Ruminants, Volume 3, Issue 3 (September 2023) – 9 articles

The objective of this study was to analyze the effect of regrouping on Holstein heifer salivary cortisol concentrations and behavior. Eighteen heifers (192.8 ± 13.6 days of age) were used during this study. Each of these heifers was introduced into a pen of older existing heifers. The heifers were assigned to four groups that corresponded to each of the four regroupings. Saliva samples were collected the day before regrouping (baseline; pre-regrouping), the day of regrouping, and the day after regrouping (post-regrouping). Video cameras continuously recorded from the hour before each regrouping through one day after each regrouping. Salivary cortisol concentrations were higher than the baseline for novel and existing heifers on the day of regrouping and one day post-regrouping (p = 0.01). More aggressive and agnostic behaviors occurred during Regroupings 1 and 4 than during Regroupings 2 and 3. Novel heifers spent more time standing (p = 0.05) and drinking (p = 0.05) than the existing heifers and less time lying (p = 0.05), but no other differences were observed between the behavior of existing and novel heifers. The salivary cortisol results of this study demonstrate that regrouping is a stressful event for both novel and existing dairy heifers. Full article

Wagyu cattle are well known for their greater intramuscular fat content which improves eating quality for consumers. These experiments were designed to investigate the impact of olive cake supplementation on Wagyu steer growth performance, longissimus muscle fatty acid composition, and in vitro rumen fermentation characteristics. We hypothesized that feeding with olive cake would improve animal performance and increase oleic acid (C18:1cis9) composition in the longissimus muscle. Experiment 1: Eighty-three American Wagyu steers (725 ± 10.7 kg) were used in this experiment. Steers were blocked by initial body weight (BW) and randomly assigned within blocks to one of two treatments. Treatments consisted of (1) control (basal ration with no olive cake) or (2) control diet + 5% supplemental olive. Steers were housed in feedlot pens (n = 4 steers/pen; 11 replicates/treatment) and fed a finishing diet typical for Wagyu cattle. Steers were individually weighed every 28 d throughout the 177 d experiment. Longissimus muscle samples were obtained for fatty acid analysis at the time of slaughter. Experiment 2: Rumen fluid from three beef steers (480 ± 10 kg) fitted with rumen canulae was used to investigate the impact of olive cake on in vitro rumen fermentation characteristics. Treatments consisted of (1) control (no olive cake) or (2) 5% olive cake. Results: Experiment 1: Steers receiving olive cake had a lower (p < 0.05) final BW and DM intake when compared to steers receiving the control diet. Longissimus muscle C18:2 and C22:6 n-3 were greater (p < 0.05) and C18:1cis9 tended (p < 0.06) to be greater in steers receiving olive cake when compared to controls. Experiment 2: Dry matter, acid detergent fiber, and neutral detergent fiber disappearance and molar proportions of short chain fatty acids were similar across treatments. The weight percentage of C14:1 was greater in in vitro rumen fluid fermented with olive cake when compared to controls. All other long chain fatty acids were similar across treatments. Under the conditions of this experiment, feeding olive cake at 5% of the diet DM reduced live animal performance and had minimal impacts on longissimus muscle fatty acid composition and in vitro rumen fermentation characteristics. Full article

The objective of this research was to determine the influence of implanting heavy wether lambs with 12 mg of zeranol (1 pellet Ralgro, Merck Animal Health. Madison, NJ, USA) 59 d before harvest. Average daily gain (ADG), feed efficiency, and carcass merit were evaluated. Polypay and crossbred wethers (n = 32) were equally divided into two treatment groups: non-implanted; (CON) or implanted with 12 mg of zeranol (IMP) in a randomized complete block design. Sixteen pens were used, resulting in eight replicate pens per treatment. Wethers were fed a finishing diet consisting of cracked corn, soybean meal, and soybean hulls ad libitum for 59 d. Lambs had access to clean water at all times from water fountains. Lambs were weighed on d -1, 1, 14, and 59. On d 59, 16 lambs (8 lambs/treatment) were harvested in the South Dakota State University Meat Lab. Hot carcass weight (HCW), dressing percent (DP), rib fat, body wall thickness, loin eye area, boneless closely trimmed retail cut percentages, and yield grades were recorded. Final body weight (BW), cumulative ADG, and gain efficiency were greater (p ≤ 0.01) for implanted lambs by 2.9%, 25.0%, and 35.2%, respectively, while dry matter intake (DMI) was unaffected by implant treatment (p = 0.18); thus, the efficiency of dietary net energy utilization was increased for IMP (p ≤ 0.01). No appreciable differences were noted (p ≥ 0.17) between treatments for any carcass traits measured. These results indicate that zeranol improves growth performance in heavy finishing lambs without detriment to carcass quality, which implies that producers can improve profitability due to increased gains and efficiency. Full article

