Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / This study aimed to evaluate different alternatives for management of natural pasture. Vegetation dynamics was evaluated for a period of six years in a natural pasture, submitted along 16 years to fire and grazing treatments. Furthermore, we evaluated the production and behavior of beef heifers from 12 to 18 months of age, maintained on natural pasture under two grazing frequencies. In the first experiment, the treatments consisted of a combination of burning factors (presence or absence) and grazing (presence or absence), in concave and convex slope positions, in a completely randomized design with factorial arrangement of four treatments and two topographic positions. Rotational grazing was used, with intervals calculated by the thermal time (760 degree days) necessary for the emergence of four leaves of Paspalum notatum and Andropogon lateralis. Burning was performed at the end of winter in a bimodal fashion. The treatments excluded from disturbances had a behavior atypical due to a burning caused by a lightning leading vegetation to a succession process. The grazed treatments had a stable prevalence of Paspalum notatum, on concave slope and its association with Andropogon lateralis, in convex slope. Natural grassland proved to be resilient to burning and grazing. However, the use of burning and grazing on concave slope areas can cause a reduction in vegetation diversity. In the second experiment, we evaluated the effect of two defoliation intervals, 375 and 750 degree days (DD), on the productive performance of beef heifers maintained on natural pasture under rotational grazing in the growing season of 2010 and 2011. The experimental design was completely randomized with two treatments and three replications. We evaluated the forage mass, height, green material and dead material in pasture. The performance measurements in animals were evaluated stocking rate, average daily gain and gain/ha. The greatest height, mass of green material, dead material and forage mass were observed in 750 DD treatment. Treatment with 375 DD presented a higher percentage of green material in relation to herbage mass. The highest average daily gain and gain per area were observed in the treatment 375 DD. The shortest interval between grazing permits satisfactory performance in rearing of beef heifers, since the natural pasture is managed with green material above 1500 kg DM/ha and grazing periods lower than three days. In the third experiment were related parameters and performance of grazing animal and its ingestive behavior. Ingestive behavior of heifers was measured as times of grazing, ruminating and resting, bite rate, bites per feeding station, feeding stations per minute, displacement rates by stations and time. The multiple regression equations had coefficients of determination of 48, 68 and 89% for grazing time, average daily gain and gain/ha. The average temperature, day of occupation, number of bites/min and bits per season were the best predictors of ingestive behavior of beef heifers grazing on natural grassland. / Este trabalho teve por objetivo avaliar alternativas de manejo de pastagem natural. Foi avaliada a dinâmica da vegetação por um período de seis anos de uma pastagem natural, submetida ao longo de 16 anos a tratamentos de fogo e pastejo. Além disso, foram avaliadas a produção e o comportamento de novilhas de corte dos 12 aos 18 meses de idade, mantidas em pastagem natural sob duas frequências de desfolha. No primeiro experimento, os tratamentos foram constituídos da associação dos fatores queima (presença ou ausência) e pastejo (presença ou ausência), nas posições de encosta e baixada, num delineamento completamente casualizado com arranjo fatorial de quatro tratamentos e duas posições topográficas. O pastejo foi rotacionado, com intervalos calculados pela soma térmica acumulada (760 graus dia) necessária para o surgimento de quatro folhas das espécies Paspalum notatum e Andropogon lateralis. A queima foi realizada ao final do inverno de forma bimodal. Os tratamentos excluídos de distúrbios tiveram um comportamento atípico devido a uma queima provocada por um raio levando a vegetação a um processo de sucessão. Os tratamentos pastejados foram estáveis com um predomínio das espécies Paspalum notatum, na encosta e de uma associação desta com Andropogon lateralis, na baixada. A pastagem natural mostrou-se resiliente a queima e ao pastejo. Entretanto, o uso da queima e pastejo, em áreas de encosta, pode causar redução na diversidade da vegetação. No segundo experimento foi avaliado o efeito de dois intervalos entre desfolhas de 375 e 750 graus dia (GD), sobre o