Leo L. Timms
Iowa State University
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Featured researches published by Leo L. Timms.
Journal of Dairy Science | 2013
A.G. Arruda; S.M. Godden; Paul Rapnicki; Patrick J. Gorden; Leo L. Timms; Sharif S. Aly; Terry W. Lehenbauer; John D. Champagne
The study objective was to compare the efficacy of 3 commercial dry cow mastitis formulations regarding quarter-level prevalence of intramammary infections (IMI) postcalving, cure of preexisting infections over the dry period, prevention of new infections during the dry period, and risk for a clinical mastitis case between calving and 100d in milk (DIM). A total of 1,091 cows (4,364 quarters) from 6 commercial dairy herds in 4 different states (California, Iowa, Minnesota, and Wisconsin) were enrolled and randomized to 1 of the 3 treatments at dry-off: Quartermaster (QT; 1,000,000 IU of procaine penicillin G and 1 g of dihydrostreptomycin; Pfizer Animal Health, New York, NY), Spectramast DC (SP; 500 mg of ceftiofur hydrochloride; Pfizer Animal Health), or ToMorrow Dry Cow (TM; 300mg of cephapirin benzathine; Boehringer Ingelheim Vetmedica Inc., St. Joseph, MO). Quarter milk samples were collected for routine bacteriological culture before dry cow therapy treatment at dry-off, 0 to 6 DIM, and 7 to 13 DIM and an on-farm record-keeping system was used to retrieve data on clinical mastitis cases. Noninferiority analysis was used to evaluate the effect of treatment on the primary outcome, risk for a bacteriological cure during the dry period. Multivariable logistic regression techniques were used to describe the effect of treatment on risk for presence of IMI postcalving and risk of a new IMI during the dry period. Cox proportional hazards regression was used to describe the effect of treatment on the risk and time for quarters to experience an episode of clinical mastitis between calving and 100 DIM. The overall crude quarter-level prevalence of infection at dry-off was 19.2%. The most common pathogen isolated from milk samples at dry-off was coagulase-negative Staphylococcus, followed by Aerococcus spp. and other Streptococcus spp. Noninferiority analysis showed no effect of treatment on risk for a cure between dry-off and calving [least squares means (LSM): QT=93.3%, SP=92.6%, and TM=94.0%] and secondary analysis showed no effect of treatment on risk for presence of an IMI at 0 to 6 DIM (LSM: QT=16.5%, SP=14.1%, and TM=16.0%), risk for development of a new IMI between dry-off and 0 to 6 DIM (LSM: QT=14.8%, SP=12.3%, and TM=14.2%), or risk of experiencing a clinical mastitis event between calving and 100 DIM (LSM: QT=5.3%, SP=3.8%, and TM=4.1%). In conclusion, no difference was observed in efficacy among the 3 products evaluated when assessing the aforementioned quarter-level outcomes.
Journal of Human Lactation | 2008
Richmond Aryeetey; Grace S. Marquis; Leo L. Timms; Anna Lartey; Lucy Brakohiapa
Subclinical mastitis (SCM) is an asymptomatic inflammation of mammary tissue and has been associated with lactation failure, suboptimal growth in early infancy, and increased risk of mother-to-child transmission of HIV via breast milk. A rapid survey was carried out to determine the prevalence of SCM among lactating Ghanaian women between 3 and 4 months postpartum. Bilateral breast milk samples were obtained from 117 lactating women in Manya Krobo, Ghana and analyzed for sodium (Na) and potassium (K). An elevated sodium/potassium ratio (Na/K) above 1.0 was considered indicative of SCM. Overall, SCM prevalence was observed among 45.3% of the women. About 30% of the women had unilateral SCM. Na/K was associated with maternal age. The high SCM prevalence in Manya Krobo suggests the need for lactation support to reduce SCM and the risk of poor infant outcomes. J Hum Lact. 24(3):263-267. La mastitis subclínica (MSC) es una inflamación sintomática del tejido mamario y se ha asociado con el fracaso de la lactancia materna, crecimiento subóptimo en la primera infancia, y aumento del riesgo de la transmisión madre-hijo del VIH a través de la leche materna. Hicimos una encuesta rápida para determinar la prevalencia de la MSC entre mujeres lactando en Ghana entre los 3 y 4 meses postparto. Se obtuvieron muestras bilaterales de leche de 117 mujeres lactando en Manya Krobo, Ghana y se analizó el sodio (Na) y el potasio (K). Niveles elevados del rango sodio-potasio (Na/K) sobre 1.0 se consideraron indicativos de MSC. En general, la prevalencia de SCM fue de 45.3% de las cuales 29.9% fueron unilateral. El Na/K se asoció con la edad materna. Alta prevalencia de MSC en Manya Krobo sugiere la necesidad de apoyo a la lactancia para reducir la MSC y el riesgo de impacto en la salud del bebe.
