Estimation of genetic parameters for racing speed at different distances in young and adult Spanish Trotter horses using the random regression model

A total of 71 522 records (from 3154 horses) with the times per kilometre (TPK), recorded in Spanish Trotter horses (individual races) from racing performances held from 1991 to 2007, were available for this study. The TPK values for the different age groups (young and adult horses) and different distances (1600–2700 m) were considered as different traits, and a bi character random regression model (RRM) was applied to estimate the (co)variance components throughout the trajectory of age groups and distances. The following effects were considered as fixed: the combination of hippodrome‐date of race (404 levels); sex of the animals (3 levels); type of start (2 levels) and a fixed regression of Legendre polynomials (order 2). Those considered as random effects were the random regression Legendre polynomial (order 1) for animals (9201 animals in the pedigree); the individual environment permanent (3154 animals with data) and the driver (n = 957 levels). The residual variance was considered as heterogeneous with two classes (ages). The heritability estimated by distance ranged from 0.12 to 0.34, with a different trajectory for the two age groups. Within each age group, the genetic correlations between adjacent distances were high (>0.90), but decreased when the differences between them were over 400 metres for both age groups. The genetic correlations for the same distance across the age groups ranged from 0.47 to 0.78. Accordingly, the analysed trait (TPK) can be considered as positive genetic correlated but as different traits along the trajectory of distance and age. Therefore, some re‐ranking should be expected in the breeding value of the horses at different characteristics of the racing. The use of RRM is recommended because it allows us to estimate the breeding value along the whole trajectory of race competition.     

Effect of protein supplementation on reproductive and productive performance in <Emphasis Type="Italic">Bos indicus</Emphasis> × <Emphasis Type="Italic">Bos taurus</Emphasis> heifers raised in the humid tropics of Costa Rica

In order to evaluate the effect of protein supplementation on the productive and reproductive performance of heifers, 45 Bos indicus × Bos taurus heifers, 673 ± 146 days of age and weighing about 340 kg, were divided into two groups. The control group (n = 23) continued without supplementation, but the supplemented group (SG; n = 22) received concentrate at a rate of 1% BW kg per day. Animals were adapted to the concentrate over a 15-day period and then supplemented for 30 days, after which estrus was synchronized using a progesterone implant. Back fat thickness (BFT) was assessed by ultrasound. The SG had better average daily weight gain than the nonsupplemented group (0.63 ± 0.16 vs. 0.51 ± 0.13 kg/day, P < 0.05) and tended to show a better percentage ovulation (P < 0.10, 77% vs. 57%, respectively). However, this tendency was not reflected in the final pregnancy rates. No differences were observed between groups in dry matter intake and body condition scores. SG with a high BFT (>0.70 cm) showed a better ovulation percentage than those with low BFT (<0.69 cm; P < 0.01). Additionally, the pregnancy rate of supplemented heifers with high BFT tended to be better than heifers with low BFT in this same group (67% vs. 30%, respectively, P < 0.10). It is concluded that protein supplementation improved reproductive performance and that ultrasonography to measure BFT may be used to estimate reproductive performance.     

Summer spatial patterning of chukars in relation to free water in western Utah

Free water is considered important to wildlife in arid regions. In the western United States, thousands of water developments have been built to benefit wildlife in arid landscapes. Agencies and researchers have yet to clearly demonstrate their effectiveness. We combined a spatial analysis of summer chukar (Alectoris chukar) covey locations with dietary composition analysis in western Utah. Our specific objectives were to determine if chukars showed a spatial pattern that suggested association with free water in four study areas and to document summer dietary moisture content in relation to average distance from water. The observed data for the Cedar Mountains study area fell within the middle of the random mean distance to water distribution suggesting no association with free water. The observed mean distance to water for the other three areas was much closer than expected compared to a random spatial process, suggesting the importance of free water to these populations. Dietary moisture content of chukar food items from the Cedar Mountains (59%) was significantly greater (P < 0.05) than that of birds from Box Elder (44%) and Keg-Dugway (44%). Water developments on the Cedar Mountains are likely ineffective for chukars. Spatial patterns on the other areas, however, suggest association with free water and our results demonstrate the need for site-specific considerations. Researchers should be aware of the potential to satisfy water demand with pre-formed and metabolic water for a variety of species in studies that address the effects of wildlife water developments. We encourage incorporation of spatial structure in model error components in future ecological research.     

Effect of the diet on lipid composition and liver histology of short snout seahorse Hippocampus hippocampus

Little is known about the nutritional requirements of ornamental fish and the effects which they may have on fish histology. Because of this, 45 young, captive‐bred seahorses (1.37 g ± 0.51) were randomly divided and put into fifteen, 35‐L, glass aquariums. Three experimental diets were tested in triplicate: live enriched Artemia (LEA); frozen enriched Artemia (FEA); and commercial Mysis (M). seahorses were fed twice daily, 6 days a week for 102 days throughout the experiment. The body weight and length of the seahorses were measured every 20 days, and at the end of the experiment, fish liver samples were taken for histological studies. Biochemical analyses of the diets and the seahorses fed on the experimental diets were recorded, and the differences in the total lipid content in each of the three diets were also observed, each reflecting their respective liver lipid content. seahorses fed with LEA treatment showed lipid vacuoles in the hepatocytes with nuclei displaced to the periphery. Similar results were also observed in FEA fed seahorses, but to a lesser extent. In contrast, the M fed seahorses were characterized by having livers with lower size hepatocytes and centrally located nuclei.     

