Data from twenty-two digestibility trials were compiled to examine the relationship between faecal N concentration and organic matter (OM) digestibility (OMD), and between faecal N excretion and OM intake (OMI) by wethers fed tropical or temperate forages alone or with supplements. Data set was grouped by diet type as follows: only tropical grass (n = 204), only temperate grass (n = 160), tropical grass plus supplement (n = 216), temperate grass plus supplement (n = 48), tropical grass plus tropical legume (n = 60) and temperate grass with ruminal infusion of tannins (n = 16). Positive correlation between OMD and either total faecal N concentration (Nfc, % of OM) or metabolic faecal N concentration (Nmetfc, % of OM) was significant for most diet types. Exceptions were the diet that included a tropical legume, where both relationships were negative, and the diet that included tannin extract, where the correlation between OMD and Nfc was not significant. Pearson correlation and linear regressions between OM intake (OMI, g/day) and faecal N excretion (Nf, g/day) were significant for all diet types. When OMI was estimated from the OM faecal excretion and Nfc-based OMD values, the linear comparison between observed and estimated OMI values showed intercept different from 0 and slope different from 1. When OMI was estimated using the Nf-based linear regressions, the linear comparison between observed and estimated OMI values showed neither intercept different from 0 nor slope different from 1. Both linear comparisons showed similar R(2) values (i.e. 0.78 vs. 0.79). In conclusion, linear equations are suitable for directly estimating OM intake by wethers, fed only forage or forage plus supplements, from the amount of N excreted in faeces. The use of this approach in experiments with grazing wethers has the advantage of accounting for individual variations in diet selection and digestion processes and precludes the use of techniques to estimate forage digestibility.

Brazil currently ranks as one of the world leaders in food production and exportation. This scenario encourages the development of animal and plant health programs to ensure the production of safe food, helping the country to become an international provider of food for excellence. However, some health problems in dairy production, such as mastitis, have garnered increasing concern. This study aimed to estimate the prevalence of bovine mastitis in select properties located in the western Santa Catarina region, to assess the susceptibility profile to antimicrobial agents used for treatment and to check for the presence of genes (icaA and icaD) associated with biofilm formation in Staphylococcus aureus. In 148 milk samples collected, 72.97% had bacterial growth (n = 108). Among the isolated microorganisms, 21.62% (n = 32) were classified as Staphylococcus aureus, 18.91% (n = 28) as Staphylococcus sp. coagulase negative, 7.43% (n = 11) as Corynebacterium sp., 6.76% (n = 10) as Staphylococcus sp. coagulase positive, 5.41% (n = 8) as Nocardia sp. and 12.83% (n = 19) classified in different bacterial genera. Among the isolates submitted for antimicrobial susceptibility testing, it was observed that 8.95% (n = 6/67) had resistance to amoxicillin, 8.04% (n = 7/87) to ampicillin, 5.88% (n = 5/85) to cephalothin, 3.40% (n = 3/88) to ceftiofur and enrofloxacin, 20.45% (n = 18/88) to streptomycin, 17.04% (n = 15/88) to gentamicin and lincomycin, 31.81% (n = 28/88) to neomycin, 14.94% (n = 13/87) to penicillin and 25% (n = 22/88) to tetracycline. Staphylococcus sp. coagulase negative isolates showed higher multidrug resistance when compared to those of S. aureus and Staphylococcus sp. coagulase positive. Thirty-one strains of S. aureus isolates were genotypically tested by polymerase chain reaction (PCR), yielding a positive result for the icaA gene in 83.87% of the samples, 80.64% positive for icaD and 74.19% of these showed both genes. The results reinforce the importance of controlling this disease by adopting strict hygiene protocols and disinfection of equipment used for milking and the prescription of appropriate therapies to clinical and subclinical cases of mastitis, as well as evaluating not only the susceptibility profile of isolates but also the biofilm formation capacity. ResumoO Brasil situa-se hoje como um dos líderes mundiais em produção e exportação de alimentos. Este cenário incita a elaboração de programas de sanidade animal e vegetal que garantam a produção de alimentos seguros, contribuindo para que o país se torne um fornecedor internacional de alimentos por excelência. Entretanto, alguns problemas sanitários na produção leiteira, como a mastite, têm acarretado crescentes preocupações. O presente estudo teve como objetivo estimar a prevalência de mastite bovina em algumas propriedades localizadas na região Oeste de Santa Catarina, avaliar o perfil de suscetibilidade aos antimicrobianos empregados para tratamento e verificar a presença de genes (icaA e icaD) associados à formação de biofilmes em ...

The aim of this study was to assess the metaphylactic effect of subcutaneous doses of trace minerals (copper, zinc, selenium, and manganese) and vitamins A and E on biochemical (NEFA, BHBA, fructosamine, urea, triglycerides, HDL, and calcium) and hormonal parameters (cortisol, insulin, and IGF-1) of Holstein cows in the transition period. Sixty animals kept in a semi-confinement system, with an average production of 22 liters of milk per day (Farm 1) and 24 liters of milk per day (Farm 2) and a diet according to NRC (2001) with a low metabolic challenge, were divided into two groups: a treatment group, supplemented with trace minerals and vitamins (MTVG) (n=30), and a control group (CG) (n=30). The collection of blood samples was performed at the moments M1 (21 days prepartum), M2 (14 days prepartum), M3 (7 days prepartum), M4 (parturition day), M5 (7 days postpartum), M6 (14 days postpartum), and M7 (21 days postpartum). The experimental design was a randomized block design and the data were submitted to analysis of variance with repeated measures in time within the random variable cow. Differences were considered significant at 5% significance level and trend at 10% level. No difference was observed between treatment and the interaction treatment × day in the assessed parameters. However, some variables showed a significant difference of day. NEFA levels (P < 0.0001) were higher on the parturition day. BHBA concentrations were higher after parturition (P=0.0031), with a peak at the third week of lactation. Fructosamine showed increasing values until the parturition day (P=0.0373), in which higher concentrations were observed. Average values of HDL were higher at 21 days postpartum (P < 0.0001). Triglycerides levels remained high during the prepartum period but showed a sudden drop on the parturition day (P < 0.0001), with lower values postpartum. Regarding serum calcium and IGF-1, lower values were observed on the parturition day (P < 0.001) for both parameters. Cortisol presented a difference regarding day, with higher values on the parturition day (P=0.0151). Thus, the use of trace minerals and vitamins A and E in animals with an adequate body score and low metabolic challenge presents a low response to biochemical and hormonal parameters.

