Auswahl der wissenschaftlichen Literatur zum Thema „Dairy environment“

AbstractThe primary objective of this research was to evaluate the impact of environmental air temperatures on the milk production of dairy cows. Therefore, the experiment was carried out at the height of summer (from 15th of June to 15th of September) in three small family dairy farms and one commercial dairy farm. In total, 51 dairy cows from the black-white breed were subjected to the study. The season of research was divided into three periods: the period before the hot season, the period of the hot season and the period after the hot season. In each period there were three test days selected that were used for recording the air temperature inside and outside the barns and cow’s daily milk yield. Unvaried associations between the test day milk yield of cows and independent environmental and cow factors were done using the linear mixed model for repeated measurements. The statistical model showed that the farm management system and the hot season of the year had significant influence on daily milk yield per cow at the level of p<0.001. The test day per periods of the season when milk control was performed and the average test day environmental temperature showed statistically significant influence on daily milk yield per cow at level p<0.01. The present results revealed that environmental air temperatures contributes to considerable loss in the milk production of dairy cows.

The paper presents problems related to the costs incurred for environmental protection in Polish dairy cooperatives. It was found, inter alia, that the costs of environmental protection in this industry sector are high and are rising rapidly. The costs of sewage disposal and treatment are of key importance as they represent the largest share in the total costs of environmental protection, i.e. nearly 95%. In 2018, they amounted to approximately PLN 1.5 million per cooperative, which was almost three times more than in 2004. Other environmental protection costs account for approximately 5% of total environmental protection costs. So, the key to environmental success in dairy cooperatives is rational wastewater management. Therefore, it is advisable for managers to consider building their own wastewater treatment plants with sizes and parameters appropriate to the scale of milk processing and the number of finished product ranges produced. The study also found that the costs of training employees and farmers on environmental protection are low, which may suggest the desirability of increasing them according to real needs, so as to ensure an appropriate level of understanding and persuasion of farmers -shareholders for further investments related to environmental protection. It was also found that the scale of milk processing and the number of manufactured assortments strongly affect the total costs of environmental protection of dairy cooperatives in Poland. Legal requirements regarding environmental protection are so restrictive and economically effective that their omission may lead to increasing financial, management, technological and legal difficulties. Therefore, the compliance of dairy cooperatives with legal environmental requirements is a must, which should generally be assessed positively.

Clarence and Elise Stolte farm the family Masterton property as 50:50 sharemilkers. They have made the 285 ha dairy farming business resilient to environmental and milk price volatility by remaining focussed on sustainable results and not productivity. Evidenced through the Dairy Systems Monitoring (DSM) and the Dairy Farm Business of the Year competition they stand in the top 10% of elite groups for financial results in both high payout in a high pasture yield season, and then in the following low payout, low pasture yield season. Being able to demonstrate consistent results comes from a deliberately well considered farm policy, skilled on-farm management, maximising home grown feed yields and strong discipline around the farm budget.

Few studies have investigated the diversity of spoilage fungi from the dairy production chain in Brazil, despite their importance as spoilage microorganisms. In the present study, 109 filamentous fungi were isolated from various spoiled dairy products and dairy production environments. The isolates were identified through sequencing of the internal transcribed spacer (ITS) region. In spoiled products, Penicillium and Cladosporium were the most frequent genera of filamentous fungi and were also present in the dairy environment, indicating that they may represent a primary source of contamination. For dairy production environments, the most frequent genera were Cladosporium, Penicillium, Aspergillus, and Nigrospora. Four species (Hypoxylon griseobrunneum, Rhinocladiella similis, Coniochaeta rosae, and Paecilomyces maximus) were identified for the first time in dairy products or in dairy production environment. Phytopathogenic genera were also detected, such as Montagnula, Clonostachys, and Riopa. One species isolated from the dairy production environment is classified as the pathogenic fungi, R. similis. Regarding the phylogeny, 14 different families were observed and most of the fungi belong to the Ascomycota phylum. The understanding of fungal biodiversity in dairy products and environment can support the development of conservation strategies to control food spoilage. This includes the suitable use of preservatives in dairy products, as well as the application of specific cleaning and sanitizing protocols designed for a specific group of target microorganisms.

This paper reviews current challenges in the Australian extension environment and provides a case for developing an adaptive extension platform for the dairy sector in Australia and New Zealand, to support evolving dairy farm systems. The variation in the public-sector engagement in extension, the diversity and number of extension providers and a relatively uncoordinated approach to define new extension roles, functions and professional requirements are current challenges for dairy extension across Australia. In the dairy sector, these challenges coincide with increasing demand for a responsive research, development, extension and education system in supporting the rapid evolution in dairy farming systems. Addressing these challenges is not an issue for extension alone; however, the required level of integration among research, development, extension and education in an environment where needs are changing and resources are scarce demands an engaged dairy-science profession. Drawing on international extension and agricultural innovation-system literature and earlier empirical research, the following three areas for development are proposed: (1) a professional development strategy that incorporates (i) an understanding of the new professional situations extension works within, (ii) leadership in cross-industry and cross-sector coordination concerning the nature of the changing client in research, development, extension and education system and (iii) clear priorities for extension; (2) a professional development plan that incorporates a workplace-learning approach; and (3) for extension specialists to be engaged in defining research priorities, the agenda for change and suitable pathways for change alongside other professional groups, including farming. This development agenda will, however, require an adaptive extension platform to advance these areas on behalf of farmers and public stakeholders.

