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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

IMPACT OF SEASON AND HEAT STRESS ON SOMATIC CELL COUNTS

Broaddus, Brent A. 01 January 2001 (has links)
Infection data were obtained monthly from June, 1999 to September, 2000 at the University ofKentucky dairy. Quarter foremilk samples were collected for bacteriological determination andsomatic cell counts (SCC). The Livestock Stress Index (LSI) estimated heat stress and is calculatedby combination of temperature and humidity. For uninfected quarters the geometric mean SCC was29,000 cells/ml. For infected quarters the geometric mean SCC was 213,000 cells/ml. Coagulasenegativestaphylococci (CNS) infections comprised 61 percent of the total infected quarters with ageometric mean SCC of 155,000 cells/ml. Staphylococcus aureus infected quarters had a geometricmean SCC of 680,000 cells/ml. There were no significant correlations between log SCC and LSIwhen looking at the total sample period. However, evaluating October, 1999 through September,2000, significant correlations were found for LSI and log SCC of uninfected quarters (P andlt; 0.05) and`infected quarters (P andlt; 0.0001). All correlation coefficients were less than 0.12. The results suggest nomarked changes in SCC were observed in uninfected quarters during hot summer weather. Hotsummer weather may have a minor impact on SCC in infected quarters, but the effect is variable.Thus, infection status of the mammary gland, not heat stress, is the major factor determining SCC.
2

A Comparison of the Effects of Heat Stress on Milk and Component Yields and Somatic Cell Count in Holstein and Jersey Cows

Smith, Daniel L 09 December 2011 (has links)
Objective 1 was to investigate effects of heat stress and breed on milk and component yield for Holstein and Jersey cows on the same farm. Objective 2 was to determine the effects of breed on udder health as measured by somatic cell count (SCC) during times of heat stress. Data were collected from DHIA records of 142 Jersey cows and 586 Holstein cows from the University herd at Mississippi State University. During heat stress Jersey milk yield and 4% fat corrected milk (FCM) increased (P<0.01). Holstein milk yield and FCM decreased during heat stress (P<0.01). Heat stress affected somatic cell count (SCC) although effects varied by intensity of heat stress. Breed did not have an affect on SCC. Milk fat and protein percentages declined for both breeds in heat stress conditions. Milk fat but not milk protein of Jersey cows increased as stress increased from mild to severe.
3

AN EXAMINATION OF MILK QUALITY EFFECTS ON MILK YIELD AND DAIRY PRODUCTION ECONOMICS IN THE SOUTHEASTERN UNITED STATES

Nolan, Derek T. 01 January 2017 (has links)
Mastitis is one of the most costly diseases to dairy producers around the world with milk yield loss being the biggest contributor to economic losses. The objective of first study of this thesis was to determine the impacts of high somatic cell counts on milk yield loss. To accomplish this, over one million cow data records were collected from Southeastern US dairy herds. The objective of the second study was to determine optimum treatment cost of clinical mastitis by combining two economic modeling approaches used in animal health economics. The last objective of this thesis was to determine how much Southeastern US dairy producers are spending to control milk quality on farm and determine if they understand how milk quality affects them economically. This was accomplished through a collaborative project within the Southeast Quality Milk Initiative.
4

Fornecimento de zinco, cobre e selênio orgânicos para vacas leiteiras e efeitos sobre a qualidade do leite e saúde da glândula mamária / Organic zinc, copper and selenium supplementation in dairy cows and effects on milk quality and mammary gland health

