The breeder's dilemma--yield or nutrition?
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Agriculture↗
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Results for “Breeding value”
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Efficiency of lignin biosynthesis: a quantitative analysis.
Lignin is derived mainly from three alcohol monomers: p-coumaryl alcohol, coniferyl alcohol and sinapyl alcohol. Biochemical reactions probably responsible for synthesizing these three monomers from sucrose, and then polymerizing the monomers into lignin, were analysed to estimate the amount of sucrose required to produce a unit of lignin. Included in the calculations were amounts of respiration required to provide NADPH (from NADP(+)) and ATP (from ADP) for lignin biosynthesis. Two pathways in the middle stage of monomer biosynthesis were considered: one via tyrosine (found in monocots) and the other via phenylalanine (found in all plants). If lignin biosynthesis proceeds with high efficiency via tyrosine, 76.9, 70.4 and 64.3 % of the carbon in sucrose can be retained in the fraction of lignin derived from p-coumaryl alcohol, coniferyl alcohol and sinapyl alcohol, respectively. The corresponding carbon retention values for lignin biosynthesis via phenylalanine are less, at 73.2, 65.7 and 60.7 %, respectively. Energy (i.e. heat of combustion) retention during lignin biosynthesis via tyrosine could be as high as 81.6, 74.5 and 67.8 % for lignin derived from p-coumaryl alcohol, coniferyl alcohol and sinapyl alcohol, respectively, with the corresponding potential energy retention values for lignin biosynthesis via phenylalanine being less, at 77.7, 69.5 and 63.9 %, respectively. Whether maximum efficiency occurs in situ is unclear, but these values are targets that can be considered in: (1) plant breeding programmes aimed at maximizing carbon or energy retention from photosynthate; (2) analyses of (minimum) metabolic costs of responding to environmental change or pest attack involving increased lignin biosynthesis; (3) understanding costs of lignification in older tissues; and (4) interpreting carbon balance measurements of organs and plants with large lignin concentrations.
Biological Transport↗
Reduced efficacy of anthelmintics in young compared with adult horses.
Studies on a Thoroughbred breeding farm in Ohio from 1982 to 1988 demonstrated the value of three anthelmintic pastes (ivermectin, oxibendazole, pyrantel pamoate) in controlling benzimidazole resistant cyathostomes (small strongyles) in adult horses. However, a comparison of drug efficacy in suppressing faecal egg counts for the full period between treatments showed a significant reduction in efficacy of all drugs in yearling horses compared with adults. Mean faecal egg counts of adult horses were generally kept below 100 eggs per gram (epg) of faeces when using oxibendazole or pyrantel pamoate at four to five week intervals and ivermectin at eight week intervals. By contrast, mean counts of young horses rose as high as 655 epg (oxibendazole), 729 epg (pyrantel pamoate) and 852 epg (ivermectin) within the same time period after treatment. Individual counts of treated yearlings sometimes exceeded 3,000 epg. Three distinct mechanisms appeared to be involved in the poor results in young horses. These were 1) anthelmintic refuge, 2) anthelmintic resistance, and 3) anthelmintic avoidance.
Age Factors↗
Relationship of beef sire expected progeny difference to maternal performance of crossbred daughters.
Cumulative milk production of crossbred daughters of sires of several breeds was estimated using weigh-suckle-weigh procedures. Pooled-across-breed analyses were conducted to determine, in retrospect, relationships of sire EPD values for milk and total maternal value to daughter milk yield and daughter's offspring weaning weight. The pooled coefficient for regression of daughter 214-d milk yield on sire milk EPD was 13.4 kg/kg (residual correlation was .14). The overall mean estimated milk yield was 1,262 kg, suggesting that a difference in sire milk EPD of 1 kg corresponded to a difference of approximately 1% in cumulative daughter milk yield. The pooled coefficient for regression of daughter's offspring 214-d weight on sire total maternal EPD was 1.18 kg/kg (residual correlation was .17). All regression and correlation coefficient stated above were significantly greater than zero. Breeders who use sire milk and total maternal EPD values as selection tools should expect such selection to be effective, on average, but should also expect that a substantial proportion of individuals or small groups may not rank as predicted.