To evaluate the effect of supplementation of iron dextran on blood variables and iron metabolism in lambs experimentally infected by Haemonchus contortus, four experimental groups were used: uninfected and non-supplemented animals (GI); infected animals supplemented with iron (GII); uninfected animals supplemented with iron (GIII); and infected non-supplemented animals (GIV). Groups II and IV received 10,000 larvae (L3) of Haemonchus contortus, and groups II and III received three doses of iron dextran (20mg/kg) intramuscularly with seven days of interval. Blood and faeces samples were collected on days 10 (D10), 17 (D17), 24 (D24), and 31 (D31), in order to determine red blood cell counts, iron metabolism, and EPG. Infected animals developed anemia from D24 and anemia was more severe on D31. Animals from GII had higher hematocrit and hemoglobin concentration compared to animals of GIV on D31. Iron stores in the bone marrow were higher in GII and GIII compared to GI and GIV. The GIV showed lower seric levels of iron on D24 compared to the other groups. The iron supplementation reduces the severity of the anemia caused by infection with Haemonchus contortus in lambs, improving erythropoietic response after blood loss.

RESUMOO objetivo deste estudo foi avaliar o uso de minerais traços (cobre, zinco, selênio e manganês) e vitaminas A e E, na forma injetável, sobre a produção e composição do leite de vacas holandesas no final do período de transição até os 60 dias de lactação. Foram utilizadas 31 fêmeas holandesas divididas em dois grupos experimentais: grupo tratado (n=15) que recebeu suplementação de minerais (10 mg de cobre, 40 mg de zinco, 5 mg de selênio e 10 mg de manganês) e de vitaminas (175 mg de vitamina A e 250 mg de vitamina E) injetável (5 mL da solução dos microminerais e 5 mL das vitaminas pela via subcutânea) aos 225 dias de gestação, aos 255 dias de gestação e no dia do parto; e o grupo controle (n=16), que recebeu injeções de solução fisiológica (na dose de 5 mL pela via subcutânea) nos mesmos dias do grupo tratado. Amostras de leite foram coletadas nos dias sete, 14 e 21 após o parto, onde avaliou-se a produção, a qualidade (colostro), e a composição (gordura, lactose, proteína, extrato seco desengordurado, sólidos totais, ureia e contagem de células somáticas (CCS)) do leite. Os valores iniciais e valores mínimos estimados pelo modelo não indicaram diferença na produção de leite e na CCS entre os grupos. Para o restante dos componentes do leite, somente a ureia apresentou diferença significativa entre os grupos tratados e não tratados (p= 0,002). Também não foi verificada diferença significativa para qualidade de colostro. Portanto, conclui-se que o uso de solução injetável contendo Cu, Zn, Se, Mn e vitaminas A e E tem efeito sobre a composição da ureia do leite, porém não se observou efeito sobre CCS e os demais componentes do leite e na sua produção, porém mais estudos devem ser realizados.

No abstract

No abstract

Tick infestation causes major problems in cattle. Tick parasitism accounts for significant economic losses in many beef and dairy herds in the vast majority of the states in the Brazilian territory including the State of Santa Catarina in the southern region of the country. Tick resistance to several active principles occurs due to a number of factors including the indiscriminate, injudicious and inadequate use of tick insecticides. Considering the great importance of fighting off tick infestations in cattle, we evaluated the efficiency of 8 different topical active principles against the ixodid tick R. microplus and identified the main factors that contribute to the development of ticks that are resistant to acaricides in the farms and bovine herds studied. For such purpose, R. microplus telegionae were collected in 39 farms locates in different municipalities of the West of Santa Catarina, south Brazil. At the time of sample collection, information about the management, the history of the acar used in the herd, the number of annual applications of these pesticides, the frequency of acaricide rotation, and the frequency of technical monitoring for strategic tick control were retrieved. We collected this data in order determine contributing factors to the development resistant R. microplus populations. For the sensitivity profile of these ticks to a number of different acaricides tested, 10 engorged females for each principle and a control were used. The results of our study show that most associations between pyrethroids and organophosphates had an efficiency between 96.6% and 100% in the control of R. microplus except for the combination of Alfacipermetrine 15%, Ethion 16%, and Chlorpyrifos 8.5% that had 93.4% of efficiency. Among the chemicals not associated with any other type of compound, Amitraz 12.5% ​​was effective in 98.3% of the cases. In contrast, Cypermethrin 15% had an efficiency in only 25.8% of the farms/herds analyzed. Based on the results of the present study, we may infer that the methods of control and management used by producers may be related to the low indexes of resistance to topical acaricides in the different populations of ticks in the study area.