Mastitis is one of the main diseases that affects dairy cattle. It is characterized by a multifactorial disease with multiple etiologies including microorganisms such as bacteria, viruses, fungi, yeasts, and algae. Mastitis caused by Mycoplasma spp. results in a contagious nature of infection and has been studied much in Brazil. The objectives of this research were (1) to investigate in clinical mastitis milk samples, by conventional PCR, the presence of the following mycoplasma species: Mycoplasma (M.) bovis, M. bovirhinis, M. bovigenitalium, M. californicum, and M. alkalescens and (2) compare the PCR Mollicutes detection rates using previous concentration and homogenization steps of the milk samples. Of the 993 clinical mastitis milk samples analyzed, 13.7% (136/993) and 8.0% (80/993) were positive for the Mollicutes class after concentration and homogenization, respectively, and all of them were PCR-negative for the five species investigated. Of the 70 expansion milk tanks analyzed, all of them were PCR-negative for the Mollicutes class. The importance of the previous concentration of milk in the routine of molecular analysis was evidenced when compared to the results obtained only with homogenization. Full article

Gastrointestinal nematodes (GIN) significantly, negatively impact livestock worldwide, and their control depends on the use of chemotherapy drugs. However, this approach is unsustainable as anthelmintic resistance (AR) is growing widespread. This article provides a comprehensive overview of the historical and current data published on AR in domestic ruminants in Brazil. Alternative measures of GIN control have been discussed to provide helpful information to prevent the development of AR in the country. This review consisted of a search of technical and scientific publications between January 1960 to January 2023, using online sources such as PubMed, Scielo and Google Scholar. Eighty-three articles published over the last six decades reporting AR in sheep (n = 43), goats (n = 20) and cattle (n = 20) were included. A total of 37.3%, 25.4% and 37.3% evaluated one, two and three or more molecule classes, respectively. Among all studies, 82.1% used fecal egg count reduction test as a method of AR diagnosis. In conclusion, AR is an urgent and emerging issue for ruminant production in Brazil. It is necessary to evaluate on a large scale the distribution and management of anthelmintic drugs and discuss strategies that delay this phenomenon’s development. Full article

This study analyzed the cattle trade network in Paraná, Brazil, for the years 2018 and 2019 to identify potential movement patterns that could contribute to the spread of brucellosis among farms. The brucellosis statuses of 1757 farms were incorporated into the analysis. Network parameters of farms with a known brucellosis infection status were statistically compared between infected and non-infected farms using traditional techniques and the quadratic assignment procedure. A multilinear regression model (MLR) was used to consider known risk factors for brucellosis infection in conjunction with the network parameters. The cattle trade network in Paraná during the study period comprised 115,296 farms linked by 608,807 cattle shipments. The movement pattern was marked by a high concentration of movements to and from a small percentage of farms. The existence of such highly connected farms could facilitate the transmission of communicable diseases via the cattle trade in Paraná. The trading communities in Paraná exhibited a spatial pattern, with proximate farms more likely to engage in trade. Brucellosis-infected farms traded more frequently than non-infected farms (odds ratio [OR] 3.61), supplied cattle to other farms more often than the regional average (OR 2.12), and received more cattle (OR 2.78). The in-degree and out-degree were associated with brucellosis infection on the farm. The mean shortest path between infected farms was significantly shorter than that between non-infected farms (4.14 versus 4.49, p = 0.004, OR 1.39). In the MLR, a higher out-degree was positively associated with infected farms after accounting for previously identified risk factors. This novel information offers insights into the factors driving the current endemic situation in the study area and can inform the development of targeted animal health policies. Full article