The study was conducted in a dairy barn and nearby environment to determine the level of air bacterial and fungi contamination. Measurements were performed in morning, noon and evening sampling periods once a week during two autumn months inside the barn and in a 25 m distant barn environment. A Merck MAS-100 air sampler was employed with different medium and incubation combinations for the capture and identification of bacteria and fungi. The results of the study showed a statistically significant difference (<i>P</i> < 0.05) between the bacterial and fungi counts measured inside and outside the barn, whereby total outside bacterial count was by 97.4% to 98.0% lower, and total outside fungi count by 85.2% to 99.4% lower than the respective indoor counts in various sampling periods. In 125 analyzed colonies, gram-positive bacteria, especially those of the genus <i>Staphylococcus</i> and <i>Streptococcus</i>, were most commonly identified in the air samples from both inside and outside the barn. Gram-negative bacteria were present at a low rate, predominated by enterobacteria and by the genus <i>Moraxella</i> and <i>Pseudomonas</i>. Nine mould genera were identified in 325 fungi colonies, predominated by the genus <i>Aspergillus</i>, <i>Penicillium</i>, <i>Rhizopus</i> and yeasts, both in the barn and in the nearby environment.

Listeria monocytogenes is a potentially lethal foodborne pathogen commonly found in the environment. European Union hygiene legislation places responsibility for safety on primary production facilities, including farms, as part of a policy to introduce traceability throughout the food chain. This study aimed to determine the occurrence of L. monocytogenes in the Irish dairy farm environment and in particular the milking facility. Two hundred ninety-eight environmental samples were collected from 16 farms in the southern region of Ireland. A number of farms within the group supply raw milk to the unpasteurized milk cheese industry. The samples taken included cow feces, milk, silage, soil, water, etc. Samples were enriched in Listeria enrichment broth and incubated for 48 h, followed by plating on chromogenic agar Listeria Ottavani & Agosti and further incubation of the plates for 24 to 48 h. Presumptive L. monocytogenes isolates were purified and confirmed by PCR targeting the hly gene. Overall, 19% of the samples (57 of 298) were positive for L. monocytogenes. These were serotyped using conventional and PCR methods; serotypes 1/2a, 1/2b, and 4b made up 78% of the typeable isolates. A correlation was found between the level of hygiene standards on the farm and the occurrence of L. monocytogenes. There was little difference in the occurrence of L. monocytogenes between farms supplying milk to the unpasteurized milk cheese industry and those supplying milk for processing. This study demonstrates the prevalence of L. monocytogenes in the dairy farm environment and the need for good hygiene practices to prevent its entry into the food chain.

