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At least 127 records · Page 7Linked to original sources
PubMed1999

Culling of dairy cows. Part III. Effects of diseases, pregnancy status and milk yield on culling in Finnish Ayrshire cows.

The effects of 15 diseases, pregnancy status and milk yield on culling were studied in 39727 Finnish Ayrshire cows that calved in 1993 and were followed until culling or next calving. Survival analysis, using the Cox proportional hazards model, was performed with diseases, pregnancy status and milk yield as time-dependent covariates. Effects of parity, calving season and herd were also accounted for. Pregnancy status was the single most influential factor affecting culling decisions, followed by milk yield. Several diseases also had a significant effect on culling, the most influential ones being mastitis, lameness, teat injuries, and milk fever. The effects of all of these factors varied according to the stage of lactation. Milk yield had a significant effect on culling decisions, depending on the stage of lactation. At the beginning of lactation, milk production did not have any effect on culling decisions, but later on, the highest producers were at the lowest risk of being culled and the lowest producers had the highest risk. Adjusting for milk yield modified the effects of parity, most diseases and also pregnancy status on culling. Effects of parity increased after including milk yield in the model, indicating that milk yield and parity are interrelated in their effects on culling. The effects of pregnancy status also increased towards the end of lactation when milk yield was accounted for in the model. The effects of mastitis, teat injuries and lameness decreased after adjusting for milk production. These diseases lower milk yield and thus, part of their effect on culling was mediated through milk production. The effects of anestrus and ovarian cysts were mainly modified by pregnancy status, but not by milk yield. The effects of milk fever on culling increased at the beginning of lactation after including milk yield in the model. This suggests that even though cows with milk fever tend to be higher producers, it is the disease as such that triggers the culling decision early in the lactation. The changes in the effects of other diseases after adjusting for milk yield varied, depending on the disease and the stage of lactation.

Animal Husbandry↗
PubMed2001

Nicotine yield from machine-smoked cigarettes and nicotine intakes in smokers: evidence from a representative population survey.

BACKGROUND: The relevance of nicotine yields from machine-smoked cigarettes for quantifying smokers' nicotine intakes and exposure to cigarette toxins has been called into question. However, most studies of the relationship between nicotine yield and nicotine intake have been on relatively small and unrepresentative samples and have included few smokers of "ultra-low" brands (i.e., those yielding around 1 mg of tar and 0.1 mg of nicotine). METHODS: We examined the relationship between salivary cotinine (a major metabolite of nicotine) concentrations and nicotine yields of machine-smoked cigarettes in a nationally representative sample of 2031 adult smokers of manufactured cigarettes surveyed in the 1998 Health Survey for England. We used standard linear regression techniques to examine associations and two-sided tests of statistical significance. RESULTS: Cotinine concentrations varied widely between smokers at any level of nominal brand nicotine yield. On average, cotinine levels were slightly lower in smokers of lower nicotine-yielding brands, but these smokers differed in terms of sex, socioeconomic profile, and cigarette consumption. After we controlled for potential confounders, nicotine yield from the brand smoked accounted for only 0.79% of the variation in saliva cotinine concentrations. Nicotine intake per cigarette smoked, as estimated from salivary cotinine level, did not correspond with machine-smoked yields at any level of nicotine yield. Nicotine intake per cigarette was about eight times greater than machine-smoked yields at the lowest deliveries (1.17 mg estimated nicotine intake per cigarette from brands averaging 0.14-mg delivery from machine smoking) and 1.4 times greater for the highest yield cigarettes (1.31-mg estimated nicotine intake per cigarette from brands averaging 0.91 mg from machine smoking). CONCLUSIONS: Smokers' tendency to regulate nicotine intake vitiates potential health gains from lower tar and nicotine cigarettes. Current approaches to characterizing tar and nicotine yields of cigarettes provide a simplistic guide to smokers' exposure that is misleading to consumers and regulators alike and should be abandoned.

Adolescent↗
PubMedDate not supplied

Initial yield to depth relation for water wells drilled into crystalline bedrock--Pinardville quadrangle, New Hampshire.

