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1.
Naturally occurring bovine sarcocystosis caused death and illness in eight dairy heifers. Clinical disease was characterized by cachexia, peripheral lymph node enlargement, and anemia. Increased amounts of serum enzymes and anti-Sarcocystis antibody titers were present in affected animal. Macroscopic findings in two heifers at necropsy included emaciation and serous atrophy. Necropsied heifers (No. 1 and 2) contained different developmental stages of Sarcocystis cruzi; each stage was characterized by specific histopathologic findings. Heifer 1 had vascular endothelial schizonts in various soft tissues, with mild mononuclear cell infiltration, alveolar capillary fibrinous thrombi, and multifocal splenic necrosis. Heifer 2 had developing young S cruzi cysts, in myofibrils of cardiac and skeletal muscles, with a concurrent multifocal degenerative myositis. Marked lymphoid hyperplasia occurred in both heifers.  相似文献   

2.
We summarized experimental data to quantify the change in final BW due to a particular implant strategy when cattle are adjusted to the same final body composition. The database developed for this study included 13 implant trials involving a total of 13,640 animals (9,052 steers and 4,588 heifers). Fifteen different implant strategies were used among these trials, including no implant (control), single implants, and combinations of implants. Individual carcass data collected at slaughter were used to calculate the adjusted final shrunk BW at 28% empty body fat (AFBW) for each treatment group within a trial, then the implant treatments were grouped into categories according to their effect on weight at 28% empty body fat (four groups for steers and two groups for heifers). All differences in AFBW between categories were significant (P < 0.01), indicating an incremental anabolic implant dose response in AFBW over unimplanted animals. Values for AFBW ranged from 520 kg in unimplanted steers to 564 kg in steers implanted and reimplanted with Revalor-S. For heifers, AFBW ranged from 493 kg in unimplanted heifers to 535 kg in heifers implanted and reimplanted with Revalor-H. After accounting for differences in mean BW and composition of gain, implanted steers and heifers had 4.2 and 3.1% higher apparent diet ME values, respectively. Increasing the anabolic implant dose increases the weight at which animals reach a common body composition. This study indicates that anabolic implant response is due to a combination of a reduced proportion of the DMI required for maintenance, reduced energy content of gain, and efficiency of use of absorbed energy.  相似文献   

3.
Intersucking is a problem that may lead to udder damage, mastitis, milk loss, and culling of breeding animals. To analyse the risk factors for intersucking in dairy heifers in Switzerland, we asked 130 randomly selected dairy farmers about a broad spectrum of environmental factors that might be associated with intersucking (such as housing conditions, management, and the feeding of calves and heifers). In total, 2768 heifers (Swiss Brown Cattle, Simmental and Holstein Friesian) were included of which 303 had ever performed intersucking. Data at the farm level were analysed using path analysis (linear and logistic regression). Two outcome variables were considered: the occurrence of intersucking on the farm and the proportion of intersucking heifers above the cut-off of 7.2%. Farms where calves had no access to barnyard or pasture, where calves were reared in pens in enclosed buildings, where heifers after weaning were not restrained while feeding, where heifers after weaning received <0.5 kg concentrate per day, and where heifers after weaning were fed ≥40% maize silage (dry-matter ratio) were most likely to have intersucking heifers.  相似文献   

4.
The effects of sex and anabolic implants on fecal egg counts and pasture contamination were examined in 77 naturally infected yearling bulls, steers, and heifers of mixed beef breeds grazing the same contaminated pasture in southern Ohio in the spring of 1990. Fecal egg counts were compared in seven groups of 10-14 animals each, twice before anabolic implants and twice after implants. Comparisons were made between untreated bulls, steers, and heifers, between steers with and without implants, and between heifers with and without implants. Bulls had significantly (P < 0.01) higher fecal egg counts than steers, and counts from steers were not significantly different to those from heifers. There were no significant differences between counts from implanted and control steers or heifers. The results have important practical implications both for parasite control and for bovine parasite research. There is a need to pay special attention to young bulls when designing parasite control programs, and to distribute the sexes equally between groups when doing research trials with cattle of mixed sexes. Some previous studies on worm population dynamics and anthelmintic evaluation may need to be re-examined in the light of sex differences.  相似文献   