desempenho produtivo de novilhas de corte mantidas em pastagem natural sob pastoreio rotacionado, na estação de crescimento entre 2010 e 2011. O delineamento utilizado foi o inteiramente casualizado com dois tratamentos e três repetições. Foram avaliados a massa de forragem, altura, material verde e material morto na pastagem. As medidas de desempenho nos animais foram a carga animal, ganho médio diário e ganho/ha. As maiores altura, massa de material verde, material morto e massa de forragem total foram observados com 750 GD. No tratamento com 375 GD foi observado maior percentual de material verde em relação à massa de forragem. Os maiores ganho médio diário e ganho por área foram observados no tratamento 375 GD. O menor intervalo entre pastoreios permite desempenho satisfatório na recria de novilhas de corte, desde que a pastagem natural seja manejada com material verde superior a 1500 kg de MS/ha e com períodos de ocupação de no máximo três dias. No terceiro experimento, foram relacionados os parâmetros da pastagem e de desempenho animal com o comportamento ingestivo dos animais. O comportamento ingestivo das novilhas foi medido pelos tempos de pastejo, de ruminação e de ócio, taxa de bocados, bocados por estação alimentar, estações alimentares por minuto, taxas de deslocamento e tempo por estação. As equações de regressão múltipla apresentaram coeficientes de determinação de 48, 68 e 89% para tempo de pastejo, ganho médio diário e ganho/ha, respectivamente. A temperatura média, os dias de ocupação, número de bocados/min e bocados por estação foram os melhores preditores do comportamento ingestivo das novilhas de corte em pastagem natural.

<p>Historically, the meat industry has struggled to provide consumers with consistent beef tenderness. Various post-harvest technologies have been used in industry; however, there is still a need to develop a natural and safe post-harvest processing system that can be used to create consistently tender products for consumers. In addition to postmortem aging being a time-consuming process, literature has suggested that it is not a sufficient method to achieve tenderization in certain cull cow muscles. This has resulted in the large supply of cull cow beef to be underutilized due to its inferior quality, specifically tenderness. Applying a combination of mechanical tenderization with additional postmortem aging may be an effective strategy to overcome deficiencies in beef tenderness. Recent studies have found that tumbling without brine addition can be successful at improving instrumental tenderness and consumer liking of tenderness of fresh beef loin. The physical disruptions of muscles, which likely occur during tumbling, may enhance activity of proteolytic enzymes and thus induce more tenderization. The overall objective of this thesis was to investigate the effects of fresh beef tumbling methods and postmortem aging times on the tenderness and proteolysis of loin muscles from both A maturity cattle and cull cows.</p> <p>The first chapter of this thesis is a literature review that will address the factors affecting tenderness and the methods used by the industry to improve tenderness, specifically focusing on meat tumbling and cull cow beef. The second chapter is a study that investigated the effects of fresh beef tumbling at different postmortem times on meat quality attributes and proteolytic features of loins. The results from this study suggest that early postmortem tumbling coupled with aging can synergistically impact the improvements of beef loin tenderness and proteolysis, shortening the necessary aging period. The third and final chapter of this thesis is a study that aimed to determine the effect of fresh beef tumbling and postmortem aging on the quality and proteolysis of loins from cull cows. The results from this study indicate that aging would be effective at improving the quality and palatability of cull cow beef loins, although tumbling could improve consumer liking of tenderness at earlier postmortem times.</p>