A model is proposed to explain the statistical relations between the mean initial water well yields from eight time increments from 1984 to 1998 for wells drilled into the crystalline bedrock aquifer system in the Pinardville area of southern New Hampshire and the type of bedrock, mean well depth, and mean well elevation. Statistical analyses show that the mean total yield of drilling increments is positively correlated with mean total well depth and mean well elevation. In addition, the mean total well yield varies with rock type from a minimum of 46.9 L/min (12.4 gpm) in the Damon Pond granite to a maximum of 74.5 L/min (19.7 gpm) in the Permian pegmatite and granite unit. Across the eight drilling increments that comprise 211 wells each, the percentages of very low-yield wells (1.9 L/min [0.5 gpm] or less) and high-yield wells (151.4 L/min [40 gpm] or more) increased, and those of intermediate-yield wells decreased. As housing development progressed during the 1984 to 1998 interval, the mean depth of the wells and their elevations increased, and the mix of percentages of the bedrock types drilled changed markedly. The proposed model uses a feed-forward mechanism to explain the interaction between the increasing mean elevation, mean well depth, and percentages of very low-yielding wells and the mean well yield. The increasing percentages of very low-yielding wells through time and the economics of the housing market may control the system that forces the mean well depths, percentages of high-yield wells, and mean well yields to increase. The reason for the increasing percentages of very low-yield wells is uncertain, but the explanation is believed to involve the complex structural geology and tectonic history of the Pinardville quadrangle.

Forecasting↗
PubMed1996

Relationship between short-range stiffness and yielding in type-identified, chemically skinned muscle fibers from the cat triceps surae muscles.

1. Transient, stretch-evoked force responses of chemically skinned muscle fibers from the cat hindlimb were investigated. The purpose of these experiments was to determine the exent to which short-range stiffness, the apparent stiffness exerted by the fiber over the first 0.5% of length change, is higher in type I than type II muscle fibers. Fibers were obtained from soleus and vastus intermedius muscles, which contain predominantly type I fibers, the LGm, a compartment of the lateral gastrocnemius muscle that contains predominantly type II fibers, and LG3, a compartment of mixed type. 2. Beyond a short range of approximately 1% of muscle length during a 0.5 muscle length/s (ML/s) stretch, most fibers exhibited an abrupt decrease in apparent stiffness or yield. Fibers from the muscles containing predominantly type S (slow twitch, or type I) fibers, soleus and vastus intermedius, exhibited such a pronounced decline in apparent stiffness that force declined as well during continued stretch. Most of the fibers from the LG3 compartment could be divided into two distinct groups depending upon whether or not they showed a force yield at the stretch velocity of 0.5 ML/s. 3. The short-range stiffness measured over the first 0.5% of stretch was greater for fibers showing force yield than for those that did not at matched initial forces and normalized stretch amplitudes. This result is consistent with the hypothesis that the same mechanism that endows the fiber with high short-range stiffness is also responsible for a greater extent of yielding. 4. Fibers from soleus were found to exhibit a force yield over a 200-fold range of velocities (0.01-2 ML/s). In contrast, most fibers from the LGm compartment showed only an increase in extent of yield with stretch velocity. Some of these fibers eventually yielded in force, but only when they were stretched at velocities > 2 ML/s. The proposed relationship between high short-range stiffness and yielding was supported by the finding that short-range stiffness increased sharply in the range of velocities where the fiber showed the greatest increase in extent of yield. 5. After the physiological experiments, fibers were subjected to SDS gel electrophoresis. Two distinct patterns of bands in the low molecular weight range were found to correspond to the two types that were identified on the basis of their dynamic mechanical properties. Fibers that did not yield at 0.5 ML/s showed a band pattern very similar to that of rabbit psoas (type II) fibers. 6. These results support the hypothesis that type I fibers are specialized in presenting a high short-range stiffness for effective postural control in advance of reflex mechanisms and that this property results from intrinsic properties of the fiber and is not due to differences in the dimensions of type I and II fibers. Yielding serves to protect the fiber from damaging levels of force during lengthening contractions. The importance of these transient properties to the mechanical behavior of muscle during ongoing movements is suggested by the observation that high stiffness followed by yielding is repeated with little alteration during successive stretches.

