 kg of the lactation diet was substituted with 1 kg of a fat‐rich (F, 23.85 DE MJ/kg) or sugar‐rich (S, 15.75 DE MJ/kg) substitution for F and S sows, respectively. For the R treatment, sows were weaned 8 days earlier than other treatments and fed a lactation diet at 3.5 kg with two doses of altrenogest as topdressing from 1 day before weaning until the day on which the other sows were weaned. The F treatment aimed to increase energy intake, and the S treatment aimed to elevate post‐prandial glucose and insulin concentrations. Weaning‐to‐ovulation interval tended to be reduced in the S treatment compared with C (p = 0.06) and F (p = 0.08) treatments. Body weight (BW) loss during the treatment period, post‐weaning follicle development, plasma oestradiol and pre‐weaning leptin did not differ among C, F and S sows, although BW loss was lower and leptin was higher in the R treatment. Post‐ovulatory progesterone concentration in the S treatment was higher (p < 0.05). Sows in the S and R treatments had a greater proportion of litters with larger litter sizes (p < 0.05). The outcome suggests that increasing circulating insulin and glucose concentrations during late lactation or a week of metabolic recovery positively improves subsequent litter size in primiparous sows.     

Effect of Progesterone and Ionomycin on Domestic Cat Sperm Motility Patterns and Acrosome Reaction

This study was aimed at assessing the changes in sperm motion patterns and the percentage of acrosome reaction (AR) in domestic cat semen after treatment with either ionomycin or progesterone (P₄). Ten ejaculates were collected from five tomcats using an artificial vagina, and were diluted, centrifuged and resuspended in a capacitation medium. Samples were evaluated and divided into seven equal aliquots and, after 2 h at 25°C, were incubated for 30 min at 38°C in 5% CO₂ and then analyzed. Computer-assisted sperm analysis and a combination of three fluorescent probes were used to assess sperm plasma, acrosomal membrane integrity and mitochondrial transmembrane potential. Thirty minutes after the start of incubation, P₄ was added (10 μg/ml) to the P1 group. Groups P2 and P3 were supplemented with P₄ (10 and 20 μg/ml, respectively) only after 2 h of incubation, and groups I1 and I2 were supplemented with ionomycin (4 and 8 μ m , respectively) 2 h after incubation. Group E was supplemented with ethanol (0.6%) at 2 h after incubation and group C received no supplementation. Ionomycin and P₄ treatments led to a hyperactivation-like sperm motion and an increase (p < 0.05) in the percentage of AR. Although a higher (p < 0.05) percentage of AR was obtained in group I2 when compared with all P₄ groups, a decrease (p < 0.05) in total and progressive motility was observed in I2 group. As I1 group was similar to I2 to induce AR without diminishing sperm motility, we can conclude that ionomycin at 4 μ m seems to be more suitable to trigger AR in domestic cat sperm.     

Organogenesis and foetal haemodynamics during the normal gestation of healthy black‐rumped agoutis (Dasyprocta prymnolopha,Wagler, 1831) bred in captivity

The objective of this study was to define the patterns of organogenesis and foetal haemodynamics during the normal gestation of healthy agoutis (Dasyprocta prymnolopha) kept in captivity. Thirty pregnant agoutis that ranged in size from small to medium and weighed between 2.5 and 3 kg underwent B‐mode and Doppler ultrasonography for the biometric evaluation of the foetal organs. The foetal aortic blood flow proved to be predominantly systolic, and the measured flow velocity was 78.89 ± 2.95 cm/s, with a maximum pressure gradient of 2.12 ± 0.27 mmHg. The liver was characterized by its large volume, occupying the entire cranial aspect of the abdominal cavity, and it was associated cranially with the diaphragm and caudally with the stomach. The flow velocity in the portal vein was estimated to equal 12.17 ± 2.37 cm/s, with a resistivity index of 0.82 ± 0.05. The gallbladder was centrally located and protruded cranially towards the diaphragm. The spleen was visualized as an elongated structure with tapered cranial and caudal extremities, and the foetal kidneys were visualized bilaterally in the retroperitoneal region, with the right kidney positioned slightly more cranially than the left. The morphological characterization and hemodynamic analysis of the foetal organs of black‐rumped agoutis via B‐mode and Doppler ultrasonography allow determination of the vascular network and of reference values for the blood flow required for perfusing the anatomical elements essential for maintaining the viability of foetuses at different gestational ages.     

Organophosphate resistance in olive fruit fly, Bactrocera oleae, populations in Greece and Cyprus

The olive fruit fly Bactrocera oleae (Gmelin) (Diptera: Tephritidae) is the most important pest of olives in countries around the Mediterranean basin. Its control has been based mostly on bait sprays with organophosphate insecticides (usually dimethoate or fenthion) for about 40 years. In the present study, the resistance status of olive fruit fly populations to dimethoate was examined in Greece and Cyprus over 2 years. Thirty-one populations from various regions of Greece, nine from Cyprus and one laboratory susceptible strain, which served as a control, were assayed by topical application of dimethoate. Considerable variation in the resistance levels to dimethoate was recorded in the populations of B. oleae, with resistance ratios ranging from 6.3 to 64.4 (ED(50) values 12.5-128.7 ng dimethoate per insect). The highest resistance ratios were found in populations from Crete, and the lowest in those from Cyprus. This variation could be attributed to different selection pressures from insecticidal applications among populations from the various regions. Migration of resistant genotypes, either autonomous or via commerce, may also be involved.     

Follicle Development during Luteal Phase and Altrenogest Treatment in Pigs

Synchronization of the oestrous cycle of gilts using altrenogest treatment has been found to increase ovulation rate. The current experiment investigated if the increase in ovulation rate after altrenogest treatment is related to increased follicle size at the end of altrenogest treatment compared with late luteal phase follicles. Crossbred gilts (n = 15) received altrenogest during 18 days [20 mg Regumate (Janssen Animal Health, Beerse, Belgium)], starting 5-7 days after onset of first oestrus. Control gilts (n = 15) did not receive altrenogest. At days 10-12 of the oestrous cycle [i.e. in the presence of corpora lutea (CL)], average follicle development was 2.51 +/- 0.20 mm (assessed with ultrasound) in altrenogest-treated gilts and 2.58 +/- 0.16 mm in control gilts (p > 0.10). During the last days of altrenogest treatment (i.e. when CL had gone into regression), average follicle size had increased to 3.01 +/- 0.31 mm (p < 0.05). Subsequent ovulation rate was 16.6 +/- 1.7 in altrenogest treated gilts and 15.1 +/- 1.2 in control gilts (p < 0.05). Altrenogest treatment resulted in increased follicle size after regression of the CL, showing that suppression of follicle growth by altrenogest alone is less severe than suppression by endogenous progesterone (either with or without altrenogest). Altrenogest treatment also resulted in a higher ovulation rate. However, it is unclear if the increased follicle size and higher ovulation rate after altrenogest treatment are causally related, as the relation between the two on an animal level was not significant.