Histologic features and results of virus isolation tests of tissues obtained from teat lesions that developed in dairy cattle during winter

OBJECTIVE: To determine microscopic features and involvement of viruses in teat-end lesions (TEL) of dairy cows during winter. SAMPLE POPULATION: Teats with TEL on lactating Holstein cows and from udders of carcasses. PROCEDURE: Tissues obtained from TEL of 10 teats from 7 cows on 2 research farms during the winter of 1994 to 1995 and 13 teats with TEL excised from udders of carcasses at an abattoir during February 1995 were submitted for virus isolation. During the winter of 1995 to 1996, an increased prevalence of TEL was observed in a research herd. After a decrease in ambient temperature, TEL were identified, and a full-thickness section of epidermis was removed from skin surrounding teat orifices. Tissues were examined by use of light and electron transmission microscopy. RESULTS: Viruses were not isolated from TEL tissues. Lesions ranged from mild elevations of the epidermis to thickened oval regions that encircled the teat orifice. The most severe lesions were dark and had thick crusts. Histologically, TEL were composed of thickened regions of epidermis most notably caused by hyperplasia of cells within the stratum spinosum. Excess production of keratinocytes was also evident, and the keratinocyte layer often contained bacteria. Ultrastructurally, squamous cells contained large amounts of keratin, but virions were not detected. Evidence of a viral etiologic agent for TEL was not detected. CLINICAL IMPLICATIONS: Development of TEL may be associated with decreases in ambient temperature. Numerous bacteria were evident in the keratin of TEL. Lesions and associated bacteria may predispose cows to mastitis.     

Evaluation of cow-level risk factors for the development of winter dysentery in dairy cattle

OBJECTIVE: To identify exposures to etiologic agents and to identify characteristics that could explain risk of disease for adult cattle in herds affected by winter dysentery (WD). ANIMALS: 229 lactating and nonlactating adult cattle (125 case and 104 control cattle) selected from 12 dairy herds. PROCEDURE: A case-control study, using multivariate conditional logistic regression and controlling for herd effects, was used to develop a model for risk factors associated with disease for each cow. RESULTS: Likelihood of developing disease increased as the ELISA value for bovine coronavirus (BCV) antigen detectable in feces increased (odds ratio [OR] = 2.94 for each 0.100 increase in BCV antigen ELISA value). Pregnant cattle were less likely to develop WD, compared with nonpregnant herdmates. Cows with high acute BCV antibody titers that seroresponded had greater odds of developing disease, compared with seroresponding cows with low acute titers. However, among those cows that did not serorespond, high acute antibody titers were associated with lower odds of developing the disease. CONCLUSION: In herds affected by WD, ill cows were more likely to shed detectable amounts of BCV antigen in their feces, and pregnancy appeared to protect cattle from the disease. The measured interaction between BCV seroresponse and acute BCV antibody titer may be evidence of an immunopathologic condition, but could also have been attributable to dynamics of the ELISA or study design. CLINICAL RELEVANCE: Factors that explained a cow's risk for illness within WD-affected herds may have been surrogate measures for that cow's nonspecific and BCV-specific immune profile.     

Inefficiency of lactation in primiparous rats: the costs of first reproduction

To investigate the energetic costs of lactation in a female mammal in relation to previous reproductive history, we compared the performance of adult female Long-Evans rats that had previously bred (multiparous) with young females that had not previously given birth (primiparous). All litters were standardized to 10 +/- 1 young. We compared maternal production (growth of pups), body mass, and energy intake (food consumption) of mothers, as well as their energy expenditure (resting oxygen consumption). The mass of litters at birth and the growth of pups during lactation did not differ according to reproductive history of the mothers. The body mass of primiparous mothers was less than that of multiparous mothers, and primiparous mothers showed an increase in mass during early lactation. To accomplish the essentially identical production of offspring under these circumstances, the primiparous mothers consumed and expended more energy than the multiparous mothers. This remarkable performance of first-time mothers results in an overall efficiency of energy allocation to reproduction amounting to only 25%, compared with 38% in multiparous mothers. The energetic inefficiency of primiparous female lactation results largely from the excessive expenditures associated with physiological and behavioral performances of first-time reproduction, together with a small component of additional expenditure due to further growth by the primiparous mothers. We suggest that this inefficiency probably contributes to the observed low reproductive success of novice breeders; furthermore, active restraint of fecundity may be an evolutionary response to the constraints of the energetic inefficiency of primiparous breeding by female mammals.     