Animals↗
PubMed1983

Weight and age at calving and weight change related to first lactation milk yield.

Daily milk yields from 400 first lactations collected from one herd over 16 yr were utilized to ascertain relations of weight and age at calving and change of body weight during first lactation on milk yield and calving interval. These relationships were evaluated for the complete lactation and for each of five 60-day segments of the lactation. The influence of sire on the interrelationship between body weight, age at calving, and milk yield also were measured in data from sires with 10 or more daughters. Average milk yield (300 day) and gain of body weight during first lactation for all records were 5544 and 56.2 kg. Both year and season of calving influenced weight at calving, milk yield, and the relationship between the two. Milk yield was the greatest and body weight gain the least for heifers calving in the fall. Analysis of all records revealed that calving weight but not calving age accounted for a significant portion of variation of milk yield during the first four 60-day periods. Both calving weight and age accounted for a significant amount of the variation of total milk yield. There was a significant effect of sire on calving weight and milk yield but not on total weight gain, age at calving, number of services, or calving interval. There was an increase of number of services and a trend toward a longer calving interval with increasing milk yield. Although age and weight at calving were nearly equal for explaining variation of total yield of milk of first lactation, age at calving was of little value in explaining variation of milk yield of the 60-day intervals. The relationship of these observations to the use of age correction factors for extended first lactation records is discussed.

Age Factors↗
PubMed1994

Simulating individual cow milk yield for milking parlor simulation models.

A method of simulating individual cow milk yield per milking as a function of herd milk yield and month was formulated for milking parlor simulation models. Milk yield per milking was modeled for each month in three herd milk yield categories: 8165, 8845, and 9525 kg/yr of milk per cow. Actual individual cow DHIA test day milk weight data for three Florida dairy herds in each herd milk yield category and month were adjusted to the mean of their respective actual milk shipped per cow on test day then pooled and converted to a basis of three times per day milk yield per milking. After minor truncation, Weibull probability distributions fitted to these data sets adequately modeled milk yield per milking per cow. Analysis of simulation results for milk yield per milking per cow indicated no significant differences between actual and simulated means for any herd milk yield category or month. Simulations of monthly and yearly total herd milk yield for each herd indicated that fitted Weibull distributions also adequately modeled monthly and yearly herd milk yield characteristics and reflected seasonal herd milk yield patterns typical of Florida.

Animals↗
PubMed1995

Bias and accuracy of single milking testing schemes to estimate daily and lactation milk yield.

This study evaluated the adequacy of an alternate a.m.-p.m. testing scheme for milk yield in comparison with the official test method based on weighing two milkings within 24 h. A total of 88,558 single test day milking weights from 15,670 Italian Friesian cows in 610 herds in the province of Milano (Italy) were collected between September 1991 and October 1992. Ratios were computed for daily milk yield to a.m. and p.m. milking weights (direct yield ratios) and ratios of a.m and p.m. milking weights to daily milk yield (inverse yield ratios). Analysis of variance indicated that the milking interval is the most important source of variation for yield ratios. Factors for estimating daily milk yield from single milking weights adjusted for milking intervals were derived through regression analysis of direct and inverse yield ratios on the length of the milking interval. Daily milk yield was estimated more precisely and accurately when adjustment factors were used than when single milking weights were doubled. The doubling of a.m. and p.m. milking weights overestimated and underestimated (5% on average) daily milk yield, respectively. For 305-d lactation yield, accuracies of these methods were comparable. In conclusion, alternate recording of a.m. and p.m. milking weights led to reliable estimates of milk yield. Effects of the alternate a.m.-p.m. testing scheme on estimates of milk components and genetic evaluations of dams of sires should be investigated.

Animals↗
PubMed1992

Adaptation of feeding to a low fat yield in breast milk.