Animals↗
Repeated matings with individual ewes by rams differing in sexual performance.
Twenty-four sexually mature rams were individually exposed to 10 estrous ewes on three occasions to determine the relationship between levels of sexual performance (ejaculation rate or serving capacity) and the incidence of repeated matings (ejaculations) with individual ewes. Rams that attained six ejaculations in a relatively short period of time (HP rams) mated fewer times with individual ewes than low-performing (LP) rams (P < .01). As a consequence, HP rams tended to mate with a greater number of different ewes than did LP rams (P < .06). In addition, time required to attain six ejaculations was inversely correlated with the number of different ewes mated (P < .03). The HP rams did not differ from LP rams in the number of different ewes investigated and courted. These findings highlight the value of using rams with relatively rapid ejaculation rates when breeding large groups of naturally cycling or synchronized ewes.
Animal Husbandry↗
Plasma triglyceride and glucose clearance in broiler-type and white Leghorn chickens with different degrees of adiposity.
Broiler-type and White Leghorn chicks were given diets containing 30.5, 26.2, or 22.3% protein with and without addition of 5% corn oil during an 8- to 9-week conditioning period. The absolute weight of the abdominal fat pad was greater in the broiler-type birds on all dietary treatments. As a percentage of body weight the abdominal fat pads were similar in broiler-type and White Leghorn birds only when the diet contained 30.5% of protein without added oil. Following a 16-hr fast, plasma glucose was higher in the broiler-type than in the White Leghorn birds, whereas plasma triglyceride concentrations were higher in White Leghorns. In birds refed a high-fat meal, plasma glucose showed little change except in the broiler chickens previously fed the 30.5% protein diet without added oil. In these birds plasma glucose declined over a 5-hr period to reach a mean value of 130 mg/100 ml. Plasma triglyceride concentrations in both breeds were markedly elevated within 45 min of refeeding with a high-fat meal, but the peak concentrations were higher in the White Leghorns than in the broiler-type birds. Previous consumption of the high-oil diet increased postprandial triglyceride concentration in the plasma of the broiler-type but reduced it in the White Leghorn chickens. The difference in response of the chickens of the different genetic stocks is attributed to differences in the development of the activities of the systems associated with 1) fatty acid absorption and movement of triglycerides from the intestinal mucosa to the circulation and 2) clearance of plasma triglycerides to the adipocytes as a result of lipoprotein lipase activity.
Adipose Tissue↗
Genetically modified laboratory animals in the name of the 3Rs?
Although the introduction of GM animal models at first was viewed as a potent way to enhance experimental biology in the name of the 3Rs by its proponents, over the years, the number of animals used has greatly increased and concerns about the suffering of these animals have emerged in the debate. The purpose of this contribution is to show the need and the urgency for a systematic evaluation of genetically modified laboratory animals (GM animals) according to the 3Rs principle. This evaluation presents various difficulties due to the special features of the genetic modifications of animals, the variety of scientific purposes connected with the use of these animals, the lack of coherent statistical data about this use and the difficulties related to the welfare assessment of these animals. In this article I discuss the significance of the procedures involving GM animals for each of the 3R principles. On this basis, I offer an answer to the question of whether these procedures are compatible with the spirit of the 3Rs.
Animal Rights↗
Breed, age, and gender differences in plasma antithrombin-III activity in clinically normal young horses.
Plasma antithrombin-III activity was quantitated in plasma samples obtained from 165 clinically normal horses 3 years old or younger. In the horses as a group, antithrombin-III activity ranged from 63 to 131% of a species-specific reference plasma. Thoroughbred horses had significantly higher antithrombin-III activity (103.3 +/- 18.3; mean +/- SD) than did Standardbred horses (92.3 +/- 14.2). The plasma antithrombin-III activities were significantly lower in horses younger than 16 months old when compared with those in more mature horses (3 years old). There was no statistically significant gender-related effect on plasma antithrombin-III activity. Breed and age factors should therefore be taken into consideration when interpreting plasma antithrombin-III activity in horses.
Age Factors↗
More information on hematologic characteristics of greyhounds.
