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1.
Accuracy and precision of intramuscular fat prediction by ultrasound (USIMF) in lean cattle were studied by developing a prediction model based on 172 pure and crossbred beef and dual purpose bulls and steers from commercial herds. The animals were scanned across the 13th thoracic vertebrae using a Pie 200 SLC scanner. Five images were collected per individual. A 2.5 cm cross sectional muscle sample at the 13th thoracic vertebrae was collected from each carcass for chemical analysis of intramuscular fat % (CHIMF; Mean 2.0%, SD 1.5%) at the scanning site. The prediction model was developed using stepwise regression procedures. The validation model R2, RMSE, overall mean bias, SEP and rP correlation between CHIMF and USIMF based on the final prediction model was 0.80, 0.66%, − 0.15%, 0.65% and 0.90, respectively. The rank correlations varied over the CHIMF parameter space (from 0.26 to 0.87). The causes of this and the implications that follow are discussed. The overall results imply that ultrasound can predict IMF in lean cattle with acceptably high accuracy and precision. Ultrasound may thus be a valuable selection tool for meat quality in such cattle populations. The importance of developing optimised prediction models, based on data representative for the actual population, is highly emphasised.  相似文献   

2.
The objective was to study the relationships between the actual European beef carcass classification scale, which classifies carcasses with regard to conformation and degree of fat cover scores, and muscle fat quality, depending on breed and mh-genotype. For this purpose samples from 100 yearling bulls from “Asturiana de los Valles” (24 AV(mh/mh), 26 AV(mh/+), 25 AV (+/+)) and “Asturiana de la Montaña” (25 AM) were analysed. The results of the study showed that breed or genotype affect carcass measurement scores and muscle fatty acid profile through its important effect on animal overall fatness. Homozygous double-muscled animals produced carcasses with high conformation and low intramuscular (IM) fat content. While early-maturing and rustic AM animals produced low carcass yield and high IM fat content. The other genotypes (mh/+, +/+) showed, in general, intermediate characteristics. Referring to correlations, carcass conformation was negatively related to saturated (SFA) (r = − 0.69, P < 0.001) and monounsaturated fatty acid (MUFA) (r = − 0.69, P < 0.001) groups, and positively to polyunsaturated (PUFA) (r = 0.72), n-6 (r = 0.72), n-3 (r = 0.71) and unsaturated fatty acid (UFA) (r = 0.69) groups, being all of them significant (P < 0.001). However, carcass degree of fat cover was positively related to SFA (r = 0.53, P < 0.001) and MUFA (r = 0.62, P < 0.001), and negatively to PUFA (r = − 0.61), n-6 (r = − 0.60), n-3 (r = − 0.62) and UFA (r = − 0.53) groups, being all of them significant. Moreover, simple and low-cost prediction equations were calculated for a rapid and sufficiently accurate fatty acid group (SFA, MUFA, PUFA, n-6, n-3, UFA) estimation (R2 > 0.46, P < 0.001). In general, meat obtained from double-muscled animals display a more appropriate IM fatty acid profile from the nutritional point of view according to actual recommendations, but it could happen the disability of these lean animals to deposit sufficient IM fat to ensure consumer overall liking or acceptability.  相似文献   

3.
Three experiments were conducted to evaluate the use of purine derivatives (PD)/creatinine ratio in spot urine samples as an index of microbial protein supply in Yerli Kara crossbred cattle (YK-C). In Experiment I, response of daily PD excretion to feed intake in YK-C at state farm was measured. In Experiment II, spot urine sampling techniques was applied at state farm and four YK-C bulls were used. In Experiment III, spot urine sampling technique was applied at small-holder farms. There were significant correlations (R2 = 0.99) between PD excretion (mmol/day) and digestible organic matter intake (DOMI) (kg/day) in Experiment I, Y = 12.5 (± 0.5) + 19.7 (± 3.5)X (R2 = 0.99, n = 16). The equation obtained from Experiment I could be expressed as: Y = − 2.3 (± 0.3) + 0.953 (± 0.06)X, (R2 = 0.99, n = 49) where Y is PD excretion (mmol/day) and X is the PDC index. The PDC index was calculated as the molar concentration ratio of PD to creatinine times the metabolic body weight (kg). The corresponding microbial-N values to PDC index of groups I, II and III in developed banding system are 15–25 g/day. Experimentally estimated DOMI was 2.21 ± 0.15 kg/day. Estimated DOMI of groups I, II, and III were 2.8 ± 0.6, 2.6 ± 0.7 and 2.7 ± 0.7 kg/day, respectively. In conclusion, the PDC index in spot urine samples could be used under similar farm condition as an indicator of microbial protein supply in YK-C cattle. Estimated DOMI from PDC index in spot urine samples under defined field conditions may help the development of feeding strategies for YK-C cattle held by small holders.  相似文献   