For several decades, the practice of farming in mountain areas has played a key role to the proper management of the landscape, the conservation of the biodiversity as well as the soil protection. Moreover, it has significantly contributed to the protection of those areas from avalanches and fires, while at the same time it keeps reinforcing the local economy, thereby acting as a counterweight to abandonment. The mountain animal husbandry is by definition multifunctional and multidisciplinary. In fact, mountainous farming consists of a complex and dynamic system. The harmony and the balance between human activities and nature requires some of the most precious human skills, like patience, self-abnegation, endurance to handiwork and frugality, to name some, but above all, love for mother nature. These are characteristics that ensure continuity and vitality of the mountain for both humans and the surrounding nature. In Italy, almost half of the total land is classified as mountainous (47.5%). Nevertheless, farmers in mountainous regions (representing 30.9% of the national total) face several limitations. These limitations, linked to the existence of natural handicaps, cannot be easily overcome with investments. For example, in mountains the average temperatures are lower, resulting in shorter vegetative period. Moreover, the excessive fractionation, the major gradients and roughness of the lands and at the same time the lower fertility of soils, create the need for special machinery (often more expensive than those used in mainland farms) as well as increased labor and extra inputs for the farms. These factors can lead to a lower land (and consequently farm) productivity, which can be translated into a limited competitiveness of the mountain farms, compared to mainland. In addition, the difficulty of access and the distance of individual dairy farms from the lowland as well as the fewer processing facilities and their small size, create higher transportation costs and lower economies of scale. Thus, the overall objective of this thesis was to verify some parameters of sustainability that are of great importance for animal husbandry in the mountain areas. The province of Trento was selected as a model area for this type of research. More precisely, we have analyzed the relationship between dairy farms and management of the Alpine pastures, in the light of the environmental value of semi-natural grasslands. The first and second contributions are related to this goal. In the last part a survey was carried out to assess the environmental footprint of dairy farms of Trento province, focusing on innovative aspects of nutrition and management of the animals bred. More specifically, the goal of the first contribution was to analyze the role of the mountain livestock sector. At a first step, data were collected from the Veterinary Services of the province concerning the structures and the management of 395 Alpine summer pastures either with cattle (83 with only heifers and 262 including dairy cows) or sheep and goats (50 summer pastures). All the heifers and more than one third of dairy cows that kept on permanent farms of the province were brought to the temporary farms on the Alpine pastures during the summer season, with a frequency greater for cows of local and dual purpose breeds than specialized breeds (e.g. Holstein Friesian). Of the 610 permanent dairy farms associated with the Provincial Federation of Farmers, we have analyzed the differences between the dairy farms that move/do not move the lactating cows to Alpine summer pastures: i.e. the traditional dairy farms (small and medium size), with tied stall, local breeds and with low productivity, frequently using the summer pasture were compared to modern dairy farms of the same province. Results showed that the practice of transhumance to summer pasture has an important role for the dairy sector of Trento province, although the farmers changed the reasons why they choose to move the animals. In fact, the role of grazing as production support in the summer is relevant just for the traditional small and medium dairy farms, while in all cases it is important to access public subsidies that are undifferentiated between lactating cows, dry cows and replacement. The study displayed the fact that there is still the need to maintain the link between dairy farms and Alpine pastures, giving particular attention to the quality of the pasture management and the multi-functionality of services that can be provided by mountain farms. The second part aimed in evaluating the effect of pasturing of dairy cows on milk yield and quality. To this purpose, a many of traits was considered. Body Condition Score (BCS), milk production and quality, milk coagulation properties, different set of parameters and information relating to dairy processing were recorded and analyzed. In total, date regarding 799 lactating cows were collected and analyzed during 2012 from 15 temporary farms on Alpine summer pastures located in the region of Trentino. The cows were reared in 109 permanent dairy farms. Effects of the breed, parity and days in milk were taken into account. The effects of Alpine summer pasture, and in particular of the amount of compound feed given to cows, were also considered. Information was gathered not only during the period that the cows spent at the Alpine summer pasture, but also before and after the alpine season, with the objective to evaluate the changes due to the environmental changes. Results showed that the summer transhumance had an effect more or less relevant in determining a decrease in production, but also depending upon the breed. Specialized breeds, with higher production levels in permanent dairy farms, suffer a greater drop in production than the local and dual purpose breeds. This was somehow expected, since local breeds have a greater adaptability and lower nutrients requirements. Even the body condition score has been strongly influenced from the summer Alpine pasture. A decline in the first phase of the pastures and a subsequent recovery at the end of the pasture period was observed. Differences between breeds existed, with those specialized breeds showing a greater decrease in body condition. After the return from the Alpine pastures a decline in the percentage of fat content in milk (more evident in specialized breeds) was observed, while the protein content remained constant. Regarding the technological properties of milk, significant differences were found with the change of environment (after the reaching of temporary summer farms and after the return to permanent farms). The major differences for lactodynamographic properties as well as the individual cheese yields were observed between June and September. In summary, this work highlighted the better adaptation of local and dual purpose breeds in the Alpine environment and their good performance under environmental changes as well as the special conditions of the farming system in summer pasture. The last part of this thesis aimed to evaluate the environmental footprint of mountain dairy cattle farms. The study was conducted in a specific area of the Province of Trento. Data were collected from 38 dairy cattle farms of mixed breeds using different farming systems. Data on the general farm management, diet, the production performance, the agronomic management of the surfaces, the management of waste, and the energy consumption were collected. A specific questionnaire was developed and tested to this purpose. This specific questionnaire could also be used for further investigation in mountain region. The above mentioned data were used to calculate the carbon footprint of the herds using the Life Cycle Assessment (LCA) approach. The study included the entire product life, i.e. from production of raw materials and their processing till the final product (the functional unit was the kilogram of milk). All the inputs and outputs associated to the functional unit were taken into account. Three categories of environmental impact of the farms were considered: i) carbon footprint (contribution to the production of greenhouse gases), ii) acidification and iii) eutrophication. The values obtained for the three impact categories had large variability, with mean and standard deviation equal to 1.46 ± 0.58 kg for CO2 equivalent (eq), 27.18 ± 8.34 g for SO2 eq. and 7.91 ± 2.31 g for PO43- eq. per kg of milk (fat and protein corrected). The values obtained are comparable with previous studies carried out in mountain areas. The overall impact was divided between on-farm and off-farm components, and was shared according to mass allocation between milk and meat. Analysis of variance showed that the considered effects of housing (free vs fixed) and feed administration (traditional vs TMR), even if appeared statistically significant for some traits, slightly affected the high variability of the impact categories that can be observed among different dairy farms of the same group. This means that there are margins to mitigate the impact and increase the efficiency of farms with different structures and management. Overall, the results of the present thesis provided with some interesting insights on the sustainability assessment of dairy farming systems in mountainous areas, adopting innovative methodological approaches. Looking ahead, the results obtained from experimental approaches could be expanded on a large pool of dairy farms to identify the indicators of reference for the evaluation of the sustainability and multi-functionality of mountain farms.