Two experiments were conducted to evaluate the in vitro and in vivo effects of a novel direct-fed microbial (DFM) containing Lactobacillus animalis LA-51, Propionibacterium freudenreichii PF-24, Bacillus licheniformis CH-200, and Bacillus subtilis King (BOVAMINE DEFEND^® Plus) against Clostridium perfringens pathogenic strains. In Experiment 1 (in vitro), an agar diffusion assay was performed to qualitatively evaluate the in vitro inhibitory effects of the DFM against C. perfringens types A and C. Including the DFM in the tested yielded inhibition zones with greater than three ring diameters in a 96-well plate. In Experiment 2 (in vivo), twenty 1-day-old beef calves were allocated to control (n = 10) or DFM (n = 10) for 21 days. All calves were orally challenged with 1.0 × 10⁸ colony forming units of C. perfringens type A strain S-107 per head. The procedures such as general health scores, body weight, and fecal sample collections were performed following the C. perfringens challenge. Daily feeding of DFM significantly reduced the incidence of diarrhea while improving general impression and appearance scores of calves. Overall, these results highlight the ability of the DFM containing L. animalis LA-51, P. freudenreichii PF-24, B. licheniformis CH-200, and B. subtilis (BOVAMINE DEFEND^® Plus) to inhibit C. perfringens types A and C under different experimental settings. Full article

Leptospirosis is a zoonotic disease that has a cosmopolitan geographical distribution, reported in domestic and wild animals, which act as reservoirs and contribute to the spread of microorganisms in the environment. In Brazil, studies on the occurrence of leptospirosis in buffaloes in the Amazon Biome are scarce. The objective of this study was to determine the occurrences of antibodies against Leptospira spp., including serovar Hardjo (Bolivia), isolated from cattle in Brazil and not yet tested in buffaloes. A total of 387 blood serum samples of animals from nine municipalities on Marajó Island, State of Pará, northern Brazil, were obtained from a biological sample bank and analyzed using the microscopic agglutination test (MAT). Serology revealed 91.5% (387/354) of the animals tested positive for anti-Leptospira antibodies. The presence of various detected serovars may have been related to the local practice of combined rearing of different livestock species, as well as to the contact with wild animals and rodents from adjacent forest areas, all factors that likely facilitated the epidemiological chain of the disease in buffaloes. Among the serovars tested, the serovar Hardjo (Bolivia) was the most prevalent, which was present in 79.3% of the reactive buffaloes. It was important to carry out serological and bacteriological surveys in order to identify the serovars that occurred in the herds, with the objective of designing efficient strategies to control leptospirosis in the production of buffaloes. Full article

Murrah buffalo and Nellore cattle meat commercialized in Southeastern Brazil were evaluated during aging. Ribeye steaks (Longissimus thoracis muscle) were analyzed during four wet aging times (0, 7, 14, and 21 days) stored at 2 ± 1 °C. The water holding capacity (WHC) decreased (p < 0.05) during aging (0.41 to 0.28), with buffalo meat having (p < 0.05) lower pH and a higher WHC than beef. Lower myofibrillar fragmentation index and shear force (WBsSF) values were observed (p < 0.05) in buffalo meat. Soluble collagen content increased (p < 0.05) during aging, with lower (p < 0.05) values in buffalo meat. Buffalo meat had (p < 0.05) higher metmyoglobin percentages, being darker (lower L* values) and with a higher red color intensity (higher C* values) than beef. There was a difference between buffalo meat and beef volatile compound profiles, with greater variation in the beef profile during aging, probably due to differences in lipid oxidation and proteolysis. It can be concluded that buffalo meat is very similar to that of Zebu cattle, with less variation during aging and greater tenderness than beef. Therefore, buffalo meat is a good alternative source for fresh marketing and processing of high-quality meat products. Full article