5.
Muscle tissue from the oesophagus and diaphragm of 500 beef cattle slaughtered in New Zealand was examined for Sarcocystis infection by microscopic examination of cysts isolated from muscle samples. All cattle were infected with Sarcocystis; based on light microscopy of cysts, 98% had thin-walled Sarcocystis cruzi cysts and 79.8% had thick-walled (Sarcocystis hirsuta/Sarcocystis hominis) cysts. Cysts were also collected for electron microscopy and transmission experiments. Thick-walled cysts could not be distinguished as S. hirsuta or S. hominis by light or electron microscopy. Thick-walled cysts were fed to three cats and one human volunteer; one cat shed sporocysts but not the human volunteer. Electron microscopy of the cysts revealed many features that have not been described previously.  相似文献   

6.
选用4头7日龄奶牛和4头4～5月龄水牛,用水牛源孢子囊感染黄牛及黄牛源孢子囊感染水牛,同时设感染对照和不感染对照,对交叉感染后黄牛与水牛体内包囊的超微结构进行了比较研究,结果发现两者无结构区别,所有包囊的超微结构均与前人对黄牛和水牛枯氏住肉孢子虫包囊的描述一致,证实水牛与黄牛同是枯氏住肉孢子虫的中间宿主。作者还首次在枯民住肉孢子虫包囊的母细胞和缓殖子发现晶状体。  相似文献   

7.
The aim was to compare the effects of two production systems on performance, carcass traits and physical‐mechanical characteristics of leather from Beefalo‐Nellore steers and heifers and to determine if the response to the production system was similar for both genders. A total of 40 Beefalo‐Nellore cattle, 20 steers and 20 heifers, were evaluated. Animals were divided into two production systems: slaughtered at 15 (intensive system) or 26 (extensive system) months of age. In the intensive system, all animals received a ration containing 600 g/kg corn silage and 400 g/kg concentrate. In the extensive system, animals were kept on a pasture predominantly based on Brachiaria sp. and supplemented with 2 kg/day concentrate. In the intensive system, there was no difference in slaughter weight (470 kg body weight) between steers and heifers but steers in the extensive system had greater slaughter weight than heifers (463 and 428 kg body weight, respectively). Leather weight was higher for animals in the intensive than extensive system but there was no difference in leather weight once excess fat was removed. Leather quality from Beefalo‐Nellore cattle slaughtered at 15 or 26 months of age is similar although carcass yield is higher for cattle slaughtered at a younger age.  相似文献   

8.
Prevalence of antibodies to Neospora caninum was determined in a cross-sectional consensus survey of 1029 bovines in a dairy herd with endemic Neospora-induced abortion. Sera were screened by indirect fluorescent antibody test (IFAT). The prevalence of N. caninum antibody in the IFAT was 17.9% in 107 neonates, 26.2% in 233 yearling heifers and steers, 39.07% in 218 mature heifers, and 26.9% in 465 milking cows. Serologic reactivity was associated with production grouping on the farm with the greatest risk of serologic reactivity appearing in the yearling and mature heifers. There was an increasing risk of serologic reactivity with increasing age only in the parity one and greater animals in the herd. Castrated males were at half the risk of similarly aged females of possessing antibodies to N. caninum. There was no clear relationship between the serologic status of dams and offspring.  相似文献   