La pratica dell’allevamento nel territorio montano ha avuto un ruolo fondamentale per la corretta gestione del paesaggio, la conservazione della biodiversità e la protezione del suolo. Inoltre svolge notevoli positività anche in termini di protezione dalle valanghe e dagli incendi, nel contrasto all'abbandono e soprattutto per lo sviluppo dell'economia locale. La zootecnia montana è per definizione multifunzionale e multidisciplinare. Infatti, spesso è artefice di uno sviluppo più complesso e dinamico, in grado di integrare altri comparti economici quali ad esempio il turismo o il sociale, assicurando continuità e vitalità alla montagna. In Italia quasi la metà del territorio è classificato come montano (47.5%) dove gli agricoltori presenti (30.9% sul totale nazionale) devono affrontare diverse limitazioni, legate all'esistenza di svantaggi naturali, che non sono facilmente affrontabili con investimenti. Le temperature medie inferiori, con conseguente periodo vegetativo più breve, l’eccessivo frazionamento, le maggiori pendenze e asperità dei suoli e allo stesso tempo la minore fertilità dei suoli stessi, la necessità di macchinari spesso più costosi come pure i tempi di lavoro più lunghi, hanno come conseguenze una minore produttività della terra, tradotto in una limitata competitività e produttività del lavoro. In aggiunta, la difficoltà di accesso e la lontananza delle singole aziende dal fondovalle, un minor numero di strutture di trasformazione e le loro ridotte dimensioni, sono la causa di maggiori costi di trasporto e minori economie di scala. L’obiettivo generale di questa tesi è di verificare alcuni parametri di sostenibilità di notevole rilievo per la zootecnia montana nella Provincia Autonoma di Trento. Nello specifico, sono state analizzate le relazioni tra bovinicoltura da latte e gestione degli alpeggi, alla luce della valenza ambientale delle praterie semi-naturali; il primo e il secondo contributo sono relativi a questo obiettivo. Nell'ultimo contributo è stata svolta un'indagine per calcolare l'impronta ambientale della bovinicoltura da latte trentina, con un innovativo focus sugli aspetti di nutrizione e gestione degli animali allevati. Nello specifico l’obiettivo del primo contributo è di analizzare il ruolo delle malghe nel comparto zootecnico montano. Sono stai raccolti dal servizio veterinario della Provincia i dati riguardanti le strutture e il management di 395 malghe dove erano presenti bovini da latte (83 solo manze e in 262 anche bovini adulti) e ovicaprini (50 strutture). Praticamente tutte le manze e più di un terzo delle vacche da latte allevate negli allevamenti di fondovalle della provincia sono portate al pascolo durante la stagione estiva, con una frequenza maggiore per le vacche di razze locali e a duplice attitudine rispetto a quelle specializzate. Delle 610 aziende di fondovalle associate alla Federazione allevatori, sono state analizzate le differenze tra le aziende che praticano/non praticano la monticazione delle vacche in lattazione: le aziende tradizionali di dimensioni medio-piccole, con stabulazione fissa, razze locali e con bassa produttività, usano più frequentemente la pratica dell’alpeggio rispetto alle aziende moderne. I risultati evidenziano come la pratica dell’alpeggio mantenga un ruolo importante per la zootecnia trentina, nonostante siano cambiate le motivazioni per cui gli allevatori scelgono di monticare gli animali. Il ruolo del pascolamento come supporto alla produzione nel periodo estivo rimane rilevante per le aziende tradizionali medio-piccole, mentre in tutti i casi riveste una particolare importanza, la possibilità di accedere a contributi indifferenziati tra bovini in lattazione, asciutta e rimonta. Si devono creare le condizioni perché il legame tra aziende e malghe possa essere mantenuto, con particolare attenzione alla qualità della gestione dei pascoli e alla multifunzionalità di servizi che possono essere forniti dalle aziende zootecniche montane. Il secondo contributo mira a valutare l'effetto della monticazione delle vacche da latte su caratteri produttivi e sulla condizione corporea, nello specifico: body condition score (BCS), produzione, qualità e proprietà di coagulazione del latte, e i parametri relativi alla trasformazione casearia. In totale sono stati raccolti e analizzati i dati di 799 vacche in lattazione, monticate nel 2012 su 15 malghe trentine che allevavano capi di diverse razze provenienti da 109 aziende permanenti. I parametri oggetto di studio sono stati messi in relazione alla razza, all’ordine di parto e ai giorni di lattazione, tenendo conto dell'effetto malga, e in particolar modo della quantità di mangime somministrato alle vacche. Il lavoro ha analizzato non solo il periodo di permanenza delle vacche in alpeggio ma anche prima e dopo la stagione di malga con l’obiettivo di valutare i cambiamenti dovuti al cambio di ambiente. I risultati evidenziano come la monticazione abbia un effetto più o meno rilevante nel determinare un calo di produzione a seconda delle razze. Le razze specializzate, con livelli produttivi più elevati nelle aziende permanenti, soffrono un maggior calo di produzione rispetto a quelle locali o a duplice attitudine, che si adattano meglio alle condizioni di alpeggio. Anche la condizione corporea degli animali è fortemente influenzata dall’alpeggio, con un calo nella prima fase della monticazione e un recupero successivo. Emergono delle differenze tra razze, con quelle specializzate che presentano un maggior calo di condizione corporea. Dopo la monticazione si è assistito ad un calo del contenuto percentuale di grasso nel latte (particolarmente evidente nelle razze specializzate), mentre il contenuto di proteine è rimasto costante. Per quanto riguarda le caratteristiche tecnologiche del latte, si sono riscontrate significative differenze sia dopo la monticazione, sia dopo il periodo estivo con il ritorno in azienda. Le maggiori differenze si sono però riscontrate tra giugno e settembre sia in termini di lattodinamografia sia in termini di rese. In conclusione, il lavoro evidenzia la migliore adattabilità delle razze locali e a duplice attitudine al cambiamento di ambiente e alle condizioni di allevamento in malga. Il terzo contributo ha l'obiettivo di valutare l’impronta ambientale di allevamenti montani di bovini da latte. È stato condotto un approfondito studio sul territorio della provincia di Trento, considerando un campione di 38 allevamenti di vacche da latte di razze miste con differenti sistemi di allevamento. Tramite visite aziendali sono stati raccolti dati relativi alla gestione e alimentazione dei bovini, alle prestazioni produttive, alla gestione agronomica delle superfici, alla gestione dei reflui e ai consumi energetici. A questo fine è stato sviluppato e testato un questionario specifico che potrà essere proposto per ulteriori indagini in ambito montano. La mole di dati raccolti è stata utilizzata per calcolare l’impronta ecologica degli allevamenti con approccio Life Cycle Assessment (LCA). Lo studio comprende l’intera vita del prodotto, dalla produzione delle materie prime, alla loro lavorazione e utilizzo finale considerando tutti gli input e gli output associati all’unità funzionale (il kg di latte). In questo studio sono state considerate tre categorie di impatto: carbon footprint (contributo alla produzione di gas serra), acidificazione ed eutrofizzazione, relative all’anno 2013. I valori ottenuti per le tre categorie di impatto presentano un’ampia variabilità, con medie e DS pari a: 1.46 ± 0.58 kg CO2 eq, 27.18 ± 8.34 g SO2 eq. e 7.91 ± 2.31 g PO43- eq. per kg FPCM. I valori ottenuti sono in linea con quanto riportato da altre ricerche condotte in ambito montano. L’impatto complessivo è stato diviso tra componenti on-farm e off-farm, e sono stati ripartiti gli impatti con allocazione di massa tra latte e carne. L’analisi della varianza ha messo in evidenza come gli effetti considerati (stabulazione, libera vs fissa, e modalità di somministrazione degli alimenti, tradizionale vs unifeed), pur significativi in alcuni casi, influiscano in maniera poco rilevante sulla variabilità delle categorie di impatto mentre esiste una rilevante variabilità dei risultati tra aziende diverse dello stesso gruppo. Ci sono quindi margini per mitigare l’impatto e aumentare l’efficienza degli allevamenti, anche con strutture e gestioni diverse. Nel complesso, i risultati della tesi offrono degli interessanti spunti sulla valutazione della sostenibilità della bovinicoltura da latte nelle aree montane, con approcci metodologici innovativi. In prospettiva, i risultati ottenuti dagli approcci sperimentali condotti potranno essere ampliati su un pool ampio di aziende al fine di identificare degli indicatori di riferimento per la valutazione della sostenibilità e multifunzionalità degli allevamenti montani.