<p>  </p> <p>Tenderness is a key sensory trait influencing beef palatability. Tumbling is a value-adding process that has been extensively applied and studied within the realm of processed meats. Various post-harvest strategies to ensure fresh beef reaches acceptable levels of tenderness have been employed, often with the aim of physically disrupting myofibrillar structure or enhancing the rate and extent of postmortem proteolysis. One such method would be the application of postmortem aging; however, the effectiveness of aging on tenderization is well-known to differ throughout individual muscles of the beef carcass. For inherently tough cuts, physical interventions such as mechanical tenderization are often used, although several detriments to quality attributes may be induced. Further, some modern consumers prefer meat products with no added non-meat ingredients. An alternative method of applying tumbling in the absence of a brine solution followed by additional postmortem aging could be a practical means to facilitate tenderization while potentially minimizing detriments to other eating quality attributes.</p> <p>To evaluate the efficacy of tumbling without brine a method of beef tenderization, the process was first assessed in the <em>longissimus lumborum </em>muscle (n=9). In this study, muscles were allocated among 0, 60, and 90 minutes of tumbling, after which aging for 0, 7, and 14 days was conducted. Immediately after the application of the tumbling process, steaks from muscles that had been tumbled were considerably more tender (24.7 N and 21.6 N for 60 and 90 minutes, respectively) than non-tumbled controls (34.8 N). Steaks from the tumbled groups maintained greater instrumental tenderness throughout the course of the aging period. These results were supported by increases in myofibril fragmentation index, as well as increased troponin-T degradation during aging. However, cooking loss was increased in tumbled steaks, which could have implications for sensory juiciness. Considering this study demonstrated that tumbling without brine inclusion followed by postmortem aging resulted in profound changes to sensory traits, further study regarding its impacts on sensory attributes and proteolysis among different beef muscles was warranted.</p> <p>The following study evaluated the combined tumbling and aging process on the quality, palatability, and proteolytic attributes of beef <em>longissimus lumborum </em>and <em>semitendinosus </em>muscles (n=16). Muscle sections were allocated among 0, 40, 80, and 120 minutes of tumbling, as well as 0 or 10 days of subsequent aging. Regardless of aging duration, tumbling for any duration increased instrumental tenderness of the <em>longissimus lumborum</em> but not <em>semitendinosus</em> muscle. Similar to the previous study, increased cooking loss was induced through tumbling. In both muscles, obvious fragmentation of the myofibrillar structure with tumbling was observed through increases in myofibril fragmentation index and transmission electron microscopy. Tumbling with aging favored the degradation of myofibrillar proteins including troponin-T and desmin; however, calpain-1 autolysis appeared mostly unchanged. Neither tumbling nor aging influenced the amount and properties of collagen, which may indicate why the process did not influence instrumental tenderness of the <em>semitendinosus </em>despite myofibrillar fragmentation and degradation. <em>Longissimus lumborum </em>muscles tumbled for any durations were rated by consumers (n=120) to be more tender with greater overall liking than control steaks. <em>Semitendinosus </em>steaks that were tumbled for 120 minutes and further aged had improved liking of tenderness with similar juiciness and flavor to control steaks at the same postmortem timepoint. These results indicated that tumbling without brine would result in myofibrillar fragmentation and favor the degradation of myofibrillar proteins during aging, while impacts on connective tissues would be minimal. Consequently, muscles without a high extent of background toughness would be effectively tenderized through tumbling, while the results would be more limited in inherently tough cuts.</p> <p>Considering these results, the process was then applied to muscles of intermediate tenderness from the sirloin, specifically the <em>gluteus medius, biceps femoris, </em>and <em>tensor fasciae latae </em>muscles (n=16). Muscles were tumbled for 0 or 120 minutes, then aged for 0 or 10 additional days. Tumbling increased the instrumental tenderness of the <em>gluteus medius </em>and <em>tensor fasciae latae </em>but not the <em>biceps femoris</em>, regardless of aging time. Cooking loss was increased with tumbling in all muscles. Similarly, myofibrillar fragmentation was also increased in all muscles, and there was some evidence to suggest that tumbling with subsequent aging would aid in the degradation of troponin-T in the <em>biceps femoris</em>. To further understand how tumbling might affect specific descriptive sensory attributes, a trained panel (n=8) was conducted on aged samples. Tumbled <em>gluteus medius </em>steaks had greater myofibrillar tenderness than non-tumbled controls; however, tenderness scores of other muscles were not affected. There was some evidence that tumbling with aging could induce the generation of off-flavors in the <em>gluteus medius </em>and <em>tensor fasciae latae</em>, as well as decrease juiciness of the <em>biceps femoris</em>.