Biomedical subjects

J P Goff

Publications and source records attributed to J P Goff.

At least 19 recordsLinked to original sources

PubMed2006

Pre-partum monensin supplementation improves body reserves at calving and milk yield in Holstein cows dried-off with low body condition score.

The objective of this study was to determine the effect of a monensin controlled-release capsule administered intraruminally at drying-off on body condition score (BCS) at calving, milk yield, fertility and concentration of energy-related blood metabolites in Holstein cows dried-off with low BCS (< or = 3.0, scale 1 to 5 with a 0.25 point of increment). Between July and August, 2001, 220 cows from parity 2 or more and dried-off 50-70 days before expected parturition, with a BCS < or = 3.0 were randomly assigned to either a treatment group (n=110; oral capsule of monensin releasing 335 mg/day for 95 days) or a control group (no capsule, n=110). At assignment, on day 21 before expected parturition, at calving, and at 7, 14, and 21 days in milk a blood sample was obtained from a random sub sample of 10 cows per group. Effects of monensin on serum NEFA, BHBA and glucose were measured. Milk yield, milk fat and protein content (%) at DHIA test days during the entire lactation, 305 ME milk production and reproductive responses were compared. Monensin significantly improved BCS at calving, increased milk yield at test days 4 and 8, decreased the percentage of milk protein, did not change the percentage of milk fat, and decreased NEFA and BHBA during the post-partum period.

Animal Feed↗

PubMed2006

Neutrophil function and energy status in Holstein cows with uterine health disorders.

The objectives of this study were to investigate the associations between peripheral blood neutrophil (PMN) function, energy status, and uterine health in periparturient dairy cows. Data were collected from 83 multiparous Holstein cows. Blood samples for PMN function determination were collected weekly from 1 week prior to calving (week -1) through 4 weeks after calving and again at 8 weeks after calving. Energy metabolites were measured and dry matter intake (DMI) was determined from weeks -2 to 5 to evaluate energy status of cows during the periparturient period. All cows were examined for uterine health disorders. Blood PMN killing ability was evaluated by determining myeloperoxidase activity and cytochrome c reduction activity in isolated blood PMN's. For cows that were diagnosed with puerperal metritis and subclinical (SC) endometritis and puerperal metritis, blood PMN functions were significantly (P<0.05) impaired during the periparturient period, compared to cows with normal uterine health. Cows with subclinical endometritis and puerperal metritis or SC endometritis also had significantly (P<0.01) higher NEFA and significantly (P<0.001) lower DMI during the periparturient period, and significantly (P<0.05) higher BHBA during early lactation, compared to cows with normal uterine health. Neutrophil function was also significantly (P<0.01) impaired in cows with peripartum negative energy balance, which was characterized by elevated blood levels of NEFA and decreased DMI. Decreased PMN function and energy balance were associated with uterine health disorders and the decreases in PMN function and energy balance occurred prior to parturition and prior to the detection of these uterine disorders.

3-Hydroxybutyric Acid↗

PubMed2006

Major advances in our understanding of nutritional influences on bovine health.

The Journal of Dairy Science has increasingly become a primary outlet for scientific research concerning the health of the dairy cow and her calf. This paper attempts to highlight Journal of Dairy Science articles that have linked nutrition and nutritional strategies to reduce disease incidence on the dairy farm. Disorders associated with an animal's inability to cope with the demands of high production include diseases such as milk fever and ketosis, which clearly are related to the cow's inability to maintain bodily functions in the face of negative calcium or energy balance. Improved nutrition of the late gestation cow can reduce the incidence of some of these disorders. Susceptibility to infectious disease is dependent on the integrity of the immune system, and recent studies have shed light on nutritional factors that affect leukocyte function. Other disorders, such as retained fetal membranes, udder edema, and displacement of the abomasum are not easily categorized as to their cause, but nutritional strategies have been developed to help prevent these disorders as well.

Acidosis↗

PubMed2006

Parturition and hypocalcemia blunts calcium signals in immune cells of dairy cattle.

