Choice of attractive conditions by beef cattle in a Y-maze just after release from restraint: Effect of sheep

To provide useful information on how to moderate post‐handling stress, Angus heifers (n = 157) were individually allowed to enter a choice area after 2 min of restraint in a crush and to choose between two pens. After the animal had chosen a pen, free access was given to both test pens and the choice area for a further 5 min. The behaviors during choice and after the first choosing were observed. In experiment 1, each heifer was given one of the following choices: pen with three familiar heifers (peers) versus pen with six sheep (sheep; n = 30); peers versus the bare pen (bare; n = 30); sheep versus bare (n = 30). When the choice combination was peers versus bare, more heifers than expected by chance chose the peers pen (χ² = 4.80; P < 0.05). However, when one of the other choice combinations was given, there was no significant difference between the number choosing a pen and the expected value. After the first choice, more heifers entered the peers pen than the bare pen (P < 0.05) or the sheep pen (P < 0.10). In experiment 2, another 67 heifers were given one of the following choices: peers versus pen with a novel object (NO; n = 19); sheep versus NO (n = 22); bare versus NO (n = 26). There was no significant difference between the number of heifers choosing a pen and the expected value in any choice combination. However, more heifers entered the peers pen than the NO pen (P < 0.01). It is concluded that sheep were not as attractive as peers, but sheep were not fearful animals for cattle.     

Cattle acclimate more substantially to repeated handling when confined individually in a pen than when assessed as a group

Chute (CS) and exit (ES) scores are common subjective methods used to evaluate temperament in cattle production systems. A pen test, which allows behavior to be observed in a non-restrained setting, may also be an effective method to evaluate temperament by allowing more variation among animals to be expressed. The merit of pen scores in assisting producers in evaluating temperament is equivocal. The objectives of this study were to validate the usefulness of a pen score in delineating temperamental cattle and to determine whether these behavioral scores change under repeated and routine management. Over 3 consecutive years, a factorial design of two measurement protocols (frequent [F], infrequent [IN]) and three recording periods was used. The F measurements were collected over 3 consecutive days and IN measurements only on day 1 within a recording period. Each year, 20 mostly Angus commercial Bos taurus heifers were randomly assigned to each protocol. Behavior was measured using a CS, ES, and exit velocity. Body temperature and heart rate also were recorded. A fecal and blood sample were collected and analyzed for levels of various metabolites including glucose concentration and serum cortisol. Following routine handling, each heifers’ response to 30 s of exposure to a human stressor was recorded both individually and in groups of four. An individual (IPS) and group (GPS) pen scores were assigned from 1 (docile) to 6 (aggressive). For all heifers, protocol, event, and their interaction, were compared on the first day of an event. For F heifers, event and day within event were instead used. Body weight was included as a covariate, with sire and year fitted as random effects. Reliability of IPS and GPS were determined using a kappa (K) coefficient. Both IPS and GPS were reliably assigned (K = 0.64 and 0.44 for IPS and GPS, respectively) and positively correlated with body temperature, heart rate, glucose, and serum cortisol (r = 0.28 to 0.37). Furthermore, F heifers acclimated to repeated handling in an individual pen setting (P < 0.05) while acclimation to handling within groups was not evident (P > 0.14). IPS provides a reliable evaluation of temperament in a non-restrained setting that is indicative of an animal’s response to stress and may be useful when attempting to make phenotypic selection decisions. However, temperamental heifers became calmer with repeated gentle handling.     

The effect of injectable vitamin C and road transit duration on inflammation,muscle fatigue,and performance in pre-conditioned beef steer calves

