RESUMO Contagem de células somáticas (CCS) e produção de leite de vacas mestiças Holandês x Gir foram utilizadas para avaliação da perda de produção de leite estimada por duas metodologias, baseadas na CCS média da lactação total encerrada ou na CCS e nas pesagens de leite em diferentes estágios de lactação. Nas primíparas consideradas com mastite subclínica (CCS ≥ 200.000 células mL-1), a perda de produção na lactação total, avaliada pela CCS média da lactação, foi de 814kg. Para as multíparas, não houve diferença na produção de leite entre vacas com e sem MSC com base na CCS média da lactação. A estimativa avaliada por meio de testes mensais de CCS e pesagens de leite em diferentes estágios de lactação, balanceada pela prevalência de mastite subclínica do mês foi de 917,9kg para primíparas e 1178,9kg para multíparas. A contraposição da produção de leite com a CCS em diferentes estágios da lactação evidenciou maior perda de produção em relação à observação da CCS média da lactação. A perda de produção de leite de vacas baseada na CCS média de toda a lactação foi subestimada quando comparada à contraposição da produção de leite com CCS em diferentes estágios da lactação.

The objectives of this study were: 1) to classify animals into groups of high and low feed efficiency using two feed efficiency indexes (Residual feed intake (RFI) and residual feed intake and body weight gain (RIG)), and 2) to evaluate if pre-weaning heifer calves divergent for feed efficiency indexes exhibit differences in performance, body measurements, digestibility, energy partitioning, and nitrogen partitioning. A total of 32 Gyr heifer calves were enrolled in a 63-d trial and classified into two feed efficiency (FE) groups based on RFI and RIG (mean ± 0.5 SD). The groups were classified as high efficiency (HE) RFI (HE RFI, n = 9; HE RIG, n = 10), and low efficiency (LE) RFI (LE RFI, n = 10; LE RIG, n = 11). The remaining animals were classified as intermediate (n = 13 (RFI) and n = 11 (RIG)). HE and LE calves had RFI values of—0.052 and 0.049 kg/d (P < 0.05), respectively. The HE RFI group consumed 8.9% less solid diet than the LE RFI group. HE RFI animals exhibited an increased digestibility of crude protein and ether extract and tended to have greater total dry and organic matter digestibility. LE RFI animals had greater gross energy and nitrogen intake, though greater fecal losses resulted in a tendency to reduce energy and nitrogen use efficiency. HE and LE calves had RIG values of 0.080 and -0.077kg/d (P ≤ 0.01), respectively. HE RIG animals exhibited greater average daily gain (9.4%), body weight (BW), and heart girth, though HE RIG group exhibited narrower hip width. HE RIG animals tended to have greater ether extract digestibility but greater methane losses (% of gross energy). HE RFI in pre-weaning heifers seems to be related to differences in digestibility. Divergent animals for RIG during the assessed phase appear to differ in body measurements, which may be related to differences in the composition of the gain.

The objective of this study was to evaluate whether pre-weaning heifer calves divergent for residual feed intake ( RFI ) or residual feed intake and body weight gain ( RIG ) exhibit differences in thermography, blood, and ruminal parameters. Thirty-two Gyr heifer calves were enrolled in a 63-d trial and classified into 2 feed efficiency ( FE ) groups based on RFI and RIG (mean ± 0.5 SD). The groups were classified as high efficiency ( HE ) RFI (HE RFI, n = 9), HE RIG (HE RIG, n = 10), low efficiency ( LE ) RFI (LE RFI, n = 10), and LE RIG (LE RIG, n = 11). The amount of whole milk provided for each calf was calculated based on their metabolic weight at birth (42% x BW 0.75 ). The liquid diet was divided into two meals at 0700 and 1400 h. The total solid diet ( TSD ) was composed of 92% concentrate and 8% of Tifton 85 hay chopped in 5-cm lengths, as fed. Intake was measured daily. Blood concentrations of insulin, beta hydroxybutyrate, urea, and glucose, and ruminal pH, N-NH 3 , and volatile fatty acids ( VFA ) were evaluated at 14, 28, 42, 56, and 70 days of age. Thermal images of the calves were taken with an infrared camera (FLIR T420, FLIR Systems Inc., Wilsonville, OR) on d 56 (±3) at 0600 h, before the morning feeding. Total VFA concentration and propionate as % of total VFA were 24.2% and 22.2% lower in HE RFI compared to LE RFI calves, respectively. On the other hand, acetate as % of total VFA was 10.6% greater in HE RFI than LE RFI calves. Blood urea concentration tended to be greater in LE RFI than HE RFI calves. High efficiency HE RIG tended to have 6.8% greater acetate and 15.4% lower propionate as % of total VFA than LE RIG. Blood insulin concentration was greater and blood glucose tended to be greater for LE RIG than HE RIG group. Low efficiency RIG group had greater left rib, left flank, and anus surface temperature measured by infrared thermography than the HE RIG group. Differences in ruminal fermentation do not seem to be associated with pre-weaning calves efficiency, while differences in protein metabolism seem to affect RFI during this phase. Infrared thermography appears to be correlated to RIG in pre-weaning heifer calves.