The stress of parturition in the dairy cow is associated with increased susceptibility to infectious disease. During the periparturient period the demands for calcium are increased; these increased demands for calcium can result in subclinical or clinical hypocalcemia. Periparturient cows also experience significant immune suppression. Because intracellular calcium signaling is a key early feature in immune cell activation, we have hypothesized that the increased demand for calcium in periparturient cows may adversely affect intracellular calcium stores of immune cells. This reduction in intracellular calcium stores in immune cells could blunt intracellular calcium release following an activating stimulus, contributing to the immune suppression seen in these animals. To test this hypothesis, peripheral mononuclear cells were obtained from 27 multiparous dairy cows spanning a period of 2 wk before and 2 wk after parturition. Following activation of these cells by anti-CD3 antibodies plus secondary antibodies, intracellular calcium release from intracellular stores was measured. The intracellular calcium released in response to the activation signal declined as calcium demand for lactation became more intense and recovered as plasma calcium normalized. Intracellular calcium stores in peripheral mononuclear cells, estimated by pretreating cells with pervanadate and ionomycin, significantly decreased at parturition and returned to normal levels as the cows' blood calcium returned to normal levels. Hypocalcemia, which is common in periparturient dairy cows, is associated with decreased intracellular calcium stores in peripheral mononuclear cells. Our data suggest that this is the cause of a blunted intracellular calcium release response to an immune cell activation signal. It is concluded that intracellular Ca stores decrease in peripheral blood mononuclear cells (PBMC) before parturition and development of hypocalcemia. This suggests that systemic calcium stress precedes measurable hypocalcemia, particularly in cows that will develop milk fever. Therefore, PBMC intracellular Ca stores are a more sensitive measure of calcium stresses in transition cow. This decrease in PBMC intracellular Ca stores before parturition and the development of hypocalcemia contributes to periparturient immune suppression.

Aniline Compounds↗

PubMed2005

Incidence of subclinical ketosis in cows supplemented with a monensin controlled-release capsule in Holstein cattle, Florida, USA.

The objective of this study was to determine the effect of a monensin controlled-release capsule on the proportion of cows with subclinical ketosis (SK). During July to August 2001, 300 cows dried-off 50-70 days before expected parturition were randomly assigned to either a treatment (n = 150, oral capsule, 335 mg/d of monesin for 95 d) or control group (no capsule, n = 150). At 14 days postpartum, a milk sample was obtained and evaluated for beta-hydroxybutyrate (BHBA) using a semi-quantitative ketone test strip. In a sub-sample of 50 cows per group a blood sample was taken and analyzed for BHBA using an ELISA kit. Milk BHBA > or = 200 micromol/L was used as the cut-off value for diagnosis of SK. The incidence of SK based on the milk test was statistically different between groups (P < or = 0.05) with a value of 26.6% for control and 14.5% for cows treated with monensin, respectively. Cows treated with monensin were 0.68 times less likely to give a positive result for milk BHBA than non-treated cows (0.53-0.80; 95% CI). Serum BHBA concentrations did not differ between groups (0.81 +/- 0.09 mmol/L versus 0.70 +/- 0.07 mmol/L for controls and treated, respectively; P > 0.05). However, for each incremental increase in serum BHBA of 0.1 mmol/L occurrence of SK increased 52% (OR = 1.52; 1.21-1.91; 95% CI).

3-Hydroxybutyric Acid↗

PubMed2005

Spin correlations in the paramagnetic phase and ring exchange in La2CuO4.

Spin correlations in the paramagnetic phase of La(2)CuO(4) have been studied using polarized neutron scattering, with two important results. First, the temperature dependence of the characteristic energy scale of the fluctuations and the amplitude of the neutron structure factor are shown to be in quantitative agreement with the predictions of the quantum nonlinear sigma model. Second, a comparison of a high-temperature series expansion of the equal-time spin correlations with the diffuse neutron intensity provides definitive experimental evidence for ring exchange.