PLOS ONE | 2015
M. Heather West Greenlee; Jodi D. Smith; Ekundayo M. Platt; Jessica R. Juarez; Leo L. Timms; Justin J. Greenlee
Bovine spongiform encephalopathy (BSE) belongs to a group of fatal, transmissible protein misfolding diseases known as transmissible spongiform encephalopathies (TSEs). All TSEs are caused by accumulation of misfolded prion protein (PrPSc) throughout the central nervous system (CNS), which results in neuronal loss and ultimately death. Like other protein misfolding diseases including Parkinson’s disease and Alzheimer’s disease, TSEs are generally not diagnosed until the onset of disease after the appearance of unequivocal clinical signs. As such, identification of the earliest clinical signs of disease may facilitate diagnosis. The retina is the most accessible part of the central nervous system, and retinal pathology in TSE affected animals has been previously reported. Here we describe antemortem changes in retinal function and morphology that are detectable in BSE inoculated animals several months (up to 11 months) prior to the appearance of any other signs of clinical disease. We also demonstrate that differences in the severity of these clinical signs reflect the amount of PrPSc accumulation in the retina and the resulting inflammatory response of the tissue. These results are the earliest reported clinical signs associated with TSE infection and provide a basis for understanding the pathology and evaluating therapeutic interventions.
Journal of Dairy Science | 2015
A. L. Robinson; Leo L. Timms; Kenneth J. Stalder; Howard D. Tyler
The objective of this study was to compare the effect of 4 antiseptic compounds on the healing rate and incidence of infection of umbilical cords in newborn calves (n=60). Late gestation Jersey cows were monitored at a commercial farm (Sioux Jersey, Salix, IA) and newborn purebred (n=30) and crossbred (n=30) calves were obtained within 30min after birth. Calves were alternately assigned by birth order to 4 treatment groups: 7% tincture of iodine, 0.1% chlorine created using a novel chlorine disinfectant technology, chlorohexidine gluconate 4.0% wt/vol, and 10% trisodium citrate. Prior to dipping (within 30min of birth), diameter of the umbilical cords (as an indicator of cord drying and healing) were determined using digital calipers. In addition, as an indicator of umbilical infections, surface temperature of the umbilical stump (along with a reference point at the midpoint of the sternum) was determined using a dual-laser infrared thermometer. These measurements were all repeated at 24±1 h of age. All data were analyzed using mixed model methods. All models included fixed effects of breed (Jersey or Jersey cross), sex (bull or heifer), and treatment. Fixed effect interactions were not included in the statistical model due to the relatively small sample size. No treatment differences were noted for healing rate of umbilical cords. Initially, mean umbilical cord diameter was 22.84±3.89mm and cords healed to a mean diameter of 7.64±4.12mm at 24 h of age. No umbilical infections were noted for calves on any treatment during the course of this study. Mean surface temperature of the umbilical stump was 33.1±2.2°C at birth (1.5±1.6°C higher than the sternal reference temperature), and at 24±1 h of age the mean temperature of the umbilical stump was 33.0±4.3°C (0.5±1.8°C lower than the sternal reference temperature). These data suggest that these antiseptic compounds are equally effective for preventing infections and permitting healing of the umbilical cord when used within 30min of birth.
