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1.
The purpose of this study was to examine the hypothesis that fenceline contact between beef calves and cows at weaning reduces indices of behavioral distress and associated temporary reductions in weight gain. One hundred Angus/Hereford-cross calves were randomly assigned to five treatments for 7 d in each of 3 yr to determine the effect of different weaning techniques on their behavior and subsequent growth. Treatments were 1) fenceline separation from dams on pasture (F-P), 2) total separation from dams on pasture (S-P), 3) total separation from dams in a drylot (corral) preconditioned to hay (S-D-P), 4) total separation from dams in a drylot not preconditioned to hay (S-D-NP), and 5) nonweaned controls on pasture (C-P). At the end of the 7-d postweaning period, all calves were placed on pasture in large groups. Calves were weighed weekly for 10 wk. In the days following weaning, F-P and C-P calves spent more time eating (grazing or eating hay) than S-P and S-D-NP calves (P < 0.05). The S-P calves spent more time walking (pacing) than calves in the other four treatments (P < 0.05), which did not differ. The S-P calves also spent less time lying down than C-P, F-P, and S-D-P calves (P < 0.05); S-P and S-D-NP calves did not differ in lying time. The F-P calves vocalized less than S-P and S-D-NP calves (P < 0.05). In general, treatment differences were greatest during the first 3 d following weaning with d 2 (20 to 30 h after weaning) showing the greatest disparity. The F-P calves spent approximately 60% of their time within 3 m of the fence separating them from their dams during the first 2 d following weaning, whereas F-P cows spent about 40% of their time within 3 m of the fence during this period. Postweaning cumulative body weight gains of the F-P calves were greater than the gains recorded for the calves in the three totally separated treatments (which did not differ). The F-P calves gained 95% more weight than the average calf in the three totally separated treatments in the first 2 wk and were still heavier at 10 wk (21.4 vs 11.0 kg, respectively, at 2 wk and 50.0 vs 38.2 kg, respectively, at 10 wk; P < 0.05). It was concluded that providing fenceline contact between beef calves and cows for 7 d following weaning reduces behavioral indices of distress seen in the totally separated calves. In addition, fenceline contact with dams at weaning minimizes losses in weight gain in the days following separation. Totally separated calves did not compensate for these early losses in weight gain even after 10 wk.  相似文献   

2.
We investigated the effects of visual and auditory information related to cow and calf stress responses at weaning. Three weaning conditions were established with physical separation only (PS), physical and visual separation (VS), and physical, visual and auditory separation (VAS). Stress responses such as vocalization and self‐grooming, and changes of three maintenance behaviors (lying, walking and grazing) were recorded for experimental cows and calves in the respective conditions. Comparison of the data revealed that the cow responses differed slightly among groups. However, the peak frequency of vocalization was higher in the PS calves than in those of either VS or VAS. Self‐grooming frequency was significantly different in calves and was high in the order of VAS, VS and PS calves. Furthermore, the percentage of time spent lying down was greater, and that of walking was less, in VAS calves than in either VS or PS calves. These results demonstrate that different information at weaning might strongly affect the stress responses of calves but not those of cows. Relative impacts of different types sensory information on stressors must be considered to plan animal‐friendly weaning.  相似文献   

3.
This study assessed the efficacy of ketoprofen for mitigating pain following dehorning with an electric cautery iron. Forty Holstein heifer calves, 4 to 8 wk of age, were randomized to receive a lidocaine cornual nerve block and either an injection of ketoprofen (3 mg/kg IM) or physiological saline, 10 min prior to dehorning. Cortisol was measured from serum obtained 10 min prior to dehorning and at 3 and 6 h post-dehorning. Calf behavior was video-recorded between 0 to 2, 3 to 5, and 6 to 8 h post-dehorning, and frequency of ear flicks, head shakes, head rubs, lying, standing, feeding, and grooming were recorded. Finally, 24-h intake of calf starter was recorded. There was no effect of treatment on cortisol (P > 0.1); however, ketoprofen-treated calves displayed less ear-flicks and total head behavior (P < 0.05), and tended to consume more starter (P = 0.09) than control calves. Ketoprofen is effective for mitigating behavioral effects of postsurgical pain following dehorning in 4- to 8-week-old calves.  相似文献   