4.
In this study we have characterized M. bovis isolates from a herd of cattle in Uvalde, Texas in which 52 of the 193 animals selected at random in 1994 from a herd of 331 were caudal fold skin-test positive. Thirty-two of 52 skin-test positive cattle had gross lesions at slaughter, and isolations of M. bovis were made from 29 animals. The herd was comprised of Red Devon cattle purchased between 1978 and 1980 (n = 26) and breeding bulls (n = 3) introduced at later times, and all were tuberculosis test negative at the time of purchase. Other animals were natural additions (offspring) of these cattle. One additional animal, a Holstein present on the ranch at the time of purchase in 1976, was retained to nurse orphaned and weak calves. Using several molecular fingerprinting techniques we have verified a clonal relationship among the M. bovis isolates consistent with infection originating with a single strain. The molecular fingerprint patterns demonstrate the stability of the profiles despite persistence and spread of the organism within the herd for two decades and confirms their use in epidemiological tracing.  相似文献   

5.
This paper presents an environmental exposure assessment model for estimating chronic intake of vanadium (a transition metal) by cattle farmed extensively in areas contaminated by vanadium pollutants. The exposure model differs from most other models in several ways: (1) it does not rely heavily on extrapolating information from the point source (e.g. stack height, exit velocity, exit diameter) to the point of exposure. (2) It incorporates the physiological constraints of the species exposed. (3) It takes into account oral as well as inhalation exposure. (4) It addresses terrain, by using measurements at the point of exposure. (5) It accounts for existing background concentrations of pollutants and pollutants from multiple sources. (6) It uses a stochastic process with distribution functions to account for variability in the data over time. Environmental inputs into the model included aerial fall-out sample vanadium (n = 566), unwashed grass sample vanadium (n = 342) and soluble soil sample vanadium (n = 342). Physiological cattle inputs were derived from two cohorts of Brahman-cross sentinel cattle (n = 30). The model provided an estimate of the chronic external exposure dose of vanadium for two separate groups of cattle grazing over a 5-year period (1999–2004) immediately adjacent (median dose = 2.14 mg vanadium/kg body weight/day) and 2 km away (median dose = 1.07 mg/kg/day) from a South African vanadium-processing plant, respectively. The final output of the model is a distribution curve of the probable vanadium intake based on the variability within the inputs over the 5-year period of the study. The model is adaptable enough for application to other transition metals and species (including man), and could be used as an alternative to plume-dispersion modelling.  相似文献   

6.
We explored the applicability of the 13C bicarbonate dilution technique for determination of energy expenditure (EE) in young bulls in comparison to whole body indirect calorimetry (IC). Twelve bulls of a F2 German Holstein x Charolais cross (4.5 months, 332 ± 16 kg BM) received a diet providing 1000 kJ ME d− 1 kg BM− 0.75 and 4.3 g crude protein d− 1 kg BM− 0.75. Bulls were housed in respiration chambers and received an intravenous bolus of NaH13CO3 (A: 3 μmol kg BM− 1 (n = 2), B: 7 μmol kg BM− 1 (n = 4), C: 17.5 μmol kg BM− 1 (n = 6), 99 at.% 13C) into the jugular vein to measure EE. Simultaneously, EE was determined by IC. After the 13C administration blood samples and breath gas were collected from the animals in the respiration chamber during a 24-h period (7.00–7.00 h). The recovery of 13C in breath CO2 (% of 13C dose) was irrespective of NaH13CO3 dose (A: 69.7 ± 2.7%, B: 70.5 ± 4.5%, C: 75.0 ± 4.9%; P > 0.05). Only small amounts of 13C were excreted in urine (3.4 ± 2.6%) and feces (2.0 ± 1.3%). The EE determined by the 13C bicarbonate method using breath and blood 13C recovery rates as correction factors was not different from that measured by IC (816 ± 81 [blood] or 827 ± 101 [breath] vs. 820 ± 90 kJ d− 1 kg BM− 0.75). Bland–Altman analysis showed a 95% confidence interval for EE of ± 99 and ± 109 kJ d− 1 kg BM− 0.75 based on blood and breath 13C recovery, respectively. In conclusion, the 13C bicarbonate dilution method is appropriate to obtain reliable estimates of EE in young bulls using blood CO2 or breath CO2 under standardized experimental conditions, i.e. in the fasting state.  相似文献   