The effect of a low milk fat yield was assessed in a blinded prospective study of healthy term infants and mothers encouraged to breast-feed. Fat yield index was calculated as milk volume collected by Egnell pump multiplied by the "creamatocrit." Two weeks after delivery mothers who had a relatively low fat yield index (less than or equal to 30th percentile) were matched with mothers with a higher fat yield index and with formula-feeding mothers. Between 2 and 6 weeks the low fat yield group had a marginally lower weight gain but similar growth in length and head circumference to that of the higher fat yield group. The low fat yield group spent more time per feeding and had more complete breast emptying, resulting in a fat yield index comparable with the higher fat yield group for the mean milk volume ingested by the infant at 6 weeks. A low fat yield had no adverse effect on maternal satisfaction or maternal-infant interaction during feeding. Formula feeders spent the least time in feeding and en face gazing. Adaptation of breast-feeding to a low fat yield sustains infant intake and growth, maternal-infant interaction, and maternal satisfaction. However, there is little reserve if milk production diminishes. Further study is needed to define the limits of adaptation and effective interventions if fat yield is inadequate.

Breast Feeding↗
PubMed2005

QTL analysis of seed yield components in red clover (Trifolium pratense L.).

Cultivars of red clover (Trifolium pratense L.), an important forage crop in temperate regions, are often characterised by an unsatisfactory level of seed yield, leading to high production costs. This complex trait is influenced by many components and negatively correlated with other important traits, such as forage yield or persistence. Therefore, seed yield has proven to be difficult to improve. Thus, the objectives of this study were to assess association among seed yield components and to provide the basis for identifying molecular markers linked to QTLs for seed yield components to assist breeding for improved red clover cultivars. A total of 42 SSR and 216 AFLP loci were used to construct a molecular linkage map with a total map length of 444.2 cM and an average distance between loci of 1.7 cM. A total of 38 QTLs were identified for eight seed yield components. The traits seed number per plant, seed yield per head, seed number per head, head number per plant and percent seed set were highly correlated with seed yield per plant, and QTLs for several of these traits were often detected in the same genome region. Head number per plant may present a particularly useful character for the improvement of seed yield since it can easily be determined before seed maturity. In addition, two genome regions containing four or five QTLs for different seed yield components, respectively, were identified representing candidate regions for further characterisation of QTLs. This study revealed several key components which may facilitate further improvement of seed yield. The QTLs identified represent an important first step towards marker-assisted breeding in red clover.

Analysis of Variance↗
PubMed2005

Combined sugar yields for dilute sulfuric acid pretreatment of corn stover followed by enzymatic hydrolysis of the remaining solids.

A number of previous studies determined dilute acid pretreatment conditions that maximize xylose yields from pretreatment or glucose yields from subsequent digestion of the pretreated cellulose, but our emphasis was on identifying conditions to realize the highest yields of both sugars from both stages. Thus, individual xylose and glucose yields are reported as a percentage of the total potential yield of both sugars over a range of sulfuric acid concentrations of 0.22%, 0.49% and 0.98% w/w at 140, 160, 180 and 200 degrees C. Up to 15% of the total potential sugar in the substrate could be released as glucose during pretreatment and between 15% and 90+% of the xylose remaining in the solid residue could be recovered in subsequent enzymatic hydrolysis, depending on the enzyme loading. Glucose yields increased from as high as 56% of total maximum potential glucose plus xylose for just enzymatic digestion to 60% when glucose released in pretreatment was included. Xylose yields similarly increased from as high as 34% of total potential sugars for pretreatment alone to between 35% and 37% when credit was taken for xylose released in digestion. Yields were shown to be much lower if no acid was used. Conditions that maximized individual sugar yields were often not the same as those that maximized total sugar yields, demonstrating the importance of clearly defining pretreatment goals when optimizing the process. Overall, up to about 92.5% of the total sugars originally available in the corn stover used could be recovered for coupled dilute acid pretreatment and enzymatic hydrolysis. These results also suggest that enhanced hemicellulase activity could further improve xylose yields, particularly for low cellulase loadings.

Catalysis↗
PubMed2001

Dependence of yield strain of human trabecular bone on anatomic site.