Incidence and prevalence of lameness in dairy cattle

A survey was made of 37 dairy farms in Wirral, mid-Cheshire, mid-Somerset and Dyfed, Wales, to assess the incidence and prevalence of lameness in the cows between May 1989 and September 1991. The incidence was obtained from records made whenever a cow was examined for lameness or received preventive foot-trimming. The mean annual incidence was 54.6 new cases per 100 cows with a range from 10.7 to 170.1 and the mean values during summer and winter were 22.9 and 31.7, respectively. The prevalence of lameness was measured by regular visits at which locomotion was scored on a scale of 1 to 5, and the prevalence of lameness was calculated for each visit as the proportion of cows with scores of 3 or more. The mean annual prevalence over the whole period was 20.6 per cent with a range from 2.0 to 53.9 per cent for the 37 farms. The mean prevalences during summer and winter were 18.6 and 25.0 per cent, respectively. The prevalence measured at a single visit in midsummer or midwinter was significantly correlated with the mean prevalence over the whole corresponding period and may be useful as an assessment of the extent of lameness in a herd and the efficacy of control measures. There was evidence that training farmers to recognise early cases of lameness and request veterinary treatment resulted in a marked reduction in the duration of cases of lameness.     

Fetal development of the white line (Zona alba) of the equine hoof

The fetal development of the white line (Zona alba) in the equine hoof is described. Its specific structure of lamellar and interlamellar horn, which in turn is composed of cap and terminal horn, is formed in the second half of the hoof's fetal development. In equine fetuses with a crown-rump length of less than 550 mm, the hoof capsule lacks a 'characteristic' white line since no borders between stratum medium, stratum internum and sole horn are discernible. In the hoof of an equine fetus with a crown-rump length of 550 mm, a narrow white line has taken shape. Its shallow lamellae are arranged like arcades. Between the horn lamellae lie the polyhedral cells of the interlamellar horn. Up until birth, the height of the horn lamellae and, therefore, the width of the white line increases significantly. In the white line of the hoof of newborn foals, the terminal horn contains horn tubules with a characteristic architecture.     

Machine milking of dairy goats during lactation: udder anatomy, milking characteristics, and blood concentrations of oxytocin and prolactin

Forty-four goats were milked and milk flow recorded without or with 1 min manual prestimulation in early, mid and late lactation. Ultrasound measurements of cross sections of the whole mammary gland were performed in a water bath. In additional experiments with 15 goats, milk flow was recorded and frequent blood samples were taken for the determination of oxytocin and prolactin concentrations. Milk yield increased from the first to the third lactation and decreased markedly during the course of lactation. Average and peak milk flow rates were closely related to the actual milk yield. The ultrasound cisternal area was 27.4 +/- 1.5% of the entire udder half cross section. Milking characteristics were scarcely different without or with prestimulation, although oxytocin was released within 30 s after the start of prestimulation, whereas oxytocin concentrations without prestimulation increased only after the start of milking. Concentrations of prolactin were higher during July and August than in April, and increased similarly with or without prestimulation during milking. In contrast to dairy cows, prestimulation and an opportune release of oxytocin during milking does not significantly influence the course of milk flow in goats, and this is probably because large amounts of cisternal milk allow milk ejection to be induced only after the start of milking without causing bimodal or otherwise reduced milk flow.     

Aetiology and Pathogenesis of abomasal displacement in dairy cattle

A clinical chemical survey is given of the complex of factors which are involved during development of clinically manifest hypotony or atony of the abomasum prior to abomasal displacemnts. The importance of a change in the acid-base balance of the animals is especially stressed as a predisposing factor. The further pathogenesis of abomasal displacement is supposed to follow different ways, according to the feeding and to prevailing periods of indigestion.     

The seasonal variation of thermophilic campylobacters in beef cattle, dairy cattle and calves

The epidemiology of clinical cases of campylobacter in temperate climates shows a striking seasonality. In the search for a seasonal environmental reservoir changes in the carriage rate and population size of campylobacters in bovine hosts with time have been measured. Most probable number (MPN) methodology was used to enumerate thermophilic campylobacters in samples taken from the small intestines of beef cattle at slaughter and the fresh faeces of four dairy herds and new-born calves. Statistical analyses revealed significant evidence for seasonal periodicity in the data from dairy herds (P = 0.044). Not only was there a departure from constancy within a 12-month interval but these data revealed a true seasonality, that is, the same periodicity in numbers from one year to the next. Each herd had two peaks per year, in approximately spring and autumn. Peaks coincided in herds on neighbouring farms but those on farms in the north preceded those on farms in the south by 2 and 1 months, respectively (P = 0.0057). Intestinal carriage by beef cattle at slaughter was 89.4% (n = 360) with an average MPN campylobacters per gram fresh weight (MPN gfw-1) of 6.1 x 10(2). Average MPN gfw-1 in faeces from the dairy herds and calves were 69.9 (S.D. 3) and 3.3 x 10(4) (S.D. 1.7 x 10(2)). There was no evidence of seasonal periodicity in the size of the campylobacter population in beef cattle at slaughter. Calves were campylobacter free at birth but became colonized with a few days.     