This study examined the effects of injectable vitamin C (VC) before transport and duration of transit on feedlot performance, inflammation, and muscle fatigue in cattle. One hundred thirty-two Angus-cross steers (393 ± 4 kg) were stratified by body weight (BW) to a 2 × 2 factorial of intramuscular injection (INJ; 20 mL/steer): VC (250 mg sodium ascorbate/mL) or saline (SAL) and road transit duration (DUR): 18 h (18-h; 1,770 km) or 8 h (8-h; 727 km). On day 0, steers were weighed and given INJ of VC or SAL immediately before transport. Upon return (day 1), BW and blood were collected before steers returned to pens equipped with GrowSafe bunks. Steers were weighed on days 0, 1, 7, 15, 30, 31, 54, and 55. Data were analyzed via ProcMixed of SAS (experimental unit = steer; 32 to 34 steers/treatment) with fixed effects of INJ, DUR, and the interaction. Blood was collected on days −5, 1, 2, 3, and 7 (n = 9 steers/treatment); blood parameters were analyzed as repeated measures with the repeated effect of day. Area under the curve (AUC) for plasma ferric reducing antioxidant power (FRAP) was calculated using R. Final BW was greater for 8 h compared to 18 h (P = 0.05) with no effect of INJ or interaction (P ≥ 0.51). Dry matter intake (DMI) from days 1 to 7 was greater for VC-8, intermediate for VC-18 and SAL-18, and least for SAL-8 (P = 0.02). Overall, DMI tended to be greatest for SAL-18, intermediate for VC-18 and VC-8, and least for SAL-8 (P = 0.08). Days 7 to 31 gain:feed (G:F) was greatest for VC-18 compared to other treatments (INJ × DUR, P = 0.05), and there was no effect of treatment on overall G:F (P ≥ 0. 19). There was no INJ or INJ × DAY (P ≥ 0.17) effect on serum lactate, haptoglobin, or non-esterified fatty acid. However, these blood parameters were greater on day 1 for 18 h compared to 8 h, and both treatments returned to near baseline by day 3 (DUR × DAY, P < 0.01). Plasma ascorbate concentrations on day 1 were greater for VC compared to SAL and returned to baseline by day 2 (INJ × DAY, P < 0.01). Plasma FRAP AUC from days −5 to 3 was greatest for VC-18, intermediate for VC-8 and SAL-8, and least for SAL-18 (INJ × DAY, P = 0.02). This suggests an antioxidant prior to long-haul transit positively influenced antioxidant capacity; however, VC did not improve overall post-transit performance. Although longer transit duration increased indicators of muscle fatigue and inflammation, post-transit performance was not appreciably different between transit durations.     

Feeding corn distillers grains as an energy source to gestating and lactating beef heifers: Impact of excess protein on feedlot performance,glucose tolerance,carcass characteristics and Longissimus muscle fatty acid profile of steer progeny

This study was conducted to determine the impact of dried distiller's grain with solubles (DDGS) from 192 days of gestation through 118 days of lactation on feedlot performance, carcass characteristics, Longissimus muscle (LM) fatty acids and glucose tolerance of male progeny (n = 36). Angus‐Simmental heifer dams were fed diets that contained either DDGS (DG) or not (CON) formulated to provide similar daily net energy for gain but differing crude protein. In the feedlot, male progeny were fed a diet devoid of DDGS. An intravenous glucose tolerance test (IVGTT) was performed on a subset of 20 steers prior to harvest. Steers were harvested at a common 12th rib fat depth. Data were analyzed with the GLIMMIX and MIXED procedures of SAS. Performance (P ≥ 0.11) and glucose and insulin concentrations during IVGTT (P ≥ 0.24) did not differ between treatments. Dressing percentage tended to be greater (P = 0.09) in DG than CON progeny, but all other carcass characteristics did not differ (P ≥ 0.18). Progeny from DG dams had greater LM 16:2, 18:0, and 20:1 n‐9 concentrations than progeny from CON dams (P ≤ 0.02). In conclusion, DDGS are a viable option for gestating and lactating beef cows.     

Practices and opinions of New Zealand beef cattle farmers towards bovine viral diarrhoea control in relation to real and perceived herd serological status

ABSTRACT

Aims: To investigate the seroprevalence of infection with bovine viral diarrhoea (BVD) virus among 75 beef herds and seroconversion in cattle during early pregnancy, and to determine the practices and opinions of farmers towards BVD control and their association with real and perceived herd serological status.

Methods: Blood samples were collected before mating in 75 beef herds across New Zealand from 15 unvaccinated heifers that had delivered their first calf that season. Serum samples were tested for BVD antibodies using ELISA individually, and after pooling samples for each farm. Animals that were antibody-negative were retested at either pregnancy diagnosis or weaning. Farmers were asked to complete a detailed survey about herd demographics, BVD testing and vaccination practices, and opinions towards national BVD control.