9.
This study was conducted to determine the effects of testosterone-propionate exposure during fetal development on sexual differentiation and growth rates in heifers. Ten pregnant cows were given subcutaneous injections of testosterone-propionate (250 mg/injection) every other day during d 40 to 60 of gestation. Four cows aborted after the end of testosterone treatment, while four heifers (androgenized females) and two bulls (androgenized males) were produced from the six remaining pregnant, testosterone-propionate treated cows. Calves from cows that did not receive exogenous hormone treatment were used as controls. At 8 mo of age, the androgenized heifers and control heifers and control steers were challenged with 1 mg estradiol-17 beta to induce a preovulatory luteinizing hormone (LH) surge. Two weeks later, pituitary responsiveness to exogenous luteinizing hormone releasing hormone (LHRH; 75 micrograms) was evaluated in androgenized heifers and in control heifers and control steers. To monitor growth rates, all animals were weighed at 28-d intervals from birth to 380 d of age. Androgenized females exhibited a partially masculinized phenotype as well as internal male reproductive structures. Treatment with estradiol-17 beta first depressed (P less than .05) serum LH concentrations in all animals, then induced (P less than .05) a preovulatory-like LH surge in control and androgenized females. Control steers did not (P greater than .05) exhibit a preovulatory-like LH surge following administration of estradiol-17 beta. Exogenous LHRH treatment stimulated peak LH concentrations (P less than .05) to a greater extent in control and androgenized females than in control steers.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

10.
Experiments were conducted at 3 US locations (California, Idaho, and Texas) to determine the effects of dietary zilpaterol hydrochloride and duration of zilpaterol feeding on carcass composition and beef palatability. At each site, 160 steers and 160 heifers were stratified within sex by initial BW (study d -1) and assigned randomly within BW strata to 1 of 4 treatments in a randomized complete block design (4 blocks/treatment for each sex). The 4 treatments were arranged in a 2 (no zilpaterol vs. zilpaterol) x 2 (20- or 40-d duration of zilpaterol feeding) factorial. When included in the diet, zilpaterol was supplemented at 8.3 mg/kg (DM basis). Each pen consisted of 10 animals. After slaughter 2 carcasses per pen (n=64 per trial site) were selected. The entire right side of the selected carcasses was collected for dissection and chemical analysis of the soft tissue. Additionally, the left strip loin was collected for Warner-Bratzler shear force determinations and aged to 28 d postmortem. Sensory analysis was conducted on the Idaho trial site samples only. All data were pooled for analyses. Feeding zilpaterol hydrochloride increased carcass muscle deposition (P<0.01) of both steer and heifer carcasses. However, carcass percentage fat of steers and heifers was not affected (P>0.11) by the zilpaterol treatment. In heifer carcasses, carcass moisture percentage was increased (P=0.04) and bone percentage was decreased (P=0.02), whereas in steer carcasses, carcass moisture and bone percentage were not affected (P>0.10). In heifer carcasses, carcass ash percentage was not affected (P=0.61) by zilpaterol, whereas in steer carcasses, carcass ash percentage tended (P=0.07) to be increased. The protein-to-bone ratio was increased (P<0.001) by zilpaterol hydrochloride treatment in both steers and heifers, whereas the protein-to-fat ratio was not affected (P=0.10). Cooking loss of the LM was not affected (P=0.41) by zilpaterol treatment of steers or heifers. However, LM Warner-Bratzler shear force was increased (P=0.003) on average (3.3 vs. 4.0 kg) due to zilpaterol hydrochloride treatment of both steers and heifers. In both steers and heifers, LM sensory panel scores of overall juiciness (6.2 vs. 6.0), tenderness (6.2 vs. 6.0), and flavor intensity (6.2 vs. 6.0) tended (P=0.06) to be decreased in cattle supplemented with zilpaterol. Zilpaterol hydrochloride is a repartitioning agent that seems to affect carcass composition primarily through protein deposition. However, zilpaterol treatment can adversely affect tenderness and other palatability traits.  相似文献   