Journal Article↗

PubMed2005

Short communication: Ca2+-adenosine triphosphatase protein expression in the mammary gland of periparturient cows.

The objectives of this study were to measure the changes in protein expression of the mammary Ca2+-ATPases during the periparturient period and to determine whether Ca2+-ATPase protein expression in the mammary gland is related to milk fever (MF) development. Abundance of Ca2+-ATPase in mammary tissue and milk fat globule membranes was determined by Western blotting. The secretory pathway Ca2+-ATPase was elevated prepartum in mammary tissue from cows that developed MF compared with non-MF cows.

Animals↗

PubMed2005

Periparturient responses of multiparous Holstein cows fed different dietary phosphorus concentrations prepartum.

Our objective was to compare the effects of different prepartum dietary phosphorus concentrations on periparturient metabolism and performance. Forty-two late pregnant multiparous Holstein cows were fed 0.21, 0.31, or 0.44% P (dry basis) for 4 wk before expected calving. After parturition, all cows were fed a common lactation diet (0.40% P). In the prepartum period, cows fed 0.21% P had lower blood serum P concentrations compared with cows fed 0.31 or 0.44% P. However, serum P concentrations of all cows were within the normal range (4 to 8 mg/dL) until the day of calving when average concentrations dropped below 4 mg/dL. From 3 to 14 d postpartum, serum P of cows fed 0.21% P was greater than that of cows fed 0.31 or 0.44% P. No cows presented with or were treated for clinical hypophosphatemia in the periparturient period. Total serum Ca was lower before calving through 2 d postpartum for cows fed 0.44% P compared with those fed 0.21 or 0.31%. Prepartum dietary P treatments did not alter blood osteocalcin, hydroxyproline, and deoxypyridinoline, indicators of bone metabolism, or concentrations of parathyroid hormone or 1,25-dihydroxyvitamin D3. Energy-corrected milk yield and milk composition (first 28 d of lactation) were not affected by prepartum dietary P concentrations. It is concluded that feeding 0.21% P (34 g of P/cow daily) prepartum is adequate for periparturient multiparous Holstein cows with high metabolic demands and genetic potential for milk production. No adverse effects on periparturient health, dry matter intake, or 28-d lactation performance resulted.

Animals↗

PubMed2004

Utilizing Solanum glaucophyllum alone or with phytase to improve phosphorus utilization in broilers.

Experiments were conducted to determine if Solanum glaucophyllum (SG), a plant containing a glycoside of 1,25-dihydroxyvitamin D, could be used as a feed additive to improve P utilization of broilers. SG leaves (1, 2.5, or 5 g/kg), 1,25-dihydroxyvitamin D (15 microg/kg), or Ca and P (to achieve a 0.92% Ca:0.65% P:0.41% nonphytate P control diet) were added to a 0.56% Ca/0.45% P/0.28% nonphytate P basal diet and fed to broilers from 7 to 28 d of age. Birds fed basal ration alone exhibited reduced weight gain, bone density, and bone mineral content when compared with birds fed the 0.92% Ca:0.65% P diet. Adding 5 g SG leaves or 15 microg of 1,25-dihydroxyvitamin D/kg to the basal diet increased body weight gain, plasma Ca and P, bone ash, and bone density above basal diet levels. Plasma P and weight gain of birds fed 5 g SG or 15 microg of 1,25-dihydroxyvitamin D/kg basal diet were equivalent to those observed in birds fed the 0.92% Ca:0.65% P diet. In experiment 2, the effect of higher doses of SG, as well as the additive effect of SG with 1,200 phytase units/kg diet, were examined in chicks fed a 0.59% Ca and 0.42% P basal diet. Two levels of SG leaves (7.5 g and 10 g), phytase, or both SG (7.5 g) and phytase were added per kilogram of basal diet. Adding SG or phytase to the basal diet increased weight gain, plasma Ca, plasma P, and bone mineral content over that observed in birds fed basal diet alone. Combining SG with phytase provided no significant gains in growth or bone parameters over treatment with phytase alone.