7.
The objective of the present study was to evaluate the effects of improved nutrition during calfhood on serum metabolic hormones, gonadotropins and testosterone concentrations, and on sexual development in bulls. Bulls received high (n = 17) or control nutrition (n = 16) diets from 10 to 30 week of age and the same control nutrition diet from 31 to 74 week of age. Improved nutrition during calfhood resulted in a more sustained period of elevated LH secretion (pulse frequency and total secretion in 10 h) during the early gonadotropin rise. GnRH-stimulated LH secretion was not affected by diet, indicating that pituitary responsiveness was not altered; therefore, improved nutrition had direct effects on GnRH secretion by the hypothalamus. Insulin and insulin-like growth factor-I (IGF-I) concentrations were greater during calfhood in bulls receiving high nutrition, indicating that these metabolic hormones might be involved in regulating GnRH and LH secretion. Improved nutrition also resulted in increased testosterone secretion that was associated with greater circulating IGF-I concentrations, suggesting a role for this metabolic hormone in regulating Leydig cell number and function. Furthermore, improved nutrition during calfhood resulted in greater testicular weight and sperm production in mature bulls, indicating that increased LH secretion during calfhood, and increased IGF-I and testosterone concentrations during calfhood and peripubertal period were associated with greater testicular cell proliferation and enhanced function.  相似文献   

8.
The objective of this study was to determine the prevalence of antimicrobial resistance among Salmonella isolated from dairy herds in New York, Minnesota, Michigan, and Wisconsin, USA. Serogroup and antimicrobial susceptibility characteristics were determined for Salmonella from cattle and environmental samples collected during August 2000–October 2001 as part of a longitudinal study where 129 herds were visited at 2-month intervals. Salmonella isolates were tested (using a broth microdilution method) for susceptibility to amoxicillin/clavulanic acid, ampicillin, ceftiofur, ceftriaxone, cephalothin, chloramphenicol, ciprofloxacin, gentamicin, kanamycin, nalidixic acid, streptomycin, sulfamethoxazole, tetracycline, and trimethoprim/sulfamethoxazole. Of the 1506 isolates tested for minimum inhibitory concentrations to these 14 antimicrobial agents, 81.2% were pan-susceptible and for most herds (81.6%) the predominant antimicrobial resistance pattern was pan-susceptible. At least 1 Salmonella isolate resistant to 5 or more antimicrobial agents was found on 23.6% of herds. This resistance phenotype was most common among serogroups B and E1 and among samples from calves and farmer-designated sick cows. Resistant samples most frequently exhibited resistance to tetracycline, streptomycin, and/or ampicillin. No samples were resistant to ceftriaxone (though 13 were in the intermediate range), and very few samples were resistant to ciprofloxacin (n = 1), nalidixic acid (n = 5), or trimethoprim/sulfamethoxazole (n = 7).  相似文献   

9.
T. Kvame  O. Vangen 《Livestock Science》2007,106(2-3):232-242
Genetic parameters for carcass traits in lambs at weaning (average age of 128 days) measured by ultrasound (n = 1821) and computer tomography (CT) (n = 234), and response to selection for ultrasound eye muscle depth (UMD) and carcass LEAN weight, were estimated. The research flock comprised a meat line (ML) and a control line (CL) of Norwegian White Sheep. The ML was crossed with Texel from 1998, and selected for UMD from 1993 to 2001, and for LEAN weight from 2001 to 2004. For CT scanning, a mean of 23 images was taken per animal. Genetic parameters were estimated with univariate and bivariate mixed-animal models using AIREML, including all animals with records and their relatives. The statistical models included fixed effects, live weight or age of lamb at weaning (covariate), and a random genetic effect.