Effect of the feeding level during rearing on performance of Large White gilts. Part 1: Growth, reproductive performance and feed intake during the first lactation

Fifty pure-bred Large White gilts were allocated to two feeding levels from 28 kg until service. They were fed a standard growing diet (13.4 MJ digestible energy (DE) per kg; 18.1% crude protein, CP; 0.96% lysine) either to appetite (AP) or at 80% of the AP level (R). Growth rate was reduced by about 20% in R gilts, whereas feed conversion ratio was unaffected by rearing treatment. First oestrus was detected earlier in AP gilts (234 versus 247 d of age). At service, AP females had larger body weight (190 versus 150 kg) and thicker backfat (20.9 versus 13.4 mm). After service, the reproductive performances of 30 of these gilts were studied during the first reproductive cycle. All gilts received 2.6 kg/d of a standard diet (12.6 MJ DE/kg; 13.9% CP; 0.59% lysine) during pregnancy and were fed ad libitum a commercial lactation diet (13.1 MJ DE/kg; 17.1% CP; 0.90% lysine) from day five after farrowing. At farrowing, AP females were larger (257 versus 225 kg) and had more backfat (23.7 versus 17.4 mm) than R ones. Reproductive performance during the first lactation was not affected by rearing treatment, and weaning to oestrus interval was similar in both groups (4.8 d, on average). During lactation, R sows consumed significantly more feed (+650 g/d) and lost less backfat depth (1.5 versus 3.8 mm) than AP ones.     

Review: effect of protein nutrition on ovarian and uterine physiology in dairy cattle

Milk production and dry matter intake of dairy cows are stimulated in response to increased intake of dietary protein, but, unfortunately, decreased fertility is often associated with this nutritional strategy. Ruminally degradable protein or ruminally undegradable protein in excess of requirement can contribute to reduced fertility in lactating cows. Dietary protein nutrition or utilization and the associated effects on ovarian or uterine physiology have been monitored with urea nitrogen in plasma or milk; concentrations above 19 mg/dl have been associated with altered uterine pH and reduced fertility in dairy cows. The uterine pH changed dynamically and inversely with plasma urea nitrogen, signaling possible changes in the uterine milieu. Mechanisms for reduced fertility include exacerbation of negative energy balance and reduced plasma progesterone concentrations when cows were fed rations that were high in ruminally degradable intake protein. Alternatively, changes in uterine secretions that are associated with high protein intake and elevated plasma urea nitrogen might be detrimental to embryos. Bovine endometrial cells in culture respond directly to increasing urea concentrations with alteration in pH gradient but respond most notably with increased secretion of prostaglandin F2 alpha (PGF2 alpha). Increased uterine luminal PGF2 alpha interferes with embryo development and survival in cows, thus providing a plausible link between elevated plasma urea nitrogen concentrations and decreased fertility. Poor fertility in high producing dairy cows reflects the combined effects of a uterine environment that is dependent on progesterone and rendered suboptimum by the antecedent effects of negative energy balance or postpartum health problems and that is further compromised by the effects of urea resulting from intake of high dietary protein.     

Peripeduncular nucleus lesions in the rat: I. Effects on maternal aggression, lactation, and maternal behavior during pre- and postpartum periods.

Bilateral peripeduncular (PPN) lesions made on the 7th postpartum day (L7) with either radiofrequency (RF) current or N-methyl-d,l-aspartic acid (NMDA)/phosphate buffered saline (PBS) reduced maternal aggression (MA) and partially inhibited lactation without producing significant deficits in other items of maternal behavior (MB). RF-PPN lesions did not interfere with prolactin secretion, which suggests that there was deficient oxytocinergic activity. The deficit in MA was not due to interruption of afferent suckling input to the PPN: either thelectomizing females (Day L6) or producing bilateral knifecuts in the mesencephalon (placed caudal to the level of the PPN; Day L7) had no effect on MA, but both procedures impaired lactation. Deficits in MA produced by RF-PPN lesions developed gradually between Days L4 and L7; lesions made either prepartum or on Day L1 did not impair MA or MB. Deficits in lactation first appeared after RF-PPN lesions on Day L1. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Assessment of the dairy production needs of cattle owners in southeastern Sicily