6-Phytase↗

PubMed2004

Relative acidifying activity of anionic salts commonly used to prevent milk fever.

High cation diets can cause milk fever in dairy cows as they induce a metabolic alkalosis reducing the ability of the cow to maintain calcium homeostasis at the onset of lactation. Adding anions to the diet can offset the effect of the high cation forages by inducing a mild metabolic acidosis, restoring the ability to maintain calcium homeostasis. The difference in mEq of dietary cations and anions (DCAD) is most often expressed as (Na(+) + K+) - (Cl- + S(--)). This equation implies that a mEq of chloride and a mEq of sulfate are equipotent in their ability to alter acid-base balance of the cow. Using blood and urine pH to monitor effects on acid-base balance, experiments were conducted to test the relative acidifying activity of various sulfate and chloride anion sources in nonpregnant, nonlactating Jersey cows. Across all experiments, chloride proved to have about 1.6 times the acidifying activity of sulfate. Calcium and magnesium, ignored by the common DCAD equation, had a small but significant alkalinizing effect when accompanying chloride or sulfate. The ranking of the anion sources tested at a dose of 2 Eq/d, from most to least potent urine acidifier, was hydrochloric acid, ammonium chloride, calcium chloride, calcium sulfate, magnesium sulfate, and sulfur. These data should allow more accurate prediction of the response of late gestation cows to dietary cation-anion manipulation.

Acid-Base Equilibrium↗

PubMed2004

Effect of a monensin controlled-release capsule on rumen and blood metabolites in Florida Holstein transition cows.

The objective of this study was to determine the effect of a monensin controlled-release capsule administered intraruminally at dry-off on rumen volatile fatty acids, NH3, lactate, pH, and energy blood metabolites in transition dairy cows fed Florida typical diets. In March 2003, 24 cows (10 primiparous and 14 multiparous) dried-off 50 to 70 d before expected parturition were randomly assigned to a treatment (n=12, oral capsule of monensin) or a control group (n=12, no capsule). Both groups received the same diet and were exposed to the same environment and management conditions. At assignment, at 21 d before expected parturition, at calving, and at 7, 14, and 21 d postpartum, blood samples were taken and body condition scores were determined. At 10 d postpartum, rumen and blood samples were obtained in the morning before the first feeding and at 2, 4, and 6 h after feeding. Serum nonesterified fatty acids (NEFA), beta-hydroxybutyrate (BHBA), and glucose were measured. Rumen samples were analyzed for concentrations of acetic, propionic, butyric, L- and D-lactic acids, and NH3. Data for rumen and blood metabolites were analyzed by ANOVA, mixed models for repeated measures. Volatile fatty acids were not different between groups. Multiparous treated cows had a significant reduction in rumen NH3 at 6 h after feeding. Treatment with monensin significantly increased body condition score at calving in multiparous cows. During the postpartum period, NEFA and BHBA were noticeably lower in treated than in control primiparous cows. This difference was not observed in multiparous cows.

3-Hydroxybutyric Acid↗

PubMed2003

Effect of calcium-energy supplements on calving-related disorders, fertility and milk yield during the transition period in cows fed anionic diets.

The objective of this study was to determine the effect of a calcium-energy supplement at calving on the incidence of calving-related disorders (CRD), fertility, BCS and milk yield in cows fed anionic diets and to establish any associations among outcome variables. In Florida, from October to December 1997, 479 cows were assigned to three groups and treated at calving as follows: Group 1: 160 nontreated cows; Group 2: 158 cows, treated orally with 60g Ca as CaCl2; Group 3: 161 cows, treated orally with 110g Ca as calcium propionate (510g) plus propylene glycol (400g). No treatment effect was detected for any of the outcome variables. An association was found between dystocia and age and retained fetal membranes (RFM). Age and RFM were associated with metritis. RFM and displacement of the abomasum were associated with ketosis. Ketosis and age were related to displacement of the abomasum. Parity, BCS, ovarian cysts, RFM and metritis were associated with fertility.