11.
Protozoan parasites of the genus Sarcocystis have been recognised for many years as intramuscular cysts of numerous vertebrates. It is only comparatively recently that the two-host nature of the life cycle has been recognised and that the intramuscular cysts are a stage in the developmental cycle of coccidian parasites of flesh eating mammals (Fayer 1974, Fayer and Johnson 1973, 1974, Rommel and others 1972, Dubey 1976). Carnivores ingest the intramuscular cysts from herbivores and presumably from other animals too and eventually shed sporulated tetrazoic sporocysts in their faeces. The cystic stages which occur in the flesh of herbivores are probably non-pathogenic but the earlier stages in which schizonts develop in vascular endothelium may be severely pathogenic. Sarcocystis cruzi, S ovicanis and S porcifelis are known to be severely pathogenic in cattle, sheep and pigs respectively (Dubey 1976). Observations on the prevalence of Sarcocystis spp in the faeces of working farm dogs, greyhounds and foxes (Vulpes vulpes) are recorded.  相似文献   

12.
Longissimus width and depth were measured using ultrasound in steers (n = 174), bulls (n = 323), and heifers (n = 347) at yearling and prior to harvest. Yearling and preharvest muscle dimensions and carcass muscle area of bulls were largest (P<0.01). Steers had wider and deeper (P<0.01) longissimus than heifers at yearling; however, preharvest muscle width and depth and carcass muscle area were greater (P<0.01) for heifers. From yearling to harvest, muscle width of bulls and heifers increased at a similar rate, which was greater (P<0.01) than that of steers. Significant (P<0.01) differences existed for muscle depth increase from yearling to harvest, where bulls had the highest deposition rates, heifers had intermediate rates, and steers had the lowest deposition rates. Correlations of carcass muscle area with muscle depth were large and positive (0.52 to 0.81) and slightly larger than correlations with muscle width (0.51 to 0.74). Muscle depth was the best single predictor of carcass muscle area; however, two-trait prediction models including both muscle width and depth were superior to single-trait prediction models. At yearling (preharvest), predicted and carcass muscle areas differed by more than 9.68 cm2 for less than 2% (5%) of steers and heifers and less than 7% (4%) of bulls. Further, yearling and pre-harvest carcass muscle area predictions were within 4.84 cm2 of carcass measurements for approximately 54 to 65% of all animals, respectively. These results indicate that ultrasound muscle width and depth may be alternative predictors of carcass muscle area and may be useful in selection of potential replacements.  相似文献   

13.
Blindness and convulsions were the predominant clinical signs in a group of feedlot steers inadvertently fed a vitamin-A deficient diet. Although vitamin A had been added to the feed at the time of preparation, it was believed that the vitamin A had been destroyed by heat, humidity, and minerals mixed in the feed. Feedlot heifers fed the same high-grain diet were clinically normal, and one heifer from which a blood sample was obtained had normal serum vitamin A content. The ingestion of sparse grasses and weeds found along the fence row of the heifers' pens was thought to have provided sufficient vitamin A to these animals. This episode demonstrated the importance of monitoring vitamin A and vitamin A precursor concentrations in stored feeds, especially those stored under adverse conditions and those fed to animals ingesting only a high-grain diet.  相似文献   

14.
Fresh preparations of micro-isolated sarcosysts from skeletal muscle of 5 wild reindeer were examined by light microscopy. Slender, spindelshaped cysts measuring 821 × 60 µm, and having short knob-like cyst wall protrusions were found in all animals. In 1 animal cysts different in structure from the cysts of the 4 previously known Sarcocystis spp. of reindeer were found, These cysts are considered to be cysts of a new Sarcocystis sp. of reindeer, for which the name Sarcocystis hardangeri has been proposed.S. hardangeri n. sp. had macroscopic, ovoid to cylindrical cysts measuring 1667 (900–2570) × 819 (450–1575) µm. The cysts were surrounded by a 8–10 µm thick layer of fibrillar material. After removal of this layer, relatively few and irregularly spaced, slanting protrusions became visible. The 20–30 µm long protrusions were tongue-like, and were lying close to the surface of the cyst.Cysts of S. grueneri, S. rangiferi and S. tarandi were not demonstrated in the 5 wild reindeer examined.  相似文献   