4.
This experiment evaluated the impacts of administering a bovine appeasing substance (BAS) to beef calves at weaning on their performance, physiological responses, and behavior during a 42-d preconditioning program. Eighty calves (40 heifers and 40 steers; 90% British × 10% Nellore) were weaned at 233 ± 2 d of age (day 0); ranked by sex, weaning age, and body weight (BW); and assigned to receive BAS (IRSEA Group, Quartier Salignan, France; n = 40) or placebo (diethylene glycol monoethyl ether; CON; n = 40). Treatments (5 mL) were topically applied to the nuchal skin area of each animal following dam separation. Within treatment, calves were allocated to one of eight drylot pens (four pens per treatment; pen being the experimental unit) and received a free-choice total mixed ration (TMR) from day 0 to 42, intake of which was assessed daily. Live behavior observations were conducted on days 1, 2, 4, 8, 16, and 32. Temperament was assessed and blood samples were collected via jugular venipuncture on days −21, 0, 3, 7, 14, 28, and 42. Hair samples were collected from the tail switch on days 0, 14, 28, and 42. Calves were vaccinated against bovine respiratory disease viruses on days −21 and 0. Average daily gain from day 0 to 42 did not differ between treatments (P = 0.57) but was greater (P = 0.05) in BAS vs. CON calves from day 0 to 28. Intake of TMR was greater (P = 0.05) during the first week for BAS vs. CON calves (treatment × week; P = 0.08). The mean proportion of calves feeding simultaneously and performance of social and play behaviors were greater (P ≤ 0.05) for BAS vs. CON calves. Escape attempts were greater (P < 0.01) for BAS vs. CON calves on day 1 (treatment × day; P = 0.03). Exit velocity was greater (P = 0.04) for CON vs. BAS calves on day 14 and tended (P = 0.10) to be greater for CON vs. BAS calves on day 7 (treatment × day; P = 0.03). Mean plasma concentrations of haptoglobin were greater (P = 0.02) in CON vs. BAS calves. Hair cortisol concentrations were greater (P = 0.05) in CON vs. BAS calves on day 14 (treatment × day; P = 0.03). Mean serum concentrations of antibodies against bovine viral diarrhea virus were greater (P = 0.02) in BAS vs. CON calves. Collectively, BAS administration to beef calves at weaning alleviated stress-induced physiological reactions, improved temperament evaluated via chute exit velocity, enhanced humoral immunity acquired from vaccination, and appeared to have accelerated adaptation to novel management scheme and environment.  相似文献   

5.
本试验旨在研究母牛舔舐对新生犊牛行为及血清应激和免疫指标的影响。选取30头初生重相近的健康荷斯坦母犊牛,依据其出生后被母牛舔舐的时长分为2组,每组15头。对照组(Con组)犊牛出生后仅被舔舐几下或没被舔舐,舔舐组(Lick组)犊牛出生后被舔舐15~20 min。录像记录犊牛被舔舐之后24 h的行为,检测犊牛被舔舐之后0和24 h血清应激激素和免疫相关细胞因子含量。结果表明:1)Lick组犊牛进入犊牛舍后初次成功站立用时有低于Con组的趋势(P=0.056),Lick组犊牛进入犊牛舍后在初次尝试站立至成功站立期间的尝试站立次数有低于Con组犊牛的趋势(P=0.094),Lick组犊牛初次尝试站立至成功站立用时显著短于Con组(P<0.05)。2)Lick组犊牛采食初乳时站立时长占总采食时长的比例有高于Con组的趋势(P=0.068),Lick组犊牛躺卧时长占总采食时长的比例有低于Con组的趋势(P=0.068)。3)采食初乳前后,Lick组犊牛站立时长和次数显著高于Con组(P<0.05),躺卧时长显著低于Con组(P<0.05),行走时长和次数显著高于Con组(P<0.05),探索时长有高于Con组的趋势(0.05≤P<0.10),探索次数显著高于Con组(P<0.05)。4)被舔舐之后0 h,Lick组犊牛血清皮质醇含量显著低于Con组(P<0.05)。在被舔舐后24 h,Lick组犊牛血清白细胞介素-2含量有低于Con组的趋势(P=0.097),白细胞介素-6含量显著低于Con组(P<0.05)。综上所述,母牛分娩后对新生犊牛进行15~20 min的舔舐可以降低犊牛的应激水平,增强新生犊牛的活力,同时使犊牛更为活跃。  相似文献   