Cortinhas, Cristina Simões 07 May 2009 (has links)
Os objetivos gerais deste estudo foram avaliar o efeito suplementação de zinco (Zn), cobre (Cu) e selênio (Se) orgânicos para vacas leiteiras e os seus efeitos sobre a qualidade do leite, saúde da glândula mamária e consumo de alimentos. Os objetivos específicos foram avaliar: a contagem de células somáticas (CCS), a prevalência de mastite clínica e subclínica,a produção e composição de leite nos 80 primeiros dias de lactação; monitorar a atividade enzimática de superóxido dismutase (CuZnSOD), glutationa peroxidase (GSH-Px) e ceruloplasmina (CP); o consumo de alimentos; a concentração plasmática de Zn, Cu e Se; e as variações de peso e escore dos animais. Dezenove vacas leiteiras, com prenhez confirmada, foram selecionadas por peso, escore de condição corporal (ECC), número de lactações e produção de leite da lactação anterior, e distribuídas ao acaso em dois grupos para receber fontes de Zn, Cu e Se orgânica (n=9) ou inorgânica (n=10). As dietas foram formuladas para suprir os requerimentos nutricionais dos animais dos 60 dias antes da data prevista do parto aos 80 dias de lactação. Amostras dos alimentos fornecidos e das sobras foram coletadas diariamente para posterior análise de composição. O leite foi coletado semanalmente a partir da 3ª semana de lactação para determinação da composição e CCS, e nos dias 1 e 7 de lactação, e quando diagnosticados casos clínicos de mastite, para cultura microbiológica. Amostras de sangue foram coletadas aos -60, -21, 1, 21, 40 e 80 dias do período experimental para análises da concentração de CuZnSOD, GSH-Px e CP. Para determinação das concentrações plasmáticas de Zn, Cu e Se amostras de sangue foram coletas aos 60 dias antes da data prevista de parto, e no 1º, 40º e 80º dias de lactação. Avaliações do escore de condição corporal (ECC) e do peso corporal (PC) foram realizadas no início e final do experimento, no parto, e uma vez por semana durante todo o período experimental. A incidência (novos casos)e o total de casos de mastite subclínica foi menor para o grupo de vacas alimentadas com fontes orgânicas de Zn, Cu e Se em comparação com os animais que receberam fontes inorgânicas. A CCS durante os primeiros 80 dias de lactação foi menor (P = 0,056) para o grupo alimentado com Zn, Cu e Se orgânicos. Não foram observados efeitos de fontes orgânicas de Zn, Cu e Se sobre as concentrações de CuZnSOD , GSH-Px e CP, Zn, Cu e Se plasmáticos, produção e composição de leite, consumo de nutrientes, ECC, mudança de ECC e PC. Foi observado efeito (P=0,024) da fonte sobre a mudança de PC. / The general objectives of this study were to evaluate the effect organic zinc (Zn), copper (Cu) and selenium (Se) supplementationto dairy cows on milk quality, mammary gland health and feed intake. The specific objectives were to evaluate: the somatic cell count (SCC), clinical and subclinical mastitis prevalence, milk production and composition during the first 80 days of lactation; the superoxide dismutase (CuZnSOD), glutathione peroxidase (GSH-Px) and ceruloplasmin (CP) enzyme activity; the nutrients intake; Zn, Cu and Se plasmatic concentrations; changes in weight and body condition score. Nineteen dairy cows, with confirmed pregnancy, were selected by body weight (BW), body condition score (BCS), number of lactation, and milk yield in previous lactation, and randomly distributed among two groups to receive organic (n=9) or inorganic (n=10) sources of Zn, Cu and Se. The diets were formulated to meet the nutritional requirements of animals from 60 days before the expected date of calving up to 80 days of lactation. Every day, food samples and leftovers were collected for composition analysis. Milk samples was collected weekly after 15 days of lactation to determine the composition and CCS, on days 1 and 7 of lactation, and when a mastitis clinical case was diagnosed for microbiological culture. Blood samples were collected on -60, -21, 1, 21, 40 and 80 days of the experimental period for CuZnSOD, GSH-Px, and CP analysis. For plasma concentrations of Zn, Cu and Se blood samples were collected at 60 days before calving, and at 1st, 40th and 80th days of lactation. Assessments of body condition score (BCS) and body weight (BW) were performed at the beginning and at the end of the experiment, the day of calving, and once a week throughout the experimental period. The incidence (new cases) and total number of subclinical mastitis cases was lower for the group of cows fed organic Zn, Cu and Se in comparison with animals that received the inorganic sources. The SCC during the first 80 days of lactation was lower (P = 0,056) for the group fed organic Zn, Cu and Se. There were no effects of Zn, Cu and Se organic supply on concentrations of CuZnSOD, GSH-Px and CP, Zn, Cu and Se plasma, production and composition of milk, consumption of nutrients, BW, BCS and changes on BCS. It was observed effect of source on BW changes (P=0,024).
5