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Animals↗
[Serum cholesterol in the dog].
The reference values of cholesterol were examined in two groups of healthy dogs. In a group of 591 dogs a value of 122-389 mg/dl or 3.2-10.1 mmol/l was calculated (95% percentile). Statistically significant variations occurred with age, sex, breed, and feeding; however they were small and do not require consideration in diagnostic procedures. Serum cholesterol is increased in numerous diseases. It is questionable whether the consideration of serum cholesterol helped in the diagnosis of hypothyroidism.
Age Factors↗
[Examination of the appropriateness of anamnestic and clinical parameters for the prediction of the course of pregnancy under field conditions].
In this paper, fertility relevant parameters which are routinely examined in practice were evaluated on the basis of their correlation to one another and their influence on the foaling rates and incidence of early embryonic death in 175 brood mares of the Hanover breeding stock. The aim was to evaluate the suitability of these parameters for inclusion in a scheme for increasing the precision of predicting the subsequent course of pregnancy, as compared to such prognoses based exclusively on the histological evaluation of the endometrium. After establishing the breeding history and completing a clinical examination, two swab specimens were obtained for bacteriological culture and cytologic smears and one biopsy specimen was taken from the endometrium for histological examination. The most statistically significant effect on the foaling rate (analysed by logistic regression with two variables) have biopsy grade (p = 0.0087) and mare age (p = 0.0259). A mare between two and nine years of age with a biopsy grade of 1 has a 71% probability of carrying a pregnancy to term. This probability decreases to 43% for a mare 15 years and older with the same biopsy grade. Mare age had a statistically significant effect on biopsy grade (p = 0.005) and on the frequency and degree of endometrosis (p = 0.001). The mare group was significantly correlated (p = 0.012) with the foaling rate (maiden mares 70.6%, foaling mares 60%, problem mares 36.1%). There is a difference of 24% between the foaling rates of foaling and problem mares, although the age and biopsy grade distributions are almost identical in the two groups. The number of barren years had a statistically significant effect (p = 0.0235) on the foaling rate. Mares that bore a foal in the previous breeding period had a foaling rate of 50.7% in the year of examination; mares that had been barren for one year hat a subsequent foaling rate of 40.6%. Mares that had been barren for two years or more had a foaling rate of only 22.7%. The overall impression resulting from the clinical examination was significantly correlated with the foaling rate (p = 0.018%). Mares without abnormal findings had a foaling rate of 54.2%, mares with poor vulval conformation a rate of 46.7%. Mares with a history of pregnancy loss in the current breeding period had a foaling rate of 25% and mares with clinical evidence of endometritis had one of 22.2%.
Animals↗
Genetic deficiency of the fourth component of complement (C4) in Wistar rats.
A chance observation has led to the discovery of single component complement deficiency in Wistar rats. During serial total haemolytic activity (CH50) determinations on 10 male rats, 2 were consistently found to have values 20% or less than that of the others. An additional 30 males (200--220 g) and 20 females (180--200 g) were screened for CH50 and the defect was found in 10 of the males but none of the females. Mixtures of sera of high and low haemolytic activity gave intermediate values between the two populations arguing against the presence of an inhibitor of the complement system. Single component analysis revealed the defect to reside in the fourth component of complement (C4). Highly purified human C4 completely reconstituted the haemolytic activity of the complement deficient rat serum. A linear relationship between C4 and CH50 titres was observed. Data from preliminary selective breeding experiments point toward an autosomal recessive mode of inheritance. Animals with intermediate values were observed indicating a gene dosage effect with which the heterozygote may be recognized.
Animals↗
Use of a homologous radioimmunoassay (RIA) to evaluate the effect of maternal and foetal parameters on pregnancy-associated glycoprotein (PAG) concentrations in sheep.