Heritability estimates for weight of LEAN, FAT and BONE were 0.57, 0.29 and 0.51 using model corrected for live weight. The heritability estimates were lower when these traits were adjusted for age. High genetic correlation was found between LEAN and UMD (0.70), and between carcass FAT and ultrasound fat depth (UFD) (0.82). The genetic trend for UMD regressed on year of birth was significantly greater for ML than CL in 2004.  相似文献   


10.
Four experiments were carried out to determine urinary creatinine excretion in Holstein growing bulls, lactating cows, and replacement heifers. In addition, we evaluated the use of spot sampling technique to estimate purine derivatives (PD) excretion. In Experiment I, 15 lactating cows were used in a randomized block design to compare creatinine excretion obtained in different time-spans of urine collection (during 6, 9, 12, 15, 18, 21, and 24 h). In Experiment II, four bulls were allocated in a 4 × 4 Latin square to evaluate the effect of diet (levels of cottonseed hulls of 0, 10, 20, and 30% of the DM) on excretion of creatinine. In Experiment III, 15 lactating cows were used to evaluate the effect of milk production (ranging from 3.9 to 36.7 kg/d) on daily creatinine and PD excretions. In Experiment IV, 22 replacement heifers were utilized to evaluate the effect of body weight (BW, ranging from 107 to 545 kg) on daily creatinine and PD excretions. For all experiments, total urine collections were made over 24 h and daily creatinine and PD excretions were determined. Different time-spans for total urine collection had no effect (P = 0.70) on creatinine excretion compared to the 24-h collection period, indicating a constant excretion rate of creatinine. The roughage source did not influence (P = 0.64) creatinine excretion by bulls, averaging 0.248 ± 0.008 mmol/kg BW. Similarly, milk production did not affect (P = 0.82) creatinine excretion in cows, averaging 0.212 ± 0.004 mmol/kg BW. In contrast, the creatinine excretion (mmol/kg BW) decreased linearly (P < 0.001) as BW of heifers increased, suggesting that creatinine excretion might vary with the degree of maturity of growing animals. There were no differences (P > 0.14) between the 24-h total collection and spot sampling technique in estimating daily PD excretion. The spot sampling technique may be used to estimate the daily excretion of urinary PD in Holstein cattle under practical conditions.  相似文献   

11.
Ninety-six pigs from Large White (LW), Synthetic Genex 3000 (SG) and Meishan-derived dam line (M) genetic lines, each with a mean live body weight (BW) of 20.7 ± 4.2 kg, were used to investigate the relationship that exist between production performance and meat quality parameters for these three genotypes. The animals were assigned to pens in groups of eight and slaughtered at 109.6 ± 3.78 kg BW. At the end of the trial, the LW pigs had the highest (P < 0.001) average daily feed intake and average daily gain and protein deposition rates, the M pigs showed (P < 0.001) the worst feed conversion, the highest daily backfat gain and the lowest residual energy intake, and the SG pigs had the lowest (P < 0.001) daily fat deposition rate. The longissimus muscle of the M pigs had higher a (P < 0.01) and b (P < 0.05) values than the LW pigs, with the SG pigs in between. The M loins also had the highest (P < 0.01) shear force value, which may be explained by the lower (P < 0.01) soluble collagen content. In spite of their lowest fat deposition rate, the highest (P < 0.001) intramuscular fat content was measured in the SG loins, and the highest (P < 0.01) protein content was found in the M loins. Eight canonical correlations were obtained between performance and meat quality data, with the first three correlation coefficients of 0.87, 0.66 and 0.64 being significant. Performance and meat quality data were related to a certain extent. Pigs with a higher average daily feed intake also had a higher average daily gain, an average protein deposition rate, residual energy intake and gain-to-feed ratio, and lower meat dry matter, intramuscular fat, a values and pigment content. Body water content seems to be higher in fast-growing pigs. Furthermore, fast-growing pigs also have lower intramuscular fat, a values and pigment content. However, there is some indication that the magnitude of these correlations can be breed-dependent. The differences among the studied genotypes are much higher in terms of growth performance than in terms of meat quality traits.  相似文献   