Journal of Dairy Science | 2013
A.G. Arruda; S.M. Godden; Paul Rapnicki; Patrick J. Gorden; Leo L. Timms; Sharif S. Aly; Terry W. Lehenbauer; John D. Champagne
The objective of this randomized noninferiority clinical trial was to compare the effect of treatment with 3 different dry cow therapy formulations at dry-off on cow-level health and production parameters in the first 100 d in milk (DIM) in the subsequent lactation, including 305-d mature-equivalent (305 ME) milk production, linear score (LS), risk for the cow experiencing a clinical mastitis event, risk for culling or death, and risk for pregnancy by 100 DIM. A total of 1,091 cows from 6 commercial dairy herds in 4 states (California, Iowa, Minnesota, and Wisconsin) were randomly assigned at dry-off to receive treatment with 1 of 3 commercial products: Quartermaster (QT; Zoetis Animal Health, Madison, NJ), Spectramast DC (SP; Zoetis Animal Health) or ToMorrow Dry Cow (TM; Boehringer Ingelheim Vetmedica Inc., St Joseph, MO). All clinical mastitis, pregnancy, culling, and death events occurring in the first 100 DIM were recorded by farm staff using an on-farm electronic record-keeping system. Dairy Herd Improvement Association test-day records of milk production and milk component testing were retrieved electronically. Mixed linear regression analysis was used to describe the effect of treatment on 305ME milk production and LS recorded on the last Dairy Herd Improvement Association test day before 100 DIM. Cox proportional hazards regression analysis was used to describe the effect of treatment on risk for experiencing a case of clinical mastitis, risk for leaving the herd, and risk for pregnancy between calving and 100 DIM. Results showed no effect of treatment on adjusted mean 305 ME milk production (QT=11,759 kg, SP=11,574 kg, and TM=11,761 kg) or adjusted mean LS (QT=1.8, SP=1.9, and TM=1.6) on the last test day before 100 DIM. Similarly, no effect of treatment was observed on risk for a clinical mastitis event (QT=14.8%, SP=12.7%, and TM=15.0%), risk for leaving the herd (QT=7.5%, SP=9.2%, and TM=10.3%), or risk for pregnancy (QT=31.5%, SP=26.1%, and TM=26.9%) between calving and 100 DIM.
Sixth International Dairy Housing Conference Proceeding, 16-18 June 2007, (Minneapolis, Minnesota) (Electronic Only) | 2007
Daniel Meyer; Leo L. Timms; Lara B. Moody; Robert Burns
Dairies, in colder climate areas, have been reluctant to use separated manure solids for bedding cows in free stalls due to cow health concerns. The primary objectives of this research was to process dairy manure through an anaerobic digester followed by a manure solids separator and investigate the effectiveness of the recovered fiber as a dairy bedding material. The secondary objective was to see if phosphorus was partitioned into the solids recovered using the solids-- separator.
Animal Industry Report | 2004
R.T. Dingwell; K.E. Leslie; Leo L. Timms; Y.H. Schukken; Jan Sargent
Data from 300 cows and 1,178 quarters were analyzed to determine factors associated with new intramammary infections (IMI). Teatends that were cracked and teats that did not close during the dry period were 1.7 and 1.8 times more likely to develop new IMI, respectively. The level of milk production on the last day of lactation significantly influenced new IMI and teat canal closure. More (P<0.05) cows (36%) producing
Journal of Dairy Science | 2018
A.L. Fordyce; Leo L. Timms; Kenneth J. Stalder; Howard D. Tyler
21 kg of milk developed new IMI than cows (18%) producing less. When milk production was 21 kg or higher, teat canals were 1.8 times more likely to remain open.