All dairy cows in Europe wear unique identification tags in their ears. These eartags are standardized and contains the cows identification numbers, today only used for visual identification by the farmer. The cow also needs to be identified by an automatic identification system connected to milk machines and other robotics used at the farm. Currently this is solved with a non-standardized radio transmitter which can be placed on different places on the cow and different receivers needs to be used on different farms. Other drawbacks with the currently used identification system are that it is expensive and unreliable. This thesis explores the possibility to replace this non standardized radio frequency based identification system with a standardized computer vision based system. The method proposed in this thesis uses a color threshold approach for detection, a flood fill approach followed by Hough transform and a projection method for segmentation and evaluates template matching, k-nearest neighbour and support vector machines as optical character recognition methods. The result from the thesis shows that the quality of the data used as input to the system is vital. By using good data, k-nearest neighbour, which showed the best results of the three OCR approaches, handles 98 % of the digits.

ABSTRACT Aim of this thesis is to evaluate the genetic and racial structure of a dairy cattle breed reared in Tropics, joint to the investigation of the best selection methodology for productive traits adapted to low/medium input production system. The genetic and racial structure of the Carora Breed, a Venezuelan dairy cattle population, was studied through the analysis of the whole pedigree. The database included 4324 living animals (including culled bulls used for AI), born from 1983 to 2010. The racial composition of Carora breed was studied clustering the current population into 5 racial groups, identified on the basis of the individual racial proportion, in order to detect the breed composition in this synthetic breed. The Carora pedigree resulted quite complete, and the inbreeding level is below the level of 1%, even if the size of this breed is reduced. From this study an increase in the Brown Swiss genes proportion was detected, indicating the possibility of a reduction in adaptability linked to the features of this breed, typically suitable for temperate climates. Genetic parameters of weight at 18 months (W18) and milk yield (MY) of 1781 Venezuelan cows were estimated with a Multiple Trait Animal Model, including the direct breed effects and the epistatic loss. Results showed that direct breeds effects and epistatic loss affected milk trait, while they seemed not important for weight. An high percentage of European genes positively influenced milk production. Four random regression models were used on 95606 test day records to obtain genetic parameters for test day yield and persistency. Akaike’s information criterion (AIC) and minus twice log likelihood (-2logL), were used to compare the models and to choose the best one fitting the data. Estimated heritability for milk yield ranged from 0.21 to 0.30, while repeatability ranged from 0.50 to 0.56. Five persistency measures were calculated taking in account different point of the lactation. In general, heritability values for the five measures of persistency ranged from low to moderate (from 0.18 to 0.26), indicating the possibility of new selection opportunities. The use of persistency indexes accounting for milk yield, may allow the selection of individuals able to express their potential genetic values in tropical environment, without incurring in excessive heat stress losses.