Validating the assessment of bull sperm morphology by veterinary practitioners

The objective of this study was to validate the assessment of bull sperm morphology done by veterinary practitioners. Out of 1606 bulls, 1400 (87.2%) and 1344 (83.7%) were designated by practitioners and an experienced andrologist, respectively, as having > 70% morphologically normal sperm. In 92% of the evaluations, there was agreement between the designations chosen.     

Porcine TLR3 characterization and expression in response to influenza virus and Bordetella bronchiseptica

We have provided a detailed structural analysis of porcine alveolar macrophage TLR3 extracellular domain (ECD). The porcine TLR3-ECD contains 18 leucine-rich repeats (LRRs) consisting of blocks of consensus motifs and non-consensus motifs containing insertions. Excluding the N-terminal and C-terminal LRRs, porcine TLR3 has two LRRs with insertions, resulting in one LRR of 39 amino acids and another LRR of 34 amino acids. Furthermore, we have conducted the first examination of the regulated expression of porcine alveolar macrophage TLR3 during in vivo co-infection with influenza virus and Bordetella bronchiseptica. There was a bi-phasic upregulation of porcine TLR3 during influenza virus infection (day 1 and day 10 post-infection). Co-infection resulted in an enhanced expression of porcine TLR3 only at day 1 post-infection. Interestingly, B. bronchiseptica induced an upregulation in alveolar macrophage TLR3 expression at day 10 post-infection. Based on our work and that of others, TLR3 likely plays a key role in the immune response of lung cells to influenza virus infection in several mammalian species.     

Variable response of open-pollinated seedling progeny of avocado to Phytophthora root rot

Phytophthora root rot, caused byPhytophthora cinnamomi Rands, is the most important disease of avocado (Persea americana Miller). In an attempt to identify root rot-resistant rootstocks that could ultimately be used under conditions in southern Florida, we screened open-pollinated progeny of avocado from the National Germplasm Repository in Miami. From 1996 to 1998, a total of 2,355 seedlings from 51 accessions were examined in potting mix artificially infested withP. cinnamomi. Most seedlings developed severe root rot, but tolerance was observed in some families (i.e., progeny of certain accessions). Although the most susceptible families developed mean disease ratings of up to 97% root necrosis, mean ratings for the most tolerant families were less than 60%. There was also a strong relationship between the racial background of the female parent and the tolerance of seedlings. Seedlings of the West Indian race and hybrids between it and the Guatemalan race were significantly more tolerant than those from other parents (P< 0.05). Individuals in several families developed < 50% root necrosis, the arbitrary standard of tolerance in this study. Twelve families accounted for 82% (188 of 229) of the tolerant seedlings, and only two of these did not have a West Indian or Guatemalan × West Indian pedigree. Broad-sense heritability for PRR tolerance was 0.45. This is the first report on the inheritance of PRR tolerance in avocado and on the influence of genotype and racial pedigree under controlled conditions.     

Modelling the impacts of agriculture in mixed-use landscapes: a review and case study involving two species of dabbling ducks

Context

This study synthesizes evidence from three separate surveys of American Black Duck and Mallard breeding habitat usage to quantify the effects of agriculture at the landscape scale.

Objectives

To assess duck breeding activity in agricultural landscapes within the Canadian maritimes in order to measure the overall impact of agricultural land use, the response to particular agricultural activities, and the influence of landscape configuration.

Methods

Models, constructed using a long-term census (SURVEY1), were used to predict habitat selection for two other independent surveys (SURVEY2, SURVEY3). Predictions incorporated information about wetland area and diversity, as well as anthropogenic factors, allowing subsequent analyses to focus on the remaining residual error attributable to agricultural effects.

Results

SURVEY2 results demonstrated that the proportion of active agriculture is an important indicator of the severity of human disturbance, yielding threshold estimates of 39% for Mallards and 60% for Black Ducks, with an overall average of 50%. Agricultural conversion beyond these thresholds deterred breeding ducks independently of other factors. SURVEY3 land cover information demonstrated that the presence of cropland intensified this deterrence effect, even at levels as low as 10%. Woodland cover (in excess of 30%) was important for both species, but its configuration was not.

Conclusions

In addition to quantifying threshold effects, this study reaffirms that woodland is an important part of the maritime landscape matrix, and contributes positively to habitat diversity in mixed use, moderate intensity agricultural regions. Wetland restoration in agricultural landscapes should monitor and promote less crop-intensive, mixed-use practices.

     

Effects of maternal subnutrition during early pregnancy on cow hematological profiles and offspring physiology and vitality in two beef breeds

This experiment evaluated the effects of subnutrition during early gestation on hematology in cows (Bos Taurus) and on hematological, metabolic, endocrine, and vitality parameters in their calves. Parda de Montaña and Pirenaica dams were inseminated and assigned to either a control (CONTROL, 100% requirements) or a nutrient‐restricted group (SUBNUT, 65%) during the first third of gestation. Dam blood samples were collected on days 20 and 253 of gestation, and calf samples were obtained during the first days of life. Pirenaica dams presented higher red series parameters than Parda de Montaña dams, both in the first and the last months of gestation. During early pregnancy, granulocyte numbers and mean corpuscular hemoglobin were lower in Pirenaica‐SUBNUT than in Pirenaica‐CONTROL cows. Calves from the SUBNUT cows did not show a physiological reduction in red series values in early life, suggesting later maturation of the hematopoietic system. Poor maternal nutrition affected calf endocrine parameters. Newborns from dystocic parturitions showed lower NEFA concentrations and weaker vitality responses. In conclusion, maternal nutrition had short‐term effects on cow hematology, Pirenaica cows showing a higher susceptibility to undernutrition; and a long‐term effect on their offspring endocrinology, SUBNUT newborns showing lower levels of IGF‐1 and higher levels of cortisol.