SPECIAL PROBLEMS IN AGRICULTURAL ECONOMICS

Swartz, Alexander Ogden 01 January 2019 (has links)
According to the USDA Economic Research service, farm-level prices are on the decline. This decline in prices particularly hurts smaller scale operators with many needing to rely on off-farm income in order to ensure they remain in operation. This thesis studies two problems of key interest to the Southeast region and the State of Kentucky by investigating dairy management practices and the environmental benefits of hemp production. As dairy prices have been on the decline and dairy co-ops have tightened their restrictions on somatic cell count (SCC) levels, dairy farmers and farm managers must decide the best course of action for maintaining milk quality in order to maintain their contract and profitability. Maintenance decisions as well as factors like sanitation and animal living conditions can all contribute to bulk tank SCC and depending on the type of incentives or penalties instituted by the co-op they can have an impact on net farm income. The objective of the dairy study is to determine which dairy management practices have the largest impact on SCC levels. Industrial hemp is produced worldwide. Historically, the major producers of hemp have been China, Europe, and Russia. In 2014, the passage of the Farm Bill opened the door to the production of Industrial hemp through the development of state pilot programs. Then the 2018 Farm Bill removed industrial hemp from the Scheduled Drug list. This has further expanded the opportunities and excitement for this crop. The plant’s versatility and the variety of products that can be made from it are coming to light. Sustainability is one of the key attributes touted concerning industrial hemp. Specifically, in the state of Kentucky, it is expected to be a replacement for tobacco and other traditional crops. However, how does the crop compare to tobacco production in terms of sustainability? The objective of the hemp study is to develop a life cycle analysis on the planting and harvesting of hemp and compare its impacts to more traditional crops.
6

Karvių melžimo operacijų įtaka somatinių ląstelių skaičiui piene / Effect of milking procedures on milk somatic cell count

Martinkus, Nerijus 18 March 2008 (has links)
Modernios pienininkystės fermos sėkmė priklauso nuo to, ar joje gaminamas pienas yra aukštos kokybės. Pagrindiniai veiksniai, turintys įtakos somatinių ląstelių skaičiui piene, yra gera melžimo organizacija, melžimo įrangos taisyklingas veikimas, klinikinių mastitų gydymas antibiotikais ir kt. Mokslininkai įrodė, kad melžti karves kas dvylika valandų yra optimaliausia, kai jos melžiamos du kartus per parą. SLS piene daug priklauso nuo taisyklingos melžimo darbotvarkės, kuri apima skirtingas melžimo operacijas (tešmens ir spenių paruošimas melžimui, spenių dirginimas, pirmųjų pieno čiurkšlių numelžimas, melžiklių užmovimas ant spenių, melžiklių numovimas pamelžus ir efektyvi spenių antiseptika po melžimo) ir nuo šių operacijų trukmės. Teisingai atliekamos melžimo procedūros yra svarbios mastito prevencijai ir užtikrina visišką pieno išmelžimą iš tešmens. Tyrėjai įrodė, kad daugiau kaip 50 % melžimo proceso laiko užtrunka pats melžimas. Dabartiniu metu melžimo operacijos vis labiau mechanizuojamos. Netaisyklingas melžimas gali pailginti pieno atleidimo laiką, didėja rizika susirgti tešmens uždegimais. Pablogėja pieno kokybė, todėl gaunami ekonominiai nuostoliai. Padidėjęs somatinių ląstelių skaičius piene ¬ svarbus mastito požymis. Perdirbamajai pramonei karvių mastitas buvo ir liks vienu iš svarbiausių trukdžių gaminant aukštos kokybės pieno produktus. Klinikine forma serga 2 – 5 % laktuojančių ir užtrūkintų karvių, o slaptuoju uždegimu – iki 50 % karvių. Viena dažniausiai... [toliau žr. visą tekstą] / Data were collected from two dairy farms. On the farm A cows were milked using full automatised milking equipment „Milkmaster“. On the farm B cows were milked with „Interpuls“ milking equipment. The DeLaval milking system was supplied with automatic cluster remover. On dairy farms A and B cows were milked twice daily. The goal of our studies was to analyse consumption of main milking operations (cow udder preparation before milking, milking and over-milking) and their influence on milk somatic cell count. Were selected 20 cows in each farm. The duration of main milking procedures were recorded. Data on milk, fat and protein yields and somatic cell count were collected.The mean duration of pre-milking udder preparation was 42 s (farm A) and 46,03 s (farm B). Some cows were prepared only for 25,50 Afarm A) s, whereas the udder preparation comprised merely inadequate cleaning of teats. The maximum duration of over-milking was 41,10 (farm B).
7