Aging↗

PubMed2003

Modeling stem cell population growth: incorporating terms for proliferative heterogeneity.

Expansion of the undifferentiated stem cell phenotype is one of the most challenging aspects in stem cell research. Clinical protocols for stem cell therapeutics will require standardization of defined culture conditions. A first step in the development of predictable and reproducible, scalable bioreactor processes is the development of mathematical growth models. This paper provides practical models for describing cell growth in general, which are particularly well suited for examining stem cell populations. The nonexponential kinetics of stem cells derive from proliferative heterogeneity, which is biologically recognized as mitosis, quiescence, senescence, differentiation, or death. Here, we examined the assumptions of the Sherley model, which describes heterogeneous expansion in the absence of cell loss. We next incorporated terms into the model to account for A) cell loss or apoptosis and B) cell differentiation. We conclude that the basic assumptions of the model are valid and a high correlation between the modified equations and experimental data obtained using muscle-derived stem cells was observed. Finally, we demonstrate an improved estimation of the kinetic parameters. This study contributes to both the biological and mathematical understanding of stem cell dynamics. Further, it is expected that the models will prove useful in establishing standardization of cell culture conditions and scalable systems and will be required to develop clinical protocols for stem cell therapeutics.

Apoptosis↗

PubMed2003

Effects of the mammary gland on functional capacities of blood mononuclear leukocyte populations from periparturient cows.

The composition and functional capacity of peripheral blood mononuclear leukocyte populations from dairy cows are altered substantially during the peripartal period. These changes are associated with a heightened susceptibility of the mammary gland to infection. It has been postulated that the metabolic demands associated with lactogenesis may impact negatively leukocyte function during the periparturient period. In the present study, serum immunoglobulin G1 concentration and functional capacities of peripheral blood mononuclear leukocytes from intact (n = 6) and mastectomized (n = 6) periparturient Jersey cows were evaluated and compared. Cell function assessments included lymphocyte proliferation, immunoglobulin M secretion, and interferon-gamma secretion by unstimulated and pokeweed mitogen stimulated mononuclear leukocytes. Data were summarized as mean responses for 5-d periods beginning 21 d prepartum and concluding at 19 d postpartum. The progressive decrease in serum immunoglobulin G in intact but not mastectomized cows before parturition likely was attributable to the selective uptake of this isotype by the mammary gland. Lymphocyte proliferation and secretion of interferon-gamma and polyclonal IgM by mitogen-stimulated leukocytes from intact cows decreased during the 15-d period before calving, reaching a nadir at 0 to 4 d postpartum. From 5 to 19 d postpartum, these functions often were comparable to those observed 2 to 3 wk prepartum. Functions of leukocytes from mastectomized cows did not change during the study period, although they often were of lower magnitude than those of cells from nonlactating cows. These results reconfirm the occurrence of a generalized reduction in blood mononuclear leukocyte function during the periparturient period. They also suggest that the reduction in leukocyte function during the period may be, in part, due to the physiologic demands imposed on the dairy cow by the lactating mammary gland.

Animals↗

PubMed2003

Effects of supplemental energy on metabolic and immune measurements in periparturient dairy cows with Johne's disease.

The present study was designed to evaluate whether feeding supplemental energy would improve the metabolic profile and alleviate some of the immunosuppression typically noted during the periparturient period in dairy cows with Johne's disease. Twelve dairy cows naturally infected with Mycobacterium paratuberculosis were fitted with rumen cannulas in late gestation and assigned to treatment groups: control, n = 6; or stuffed, n = 6. Cows in the control group were allowed to consume feed ad libitum. Cows assigned to the stuffed treatment group were also fed ad libitum but received additional total mixed rations by manually stuffing their rumens with refused feed to maintain dry matter intake of 2% body weight per day before calving and 2.5% body weight per day after calving. Serum nonesterified fatty acid levels were significantly decreased in stuffed cows compared with control cows, indicating that stuffing to maintain dry matter intake improved the energy balance in the cows. In addition, periparturient serum calcium and magnesium concentrations were significantly higher in stuffed cows. Stuffing modulated cell-mediated immunity by reducing lymphocyte proliferative responses to T-cell mitogens during early lactation. Stuffing resulted in an increase in the secretion of in vitro immunoglobulin by peripheral blood mononuclear cells after parturition when compared to control cows. These data demonstrate that energy balance is improved by providing additional energy in this manner and suggest energy supplementation can improve some aspects of immune function during the periparturient period.