Early pregnancy detection and prediction of the number of lambs would be profitable for sheep breeders because it enables them to adjust nourishment of pregnant ewes according to the individual needs in order to prevent health problems around parturition. The concentration of ovPAG has previously been reported to be related with maternal parameters (farm, breed and age) as well as foetal parameters (number of lambs, their sex and birth weight), but contradictory results were obtained in different small-scale studies. This large-scale study evaluates the effect of these parameters on the ovPAG concentration, determined by a homologous radioimmunoassay (RIA), and it further investigates the possibility to predict the number of lambs by means of homologous ovPAG determination. Eighty-three and ninety-five ewes of the Suffolk and Texel breed, respectively, housed on four different farms (experiment 1) and 68 ewes of the Suffolk breed, housed on two different farms (experiment 2) were included in this study, and their estrous cycles were synchronised using a progesterone analogue. On the day of synchronisation (D-14) and at 25 (D25), 35 (D35) and 45 (D45) days after insemination, blood samples were taken and a homologous radioimmunoassay (RIA) was used to determine the ovPAG concentrations. At parturition, age of the ewe, number and sex of the lambs (experiment 1) and birth weight (experiment 2) were registered. OvPAG concentrations were not affected by age of the ewe and sex of the lambs. Farm and breed of the ewes, number and birth weight of the lambs had a significant effect on ovPAG concentrations at all time points (P<0.05). The odds of multiple lambs increased significantly with increasing ovPAG concentration, although prediction of litter size based on ovPAG concentration at the individual ewe level was not useful due to small sensitivity and/or specificity whatever the cutoff value used. In conclusion, the ovPAG concentration is affected by farm and breed of the ewes, and number and birth weight of the lambs.
Age Factors↗
Hematology, plasma biochemistry, and serosurvey for selected infectious agents in southern giant petrels from Patagonia, Argentina.
In conjunction with reproductive and feeding ecology studies on southern giant petrels (SGP, Macronectes giganteus) blood samples were collected for baseline health evaluations. Twenty-five adult SGP from a breeding colony in Chubut, Argentina, were sampled during two consecutive breeding seasons, 1999-2000 (n = 15) and 2000-01 (n = 10). Values for hematology, plasma biochemistry, and minerals are described for 20 birds in apparent good physical condition. A serologic survey of exposure to selected infectious agents was also conducted on all 25 birds sampled. Southern giant petrels were serologically negative for evidence of exposure to infectious laryngotracheitis virus, avian encephalomyelitis virus, avian influenza virus, avian reovirus, infectious bursal disease virus, infectious bronchitis virus, paramyxovirus 1, 2, and 3 virus, Chlamydophila, and Aspergillus. Antibodies to avian adenovirus were found in 14% of SGP during the first sampling season, and 60% in the second year. Additionally, all birds were negative for antibodies to Salmonella pullorum at the first sampling date, but 90% had low titers the following breeding season. This study contributes to understanding the health status of South Atlantic seabirds and to establishment of baseline information for SGP. Long-term monitoring of pelagic predator-scavenger seabirds such as SGP should be established for the surveillance of marine ecosystem health.
Adenoviridae Infections↗
Genetic diversity analysis of six Spanish native cattle breeds using microsatellites.
Six native Spanish cattle breeds have been characterized by using 30 microsatellite markers. The studied populations can be divided into three groups: Brown orthoid (Asturian Mountain, Asturian Lowland and the Nord-west Brown Group), Red convex (Pyrenean and Menorquina) and the Iberian bovine (Fighting bull). Allele frequencies were calculated and used for the characterization of the breeds and the study of their genetic relationships. Different genetic distance measures were calculated and used for dendogram construction. The closest populations were those representing Asturian breeds, the most divergent being Menorquina and Fighting Bull. The latter also showed the lowest diversity values (mean number of alleles per locus and heterozygosity). Genetic distances obtained between the other populations under analysis were similar to those reported for different European cattle breeds. This work analyzes the recent origin of these populations and contributes to the knowledge and genetic characterization of European native breeds.
Alleles↗
Prevalence and inheritance of and selection for elbow arthrosis in Bernese mountain dogs and Rottweilers in Sweden and benefit: cost analysis of a screening and control program.