This study, being part of a larger project - "Canadian/New Zealand GxE Interaction Trial" - is comparing Canadian and New Zealand sired heifers for growth traits within Canada, since differences for growth traits were found in the Polish strain comparison (Jasiorowski et al., 1987) and due to selection programs in the two countries. Twenty Canadian Holstein and twenty New Zealand Friesian progeny tested, A.I. bulls were randomly mated to over 1,000 cows in 10 Canadian herds. 3,539 records of weight and wither height from 475 heifers (i.e. 241 Canadian and 234 New Zealand sired) were generated. Subsets of the data for different stages of heifer maturity were analyzed separately. Herd and strain effects least squares means were estimated using analysis of variance. Genetic and phenotypic and correlations and heritability for weight and wither height were estimated by a Derivative-Free Restricted Maximum Likelihood (DFREML) algorithm and an animal model (AM). No differences were found between sire strains for weight except at 15 and 18 months where sib groups of Canadian (CN) sires were heavier than their New Zealand (NZ) contemporaries (393 vs 386 kg and 447 vs 445 kg, respectively). CN sired heifers were taller at all ages except at birth, 3 and 9 months of age. At 24 months CN heifers were 136 cm while NZ heifers were 133 cm. Heritability estimates for weight at birth was 0.62 for the CN strain and 0.59 for the NZ strain. CN estimates (3 to 6 months) and NZ estimates (3 to 9 months) were close to zero. Between 9 to 24 months CN strain estimates ranged from 0.44 to 0.69 while NZ estimates were 0.17 to 0.51. The joint estimates ranged from 0.10 to 0.66. Heritability estimates for wither height for CN strain at birth and between 9 to 21 months were between 0.34 to 0.66 and close to zero between 3 to 6 and at 24 months. The NZ estimates at birth, 18, 21 and 24 months were between 0.36 to 0.93 but close to zero between 3 to 15 months. The joint estimates ranged from 0.32 to 0.75 between 12 to 24 months. Genetic correlations between weight and wither height ranged from 0.62 to 1.0 for CN strain and from -0.04 to 0.91 for NZ strain between 4.5 to 21 months. At six months of age the genetic correlation for CN strain was -0.01 and NZ strain was 0.54. At birth, both sire groups had a genetic correlation of 1.0. At 24 months NZ strain had a genetic correlation of 0.84 while that of the CN strain was 0. Genetic correlations for the joint analysis ranged from 0.61 to 1.0 for all ages except at 6 months (0.18). Phenotypic correlations between weight and wither height were between 0.33 to 0.60 for CN group and 0.33 to 0.62 for NZ group. The joint estimates were 0.36 to 0.61. There were no differences in the phenotypic variances except at 9, 12 and 15 months. Genetic variances were different at all ages except at birth for weight.
Land and Food Systems, Faculty of
Graduate

Staphylococcus aureus is the major cause of bovine mastitis in European countries, a disease of major economic importance to the dairy industry. S. aureus isolates from intra-mammary infections were isolated from diverse clinical and geographical origins and were characterised by phenotypic and genotypic methods. S. aureus isolates were identified by their cultural and biochemical properties and were analysed by pulsed field gel electrophoresis (PFGE) after Smal digestion of DNA. A total of 382 S. aureus isolates from bovine intra-mammary infections, bovine skin lesions, milking personnel and non-farm-related human carriers were tested. Ten commercial dairy herds from NE Scotland were included in this study. S. aureus was not isolated from two of them. One herd showed the typical S. aureus infection (102 - 103 cfu ml-1) of low Total Bacterial Counts and low S. aureus numbers, while in the other seven herds S. aureus was isolated only in low numbers, indicating that elevated Bulk Tank Somatic Cell Counts were due to other organisms. S. aureus isolates were assigned by PFGE to 62 electrophoretic types (discriminatory index D = 0.91) and 17 antibiotypes (D = 0.68). The predominant electrophoretic type consisted of 81/382 isolates and its sub-type by 57/382 isolates. Clonal types of bovine intra-mammary infection S. aureus isolates were compared with isolates from other sites on the cows. In addition, epidemiologically unrelated S. aureus isolates from non-farm-related humans were also tested to compare the human and bovine reservoir of S. aureus. Certain clonal types prevailed in individual herds throughout the twelve-month sampling period, whereas the presence of other clonal types, were more sporadic. Certain clonal types were found in more than one herd suggesting that S. aureus isolates that belonged to these clonal types were particularly well-adapted to colonise and persist in the bovine mammary gland. Certain clonal types of S. aureus isolates recovered from cases of bovine mastitis had a broad geographical distribution, comprising isolates from N, NE, SW Scotland and Ireland. The findings of the present study confirm that certain clonal types have remained in circulation for the last 50 years. On the other hand, certain clonal types were found only in one particular geographical area. S. aureus was present in low numbers on bovine body sites from both beef and dairy cattle with the majority of isolates being recovered from the nasal cavity. S. aureus isolates recovered from cows' body sites belonged to different clonal types than those obtained from milk samples. S. aureus was not recovered from farm personnel. Furthermore, PFGE analysis of S. aureus bovine and non-farm-related human isolates suggested that there was no connection between these two sources. Sixty percent of S. aureus isolates tested in the present study were ?-lactamase positive. A high-level of tetracycline resistance was found among S. aureus isolates from a herd where the treatment used for eradication of the infection included tetracycline antibiotics. The induction of -S, aureus L-forms (cell wall-less forms) by antibiotics that inhibit cell wall synthesis was examined. Twelve isolates of S. aureus were treated with antibiotics. Ten were induced to L-forms, while two isolates produced no L-forms under the conditions used. Resistance to penicillin appeared to play no role in the induction of L-forms. S. aureus L-forms were not isolated from milk samples of dairy cattle infected with mastitis. The results of this study support the hypothesis that some S. aureus isolates are more persistent than others and widely distributed clonal types could be responsible for cases of bovine mastitis. Bovine skin lesions and the human reservoir probably are not able to serve as reservoirs of S. aureus isolates involved in bovine mastitis. Furthermore, the ability to induce L-forms in vitro suggests that these forms may have a role in the persistence of the disease.