15.
To determine the prevalence of Giardia genotypes in 12–24 month old dairy heifers, fecal specimens were collected from two farms each in Vermont, New York, Pennsylvania, Maryland, Virginia, North Carolina, and Florida. Specimens, cleaned of fecal debris and concentrated using CsCl density gradient centrifugation, were subjected to PCR and DNA sequence analysis. Prevalence of Giardia infection, ranged from 11% to 75% on 14 farms with an average prevalence of 36% (204 positive cattle out of 571 examined). DNA sequence analysis of the 16S rRNA gene revealed 91% of the 204 Giardia isolates were Assemblage E, and 9% were Assemblage A. The prevalence of these genotypes varied greatly from farm to farm, with four farms having exclusively Assemblage E Giardia. Overall, Assemblage E was present in 33% of all animals tested and Assemblage A was present in 3% of the animals. Thus, while many of the heifers were infected with a genotype that is not known to be infectious for humans, 1–2 year old heifers on 10 of 14 farms did harbor zoonotic Assemblage A Giardia. Therefore, heifers cannot be overlooked as a potential source of human infectious cysts in the environment, with some farms representing a much higher risk than others.  相似文献   

16.
The effects of larvae, nymphs and adults of the brown ear-tick Rhipicephalus appendiculatus on the growth of Bos indicus X B. taurus (Sanga) steers and on B. taurus steers and heifers was measured by exposing groups, maintained in the same pastures, to different levels of tick challenge. Larvae and nymphs had no significant effect on liveweight gains, but adults had a large effect. Each engorging female tick counted was associated with a loss of 4 g. Their effect on the Sanga cattle was minimised by host resistance which severely limited the number of ticks feeding on them. The B. taurus animals were severely affected and suffered extensive ear damage. Both breeds were subjected to screw-worm fly (Chrysomya bezziana) strike in the lesions caused by heavy tick infestations, but the B. taurus animals were much more prone to attack. The results provide a basis for calculating losses in production caused by this species of tick which is widespread in Africa.  相似文献   

17.
Tissue samples comprising the oesophagus and diaphragm were collected from 400 sheep and 400 goats slaughtered at the abattoirs in the study area. Out of this number, 36 were positive for Sarcocystis cysts (sarcocysts) in sheep and 56 in goats. The sarcocysts in sheep measured 35.7 to 500 microns lengthwise and the cyst-wall 2.4 microns. They were identified to be Sarcocystis tenella. The cysts in goats measured 98 to 700 microns and the cyst-wall 2.7 microns. They were identified to be Sarcocystis capracanis. In both animals species, the sarcocysts were more frequent in the oesophagus than in the diaphragm. All sarcocysts seen were microscopic.  相似文献   