Skirtingų veislių karvių melžimo savybių palyginimas / Comparison of milking properties of cows of different breeds

Lembertas, Klaudijus 18 June 2014 (has links)
Šio darbo tikslas - palyginti skirtingų veislių karvių melžimo savybes. Darbo uždaviniai. 1. Išanalizuoti Lietuvos juodmargių ir Lietuvos žalųjų veislių karvių melžimo savybes. 2. Nustatyti laktacijos įtaką karvių melžimo savybėms. 3. Nustatyti melžimo laiko įtaką tiriamų veislių karvių pieno kiekiui ir vidutiniam pieno atidavimo greičiui. 4. Įvertinti ūkio įtaką melžimo savybėms. 5. Atlikti somatinių ląstelių skaičiaus (SLS) ir melžimo savybių koreliacinę analizę. Išvados: 1) Išanalizavus tirtų Lietuvos juodmargių ir Lietuvos žalųjų veislių karvių pagrindinių melžimo savybių rezultatus nustatyta, kad: 1.1. Vidutinis pieno tekėjimo greitis Lietuvos žalųjų (0,02 kg/min) buvo didesnis nei Lietuvos juodmargių veislės karvių (p<0,05). 1.2. Didžiausia pieno tekėjimo srovė buvo Lietuvos juodmargių buvo 0,05 kg/min didesnė nei Lietuvos žalųjų (p>0,05). 1.3. Melžimo laikas 0,11 min. buvo ilgesnis Lietuvos žalųjų veislės karvių. 2) Atlikus skirtingų laktacijų karvių produktyvumo ir melžimo savybių analizę, nustatyta, kad I laktacijos karvių bendras pieno kiekis (kg) ir vidutinis pieno atidavimo greitis (kg/min). buvo didžiausias Lietuvos žalųjų karvių, tačiau I laktacijos karvių melžimo trukmė buvo ilgesnė nei Lietuvos juodmargių veislės karvių. 3) Nustatyta, kad Lietuvos juodmargių, kurios melžėsi ilgiau nei 6 minutes buvo 4,73% daugiau nei Lietuvos žalųjų veislių karvių (p<0,05) Iš pateiktų duomenų matome, kad Lietuvos žalųjų buvo beveik 5% daugiau nei Lietuvos juodmargių, kurios... [toliau žr. visą tekstą] / The aim of this thesis was to assess milking properties of cows of different breeds. Objectives of the paper: 1. Analyze the Lithuanian Black and White and Lithuanian Red cows milking qualities. 2. Determine lactation influence milking performance. 3. Determine the time of milking cows tested influence on milk yield and milk the average speed of the output. 4. To evaluate the farm impact of the milking properties. 5. Perform somatic cell count and milking performance correlation analysis. The scientific research was carried out between 2012-2014 at the Department of Animal Breeding of the Veterinary Academy of the Lithuanian University of Health Sciences and 2 dairy farms. Descriptive statistics: the average of investigated traits (M), standard errors were calculated using the EXEL and “R” (The R Project for Statistical Computing, 2012) statistical packages Milking properties were analyzed with the help of the device Lactocorder. In total 81 cows of Lithuanian black and white and Lithuanian red cattle breeds from two farms were analyzed. Lithuanian black and white cows constituted 71.6 percent, while Lithuanian red cows constituted 28.4 percent. According to lactation all analyzed cows were divided into the following three groups: lactation I, lactation II, lactation III and later. The first lactation cows constituted 6.1 % , the second lactation cows constituted 19.75 % and the group of cows of the third and later lactation was the largest and constituted 74.07 % . The... [to full text]
8