6.
A study was conducted to evaluate effects of age at weaning in combination with different weaning procedures on 2 breeds of lambs (Merinoland, Rhoenschaf). Lambs were either weaned at 8 or 16 wk of age in 2 stages or with the traditional method of weaning by abrupt separation. In the 2-stage treatment, lambs were prevented from nursing their dam for 1 wk (stage 1) before their separation (stage 2). Control animals were nursed by their dams until they were separated. Lamb BW and behavior (vocalization, agitation) were recorded before and after separation. After separation, lambs weaned at 8 wk of age had greater (P = 0.004) ADG compared with lambs weaned at 16 wk of age. Control lambs had greater (P < 0.001) agitation scores [1 = no agitation (normal behavior; i.e., feeding, resting, lying, standing, or play behavior) to 3 = high agitation (continuously moving, restlessness, or vocalization)] irrespective of weaning age and breed. On the day of separation, 2-stage lambs had scores from 1.17 to 1.35, whereas control lambs were scored from 1.70 to 1.79. After separation, lambs weaned in 2 stages vocalized up to 98.2% less (P = 0.001) than control animals. Furthermore, bleats were greater for Rhoenschaf lambs and at a weaning age of 8 wk (P < 0.05). Differences between treatments were greatest on the day of separation. Vocalization decreased continuously within the first 3 d of weaning to zero. Lambs weaned in 2 stages were less distressed than lambs weaned by the traditional method of abrupt separation based on behavioral data, but ADG until 12 and 16 wk of age did not differ (P > 0.05) for either treatment in this study.  相似文献   

7.
The objectives of this study were to compare the progeny of 1) late-maturing beef with dairy breeds and 2) Charolais (CH), Limousin (LM), Simmental (SM) and Belgian Blue (BB) sires bred to beef suckler dams, for feed intake, blood hormones and metabolites, live animal measurements, carcass traits and carcass value in bull and steer production systems. The bull system included 50 late-maturing beef breeds and 22 Holsteins (HO) slaughtered at approximately 15 months of age, whereas the steer system consisted of 56 late-maturing beef breeds and 23 British Friesians (FR) slaughtered at approximately 24 months of age. Beef breeds were suckled until approximately 8 months of age, while dairy breeds were artificially reared until weaning at approximately 3 months of age. All animals were finished on an ad libitum concentrate diet. Mean live weight, live weight gain, carcass gain and feed efficiency were greater (P < 0.05) in beef than dairy breeds in both systems during the finishing period when offered concentrates. Although there was no difference in feed intake between beef and dairy breeds, intake expressed relative to live weight was lower (P < 0.001) in beef breeds in both systems. At 10 months of age and pre-slaughter, beef breeds had higher (P < 0.001) muscularity scores and greater scanned muscle depth (P < 0.001) than their dairy contemporaries. Carcass weight, kill-out proportion, carcass conformation score, meat proportion and value were greater (P < 0.001) and carcass fat and bone proportions were lower (P < 0.05) in beef than dairy breeds in both systems. Insulin concentrations were lower (P < 0.001) in beef than dairy breeds, whereas there was no difference in blood metabolites or IGF-1 concentrations. Feed intake expressed relative to live weight or feed efficiency did not differ between CH, LM, SM or BB sired progeny. Muscularity scores were greater (P < 0.05) in BB than SM, whereas skeletal scores were lower (P < 0.05) in LM than SM. Limousin had lower (P < 0.05) carcass gain per day of age than CH and SM, whereas SM had a lower (P < 0.05) carcass conformation score than BB and CH and a higher (P < 0.05) carcass fat score than CH. Simmental had a lower (P < 0.05) carcass meat proportion and a higher (P < 0.05) carcass fat proportion than CH, LM and BB, which were similar (P > 0.05). The improvement obtained for beef over dairy breeds in live weight gain was 12%, while the improvements in carcass gain and meat produced was 24% and 33%, respectively. This demonstrates that the importance of carcass data contributing to breed comparison studies cannot be over-emphasised.  相似文献   