Animal Feed↗

PubMed2003

Role of vitamin D in calcium homeostasis and its use in prevention of bovine periparturient paresis.

Calcium (Ca) is essential for life in higher animals. It is involved in the normal functioning of a wide variety of tissues and physiologic processes which include bone formation, muscle contraction, nerve transmission, blood clotting and as a second messenger regulating the actions of many hormones. In order for these functions to be carried out properly, blood Ca concentrations must be monitored and regulated within strict limitations. The discovery of the vitamin D endocrine system has resulted in the realization that Ca regulation in mammals and birds involves a coordinated effort between the hormones parathyroid hormone (PTH), calcitonin and the hormonally-active form of vitamin D3, 1,25-dihydroxyvitamin D3 [1,25(OH)2D3]. Failure of this system to maintain normal blood Ca concentrations at parturition is a common occurrence in ruminants leading to clinical (periparturient paresis, milk fever) and subclinical hypocalcemia. Vitamin D sterols have played a significant role in efforts to avoid parturient hypocalcemia and this report will summarize advantages and disadvantages associated with their use.

Animals↗

PubMed2003

Role of acid-base physiology on the pathogenesis of parturient hypocalcaemia (milk fever)--the DCAD theory in principal and practice.

The hypocalcemia associated with the clinical disease known as milk fever is due to a failure of the calcium homeostatic mechanisms in the cow to restore normal blood calcium concentration in a timely manner at the onset of lactation. The defect in calcium homeostasis appears to reside in the sensitivity of bone and kidney tissues to parathyroid hormone (PTH) stimulation. Evidence suggests the acid-base status of the cow dictates the sensitivity of the tissues to PTH stimulation, and that metabolic alkalosis is responsible for blunting tissue PTH responsiveness. Hypomagnesemia can also reduce tissue PTH responsiveness but hypomagnesemia can be corrected in most rations. Excessive dietary potassium is very common and is the most important factor causing metabolic alkalosis in dairy cows. Formulation of rations to reduce metabolic alkalosis and/or induce a compensated metabolic acidosis in the pre-partal cow has proved a useful strategy for prevention of milk fever. The concept of dietary cation-anion difference manipulation and the physiologic effects this can have in the cow are presented, with special emphasis on the Strong Ion Difference theory of acid-base physiology.

Acid-Base Imbalance↗

PubMed2003

Milk fever control in the United States.

Strategies for the prevention of milk fever in the United States have made several 180 degree changes over the last several decades. During the 1950's and 1960's evidence suggested that low calcium diets could be utilized to stimulate the parathyroid prior to calving to initiate calcium homeostasis prior to the onset of lactation. High calcium diets were avoided and the strategy worked--for a while, until more concentrated farming practices changed the cation composition of the forages. Although Norwegian scientists presented evidence of a role for cations and anions in milk fever during the late 1960's, recent studies have more precisely defined the physiological link between high diet potassium and tissue sensitivity to parathyroid hormone as a leading cause of milk fever. Manipulation of dietary cation-anion balance has been growing rapidly as a means of controlling not only milk fever but sub-clinical hypocalcemia as well. A recent United States survey found that 45% of dairy operations feed dry cows a "low potassium diet" to reduce milk fever. In addition some use anionic salts. About 27% of dairy farms feed dry cows a diet with added anions to induce a compensated metabolic acidosis which has proved effective in reducing subclinical hypocalcemia. These diets are often high in calcium.

Animal Husbandry↗