Journal of Dairy Science | 2018
M. Al-Qaisi; E. A. Horst; S. K. Kvidera; E. J. Mayorga; Leo L. Timms; L. H. Baumgard
The goal of dipping the umbilical cord after birth in calves is to promote healing of the umbilical stump, prevent infection, and encourage the umbilical tissue to detach from the body. Treatment applied to the umbilical area is an important management step for preventing morbidity and mortality in calves. The objective of this study was to compare the effect of 4 umbilical dips on the healing rate, incidence of infection, and age at umbilical cord detachment using newborn Holstein heifer calves (n = 73). Calves were alternately assigned by birth order to 4 treatment groups: 7% iodine, a dry dip formulated using an antibacterial peptide (nisin) mixed with talc (3.105 g of nisin per 100 g of talcum powder on a weight per weight basis), liquid nisin (64 µg/mL), and 4% chlorhexidine mixed with alcohol in a 50:50 solution. Umbilical cords were dipped 30 min after birth. Before initial dipping, umbilical cord diameter (as an indicator of the rate of cord drying and healing rate) was determined using a digital caliper. The caliper measurements were repeated at 24 ± 1, 48 ± 1, and 72 ± 1 h (±standard deviation) of age and were continued daily until the umbilical cord healed and detached from the animals body. Diagnosed umbilical infections were documented by veterinary staff based on a combination of clinical symptoms (redness, swelling, purulent discharge, painful response (flinch or kicking) to palpation of the umbilical stump) in addition to a lack of appetite and fever. Data were analyzed using MIXED model procedures with fixed effect of umbilical treatment. No treatment differences were noted between dips on the umbilical cord drying rate or days for umbilical cord to detach. Treatment effects were observed on incidence of umbilical infection (incidence of infection for calves across all treatments was 9.0%).
Animal Industry Report | 2016
Jenn Bentley; Leo L. Timms; Larry F. Tranel; Greg Brenneman; Kris Kohl; Ron Lenth
Precisely studying the biological consequences of heat stress (HS) in agriculturally relevant animals typically requires expensive climate-controlled facilities, infrastructure inaccessible to most researchers. Thus, study objectives were to explore the efficacy of an electric heat blanket (EHB) as an alternative method for evaluating HS and to determine whether EHB-induced hyperthermia affects production parameters similar to natural HS. Lactating Holstein cows (n = 8; 133 ± 3 d in milk; 709 ± 31 kg; 2.6 ± 0.3 parity) were housed in individual box stalls and allowed to acclimate for 3 d. After acclimation, the trial consisted of 2 experimental periods (P). During P1 (3 d), cows were housed in thermoneutral conditions for collecting baseline data. During P2 (7 d), cows were fitted with an EHB. During the entire experiment cows were fed ad libitum, and dry matter intake (DMI) was recorded daily. Cows were milked twice daily (0600 and 1800 h), and milk samples were collected on d 2 and 3 of P1 and d 3 and 7 of P2. Rectal temperature, respiration rate, heart rate, and skin temperature were obtained twice daily (0600 and 1800 h) during both P1 and P2. Overall, there was an increase in rectal temperature and respiration rate at 0600 h (1.0°C and 25 breaths/min, respectively) and 1800 h (1.2°C and 29 breaths/min, respectively) during P2. The EHB decreased DMI and milk yield (25 and 21%, respectively) by the end of P2. During P2, milk protein tended to decrease (4.4%) compared with P1. In contrast, milk urea nitrogen increased (33%) during P2 relative to P1. No other differences were observed in milk composition. In summary, our results indicate that employing an EHB affects physiological and production parameters similarly to natural HS (i.e., increased rectal temperature and respiration rate, decreased DMI and milk yield); thus, the EHB is an effective and inexpensive research tool for evaluating the biological consequences of HS in lactating dairy cows.