8.
Four-month-old beef calves were implanted with 36 mg zeranol, and their growth compared with untreated calves. Treated steer and heifer calves gained 10 kg more bodyweight to weaning at 7.5 months of age. The trial was conducted at 2 research centres and calves at both centres showed significant responses for the first 45 days (P less than 0.001) after treatment but during the following 30 days only calves at one centre showed a continued response (P less than 0.05). No differences in growth rate occurred between treated and untreated calves over the final 30 days before weaning at either centre. The backfat measurement of untreated animals increased more than that of the implanted animals (P less than 0.05) at one centre but not at the other.  相似文献   

9.
Abstract

This study was carried out to investigate the effects of individual versus combined housing systems on behavioural and growth responses of dairy calves in order to test the hypothesis that when calves were kept in early age individually and later in groups, they would increase growth performance and social behaviours. Twenty-four Holstein Friesian calves were allocated to two different housing systems. After three days of colostrum feeding, individually housed (IH) calves were kept in pens (1 m×1.5 m) for 60 days while combined housed (CH) calves were kept in group pens (3 m×3 m) for 30 days after individual housing during the period of 4–33 days. Each calf was monitored twice a week for a period of 1 h starting at 08.00, 10.00, 12.00, 18.00, 20.00 and 22.00 h at 10-min intervals. Behavioural activities were playing, walking, licking objects, idle standing, lying, restlessness, grooming and tongue playing. Calves’ live weights, body measurements and feed intakes were determined on a weekly basis. The results were: 1) combined housing calves increased their calf starter intake (37.35±1.24 kg vs. 23.39±0.86 kg; p<0.001), alfalfa hay intake (8.76±0.35 kg vs. 7.14±0.43 kg; p<0.05) and total feed intake (46.11±1.04 kg vs. 30.53±0.86 kg; p<0.001) compared to individual housed calves; 2) combined housing increased the proportional events of playing (12.80 vs. 2.86%), walking (19.14 vs. 3.81%) and grooming (8.06 vs. 4.60%), but decreased licking objects (1.03 vs. 2.94%), idle standing (20.73 vs. 36.29%), lying (30.19 vs. 39.53%) and restlessness (1.69 vs. 3.47%) compared to individual housing systems (p<0.001) without affecting tongue rolling (6.36 vs. 6.50%); 3) combined housing system increased body weight gain by about 2.36 kg and body length by about 1.48 cm per calf compared to those kept in individual pens (p<0.05). In conclusion, combined housing system provided calves more opportunity to show their walking, playing and grooming activities, reflecting increases in feed intake, body weight gain and length compared to individual housing system.  相似文献   

10.
[目的]为探索适宜当地的犊牛早期断奶时间,促进犊牛早期生长发育和使母牛尽快恢复体况,进入下一个繁殖周期。[方法]选择体格大小一致、健康无疾病、体重接近,父本相同,3月龄西杂犊牛20头作为试验牛,随机分成A组和B组,每组10头(公、母数量相同)。A组经过1个月断奶精料、粗料和多汁饲料的过渡性适应,4月龄断奶,并根据犊牛生长发育逐渐增加精料、多汁饲料,B组按照养殖场饲喂方法饲养,并于6月龄断奶,A组与B组犊牛6月龄断奶后自由采食粗饲料、按体重1%饲喂精饲料,分别在犊牛6,12,18月龄称重。[结果]结果表明:肉牛18月龄时A、B组犊牛的平均体重分别为638 kg,546 kg,A组高于B组92.00 kg(P0.01),表明犊牛早期断奶、在满足营养需要的前提下,后期的生长速度比6月龄断奶高。[结论]犊牛早期断奶技术是一项实用技术,值得在养殖场和规模养殖户中大力推广的应用。  相似文献   