Crossbreeding has been used to improve performance in beef cattle, however the effects of breed composition on methane (CH 4 ) production, yield and intensity from cattle raised in tropical intensive and integrated systems remain unknown. To assess the impact of breed composition on performance and methane emissions, Nellore (NEL; yr 1: BW = 171.5 ± 19.4 kg; n = 10; yr 2: BW = 215.8 ± 32.3 kg, n = 25) and Angus x Nellore crossbred (AN; yr 1: BW = 214.2 ± 26.4 kg, n = 10; yr 2: BW = 242.5 ± 32.2 kg, n = 25) were compared. The animals grazed on integrated crop-livestock system in the growing phase (stocking rate 2452 kg BW/ha, herbage mass 4,884 kg dry matter (DM)/ha, forage allowance 5.9 kg DM/100kg BW) and then were finished in a feedlot. Steers (n = 8) from each breed composition were randomly selected in each phase to measure CH 4 production using a sulfur hexafluoride (SF 6 ) tracer technique and DM intake (DMI) using titanium dioxide. Compared with NEL, AN had both superior total gain and average daily gain (ADG) in the grazing period. The AN presented greater ADG in the feedlot with a shorter finishing period and resulted in greater carcass yield and carcass ADG. Methane production (kg/period) was lower in NEL (19% less) than AN in grazing ( P <0.01), and no difference was observed in feedlot. The NEL had less CH 4 intensity (CH 4 /BW) in grazing but greater CH 4 per unit of ADG in the feedlot compared to AN. Breed composition did not influence the CH 4 yield (CH 4 /DMI) in either phase, despite the difference in feedlot DMI (kg/day). In conclusion, crossbreeding may be an option to improve performance and reduce the CH 4 per ADG in tropical climate conditions, resulting in lower methane emission per kg of meat produced.

ABSTRACT.-Molina L.R., Costa H.N., Leão J.M., Malacco V.M.R., Facury Filho E.J., Carvalho A.U. & Lage C.F. A. 2017. Efficacy of an internal teat seal associated with a dry cow intramammary antibiotic for prevention of intramammary infections in dairy cows during the dry and early lactation periods. Pesquisa Veterinária Brasileira 37 (5) , Florham Park, Nova Jersey, USA), in preventing new infections during the dry-off and early postpartum period. A total of 150 Holstein cows (average production of 9,000 kg of milk per lactation), with four functional udder quarters without clinical mastitis was included in the study. All animals were dried-off 60 days before the expected calving date. Two teats positioned diagonal-contralaterally received only dry cow antibiotic, control group C (n=300) and the other two teats, treatment group T (n=300) received dry cow antibiotic and infusion with an internal teat seal. Data from SCC variable were transformed by log base-10 transformation. Duncan's test was used accepting 5% as the level of statistical significance. The occurrence of intramammary infection (IMI) and chronicity rate, and frequency of microorganisms isolated at drying and immediately postpartum in teats of group C and group T were evaluated using a non-parametric Chi-square Test, accepting 10% as the statistical significance level. There was a decrease in the occurrence of new infections in the early postpartum in cows which the sealant was used (C=19.6%, T=11.4%). In the postpartum period, Gram-negative bacteria were isolated from 16 teats in C and seven in T. The greatest reduction was observed for Escherichia coli (8 vs 1) in group T. There was no effect using the internal sealant on the frequency of isolation of environmental Streptococus. The use of sealant reduced the prevalence of subclinical mastitis cows between drying-off and the early postpartum period (C=51% versus T=42%) and resulted in a lower somatic cell count (SCC) in the treatment group when compared with the control group (T=1,073x10). The use of the internal teat seal combined with dry cow antibiotic is effective in the prevention of IMI during the dry period and early lactation and results in the reduction of SCC in immediate postpartum period. The treatment is effective in reducing infection between dry-off and the immediate postpartum caused by major and minor pathogens. However, no effect on infections caused by contagious pathogens was observed. , Florham Park, Nova Jersey, EUA) em prevenir novas infecções durante o perío-do seco e pós-parto imediato. Foram utilizadas 150 vacas Holandesas (produção média de 9,000 kg de leite por lactação), com os quatro quartos mamários funcionais e sem mastite clínica, que foram secas 60 dias antes da data prevista para o parto. O teto constituiu a unidade experimental. O grupo controle (C) foi representado por dois tetos diagonais-contralaterais (n=300), que receberam somente o antibiótico de vaca seca. Os outros dois tetos (n=300) constituíam o grupo tratado (T) e recebiam o antibiótico de vaca seca as...