Understanding the dependence of human trabecular bone strength behavior on anatomic site provides insight into structure-function relationships and is essential to the increased success of site-specific finite element models of whole bones. To investigate the hypothesis that the yield strains of human trabecular bone depend on anatomic site, the uniaxial tensile and compressive yield properties were compared for cylindrical specimens from the vertebra (n=61), proximal tibia (n=31), femoral greater trochanter (n=23), and femoral neck (n=27) taken from 61 donors (67+/-15years). Test protocols were used that minimized end artifacts and loaded specimens along the main trabecular orientation. Yield strains by site (mean+/-S.D.) ranged from 0.70+/-0.05% for the trochanter to 0.85+/-0.10% for the femoral neck in compression, from 0.61+/-0.05% for the trochanter to 0.70+/-0.05% for the vertebra in tension, and were always higher in compression than tension (p<0.001). The compressive yield strain was higher for the femoral neck than for all other sites (p<0.001), as was the tensile yield strain for the vertebra (p<0.007). Analysis of covariance, with apparent density as the covariate, indicated that inter-site differences existed in yield stress even after adjusting statistically for density (p<0.035). Coefficients of variation in yield strain within each site ranged from only 5-12%, consistent with the strong linear correlations (r(2)=0.94-0.98) found between yield stress and modulus. These results establish that the yield strains of human trabecular bone can differ across sites, but that yield strain may be considered uniform within a given site despite substantial variation in elastic modulus and yield stress.

Adult↗
PubMed1999

Analysis of correlated continuous repeated observations: modelling the effect of ketosis on milk yield in dairy cows.

This study used mixed models analysis to demonstrate the advantages of a repeated measures technique for a continuous variable over a single measure technique. As an illustration, the loss of milk yield due to ketosis was studied in 2604 multiparous New York State Holstein cows belonging to eight herds, calving between 1991 and 1993. Two methods of analysis were presented: The first treated milk yield as a continuous, summary measure (projected 305-day milk yield); the second treated milk yield as repeated measurements (test-day milk yields). In the first example, with 305-day milk yield as the outcome, ketosis was treated as a binary covariate. Ketosis had no effect on the 305-day milk yield. In the second example, with monthly test-day milk yields as the outcome, four different covariance structures (simple, compound symmetry, autoregressive, and unstructured) to model the association among the repeated measurements were compared. With this approach, ketotic cows yielded significantly less milk per day both before and immediately after diagnosis than did non-ketotic cows. Based on the goodness-of-fit statistics, it was unclear whether an autoregressive or unstructured covariance structure was best. However, an autoregressive structure, in which the previous and current test-day milk yields are assumed to be correlated, was considered more suitable in this study; it is a simpler and more appropriate covariance structure for this particular problem than is an unstructured covariance structure. Nevertheless, with the test-day approach, any of these correlation structures could be used to estimate milk loss after disease. Based on these findings, it is recommended that a repeated measures approach, rather than a single measure approach, be used to study the short-term effect of disease on milk yield.

Animals↗
PubMed2002

Stiff and strong compressive properties are associated with brittle post-yield behavior in equine compact bone material.

Our hypothesis was that post-yield mechanical behavior of compact bone material in compression, defined as the stress, strain, or energy absorbed between 0.2% strain-offset and the point of maximum stress, is correlated with material density, modulus, strength, histomorphometric evidence of remodeling, and post-failure gross specimen morphology. Post-yield behavior of compact bone material from the third metacarpal bone of 10 horses, ages 5 months to 20 years, was investigated using single-load compression-to-failure. The post-yield stress, strain, and absorbed energy were compared with the compressive elastic modulus, yield stress, ash density. post-failure macroscopic appearance of the specimen, and histologic evidence of remodeling. High values of elastic modulus, yield stress, and ash density were associated with low values of post-yield mechanical properties (stress, strain, and absorbed energy). Macroscopic post-failure morphology was associated with post-yield mechanical behavior, in that specimens displaying fractures were associated with lower post-yield mechanical properties, and that those without evidence of frank fracture were associated with higher post-yield mechanical properties. Microscopic evidence of remodeling activity was associated with high post-yield mechanical properties, but not with gross post-failure morphology. There was an abrupt change from relatively high values to extremely low values of post-yield mechanical properties at intermediate levels of ash density. This feature may serve as a functional tipper limit to the maximization of bone material stiffness and strength.