Results: Based on the pooled serum antibody ELISA results, there were 28/75 (37%) negative herds, 15/75 (20%) suspect herds, and 32/75 (43%) positive herds. Of 1,117 animals sampled 729 (65.3%) tested negative for BVD virus antibodies; when retested, 47/589 (8.0%) animals from 13/55 (24%) herds had seroconverted. Among 71 famers providing survey responses 11 (15%) believed their herd was infected with BVD, 24 (34%) were unsure and 36 (51%) did not think their herd was infected. Only 19/71 (18%) farmers had performed any BVD testing within the past 5 years and 50/70 (71%) had not vaccinated any cattle for BVD. Support for national BVD eradication programme was strong in 51/71 (56%) respondents, but the biggest challenge to BVD control was considered to be famer compliance. Compared to farmers who did not think their herd was infected, more farmers who thought BVD was present in their herds had previously tested for BVD, would consider testing all replacement calves, and would support establishing a national BVD database; fewer would consider purchasing BVD tested or vaccinated cattle only.

Conclusions and clinical relevance: Only 15% of the beef farmers in this study believed their herds were infected with BVD virus and few of them had undertaken BVD screening. Nevertheless many were supportive of implementing a national BVD control programme. It is likely that the lack of farmer awareness around BVD and the failure of farmers to recognise the potential impacts in their herds are hindering progress in controlling the disease in New Zealand. There are opportunities for New Zealand veterinarians to be more proactive in helping beef farmers explore BVD management options.     

Effect of regular walking exercise on glucose tolerance and insulin response to i.v. glucose infusion in growing beef steers

The purpose of the present paper was to investigate the effect of regular walking exercise on glucose tolerance and insulin response to i.v. glucose infusion in growing beef steers. Four crossbred beef steers walked on a treadmill during a 6 week exercise period (1.2 km/h, 1 h/day and 5 days/week). The changes in plasma glucose and insulin levels following glucose infusion were analyzed immediately prior to (bodyweight: 260.4 ± 24.2 kg) and after (295.7 ± 30.1 kg) the exercise period. The basal levels of plasma glucose (86.4 vs. 82.0 mg/dL, P = 0.040) and insulin (24.5 vs. 14.3 μU/mL, P = 0.016) were significantly lower after the exercise period. Further, the increase in the levels of plasma glucose (420.4 vs. 280.8 mg/dL, P < 0.001) and insulin (94.5 vs. 73.1 μU/mL, P = 0.028) following the glucose infusion decreased after the exercise period. The area under the curve of plasma glucose (108.8 vs. 62.9 mg/dL per min, P < 0.001) and insulin (53.6 vs. 29.7 μU/mL per min, P = 0.018) indicated more rapid clearance of exogenous glucose and less insulin secretion for glucose clearance after the exercise period. These results suggest that regular exercise improves glucose tolerance, with lower insulin response to glucose infusion in growing steers, as observed in rodents and humans.     

Post-ruminal non-protein nitrogen supplementation as a strategy to improve fibre digestion and N efficiency in the ruminant

The ruminant is able to transform plant fibres and non-protein nitrogen (NPN) into edible foods for human consumption. In an effort towards improving our understanding of this process, we sought to challenge convention and examine how the source, amount and site of NPN delivery in the gastrointestinal tract of the ruminant may affect fibre digestibility, rumen stability and N metabolism. In the first study presented here, we used four ruminally cannulated non-lactating heifers in a Latin square design to infuse 59 g/days of N in the form of ammonia (A) or urea (U) into either the rumen (R) or the abomasum (A). We found that intake was higher (p = .03) for animals receiving supplementary NPN as urea compared with ammonia. In addition, abomasally infused urea (UA) improved fibre fermentation by 9.4% (p = .05) and decreased ruminal pH fluctuations (lower slope in the cumulative pH parameters, p = .04) when compared with the same amount of urea infused ruminally (UR). In a second study, using the same group of heifers, we infused 50 or 150 g/day of urea into the rumen (UR50 and UR150) or 150 g of urea in the abomasum (UA150) or 50 g in the rumen and 100 g in the abomasum (URA150). Fibre digestion was improved by 4% (p = .02) when the same dose of urea was infused into the abomasum compared with the rumen, while estimated microbial protein production and N efficiency were not different between a low rumen dose and high post-ruminal dose of urea. Collectively, these studies provide insight into the viability of post-ruminal NPN supplementation as a strategy to improve fibre digestion and NPN inclusion in the ruminant diet.     