18.
Two experiments were conducted to determine the effects of sex on carcass traits and cooked beef steak palatability. In Exp. 1, steers (n = 99), heifers (n = 51), and intravaginally spayed heifers (n = 46) were fed a high-energy diet for 161 d. No implants were administered, and heifers were not fed melengestrol acetate to suppress estrus. In Exp. 2, 60 steers and 60 intact heifers from the same ranch source used in Exp. 1 were fed in 2 locations (sites 1 and 2). All management factors were equal across experiments except that intact heifers were fed melengestrol acetate to suppress estrus in Exp. 2. Steers in Exp. 1 were 25 kg heavier (P < 0.01) in HCW than heifers at comparable (P = 0.39) carcass fat thickness. Spayed heifers (Exp. 1) had a 5.7% smaller (P < 0.05) LM area compared with steers and intact heifers, which were similar. In Exp. 2, there was no difference (P = 0.2) in carcass weight, and heifers had greater (P < 0.01) 12th rib fat thickness compared with steers. Calculated yield grades were similar (P = 0.21) among treatments in Exp. 1 and tended (P = 0.08) to be greater for heifers compared with steers in Exp. 2. In Exp. 1, USDA quality grades and marbling scores were lower (P < 0.01) for steers compared with intact and spayed heifers, which were similar. The effects of sex on tenderness were examined at a common level of fat-thickness and marbling by covariate analysis. Steaks from steers, compared with those from nonimplanted, intact heifers, in the 2 experiments combined were: (a) superior (P < 0.05) in 2 of 9 palatability assessments when subcutaneous fat thickness (at the 12th rib) was adjusted to a common level, and (b) superior (P < 0.05) in 6 of 9 palatability assessments when marbling score was adjusted to a common level. In Exp. 1, steaks from nonimplanted steers compared with those from nonimplanted spayed heifers were: (a) superior (P < 0.05) in 0 of 8 palatability assessments when subcutaneous fat thickness (at the 12th rib) was adjusted to a common level, and (b) superior (P < 0.05) in 3 of 8 palatability assessments when marbling score was adjusted to a common level. These findings suggest that sex should be added to the list of antemortem factors contributing to variation in cooked beef steak tenderness. However, more research is needed to precisely identify those factors contributing to the lower tenderness observed for steaks from heifer carcasses.  相似文献   

19.
Physiological and behavioural field studies on long distance road transport of 116 heifers, 135 bulls and 64 steers in 10 goose-necked double decked semitrailers from northern Germany to mediteranean ports showed different impacts of handling during pre-transport (i.e. collection of animals, weighing, loading), transport journey itself and post transport handling (i.e. lairage time) on coping strategies of the different categories of cattle. It was found loss of body weight in steers (-6.65%) coming from pasture was higher compared to bulls (-4.6%) during transport, but they recovered during lairage time in a better way. All categories of cattle showed catabolic energy metabolism during transport, but only in bulls and to a farer extent in heifers this leads to a tendency of a ketotic metabolism during second parts of transport and lairage time. During whole transport time no more than 20% of bulls and steers were laying down, and less than 5% were feeding during driving intervals. In all parts of transport general stress parameters like heart rate (with exception to steers) and cortisol were elevated as a part of adaptation to the transport environment, but indicating high physical and emotional loads on the animals with no resting possibilities. In this context animals have to be prepared carefully to be transported, i.e. in reference to energy and fluid balance, and to be feed in sufficient time intervals (breaks) and lengths to maintain fundamental behavioural and physiological needs of the animals during transport. The lairage facilities are very important for the bulls and in the case of heifers the feeding regime during lairage time must be improved to ensure the possibility for a real resting and recovery of the animals after transport.  相似文献   

20.
Skeletal muscle of 5 wild reindeer was examined for sarcocysts and used for experimental infection of 6 foxes. Skeletal and cardiac muscle of another reindeer were only examined for sarcocysts. The skeletal muscle of all animals was infected with Sarcocystis sp.. In 2 of the animals cysts of S. hardangeri were also present. The single heart examined contained only cysts of S. grueneri.Four foxes given skeletal muscle containing apparently only cysts of Sarcocystis sp., started shedding Sarcocystis sporocysts, measuring on average 13.6×9.8 µm, after a prepatent period of 10–12 days. Two foxes given skeletal muscle containing cysts of both Sarcocystis sp. and S. hardangeri shed similar sporocysts, measuring on average 13.5×9.7 µm, after a prepatent period of 10–12 days.Based on the results from the present and previous investigations, Sarcocystis sp. is considered to have foxes (Vulpes vulpes and Alopex lagopus) and dogs (Ganis familiaris) as definitive hosts, becoming the second species of Sarcocystis with a known reindeer/Canidae life cycle. The name Sarcocystis tarandivulpes n. sp. is proposed as a replacement name for Sarcocystis sp. Gjerde, 1984 from skeletal muscle of reindeer.  相似文献   

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