Stocking density serves as a sub-clinical stressor impacting natural behavior and affective state of dairy cows. However, cows rarely experience stocking density as an isolated stressor. Understanding the effects of stocking density with additional management stressors such as low-fiber diets or feed restriction is the next step in alleviating stress and improving the well-being of lactating dairy cows housed in freestall barns. The overall goal of this dissertation was to evaluate the interaction of stocking density and the feeding environment on short-term production, behavioral, ruminal fermentation, and stress responses of lactating dairy cattle. The first two studies (Chapter 2 and 3) served as preliminary research for the main studies of this dissertation. The first study objective was to evaluate the effectiveness of using chopped wheat straw to reduce sub-acute ruminal acidosis (SARA) in order to formulate diets for the first main study. Treatments were low straw (0 kg dry matter (DM)/d; LS) and high straw (1.36 kg DM/d; HS). High straw appeared to effectively reduce SARA by lowering time below pH 5.8 with minimal impact on feed intake and rumination. The second study objective was to evaluate the effect of type of blood collection tube on haptoglobin concentration across two commercially-available haptoglobin assays and evaluate assay agreement in order to determine haptoglobin concentrations for the main studies. Lithium heparinized, sodium heparinized, and K2-EDTA plasma resulted in increased haptoglobin concentrations compared to serum using the Tri-Delta colorimetric assay, but no differences were observed using the Life Diagnostics ELISA assay. However, there was a lack of agreement between assays and further identification of a gold-standard assay is needed before analyzing haptoglobin for the main studies. The third study (Chapter 4) investigated the interaction of stocking density (100% and 142% of freestalls and headlocks) and source of forage fiber (no added straw and added straw at 3.5% ration DM). Treatments did not impact feed intake, but straw diets tended to reduce milk production. Increasing stocking density reduced lying time but increased efficiency of stall use. Though feeding and rumination times were unaffected, overstocking shifted the location of rumination away from the freestall. Increased stocking density tended to increase stress responses. Both greater stocking density and no straw diets increased SARA, and the combination of these stressors tended to exacerbate this pH response. Adding straw to the diet reduced the negative impacts of overstocking on ruminal pH. The fourth study (Chapter 5) evaluated the interaction of stocking density (100% and 142%) and feed access (5-h reduced feed access and no reduced feed access). Treatments had minimal impact on short-term feed intake and production. Overstocking affected behavior similar to responses observed in Chapter 4. Reducing feed access decreased feeding time, though cows altered feeding and rumination responses to maintain daily rumination. Both treatments shifted priorities for feeding and lying behavior, though increased stocking density had the larger impact. Though reduced feed access did not impact ruminal pH, an exacerbated response was observed when combined with increased stocking density. The combination of stocking density and feeding environment stressors exacerbate negative effects on biological function and should be avoided.

Ruminants provide human society with high quality food from non-human-edible resources, but their emissions negatively impact the environment via greenhouse gas production. The rumen and its resident microorganisms dictate both processes. The overall goal of this project was to determine whether a causal relationship exists between the rumen microbiome and the host animal's physiology, and if so, to isolate and examine the specific determinants that enable this causality. To this end, we divided the project into three specific parts: (1) determining the feed efficiency of 200 milking cows, (2) determining whether the feed- efficiency phenotype can be transferred by transplantation and (3) isolating and examining microbial consortia that can affect the feed-efficiency phenotype by their transplantation into germ-free ruminants. We finally included 1000 dairy cow metadata in our study that revealed a global core microbiome present in the rumen whose composition and abundance predicted many of the cows’ production phenotypes, including methane emission. Certain members of the core microbiome are heritable and have strong associations to cardinal rumen metabolites and fermentation products that govern the efficiency of milk production. These heritable core microbes therefore present primary targets for rumen manipulation towards sustainable and environmentally friendly agriculture. We then went beyond examining the metagenomic content, and asked whether microbes behave differently with relation to the host efficiency state. We sampled twelve animals with two extreme efficiency phenotypes, high efficiency and low efficiency where the first represents animals that maximize energy utilization from their feed whilst the later represents animals with very low utilization of the energy from their feed. Our analysis revealed differences in two host efficiency states in terms of the microbial expression profiles both with regards to protein identities and quantities. Another aim of the proposal was the cultivation of undescribed rumen microorganisms is one of the most important tasks in rumen microbiology. Our findings from phylogenetic analysis of cultured OTUs on the lower branches of the phylogenetic tree suggest that multifactorial traits govern cultivability. Interestingly, most of the cultured OTUs belonged to the rare rumen biosphere. These cultured OTUs could not be detected in the rumen microbiome, even when we surveyed it across 38 rumen microbiome samples. These findings add another unique dimension to the complexity of the rumen microbiome and suggest that a large number of different organisms can be cultured in a single cultivation effort. In the context of the grant, the establishment of ruminant germ-free facility was possible and preliminary experiments were successful, which open up the way for direct applications of the new concepts discovered here, prior to the larger scale implementation at the agricultural level.