FAKTORY NEGATIVNĚ OVLIVŇUJÍCÍ HLADINU SOMATICKÝCH BUNĚK V SYROVÉM KRAVSKÉM MLÉCE / THE FACTORS NEGATIVELY INFLUENCING A SOMATIC CELL COUNT IN RAW COW´S MILK

SOUKUP, Petr January 2007 (has links)
The objective of my study was to analyse the factors negatively influencing a somatic cell count (SCC) in raw cow´s milk. Milk samples were tested in three breeds with different technology of breeding and milking for a time period of three years. The SCC values were determined by Fluoro-opto-electronic method on a Fossomatic apparatus. Significant factor influencing SCC was quality practise hygiene of mammary gland. The lowest average values of SCC were determined in breed where was practise thoroughly hygiene of mammary gland (avarage SCC in year 2006 was 223,3.103 SB.ml-1). Next factors negatively influencing SCC were age of cows, annual period, quality of feed and frequency exchanges a udder sleeve. Influence a technology of breeding, milking and size breed on somatic cell count in milk was not extended.
9

Počet somatických buněk v syrovém kravském mléce v souvislosti s použitými metodami prevence mastitid / Somatic cell count in raw cow milk in relation to the used methods of mastitis prevention

MÍKOVÁ, Andrea January 2008 (has links)
Graduation theses are inquired into question of somatic cell count (SCC) in row cow milk in relation to the used methods of mastitis prevention. In the year 2005 and 2006 was following values of SCC in raw cow milk in tetra breeding dairy cows. Breeds are differentating from each other with technology of breeding (horsy, summer pasture), technology of lairege and milking. SCC in bulk tank milk was determined according to ČSN EN ISO 133366 {--} 3 milk. Lowest average funds PSB (156,3 {$\cdot$} 10{$^3$} {$\cdot$} ml&#713;{$^1$}) was determined in breeding with summer pasture (loos pen bedding housing). Breed with stanchion bedded housing without pasture (SCC 277,3 {$\cdot$} 10{$^3$} {$\cdot$} ml&#713;{$^1$}) and breed with bedding{--}free slatted-floor housing without pasture (SCC 277,4 {$\cdot$}10{$^3$} {$\cdot$} ml&#713;{$^1$}) was in a tight spot with inadequancy hygiene of stable and milking. The highest average values of SCC were determinated in loose bedded cubicle housing without pasture (289,1 {$\cdot$} 10{$^3$} {$\cdot$} ml&#713;{$^1$}), where was deficiencies in feeding (feeding mouldy silage) and higher dustiness environment. We proved a statistically highly significant difference (P<0,001) between farm using summer pasture and farms without pasture. Main deficiencies in methods of mastitis prevention is that breeds doesn't use individual disposable tissue cloths for the udder wiping, farms doesn't use preddiping, inadequancy in hygiene of lairege and milking, feeding mouldy silage and inadequancy in ransack confirmed dairy cows. Key words: raw cow milk, somatic cell count, technology
10

Efeito da contagem de celulas somaticas do leite na fabricação do queijo prato / Effect of the somatic cell count on the manufacture of the prato cheese

Mazal, Guillaume 08 August 2005 (has links)
Orientadores: Mirna Lucia Gigante, Marcos Veiga dos Santos / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-08-05T00:26:38Z (GMT). No. of bitstreams: 1 Mazal_Guillaume_M.pdf: 1093019 bytes, checksum: a2931e0c265f17d65f21671d7680bb5a (MD5) Previous issue date: 2005 / Mestrado / Mestre em Tecnologia de Alimentos

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