Physical conditions in a cattle vehicle during spring and autumn conditions in Japan, and reactions of steers to long distance transport

The objective of this study was to investigate transportation conditions and behavioral and physiological responses of beef steers to long distance commercial transport in Japan. In spring (May) and autumn (September), eight (16 in total) Japanese Black × Holstein steers (7.8 ± 0.6 month of age; 310.3 ± 13.9 kg) were transported by truck. The transport distance was 1013.1 km (25 h including lairage periods) comprising 627.6 km (6.4 h) on expressways, 143.5 km (3.5 h) on arterial roads and 242.0 km (10.5 h) by ferry. The loading space of the truck gave a space allowance of about 1.62 m²/head. Internal temperature (±SD) and humidity (±SD) of the truck were 14.7 ± 4.7°C and 72.7 ± 22.4% in spring, 24.4 ± 2.8°C and 70.8 ± 14.4% in autumn. Vibration acceleration (±SD) of the truck in the longitudinal direction was greater in spring (?0.19 ± 0.43 m/s²) than in autumn (?0.15 ± 0.20 m/s²) (P < 0.05). There were no effects of season and driving conditions on the internal noise. Internal airflow velocity (±SD) of the truck was greater in spring (0.75 ± 0.70 m/s) than in autumn (0.45 ± 0.40 m/s) (P < 0.05), and it was greater while moving on expressways (0.77 ± 0.40 m/s) and arterial roads (0.63 ± 0.61 m/s) than when parked (0.16 ± 0.26 m/s) (both P < 0.05). Steers lay down more frequently while moving on expressways than the expected frequency (χ² = 121.9, P < 0.01). Steers were oriented parallel to the direction of travel (to the front cabin: 27.9%; to the tailgate: 23.4%) more frequently than the expected probability (12.5%). Blood glucose concentration, serum ALT activity and plasma cortisol concentration were greater in spring than in autumn (all P < 0.05). Serum pH was higher in autumn than in spring (P < 0.01). Blood glucose concentration was significantly higher at the market before transport, and serum total protein, triiodothyronine and total cholesterol concentrations were also significantly higher at the market and just after transport than 1 week after transport (all P < 0.05). However, the other physiological measurements such as plasma cortisol and blood lactate concentrations, serum pH and heart rate did not change after transport. The results indicate that in Japanese spring and autumn conditions, long distance transport with appropriate conditions including low stocking density and enough lairage time with provision of food and water might not cause severe stress for steers.     

Basal levels and responses to glucose infusion of plasma glucose and insulin in beef steer before and after the end of the growing phase on pasture

We examined the effect of grazing during the growing phase on plasma glucose and insulin behavior at the end of the growing phase and at the early stage of the subsequent fattening phase in beef steers. From 13 to 45 weeks of age (growing phase), crossbred beef steers were grazed with minimal supplement (group G: n = 5) or housed while being fed on hay and concentrate (group H: n = 5). Following this phase, both groups were housed for finishing (fattening phase). At the end of the growing phase, group G showed faster plasma glucose disappearance after intravenous glucose infusion, with a smaller plasma insulin response, compared with group H. At the third week of the fattening phase, group G still showed higher glucose tolerance, although they experienced abrupt changes in nutritional and environmental factors. The results suggest that grazing during the growing phase probably improves the glucose tolerance and insulin response to glucose infusion in steers compared with animals that were housed during the corresponding period, and the improved properties may persist at least a few weeks after the commencement of fattening.     