This study was undertaken to investigate research and outreach priorities for Progetto Ibleo (Project Ibleo), a center created in 1990 with tripartite government funding to serve dairy producers in the Hyblean region of Sicily. Data comprised values for production and composition of milk from 1984 to 1989 from 35 herds of Modicana cows on a system based on pasture and that from 69 input-intensive herds of Holstein cows, associated lactation and reproduction measures, and yield and composition of forages from 4 of these farms in 1988. Season had a large effect on the neutral detergent fiber and crude protein composition of forages, production and composition of milk, and predicted yield of fresh Ragusano cheese manufactured from the milk of these cows. The poorest forage quality and the poorest cow performance were observed in summer and fall months (May to October). Lactation curves that were flat, without a discernible peak, or convex were observed for both systems, especially for cows calving in spring and in the dry summer seasons (March to July). These abnormalities, signifying substantial sacrifices in production potential, probably had a complex etiology that stemmed from low nutrient intake and high neutral detergent fiber and low crude protein composition of the grazed and preserved forages. Research and outreach priorities to support the Hyblean dairy industry should include chemical evaluation of forages and other feedstuffs, low moisture ensiling of high quality winter forages, better formulation of diets that are dense with nutrients, and the shifting of calving patterns to better exploit high quality winter forages.     

myo-Inositol metabolism during lactation and development in the rat. The prevention of lactation-induced fatty liver by dietary myo-inositol

Effects of dietary myo-inositol deprivation were examined during prenatal and postnatal development and during lactation in the rat. The deficient diet contained no detectable myo-inositol while the supplemented diet contained 0.5% (w/w) myo-inositol while the supplemented diet ct contained 0.5% (w/w) myo-inositol at the expense of sucrose. Both diets contained 25% casein, adequate amounts of all known vitamins, choline, and essential fatty acids as well as 0.5% (w/w) phthalylsulfathiazole to depress myo-inositol contribution to the diet by microorganisms. Pregnant rats of the Holtzman strain were fed the respective diets during gestation and lactation, and pups were fed the corresponding diet after weaning until 3 months of age. There were no significant differen-es in body weight between experimental groups. Supplementation of the diet with myo-inositol significanly increased the levels of myo-inositol in plasma, liver, kidney, and intestine of pups at all ages examined, and significantly increased the levels of myo-inositol in the milk and mammary tissue during lactation. During lactation, the myo-inositol deprived dams developed severe fatty livers (31% w/w) characterized by diminished phosphatidyl-inositol (50%) and total phospholipid phosphorus (57%) levels as compared with controls. After weaning, the liver lipid content of the myo-inositol deprived dams returned to normal (4.5%). The data suggest that a possible threshold level of free myo-inositol (approximately 0.15 mumoles/g lipid-free tissue) was required to prevent fatty liver in lactating dams under these dietary conditions. Effects of the deficient diet on fertility were also examined. Based on sperm count and production of offspring, there were no differnences between the experimental and control males. Females of both groups showed equal ability to produce offspring.     

A clinico-radiological correlation of breast diseases during lactation and the significance of unilateral failure of lactation

OBJECTIVES: The Ishikawa endometrial cancer cell line is hormonally responsive, expressing estrogen and progesterone receptors (ER, PR) when grown in traditional monolayer culture. The purpose of this paper is to demonstrate a three-dimensional spheroid culture system for cancer cells. We used this system to determine the response of the Ishikawa cell line to estradiol-17 beta (E), tamoxifen (T), megestrol acetate (MA), and progesterone (P). METHODS: Ishikawa cells were incubated in polyurethane culture bags using phenol red-free media containing ethanol (0.1%, controls), E (1 mumol, or 1 nmol), T (1 mumol, or 10 nmol), MA (1 mumol, or 10 nmol), or P (1 mumol). Cellular morphology was assessed by hematoxylin and eosin staining, and expression of estrogen and progesterone receptors was determined immunohistochemically using an immunoperoxidase technique. RESULTS: Cells in control cultures demonstrated minimal organization and lacked hormone receptors. In contrast, cells exposed to either E or T displayed significant glandular formation, with multicellular, microvilli-rich, columnar epithelia exhibiting polarized nuclear arrangements. Within 4 weeks, E- and T-treated cultures showed upregulated nuclear staining for PR, with little ER present. Cells treated with MA or P showed less glandular organization but expressed ER with PR downregulation. CONCLUSIONS: These data support the use of this novel three-dimensional culture system to study the modulation of tumor cell biologic activity in response to hormonal agents. Future applications of this model include examining in vitro responsiveness of cancer cell lines to additional biologic agents and chemotherapeutic regimens.     