11.
Glucagon-like peptide-1 (7-36) amide (GLP-1), secreted by the small intestine, has insulinotropic and glucose-lowering action. Basal plasma GLP-1 concentrations were measured in calves around the weaning period, the effect of short-chain fatty acids (SCFA) on plasma GLP-1 concentrations was examined, and the effects of GLP-1 administration on plasma insulin, glucagon, and glucose concentrations were measured. Thirteen Holstein bull calves were fed whole milk and solid feed and weaned at 7 wk of age. Preprandial plasma samples were obtained from 5 calves once a week from week 0 to 13 to measure basal concentrations of plasma GLP-1 and insulin (experiment 1). Four calves were intravenously administered with a mixed solution of SCFA (2.4 mmol/kg body weight [BW]) in week 2 and 11 to measure plasma GLP-1 concentrations (experiment 2). Another 4 calves were intravenously injected with GLP-1 (1.0 μg/kg BW) to elucidate the response of plasma insulin, glucagon, and glucose concentrations in week 1, 2, 4, 6, 7, 9, 11, and 13 (experiment 3). In experiment 1, age and weaning did not affect preprandial basal concentrations of plasma GLP-1 throughout the experimental period. Preprandial insulin concentrations increased after weaning (P < 0.05), and GLP-1 and insulin were more strongly correlated postweaning than preweaning. In experiment 2, intravenous treatment with SCFA increased plasma GLP-1 concentrations in both week 2 and 11 (P < 0.05.) In experiment 3, intravenous GLP-1 treatment decreased plasma glucose concentrations throughout the experiment (P < 0.05), but increased plasma insulin concentrations only after weaning (P < 0.05). Treatment with GLP-1 did not affect plasma glucagon concentrations, regardless of age. These results indicate that preprandial basal concentrations of plasma GLP-1 in calves are not changed by weaning, but SCFA stimulate GLP-1 secretion. The insulinotropic action of GLP-1 is detected only after weaning, but the glucose-lowering action of GLP-1 is not affected by weaning.  相似文献   

12.
This study assessed the effects of age at weaning (early weaning at 90 d or traditional weaning at 150 d) and breed (Parda de Montaña or Pirenaica) on calf performance and carcass and meat quality in autumn-calving beef cattle. At calving, 14 Parda de Montaña and 14 Pirenaica cow–calf pairs were randomly assigned to one of two weaning treatments, and kept indoors during lactation. After weaning, calves were fed an intensive diet until slaughter at 450 kg. The interaction between age at weaning and breed was not significant for any of the parameters studied. From 90 d to 150 d, early weaned calves had greater ADG (P = 0.001) and IGF-I concentrations (P = 0.001) than traditionally weaned calves, but their leptin concentrations were similar (P = 0.15). During the finishing phase, performance, daily feed intake, and efficiency did not differ between treatments. Early weaning did not affect age at slaughter, carcass weight, fatness score, fat colour, and meat quality, but improved carcass conformation (P = 0.04). Early weaned calves had greater total DMI (P = 0.002) with greater concomitant feed costs (P = 0.001) and yielded a slightly greater income than traditionally weaned calves; therefore, economic margins did not differ. Parda de Montaña calves tended to have greater ADG from birth to 90 d and were heavier at 90 d (P = 0.01) than were Pirenaica calves. From 90 d to 150 d, performance and IGF-I and leptin concentrations did not differ between breeds; thus, Parda de Montaña calves remained heavier at 150 d. During the finishing phase, at times, weight gains of Parda de Montaña and Pirenaica calves differed, but the overall performance, feed intake, and efficiency of the two breeds were similar. Pirenaica calves had heavier carcasses (P = 0.04) with greater conformation scores (P = 0.04) than Parda de Montaña calves; thus, income per carcass was greater for the former than the latter (P = 0.007). As feed costs were similar for both breeds, the economic margin of Pirenaica calves was greater than that of Parda de Montaña calves (P = 0.01). In conclusion, in both breeds weaning strategies had similar effects on performance and carcass and meat quality; however, from an economic point of view, and considering only the costs associated with the calf, raising Pirenaica calves would be more profitable, at either age at weaning.  相似文献   

13.

Now that group housing is replacing individual crates, so that calves can lie, stand and walk on the pen floor, the quality of the floor for group-housed calves has become the focus of attention. The reaction of two groups of four calves to a double area of floor made from two materials (wooden slats and synthetic slats with a rubber coating) was examined round the clock for 5 days. The calves were switched between pens twice, and in each case the 5 day observation period was repeated. In all three phases all calves spent significantly more time ( P <0.01) lying on the wooden floor: on average 656 min day -1 compared with 294 min day -1 on the synthetic floor. The time spent in the standing/walking position on both floors, occurrence of slip incidents and self-maintenance behaviour did not differ significantly between floors. The observations on use of the pen floor for lying and for standing/walking in combination with feeding, plus observations on fouling of the floors with excreta suggest that future pen design could be functionally divided into lying and walking/eating areas.  相似文献   