Meiotic recombination is one of the important phenomena contributing to gamete genome diversity. However, it is not well studied in livestock including cattle. The general objectives of this project were to perform genetic analyses of recombination and PRDM9 alleles and study their implications in dairy cattle breeding. The specific objectives were: 1. Analyze variation in recombination across individuals, breeds, and environments; 1.1.Construct individual-level recombination maps; 1.2.Compare recombination features between bulls held under different environmental conditions in US and Israeli; 2. Examine genetic basis of recombination variation in cattle; 2.1.Characterize PRDM9 alleles and their impacts on total and locus-specific recombination features; 2.2.Validate pedigree-based recombination maps using single sperm sequencing and typing; 3. Investigate the impacts of recombination on dairy cattle breeding; 3.1.Evaluate correlation between recombination and dairy production and health traits; 3.2.Evaluate the benefits of incorporating recombination as novel quantitative trait into genomic selection scheme.

Willingness to reduce meat and dairy consumption across the population is relatively low (12.8%-25.5%), albeit increasing. While women and higher socio-economic groups tend to show greater awareness of an environmental rationale and subsequent willingness for change, this difference does not emerge strongly in studies reporting behavioural outcomes. A broad set of search terms was used to identify literature in this area, but focused on: Evidence of the potential for behaviour change in response to sustainability, environmental and climate change agendas. The reduction of meat or dairy consumption, rather than stopping altogether. Motives and barriers to reduction rather than stopping could differ considerably. Research was also specifically searched to explore the impact of socio-demographic characteristics on willingness to reduce meat and dairy consumption. This study was used to inform the primary research on Psychologies of Food Choice: Public views and experiences around meat and dairy consumption.

Mastitis, an inflammatory response of the mammary tissue to invading pathogenic bacteria, is the largest health problem in the dairy industry and is responsible for multibillion dollar economic losses. E. coli are a leading cause of acute mastitis in dairy animals worldwide and certainly in Israel and North America. The species E. coli comprises a highly heterogeneous group of pathogens, some of which are commensal residents of the gut, infecting the mammary gland after contamination of the teat skin from the environment. As compared to other gut microflora, mammary pathogenic E. coli (MPEC) may have undergone evolutionary adaptations that improve their fitness for colonization of the unique and varied environmental niches found within the mammary gland. These niches include competing microbes already present or accompanying the new colonizer, soluble and cellular antimicrobials in milk, and the innate immune response elicited by mammary cells and recruited immune cells. However, to date, no specific virulence factors have been identified in E. coli isolates associated with mastitis. The original overall research objective of this application was to develop a genome-wide, transposon-tagged mutant collection of MPEC strain P4 and to use this technology to identify E. coli genes that are specifically involved in mammary virulence and pathogenicity. In the course of the project we decided to take an alternative genome-wide approach and to use whole genomes bioinformatics analysis. Using genome sequencing and analysis of six MPEC strains, our studies have shown that type VI secretion system (T6SS) gene clusters were present in all these strains. Furthermore, using unbiased screening of MPEC strains for reduced colonization, fitness and virulence in the murine mastitis model, we have identified in MPEC P4-NR a new pathogenicity island (PAI-1) encoding the core components of T6SS and its hallmark effectors Hcp, VgrG and Rhs. Next, we have shown that specific deletions of T6SS genes reduced colonization, fitness and virulence in lactating mouse mammary glands. Our long-term goal is to understand the molecular mechanisms of host-pathogen interactions in the mammary gland and to relate these mechanisms to disease processes and pathogenesis. We have been able to achieve our research objectives to identify E. coli genes that are specifically involved in mammary virulence and pathogenicity. The project elucidated a new basic concept in host pathogen interaction of MPEC, which for the best of our knowledge was never described or investigated before. This research will help us to shed new light on principles behind the infection strategy of MPEC. The new targets now enable prevalence and epidemiology studies of T6SS in field strains of MPEC which might unveil new geographic, management and ecological risk factors. These will contribute to development of new approaches to treat and prevent mastitis by MPEC and perhaps other mammary pathogens. The use of antibiotics in farm animals and specifically to treat mastitis is gradually precluded and thus new treatment and prevention strategies are needed. Effective mastitis vaccines are currently not available, structural components and effectors of T6SS might be new targets for the development of novel vaccines and therapeutics.