Animals↗
PubMed2004

Optimizing buccal cell DNA yields in mothers and infants for human leukocyte antigen genotyping.

Buccal cells provide a convenient source of DNA for epidemiologic studies. Mouthwash rinses yield a higher quality and quantity of DNA than cytobrushes but are not practical for collection from infants. Although cytobrushes yield sufficient DNA for most genotyping analyses, human leukocyte antigen (HLA) analysis can require 1,000-fold more DNA. In Iowa City, Iowa, in 2002, the authors tested two cytobrush collection methods to optimize total DNA yield and purity for HLA genotyping in mothers and infants: 1) brushing the left and right inner cheeks (standard method) and 2) brushing the upper and lower "gutters", that is, the space between the gums and the inner lips/cheeks along the front and sides of the mouth (test method). Storage and mailing experiments were performed to define conditions for optimizing DNA yield and purity. Mothers' gutter samples yielded significantly higher total amounts of DNA (mean yield = 15.0 micro g/two brushes) than cheek samples (mean yield = 7.6 micro g/two brushes) (paired t test: p < 0.001), while DNA yields from cheek and gutter collections from infants were equivalent. Cytobrushes stored and/or mailed in paper envelopes yielded significantly more and higher-purity DNA than brushes in plastic bags or tubes. Cytobrush sampling of the mouth's gutter areas can enhance DNA yield in mothers but not in young infants. DNA yields can be further optimized by controlling mailing and storage conditions.

Cheek↗
PubMed1981

Trends in tar, nicotine, and carbon monoxide yields of UK cigarettes manufactured since 1934.

The tar, nicotine, and carbon monoxide yields of cigarettes manufactured in the United Kingdom between 1934 and 1979 were studied. Over this period the average tar yield decreased by 49%, the nicotine yield by 31%, the carbon monoxide yield by 11%, all estimated on a sales-weighted basis. The average tar yield decreased progressively after the second world war, owing both to the introduction of filter cigarettes and to changes in the manufacture of plain cigarettes. The average nicotine yield increased initially, decreased by 43% from about 1950 to 1974, but increased again by 9% between 1974 and 1979. The average carbon monoxide yield started to decrease after about 1961; while it decreased substantially in plain cigarettes, the rapid increase in sales of filter cigarettes at this time, at the expense of plain cigarettes, largely offset the reduction in carbon monoxide yield that would otherwise have occurred. As with nicotine, carbon monoxide yield showed a small rise in later years (4% between 1976 and 1979). The trends in tar yield may well explain the reduction in lung cancer in the UK better than has been suspected hitherto. The trends in nicotine and carbon monoxide yields are probably not sufficiently different to distinguish which of them might be the more likely cause of cardiovascular disease.

Carbon Monoxide↗
PubMed1998

Roll-your-own smoke yields: theoretical and practical aspects.

OBJECTIVE: To identify the key parameters that influence smoke yields from roll-your-own (RYO) cigarettes and to compare smoke yields of cigarettes made under laboratory conditions with those made by habitual RYO consumers. DESIGN AND SETTING: One-way parametric variations in the laboratory-based production of RYO cigarettes complemented by a consumer survey conducted in a busy street at Romford, Essex, United Kingdom. SUBJECTS: 26 habitual RYO consumers. MAIN OUTCOME MEASURES: Cigarette weights, puff numbers, and yields (carbon monoxide, nicotine, and tar). RESULTS: Smoke yields vary for specimen changes in weight of tobacco used, paper porosity, and the incorporation of a filter in the cigarette. Yields of cigarettes produced by 26 RYO smokers ranged from 9.9 to 21.0 mg tar per cigarette and from 0.9 to 1.8 mg nicotine per cigarette, and were generally lower than yields of laboratory-produced RYO cigarettes. CONCLUSIONS: Laboratory studies can provide useful information concerning the parameters that affect smoke yields of RYO cigarettes such as the incorporation of a filter to reduce yields. However, such studies must be complemented by surveys of cigarettes made by actual current RYO smokers. In one such investigation, it was found that the mean tar yields from cigarettes produced by 57% of the smokers were above the current maximum of 15 mg per cigarette for manufactured cigarettes. Currently 8% of manufactured cigarettes in the UK have a declared nicotine yield of greater than 1.1 mg per cigarette whereas 77% of RYO smokers produced cigarettes with a nicotine yield greater than this value.