14.
The objectives were to assess the degree of thermolysis capacity as a characteristic of heat tolerance of the Simmental beef cattle and evaluate the effects of shade and shade type (artificial: AS, trees: TS, or no shade: NS) on daily behavior patterns during summer. Black globe temperature (BGT) was different under the two types of shade (P < 0.05) and was lower under the TS (P < 0.01) and under AS (P > 0.01) than average BGT in the sun. Animals when in AS used more intensely the shade (P = 0.002) mostly lying down under it (10.00–14.00 hours), while time standing was similar (P = 0.107) between TS and NS. Bulls without shade (NS) spent significantly more time at the water trough and most part of the day standing idle (72.4%, 10.1 h/14 h). TS bulls spent more time grazing/standing (P < 0.001). The Simmental bulls that were in TS and AS spent more time ruminating than bulls that stay without shade (NS). The availability of shade changes grazing, rumination and idling behavior of cattle in response to environmental conditions. Shade provided by trees can be more efficient than artificial shading as cattle spent more time grazing when tree shade was available. Thermolysis capacity can be used to select heat‐tolerant animals.  相似文献   

15.
We investigated the effect of cellooligosaccharide (CE) or a combination of dextran and Lactobacillus casei ssp. casei strain JCM1134T (synbiotic; SB) feeding on growth performance, fecal condition and hormone concentrations in Holstein calves. Fifty‐two female Holstein calves were randomly assigned to three treatment groups: CE feeding group (n = 16), SB feeding group (n = 18), and control group (n = 18). Body weight at 90 days of age, as well as daily body weight gain (DG) and feed efficiency after weaning to 90 days of age were greater (P < 0.05) in the CE feeding group than in the control group. The total fecal score tended to be lower (P < 0.1) in the SB feeding group than in the control group. Plasma insulin concentration was higher (P < 0.05) in the CE feeding group than in the control group at 90 days of age. Our results indicate that CE feeding improved DG and feed efficiency in calves. On the other hand, there was less effect on growth performance and fecal Escherichia coli counts in calves fed SB.  相似文献   

16.
The test was conducted to study the effect of different culture ways on health and development of Japanese Black calves in cold area,20 healthy and newborn calves were divided into 2 groups using single factor randomized block design.Calves of control group were fed using traditional feeding method while calves of experimental group were fed using artificial feeding method.The test period was 180 d,body weight and body steep size indexes of calves were measured,and the health condition of calves were observed.The results showed that when weaned at 3 months old,body weight and average daily gain of calves in experimental group were significantly higher than that of control group (P<0.05);Body weight and average daily gain of calves with 6 months old in experimental group were significantly higher than that of control group (P<0.05);The fecal index,diarrhea rate,diarrhea frequency and death rate of experimental group were lower than that of control group,and the difference of diarrhea rate and diarrhea frequency were significant (P<0.05).And the respiratory disease incidence,incidence frequency and death rate of experimental group were lower than that of control group,the difference of the three indexes were significant (P<0.05).The results suggested that artificial feeding method could improve the Japanese Black calves survival rate,strengthen the prevention of diarrhea and respiratory disease and sufficiently play the potential to improve calf weaning weight.It not only could reduce the economic costs of farms,and also significantly improve the economic efficiency of domestic high-quality beef cattle.  相似文献   

17.
The results of epidemiological studies of helminths in young beef cattle in Central Queensland over a 2½-year period commencing in January 1964 are reported. Studies were made on ten beef cattle properties, which have a total annual calf crop of approximately 2500 calves. Twenty-five faecal samples were collected monthly at random from 30 to 40 permanently identified calves on each property, to determine the types and intensity of helminth infections. Although rainfall was well below average, infections with most of the helminth species commonly found in Queensland were detected. Increases in infection levels occurred, after rainfall of two inches or more, in animals up to 21 months of age. Only on a property where pastures were irrigated and the stocking rate was higher than normal for the area did a high percentage of calves show clinical symptoms of parasitic gastroenteritis. Haemonchus placet and Oesophagostomum radiatum were the predominant species. An immunity developed to O. radiatum during the first 12 to 15 months of the calf's life. The immunity to H. placet was variable with some animals susceptible to re-infection up to 21 months of age. Recommendations for the control of helminths in beef cattle in this area are given.  相似文献   