The aim of this paper was to evaluate the effects of including virginiamycin (VM), sodium monensin (MON) or the association (VM+MON) in the energetic mineral supplement, on the intake and performance of beef cattle on pasture. Forty Nellore heifers with 24 months of age and initial body weight (BW) of 251.5±16.6kg, were distributed in four treatments in a randomized block design. Treatments consisted of adding VM, MON or VM+MON to the supplement (CONT). Additive concentrations were defined to reach a dose of 40 to 45mg/100kg BW. The herbage allowance was not a limiting factor for the animals’ intake. Supplement intake was lower than expected, with 33.0, 18.8 and 26.3mg per 100kg BW for VM, MON and VM+MON, respectively. Dry matter intake (DMI, mean=2.65% BW) and animal performance were not affected by the inclusion of additives. The average daily gain (ADG) was 0.561kg/animal day-1. The inclusion of additives in energetic mineral supplement does not affect the DMI and the ADG of grazing animals. The variability in supplement intake and daily dose intake of additives may have influenced the performance of the animals. Monensin inclusion presented the less expensive supplementation cost, due to reduction in supplement intake without changing weight gain.

Circadian disruption increased insulin resistance and decreased mammary development in late gestation, non-lactating (dry) cows. The objective was to measure the effect of circadian disruption on transcriptomes of the liver and mammary gland. At 35 d before expected calving (BEC) multiparous dry cows were assigned to either control (CON) or phase-shifted treatments (PS). CON was exposed to 16 h light and 8 h of dark. PS was exposed to 16 h light to 8 h dark, but phase of the light-dark cycle was shifted 6 h every 3 d. On d 21 BEC, liver and mammary were biopsied. RNA was isolated (n=6 CON, n=6 PS per tissue), libraries prepared and sequenced using paired end reads. Reads mapping to bovine genome averaged 27 M ± 2 M, and aligned to 14,222 protein coding genes in liver and 15,480 in mammary analysis. In the liver, 834 genes, and in the mammary gland, 862 genes were different (nominal P < 0.05) between PS and CON. In the liver, genes upregulated in PS functioned in cholesterol biosynthesis, endoplasmic reticulum stress, wound healing, and inflammation. Genes downregulated in liver function in cholesterol efflux. In the mammary gland, genes upregulated functioned in mRNA processing and transcription, downregulated genes encoded extracellular matrix proteins and proteases, cathepsins and lysosomal proteases, lipid transporters and regulated oxidative phosphorylation. Increased cholesterol synthesis and decreased efflux suggests circadian disruption potentially increases the risk of fatty liver in cows. Decreased remodeling and lipid transport in mammary may decrease milk production capacity during lactation.

709 clinical mastitis cases were analyzed and treated with antimicrobial combination cephalexin-neomycin and the anti-inflammatory prednisolone. A sample of milk was collected to perform a microbiological culture before starting the treatment and 14 days later. Somatic cell count (SCC) was obtained from samples collected on the day of the clinical case (D0), 14 days after (D14) and 28 days after (D28). Of the total, 435 (61.4%) at the D0 exhibited growth of microorganisms. Of the isolated agents, 365 (84%) were Gram-positive, and 66 (16%) were Gram-negative. A clinical cure was achieved in 63% of cases. Bacteriological cure occurred in 75% of cases. Only at D28 after the clinical case a significant SCC reduction was verified. The logistic regression for clinical cure showed significant effects for days in milk and parity (P< 0.05). For bacteriological cure, there were significant effects of Log (SCC) D0; clinical cure and quarter affected (P< 0.05). In the principal component analysis, the Temperature-Humidity Index was associated with reduced clinical cure of clinical mastitis cases.