Humans↗
PubMed2001

Evaluation of ultrasound imagery and body shape to predict carcass and fillet yield in farm-raised catfish.

Accurate prediction of meat yield in live animals may allow more efficient genetic improvement of meat yield in farm-raised catfish. An initial trial with 30 channel catfish demonstrated significant correlations among weight-adjusted residuals for muscle area measured from transverse ultrasound images and transverse sections at five locations along the trunk musculature (r = 0.30 to 0.70). Relationships of weight-adjusted residuals for three meat yield traits (carcass, whole fillet, and shank fillet) with weight-adjusted residuals for 15 external body shape measurements and five transverse ultrasound measurements of muscle area were determined for 51 female and 91 male channel x blue catfish backcross hybrids. Compared to males, females had smaller heads; deeper, wider, shorter bodies; larger ultrasound muscle area; and higher meat yield. Correlations between carcass traits and body shape and carcass traits and ultrasound measurements were generally higher for females than for males. Correlations among carcass traits and ultrasound muscle area were typically higher than correlations among carcass traits and external body shape in both sexes. A single ultrasound measurement explained 40 to 50% and 16 to 23% of the variation in meat yield traits of females and males, respectively. The best three-variable model using ultrasound and body shape traits explained 48 to 56% and 31 to 38% of the variation in meat yield traits in females and males, respectively. Differences between males and females for the variability in meat yield traits explained by the models may be related to sexual dimorphism for body shape and fillet yield observed in catfish. Ultrasound has potential for predicting meat yield in live fish, but improved prediction accuracy is needed. Differences in meat yield traits between males and females and among individuals within sexes suggest that selecting for fish with smaller heads and deeper, shorter body shape posterior to the visceral cavity will increase meat yield in catfish.

Animals↗
PubMed2002

Influence of slaughter weight and sex on yield and quality grades of Hanwoo (Korean native cattle) carcasses.

To assess the effects of slaughter weight and sex on APGS (Animal Products Grading Service) quality and APGS yield grade of Korean Hanwoo (n = 20,881) cattle, data were collected from cow, bull, and steer carcasses during a 1-yr period. Factors used to determine quality grade (marbling, meat color, fat color, texture, and overall maturity score) and yield grade (cold carcass weight, adjusted fat thickness, and longissimus muscle area) by the Korean grading system were recorded. Both yield and quality grades were improved (P < 0.01) with heavier slaughter weight, but there was no difference in yield grade for Hanwoo cattle classes heavier than 551 kg (P > 0.01). Longissimus muscle area, adjusted fat thickness, and marbling score increased (P < 0.01) with carcass weight. Bull carcasses showed higher yield but lower quality than those of cows or steers (P < 0.01). The quality grade of steer carcasses was higher (P < 0.01) than that of cow carcasses due to higher marbling scores, lower maturity scores, and heavier carcass weights. Hanwoo carcasses with larger longissimus muscle areas in relation to their carcass weight had lower APGS quality grades. The APGS quality grades were different between yield grade A and B carcasses (P < 0.01), but quality grade was not improved by increased fat thickness beyond the point of yield grade B. Adjusted fat thickness and marbling score showed significant (P < 0.01) differences among all yield grade classes, and this resulted in increased quality grade as yield grade decreased. Adjusted fat thickness showed the strongest correlation (r = -0.63) with yield grade, whereas marbling score had the strongest correlation (r = 0.81) with quality grade. Results showed a negative effect of castration on yield but a positive effect on quality. Also, data showed that Hanwoo carcasses with heavier weights had higher quality grades than those of lighter weight.

Animals↗