18.
Only limited knowledge exists on how to produce high-quality beef carcasses when the cattle also are grazing semi-natural grasslands for nature conservation purposes. The objectives of the two factorially-designed trials were to determine the effects of indoor feed intensity (low vs. high) and slaughter age (18 vs. 22 months) on performance and carcass quality of beef heifers, raised from weaning until slaughter and grazing semi-natural grasslands during growing seasons. In the first trial, 56 Charolais heifers were used of which 28 were fed only grass-clover silage ad libitum (low; CL), and another 28 heifers were fed 2.0 kg of grain daily in addition to the silage (high; CH). In the second trial, 28 Angus heifers were fed grass-clover silage at 80% ad libitum (low; AL), whereas another 28 heifers were fed silage ad libitum (high; AH). According to a national nature conservation score, the grazing pressure on the semi-natural grassland was classified as having been satisfactory to maintain the floristic diversity as no litter had been accumulated onto the sward. From weaning until slaughter, no difference in average daily gains (ADG) was found between the CH and the CL, whereas the AH had higher ADG than the AL (693 vs. 573 g, P < 0.001). Heifers in both trials had higher carcass weights and more fat, Charolais heifers also had better conformation and Angus heifers had higher dressing percentage at 22 months than at 18 months of slaughter age (P < 0.05). In conclusion, carcass traits in both trials were more affected by slaughter age than by feed intensity and desirable grazing effects were achieved on the pasture.  相似文献   

19.
Two field trials were conducted in a beef cow herd in Saskatchewan to determine the effectiveness of a combined Pasteurella haemolytica and Haemophilus somnus vaccine in increasing passively and actively acquired antibodies in beef calves. Vaccination of dams at 4 and/or 7 weeks prepartum was associated with increased antibody titers to P. haemolytica and H. somnus in their serum (P < 0.05), colostrum (P < 0.05), and serum of their calves at 3 days and 1 month of age (P < 0.05). There was no significant (P > 0.05) difference in antibody titers in the colostrum and serum of calves from single or double vaccinated dams. Calves vaccinated at 1 and 2 months of age in the face of maternal antibodies to P. haemolytica and H. somnus had significantly (P < 0.05) higher antibodies to P. haemolytica and H. somnus at 4 and 6 months of age than did unvaccinated calves. Calves vaccinated at 3 and 4 months of age in the face of low levels of preexisting antibodies had significantly (P < 0.05) higher antibodies to P. haemolytica at 5 months of age and to H. somnus at 5 and 6 months of age than did unvaccinated calves. Calves vaccinated once at 4 months of age had significantly (P < 0.05) higher antibody titers to P. haemolytica and H. somnus at 4.5 months of age than did unvaccinated calves, but this difference was not apparent at 6 months of age.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

20.
The potential effect of dietary forage supplementation on the performance and rumen development in dairy calves is well established. However, limited research has been directed to the comparative effects of forage offering methods on calf performance. The objective of the present study was to determine the effects of forage provision methods (total mixed ration or free choice) on the performance, nutrient digestibility, rumen fermentation and nutritional behaviour in newborn calves. Forty‐five Holstein dairy calves (3 days of age and 41 ± 2 kg of body weight) were assigned to the following three groups (n = 15): (i) starter without forage provision (CON), (ii) starter supplemented with 10% alfalfa hay (AH) as a total mixed ration (AH‐TMR) and (iii) starter and AH as a free‐choice provision (AH‐FC) for a period of 70 days. All the calves were offered 5 l of milk/day from day 3 to 50, and 2.5 l/day from day 50 until weaning on day 56. Dry matter intake (DMI) was greater (p < 0.01) in the AH‐TMR and AH‐FC treatments than in the CON during the pre‐ and post‐weaning periods. Calves fed the AH‐FC diet showed the highest post‐weaning DMI among the treatments. The calves receiving ad libitum forage tended (p = 0.08) to increase crude protein digestibility and overall volatile fatty acids (VFA) concentrations in the rumen. No differences were observed among the treatments at the time spent on standing, lying, eating and performing non‐nutritive oral behaviours. Compared to CON calves, animals in the AH‐TMR treatment spent more time (p < 0.05) ruminating. In conclusion, our data suggest that forage supplementation in both forage offering methods increased total DMI, ruminal pH and ruminating time in dairy calves. Hence, there is no benefit in the free‐choice provision of AH in dairy calves.  相似文献   

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