12.
Physical and reproductive conditions of cull sows (3158) from two U.S. Midwestern harvest plants were assessed. Body condition, feet, shoulders, teeth, lungs, and reproductive tracts were visually evaluated for gross lesions on harvested sows. PROC FREQ (SAS, Cary, NC) was used to calculate the frequency of each binary trait event. Pearson chi-square tests were used to test the alternative hypothesis that a linear association existed between binary traits and body condition score (BCS). The most common foot lesions observed were rear (n = 2064, 67.5%) and front (n = 1024, 32.9%) heel lesions. Cracked hooves were found on the front feet of 703 (22.6%) and rear feet of 552 (18.1%) sows. Rear digital overgrowth was observed in 644 (21.1%) sows. The most common reproductive gross lesion observed among harvested cull sows was acyclic ovaries (n = 277, 9.0%). Presence of acyclic ovaries increased (p < 0.01) as BCS decreased. Cystic ovaries were found in 192 (6.3%) sows, which increased (p < 0.01) as BCS increased. Pneumonia was observed in 298 (9.7%) sows, and increased in frequency as BCS decreased (p < 0.01). The most frequently observed shoulder lesion among harvested cull sows was shoulder abrasions (n = 394, 12.5%). The presence of shoulder abrasions increased (p < 0.01) as BCS decreased. The prevalence of reproductive lesions detected in the present study was less than the reported percentage of sows culled for reproductive failure from previous studies based on record keeping summaries.  相似文献   

13.
The objective of the present study was to evaluate changes in concentrations of free insulin-like growth factor (IGF)-I in follicular fluid (FFL) during follicle development in the mare. Mares (n = 14) were classified as either in the follicular phase (n = 8) or luteal phase (n = 6). Follicles (n = 92) were categorized as small (6–15 mm; n = 54), medium (16–25 mm; n = 23) or large (>25 mm; n = 15) and FFL was collected. Free IGF-I levels in FFL in large follicles of follicular phase mares were greater (P < 0.05) than in large follicles of luteal phase mares and small or medium follicles of luteal and follicular phase mares. Free IGF-I concentrations were greater (P < 0.05) in large follicles of luteal phase mares than small but not medium follicles of luteal phase mares. FFL ratio of estradiol:progesterone paralleled changes in free IGF-I. Free IGF-I concentrations were negatively correlated (P < 0.05) with insulin-like growth factor binding protein (IGFBP)-2, -4 and -5 but not IGFBP-3 levels. In addition, free IGF-I concentrations in FFL were positively correlated (P < 0.01) with FFL estradiol, progesterone, androstenedione, estradiol:progesterone ratio, total IGF-I and total IGF-II. We conclude that increases in intrafollicular levels of bioavailable (free) IGF-I are associated with increased steroidogenesis in developing mare follicles.  相似文献   

14.
The tick Boophilus microplus represents a serious pathological constraint to livestock production in New Caledonia. Cattle ticks are controlled by chemical application of two acaricides that are currently used in New Caledonia; deltamethrin is used at 46% of the cattle production facilities and amitraz at the remaining 54% premises where resistance to deltamethrin has been identified. In 2003, a modified Larval Packet Test (LPT) was used to conduct a survey for amitraz resistance. Ticks were collected from 29 farms, including farms using deltamethrin (n = 8) or amitraz (n = 21). Of eighteen different tick populations, sixteen populations were defined susceptible to amitraz and two populations were considered amitraz-resistant. This is the first report of populations of B. microplus being resistant to amitraz, using the modified LPT in New Caledonia. A thorough survey of tick susceptibility to amitraz in cattle farms of the country should be conducted to assess the presence of amitraz-resistant populations. The emergence of amitraz resistance so soon after its introduction has some important implications for the strategy and organisation of tick control in New Caledonia, and this paper discusses some of the urgent actions that should be undertaken.  相似文献   