Genetic associations of visual scores with subsequent rebreeding and days to first calving in Nellore cattle

Records of Nellore animals born from 1990 to 2006 were used to estimate genetic correlations of visual scores at yearling (conformation, C; finishing precocity, P; and muscling, M) with primiparous subsequent rebreeding (SR) and days to first calving (DC), because the magnitude of these associations is still unknown. Genetic parameters were estimated by multiple‐traits Bayesian analysis, using a nonlinear (threshold) animal models for visual scores and SR and a linear animal models for weaning weight (WW) and DC. WW was included in the analysis to account for the effects of sequential selection. The posterior means of heritabilities estimated for C, P, M, SR and DC were 0.24 ± 0.01, 0.31 ± 0.01, 0.30 ± 0.01, 0.18 ± 0.02 and 0.06 ± 0.02, respectively. The posterior means of genetic correlations estimated between SR and visual scores were low and positive, with values of 0.09 ± 0.02 (C), 0.19 ± 0.03 (P) and 0.18 ± 0.05 (M). On the other hand, negative genetic correlations were found between DC and C (?0.11 ± 0.09), P (?0.19 ± 0.09) and M (?0.16 ± 0.09). The primiparous rebreeding trait has genetic variability in Nellore cattle. The genetic correlations between visual scores, and SR and DC were low and favourable. The genetic changes in C, P and M were 0.02, 0.03 and 0.03/year, respectively. For SR and DC, genetic trends were 0.01/year and ?0.01 days/year, respectively, indicating that the increase in genetic merit for reproductive traits was small over time. Direct selection for visual scores together with female reproductive traits is recommended to increase the fertility of beef cows.     

Breeding objectives for the Boran breed in Kenya: Model development and application to pasture-based production systems

Bio‐economic profit models were developed and applied to evaluate biological and economic variables that characterize production systems utilizing the Boran breed. Production systems were described according to their sale age (24 months short‐fed or 36 months long‐fed), levels of input (low, medium or high) and final goal (beef or dual purpose) representing practical circumstances that exist in the various beef cattle farms in Kenya. The input variables were classified into production and economic variables. The outputs from the profit models included revenue, costs and feed intake of cows, heifers and steers in the different production systems. These models can be used to simulate changes in production and marketing circumstances. The biological relationships and assumptions in the model are general and flexible and can therefore be applied to a wide range of beef cattle production circumstances by changing the input variables. In addition, by modifying the herd dynamics and management variables this model may be applied in Kenya or other countries to production systems that utilize indigenous cattle genetic resources or their crosses with Bos taurus breeds.     

2个与HSP70基因连锁的微卫星座位与牛运输应激性状的关联分析

试验探讨了2个与HSP70基因连锁的微卫星座位与牛运输应激性状的关联分析。选择120头12月龄、体重250 kg左右的健康西门塔尔杂种肉牛进行运输应激试验,并根据牛基因组遗传图谱,选择23号染色体上与HSP70基因连锁的微卫星座位BMS468和BM1258检测其在西门塔尔杂种肉牛样本群体中的多态性,采用最小二乘拟合一般线性模型分析微卫星座位与运输应激性状部分指标之间的关联效应。结果显示：微卫星座位BMS468共检测到5个等位基因（128、134、140、146、154 bp）,优势等位基因为128和134 bp,有效等位基因数（Ne）、多态信息含量（PIC）和遗传杂合度（He）分别为3.66、0.68和0.73,遗传多态性较高,关联分析显示与运输后7 d平均日增重和发病率显著相关,其中128/128 bp基因型个体的运输后7 d平均日增重最大（P < 0.05）,134/128 bp基因型个体的发病率最低（P < 0.05）;微卫星座位BM1258座位共检测到6个等位基因（99、101、103、113、117、119 bp）,优势基因为101 bp,Ne、PIC和He分别为4.30、0.73和0.77,遗传多态性较丰富,关联分析显示,其与发病率显著相关,其中99/99 bp基因型个体的发病率最低（P < 0.05）。综上所述,2个微卫星座位可作为牛运输应激性状的潜在遗传标记,为开展牛抗运输应激性状的标记辅助选择提供科学依据。     

Pasture improvement in relation to animal health and production

Extract

In this talk I shall be dealing with two quite distinct groups of people who find common ground in some 40,000,000 humble animals—the sheep and cattle populations of New Zealand. You, as practising veterinarians form the first group, and your prime concern is the health (or, if you prefer it, the diseases) of these two species. The second is composed of what, for want of a better term, I shall call pasture workers, and it is concerned, directly or indirectly, with the provision of feed for those same domestic animals. The name is chosen because, under New Zealand conditions, “feed” and “pasture herbage” are virtually synonymous terms.     