Kidney function and nitrogen balance of high yielding dairy cows at the onset of lactation

The balance of water, Na+, K+, Cl-, and total solute in the kidney and the N balance of the whole body were measured for six high yielding cows at 2 wk prepartum (period 1) and at 2 wk (period 2) and 7 wk (period 3) postpartum during winter and autumn in Israel. The onset of lactation was not followed by an increase in glomerular filtration rate and urine volume. To meet the deficiency in Na+, K+, and Cl- ions, the kidney conserves them during early lactation, mainly by increasing tubular reabsorption. An interdependent relationship exists between the excreted urea and nonurea solutes. Thus, reduction of ion concentrations in urine during early lactation reflects both the need to excrete a large load of urea and the effort to conserve Na+, K+, and Cl-. The high load of urea during early lactation was a result of a negative N balance that was most likely related to a negative energy balance. We concluded, through a comparison of our results with those of a similar study during summer, that the role of the kidney in ion conservation is more pronounced during summer than during winter and that the recovery of cows from a negative balance of energy and N is faster in summer than in winter.     

Blood groups and milk and type traits in dairy cattle: after forty years of research

This study addresses the utility of 11 blood groups as selection aids in Holstein breeding schemes and considers issues inherent to the approach of resolving quantitative variation into components that are due to quantitative trait loci. The data consisted of predicted transmitting abilities of 22,614 bulls, first lactation information on 1,924,171 cows, and type scores on 447,800 cows. Linear models were fitted under male half-sib designs, female half-sib designs, and granddaughter designs as well as under the assumption of direct effects of the markers. The evolution of allele frequencies through time was determined, and previous research results were synthesized according to criteria of consistency of biological significance. The inconsistency of results across studies and analytical designs alludes to the importance of the intrinsic nonadditivity of genetic and biological phenomena to quantitative trait locus detection and marker-assisted selection. In our analyses, three associations met the criteria of consistency--a C blood group effect on rump angle, an L effect on milk yield and composition traits, and an S effect on milk fat yield. The M locus appears to be directly associated with effects on milk and protein yields. An enhanced understanding of the biochemical and physiological bases of quantitative genetics should be a long-term objective of this type of genetic analysis.     

Influence of parity and stage of lactation on the somatic cell count in bacteriologically negative dairy cows

This study examines the influence of parity, stage of lactation, and single isolations (i.e., the isolation of a microorganism that could not be reisolated in the same quarter in the next sampling) of staphylococci other than Staphylococcus aureus (coagulase-negative staphylococci), Corynebacterium bovis, or esculin-positive cocci other than Streptococcus uberis (referred to as esculin-positive cocci throughout) on the monthly log(e)-transformed somatic cell count (SCC) for 180 first, second, and third parity cows that were observed over a whole lactation. Repeated measures ANOVA was used to analyze the data. No significant effect was found for the infection variable. However, the results indicated that even single isolations of coagulase-negative staphylocci, C. bovis, or esculin-positive cocci resulted in a numerical or statistically significant increase in SCC. Least squares mean SCC (log(e)-transformed) for bacterio-logically negative cows and cows with single isolations of coagulase-negative staphylococci, C. bovis, or esculin-positive cocci were 3.90, 3.97, 4.08, and 4.17, respectively. Significant effects of parity, stage of lactation, and the interaction of parity and stage of lactation could not be found when only bacteriologically negative cows were considered. Least squares mean SCC for first, second, and third parity cows were 3.80, 3.93, and 3.97, respectively. However, the effects of parity, stage of lactation, and the interaction of parity and stage of lactation were significant when all 180 cows were included. Therefore, these effects must be due to factors that were present in the infected groups.     

Misidentification rate in the Israeli dairy cattle population and its implications for genetic improvement

The DNA microsatellites can be efficiently used to determine incorrect paternity attribution of cattle without genotyping of dams. Allelic frequencies of the population were determined for 12 microsatellites using the maternal alleles of 102 AI sires. The frequency of the most common microsatellite allele ranged from 0.27 to 0.58. Most loci had at least one allele that was present in only a single individual. Paternity of 9 of 173 cows (5.2%) and 3 of 102 bulls (2.9%) was excluded because putative paternal alleles were not present in progeny for at least one locus. For 4 of the 9 cows and all 3 bulls, exclusion was based on at least two loci. Mean probability of exclusion was 0.85 for cows and 0.99 for bulls. With an assumed cost of US $5 per genotype, a misidentification rate of 5%, and a discount rate of 0.05, additional profit for the Israeli-Holstein breeding program from genotyping 100 test daughters of each young sire becomes positive within 10 yr and reaches nearly US $2.4 million after 20 yr.