OBJECTIVE: To determine the prevalence and charges over time in the prevalence of elbow arthrosis in Bernese Mountain Dogs and Rottweilers, to ascertain whether prevalence or severity of elbow arthrosis was associated with sex of the dogs, age at the time of elbow joint examination, or ancestral background, to determine the effects of selective breeding, and to conduct an economic evaluation of the elbow arthrosis program operated by the Swedish Kennel Club. DESIGN: Analysis of radiographic evaluations of elbow joint conformity. ANIMALS: 4,515 dogs from 2 breeds registered by the Swedish Kennel Club. PROCEDURE: All radiographs were scrutinized by a single radiologist (LA), and elbow joint conformation was classified as normal or arthrotic, with the degree of arthrosis classified as 1, 2, or 3. RESULTS: Decreasing prevalence of elbow arthrosis corresponding to selection of breeding stock and high heritabilities was found. Sex differences were documented in both breeds, but with contradictory directions. This was interpreted as breed differences in the distribution of genes related to elbow arthrosis. Economic analyses showed that costs of screening and registration of elbow joints was less than the value of dogs estimated to have been saved from moderate and severe elbow arthrosis in both breeds. CLINICAL IMPLICATIONS: Documented effects of age suggest that all dogs should be screened at the same age, rather than screening a few dogs at an older, more revealing age. In screening and control programs based on an open registry with access to family records, decreasing prevalence of elbow arthrosis can be expected, and related to selection of breeding stock.
Age Distribution↗
Allometric scaling of M-mode cardiac measurements in normal adult dogs.
Indices for M-mode measurements in dogs usually have been based on the assumption that a linear relationship exists between these measurements and body weight (BW) or body surface area (BSA). The relationships between the geometry of 3-dimensional objects do not support this assumption. The purposes of this study were to retrospectively examine M-mode data from a large number of dogs of varying sizes and breeds that were examined by a large number of ultrasonographers, to use the allometric equation to determine the appropriate BW exponent required to predict these cardiac dimensions, and to determine normal mean values and prediction intervals for common M-mode variables. Linear regression analyses of data from 494 dogs (2.2-95 kg) revealed a good correlation between M-mode measurements and BW after logarithmic transformation of the data (r2 = .55-.88). Most variables were most closely related to an index of body length, BW(1/3), although the exponent that best predicted diastolic and systolic left ventricular wall thicknesses was closer to 0.25. No variable indexed well to BW or BSA. With these data, appropriate mean values and prediction intervals were calculated for normal dogs, allowing veterinarians to correctly and appropriately index M-mode values. The equations developed from this study appear to be applicable to adult dogs of most breeds.
Animals↗
Genetic diversity analyses of 10 indigenous Chinese pig populations based on 20 microsatellites.
To study the genetic diversity of Chinese indigenous pig breeds, a total of 403 pigs from 10 local populations and 1 exotic Duroc breed were genotyped for 20 microsatellite markers. Heterozygosity and Wright's F-statistics (F(IS), F(ST), and F(IT)) were calculated to determine the genetic variation in those populations. The observed heterozygosities were in the range of 0.31 (Duroc) to 0.66 (Shengxian). The F(IS) value was in a range of -0.07 to 0.48. The mean F(ST) showed that approximately 78% of the genetic variation was within-population and 22% was across the populations. The 10 Chinese local breeds were classified into two major groups according to the phylogenetic tree, which was based on standard genetic distance. Four pig populations, Jianli, Ganxi Two Ends Black, Shaziling, and Dongshan were grouped into one branch. Before the study, these four populations were all classified as Central China Two Ends Black according to coat color, shape of the head, and shape of the ear. The Jinhua pig, which also has the two-ends-black coat color, was also grouped to the same branch but was not traditionally classified into this type. The five populations were located in various provinces in central China. The other five populations, Nanyang Black, Hainan Spotted, Huainan Black, Jiaxing Black, and Shengxian Spotted (black body, white feet), were grouped into another branch. The two groups of pig breeds had the same F(ST) value (0.14) when calculated separately. This value was similar to that of Iberian pigs (0.13) but smaller than that of the European pigs (0.27) as reported by other researchers. Our study showed that large genetic differentiation exists in Chinese pig breeds. The grouping of the five two-ends-black populations into one branch of the phylogenetic tree may indicate that the number of conservation farms can be decreased for this type of pig.
Animals↗