15.
Eighteen Iberian barrows of 100 kg initial BW were used in a comparative slaughter experiment to investigate the effects of feeding level (FL; 0.70 and 0.95 × ad libitum) on growth, protein- and fat-deposition rates and body composition. They were fed on a diet supplying the optimum level of digestible ideal protein:ME ratio (4.82 g/MJ) and slaughtered at 150 kg BW. The apparent digestibility of DM, OM, total N and GE, and the ME:GE and ME:DE ratios were not affected by FL. The average daily gain increased with the increase in FL (691 and 918 g/day respectively). Neither the gain:feed (g/g DM) nor the gain:ME intake (g/MJ) ratios were significantly affected however. An energy cost of 59.9 kJ ME/g gain was calculated. The rate of whole-body protein deposition was not significantly altered by FL. On average it reached 80 g/day. The pigs fed at the lowest level exhibited lower fat deposition (P < 0.01) and total energy retention (P < 0.01) than those in the group subjected to only a slight feed restriction. The overall efficiency of utilization of ME for energy gain (ER:ME intake) remained at 0.363 on average, irrespective of the FL imposed. Relative proportions of energy retained as protein and fat were not statistically altered by changes in FL. Mean values for ERP:ER and ERF:ER were 0.100 and 0.903 respectively. No differences between treatments were observed in fat, ash, water or energy content of the whole-body (g/kg) at 150 kg empty BW, the mean values (n = 12) being 512 ± 8.5, 27.6 ± 0.63 and 353 ± 6.7 g/kg for fat, ash and water respectively and 22.90 ± 0.31 MJ/kg for energy. Nevertheless, the proportion of protein tended to decline with the increase in FL (111 vs 104; P = 0.069). At 150 kg the Iberian pigs contained more fat and energy and less ash and water than at 100 kg. Whilst the percentage of lean tissue decreased significantly (P < 0.05) and protein content in the carcass showed a strong tendency to decline in the pigs fed close to ad libitum (104 vs 96; P = 0.056), the proportions of fat, ash, water and energy remained constant at 564 ± 9.0, 22.2 ± 0.91, 312 ± 6.6 g/kg, and 24.82 ± 0.32 MJ/kg, respectively. It was concluded that a degree of feed restriction may result in a discernible improvement in carcass quality.  相似文献   

16.
We collected samples of teat duct material and mammary secretion from ewes in three farms (flock A, polyparous n = 7; flock B, polyparous n = 6, primiparous n = 4; flock C, polyparous n = 4): 14 samples immediately after lambing (before sucking of lambs), 244 samples during the suckling period and 156 samples during the milking period. Conventional bacteriological techniques were used. The results were modeled using survival analysis, initially by the Kaplan–Meier method and then by the Cox Proportional Hazards method. Then, we calculated the minimum true risk of an “at-risk” teat or mammary gland being infected and analyzed these data with STATA using the GLLAMM program for Generalised Linear Latent and Mixed Models. During the suckling period, bacteria were isolated from 52 (21%) duct material and 19 (8%) secretion samples; respective results for the milking period were 20 (13%) and 9 (6%). There was an increased risk of duct rather than secretion samples being infected (P < 0.001). There was a significant difference among flocks in isolating bacteria from duct (P < 0.01) or secretion (P < 0.001) samples during suckling period, but not during hand-milking period (P > 0.4 and 0.1, respectively). There were no differences between isolation of bacteria from duct (P > 0.5) or secretion (P > 0.7) samples among primiparous and polyparous animals. Most bacterial isolates were staphylococci. Persistent isolation of the same bacterial species from duct material samples obtained from a particular ewe was recorded with five Staphylococcus spp. and two Mannheimia haemolytica isolates. The results indicate that infections of the teat duct can take place easily; however, not all infections result to infection of the mammary gland. The results support experimental evidence that defence mechanisms of the healthy teat are able to limit the infection. Maintenance of healthy teats contributes to effective defence mechanisms, and coupled with minimal infections of the teat duct, would contribute to the prevention of mastitis in ewes.  相似文献   

17.
The aim of the present study was to assess the influence of different levels of iodine supplementation on animal growth and the iodine content of food from beef cattle. In a dose–response experiment with 34 growing fattening bulls of the “German Holstein” breed, in the range from 223 to 550 kg body weight, three iodine dosages were tested. The animals were fed a corn silage/concentrate ration. Iodine concentration in the diet amounted to 0.79 (Group 1), 3.52 (Group 2) and 8.31(Group 3) mg I per kg dry matter (DM). After slaughtering, I was determined in blood, serum, plasma, thyroid, liver, kidneys and meat (M. longissimus dorsi, M. glutaeus medius) by ICP-MS. I-supplementation did not significantly influence DM intake, daily weight gain (1453 (1), 1419 (2) and 1343 (3) g; p > 0.05) or slaughtering performance, but the weight of the thyroid gland increased significantly with the highest I dosage (32 (1), 26 (2) and 42 (3) g animal− 1, p < 0.05). I-supplementation significantly increased I-concentration in muscle, liver, kidney and thyroid gland (p < 0.05). The contribution of beef food to I-intake of humans is relatively low, therefore there is no need to reduce the EU-upper limit (10 mg kg− 1 feed) for growing fattening cattle from the view of consumer safety. In view of animal health and performance more dose–response studies seem to be necessary.  相似文献   