肉牛疾病防疫及治疗中易忽视技术要点

部分农场对于肉牛的养殖,在发生疾病前没有做好相应的预防工作,忽视肉牛发生疾病中需要使用的技术要点。为保证肉牛健康成长,为养殖户及其他商家带来实际的利益,为广大人民有安全健康的饮食,务必重点关注肉牛疾病等相关的工作,落实疾病治疗时的相关技术。该文主要论述肉牛疾病等相关事宜,简要分析其中易忽视的技术关键点,希望可促使人们在相关问题上做好实际的工作。     

Questionnaire investigation to clarify the occurrence rate and characteristics of maternal rejection behavior in Japanese black cattle (Bos taurus)

We conducted a questionnaire investigation among breeding farmers to clarify the actual conditions of maternal rejection in Japanese Black cattle. We asked keeping experience of maternal rejective cows and compared occurrence patterns, rejective behavior manners, birth assistance methods, colostrum feeding method for calves, parity and rearing conditions of the cows. We found that 24% of the farms had kept rejective cows and 6% of the cows in these farms indicated maternal rejections. The most common occurrence pattern was ‘Occurred from the first birth (65.6%)’ and behavior manner was performing no maternal grooming with aggressive behavior (75%). Almost all the farmers assisted in each parturition (P < 0.05). There was not a significant difference among the colostrum feeding methods, but a significant difference in the rearing conditions of the cows, except for the cows with no data (P < 0.005). The parity of the rejective cows did not significantly differ in association with rejective behavior manners, birth assistance methods, colostrum feeding methods or rearing conditions. These results suggest that the occurrence rate of maternal rejection in Japanese Black cattle was approximately 6% and many of the rejective cows continuously performed no maternal grooming with aggressive behavior.     

Behavioral and performance response associated with administration of intravenous flunixin meglumine or oral meloxicam immediately prior to surgical castration in bull calves

The objective of this study was to determine the effects of flunixin meglumine or meloxicam on behavioral response and performance characteristics associated with surgical castration in crossbred bulls. Intact male Bos taurus calves (n = 252; averaging 176 kg) were randomly allocated into one of three treatment groups within pen: control (CON), flunixin meglumine (FLU; 2.2 mg/kg intravenous injection), or meloxicam (MEL; 2.0 mg/kg per os). The individual animal was the experimental unit. Calves were individually weighed on days 0 and 14 of the trial to evaluate performance outcomes. On study day 0, treatments were administered, according to their random allocation, immediately prior to surgical castration using the Henderson tool method. Visual analog scale (VAS) assessment and categorical attitude score (CAS) were collected on days −1, 0 (6 h post-castration), 1, 2, 3, and 4 in the study. The VAS was assigned using a 100 mm horizontal line with “normal” labeled at one end of the line and “moribund” at the other end of the horizontal line. The masked observer assigned a mark on the horizontal line based upon the observed severity of pain exhibited by that individual animal. The CAS was assigned by the same observer using five different categories with a score of 0 being “normal”. Average daily gain tended (P = 0.09) to be associated with the treatment group, and MEL had a greater (P = 0.04) average daily gain through day 14 compared with CON. A significant (P < 0.01) treatment by day interaction was indicated for VAS score, and MEL had lower VAS scores on days 0, 1, 2, and 3 post-castration compared with CON; FLU had lower VAS scores on days 0 and 1 compared with CON. A significant treatment by day interaction was not present (P = 0.25) for CAS. The FLU had lesser percent CAS ≥1 (17.5%; P = 0.05) compared with CON (29.4%); MEL has lesser percent CAS ≥1 observations (14.9%; P = 0.01) compared with CON. The median VAS increased as CAS was more severe. Results indicated MEL and FLU calves temporally improved behavioral responses following surgical castration with positive numerical trends for a 14 d average daily gain (ADG). The VAS system appeared to be an effective method of subjective evaluation of pain in beef calves in this study. Route of administration, duration of therapy, and low relative cost make oral meloxicam a reasonable analgesic treatment in calves when administered at the time of surgical castration.     

Potential role of Anitschkow cells in cardiovascular disease in human and veterinary medicine: A review of the literature

Anitschkow cells (AC) are a peculiar type of stromal cells observed in myocardium, cardiac valves and coronary vessels wall whose origin, characterization and role remain controversial. In human heart, they represent a histological hallmark of Aschoff nodules in rheumatic fever, but they have also been observed in other myocardial pathologies. Firstly, they have been considered a myocyte‐derived cells, but light microscopy, immunohistochemical and ultrastructural studies pointed out that a macrophagic/histiocytic origin cannot be excluded. Many authors also reported extracardiac AC or an Anitschkow nuclear pattern, thus suggesting that these cells may represent a chromatin pattern rather than a specific cell type. In veterinary medicine, AC were described in myocarditis, myocardial necrosis, degenerative and inflammatory endocardial diseases of several species. Recently, AC have been observed in intramural coronary arteries of different animals (including cattle and fish) affected by arteriosclerotic processes. Stress related to the intensive livestock farming could represent a mechanotransduction promoting factor of arteriosclerotic changes allowing the development of Anitschkow chromatin pattern. Further studies both in human and veterinary medicine are needed to confirm the origin and role of these peculiar cells.     

Genetic potential for residual feed intake and diet fed during early- to mid-gestation influences post-natal DNA methylation of imprinted genes in muscle and liver tissues in beef cattle

Discovery of epigenetic modifications associated with feed efficiency or other economically important traits would increase our understanding of the molecular mechanisms underlying these traits. In combination with known genetic markers, this would provide opportunity to improve genomic selection accuracy in cattle breeding programs. It would also allow cattle to be managed to improve favorable gene expression. The objective of this study was to identify variation in DNA methylation between beef cattle of differential pre-natal nutrition and divergent genetic potential for residual feed intake (RFI). Purebred Angus offspring with the genetic potential for either high (HRFI) or low (LRFI) RFI were prenatally exposed to either a restricted maternal diet of 0.5 kg/d average daily gain (ADG) or a moderate maternal diet of 0.7 kg/d ADG from 30 to 150 d of gestation. We performed DNA methylation analysis of differentially methylated regions (DMR) of imprinted genes (Insulin-like growth factor 2 (IGF2) DMR2, IGF2/H19 imprinting control region (ICR) and IGF2 receptor (IGF2R) DMR2) using post-natal samples of longissimus dorsi (LD) muscle taken from male and female calves at birth and weaning, and of LD muscle, semimembranosus (SM) muscle, and liver samples collected from steers at slaughter (17 months of age). Interestingly, for all three DMR investigated in liver, LRFI steers had higher levels of methylation than HRFI steers. In LD muscle, IGF2/H19 ICR methylation differences for heifers at birth were due to pre-natal diet, while for steers at birth they were mostly the result of genetic potential for RFI with LRFI steers again having higher levels of methylation than HRFI steers. While results from repeated measures analysis of DNA methylation in steers grouped by RFI revealed few differences, in steers grouped by diet, we found higher methylation levels of IGF2 DMR2 and IGF2R DMR2 in LD muscle of restricted diet steers at weaning and slaughter than at birth, as well as increased methylation in LD muscle of restricted diet steers compared with moderate diet steers at weaning and/or slaughter. Our results suggest that differential pre-natal nutrition, and divergent genetic potential for RFI, induces tissue- and sex-specific alterations in post-natal IGF2 and IGF2R methylation patterns and that these patterns can vary with age in Angus beef cattle.     

Effects of body condition and supplementation on ovarian function,growth factors and response to estrus synchronization in postpartum beef cows in Tamaulipas,Mexico

ABSTRACT

Eighteen beef cows with their calves were assigned to 3 groups considering body conditions scores at calving (BCSC): T1 (high BCSC, maintained throughout the study); T2 (low BCSC, increased during the study); and T3 (low BCSC, maintained throughout). An estrus synchronization protocol was implemented, with fixed time artificial insemination on day 70. Follicular or luteal growth, and pregnancy rate were similar between groups. Of all cows, five showed multiple ovulations (2–6); increasing number of ovulations reduced preovulatory follicle diameter and individual luteal volume (P?<?0.05), but total luteal volume was greater in cows with 2 or 3 ovulations on day 14 after insemination (P?<?0.05). Estradiol and progesterone levels were associated to follicular and luteal growth, respectively. No difference was found in IGF1 or GDF9 levels between groups or associated to fertility. No association was found between BCS, IGF1 or GDF9 levels and the reproductive process.