18.
The utility of x-ray computed tomography (CT) scanning in predicting carcass tissue distribution and fat partitioning in vivo in terminal sire sheep was examined using data from 160 lambs representing combinations of 3 breeds (Charollais, Suffolk, and Texel), 3 genetic lines, and both sexes. One-fifth of the lambs were slaughtered at each of 14, 18, and 22 wk of age, and the remaining two-fifths at 26 wk of age. The left side of each carcass was dissected into 8 joints with each joint dissected into fat (intermuscular and subcutaneous), lean, and bone. Chemical fat content of the LM was measured. Tissue distribution was described by proportions of total carcass tissue and lean weight contained within the leg, loin, and shoulder regions of the carcass and within the higher-priced joints. Fat partitioning variables included proportion of total carcass fat contained in the subcutaneous depot and intramuscular fat content of the LM. Before slaughter, all lambs were CT scanned at 7 anatomical positions (ischium, midshaft of femur, hip, second and fifth lumbar vertebrae, sixth and eighth thoracic vertebrae). Areas of fat, lean, and bone (mm(2)) and average fat and lean density (Hounsfield units) were measured from each cross-sectional scan. Areas of intermuscular and subcutaneous fat were measured on 2 scans (ischium and eighth thoracic vertebra). Intramuscular fat content was predicted with moderate accuracy (R(2) = 56.6) using information from only 2 CT scans. Four measures of carcass tissue distribution were predicted with moderate to high accuracy: the proportion of total carcass (R(2) = 54.7) and lean (R(2) = 46.2) weight contained in the higher-priced joints and the proportion of total carcass (R(2) = 77.7) and lean (R(2) = 55.0) weight in the leg region. Including BW in the predictions did not improve their accuracy (P > 0.05). Although breed-line-sex combination significantly affected fit of the regression for some tissue distribution variables, the values predicted were changed only trivially. Within terminal sire type animals, using a common set of prediction equations is justified. Tissue distribution and fat partitioning affect eating satisfaction and efficiency of production and processing; therefore, including such carcass quality measures in selection programs is increasingly important, and CT scanning appears to provide opportunities to do so.  相似文献   

19.
Vertical transmission of Trichinella spiralis was evaluated in ferrets (n = 21), foxes (n = 11), pigs (n = 12), guinea pigs (n = 16), and mice (n = 41). The placental barrier to be crossed by migratory Trichinella larvae varies structurally in different animal species. Ferrets and foxes have an endotheliochorial placenta structure, guinea pigs and mice a haemochorial, and pigs an epitheliochorial placenta. The non-encapsulating Trichinella pseudospiralis larvae have an extended muscle migration prior to entering a muscle cell. To evaluate if T. pseudospiralis was more likely to be transmitted to offspring, an additional group of foxes (n = 11) infected with T. pseudospiralis was included. Two different dose levels were used for ferrets, pigs, guinea pigs, and mice. In pigs and guinea pigs, infection was given at different times of the gestation period. Vertical transmission, measured as recovery of muscle larvae in the offspring, was demonstrated in both ferrets groups, in all four guinea pig groups, and in the high dose mouse group, but not in any fox or pig groups.  相似文献   

20.
Two experiments were completed to determine whether cooling Holstein cows during their 60-day prepartum period improved their immediate physiological status as well as subsequent postpartum performance. In Experiment 1, 38 cows were divided into two pens that were not cooled, or where the cows were moved twice daily to be cooled by soaking until their body was completely wet. Prepartum respiration rate (RR) and rectal temperatures (RT) did not differ between groups, indicating that the cooling system was largely ineffective, which was consistent with differences that only numerically favored the treated group in postpartum productive (milk production, milk fat content and related response variables), and reproductive (services per conception and days open) performance. In Experiment 2, 52 Holstein cows were used over 3 years (n = 24 in year one; n = 12 in year two; n = 16 in year three) and cows were housed in pens either not cooled or cooled with water spray and fans. Cooled cows had lower RR and RT prepartum at 14:00 and 18:00 h vs. non-cooled cows, indicating that the cooling system was effective, and this was consistent with improved productive (milk production, milk fat content and related response variables), and reproductive (services per conception and days open) performance postpartum. In addition, there was a trend (P = 0.10) to higher birth weights of calves from cooled mothers (which was consistent with a numeric difference in Experiment 1). Use of effective cooling systems under hot and dry conditions during the dry period can improve postpartum productive and reproductive performance of Holstein cows.  相似文献   

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