</p> <p>Taken together, these results support that tumbling without brine inclusion would be an effective strategy to improve beef tenderness and palatability, dependent on the traits of the individual cut. Improved tenderness would be primarily attributed to the fragmentation and degradation of myofibrillar structure. However, the results indicate that tenderization would be limited in cuts with a high extent of background toughness, which tumbling alone would be largely unable to disrupt. Future studies should focus on the effects of tumbling without brine inclusion with aging on oxidative stability and the potential introduction of hazards prior to industry application. Further elucidation of how the process could be optimized to maximize tenderization while minimizing potential negative impacts to flavor and juiciness would be beneficial to improving overall palatability.</p>

In the discourse of crime and place, the focus has rarely fallen on rural crime. While experiencing comparably lower crime levels than urban counterparts, the common association with rural areas as being symbols of peace and friendly social interaction is not necessarily accurate. One group that often are thought of as inherently rural is farmers, who’s workplaces may possess certain unique vulnerabilities to crime compared to other locations. This thesis aims to obtain a better understanding of the threats against farmers related to animal production in a Swedish context, adding to the knowledge base regarding rural crime and sustainable development of rural and urban areas. The objectives of the study are: • to investigate the nature of the victimization of farmers devoted to animal production in Sweden, especially related the situational conditions of farms and rural areas. • to explore new data that could be used to approximate the scale of the threats against farmers using data from media archives from 2009 to 2019. This study reports types, frequency, and location of crimes against animal production with a focus on mink, rabbit and pig farms. Geographical Information Systems (GIS) is used to report the geography of these offences at municipal level. The theories of the routine activity approach and situational crime prevention are used to try to explain certain conditions that may facilitate crime on farms, while the offenders are explored using the theory on techniques of neutralization. The findings of the study show that the experience of the chosen actor’s varied greatly, but with crimes such as trespassing, vandalism and theft being common types of offenses across the board. The locations of the crime events were focused in the southern to mid of Sweden. Situational conditions that may have facilitated crime includes: the large size of farms and low population density providing low detection of crime, high value targets, and relatively high accessibility to the farms. From the data, mainly three techniques of neutralization were observed to be utilized: denial of the victim, denial of injury and appeal to higher loyalties. Multiple techniques were observed to be utilized together, while simultaneously exploiting situational conditions to facilitate the neutralization.

Die Wasserknappheit wird aufgrund des Klimawandels voraussichtlich häufiger und intensiver auftreten, wodurch die Wasserkonkurrenz zunimmt und die Nahrungsmittelproduktion gefährdet wird. Höhere Temperaturen und längere Dürren können auch die Wasserverfügbarkeit der Tierhaltung beeinflussen. In Folge dessen kann es zu einer Verringerung des Futterangebots und damit zu einer Beeinträchtigung der Produktion kommen. Auch aus diesem Grund sind nachhaltige und resiliente Produktionssysteme erforderlich, um den Nahrungsmittelbedarf einer wachsenden Bevölkerung zu decken. Auf Pflanzenproduktion und Tierhaltung entfallen 72 % der weltweit entnommenen Wassermenge. Der Löwenanteil des Wasserbedarfs in der Tierhaltung besteht bei der Futtermittelproduktion. Weiterhin wird Wasser für die Trinkwasserbereitstellung sowie für die Reinigung und die Kühlung der Ställe benötigt. Tierproduktionssysteme müssen zukünftig mit betrieblichen Maßnahmen die Wasserressourcen besser ausnutzen. Die Steigerung der Wasserproduktivität in der Pflanzenproduktion und der Tierhaltung durch eine integrierte Bewirtschaftung und Steuerung der eingesetzten Wasserressourcen sind hierfür von entscheidender Bedeutung. Die Wasserproduktivität beschreibt das Verhältnis von Output zu Input: das Verhältnis von Output (z. B. kg Milch) zu produktivem Wasserinput (z. B. m³ Transpiration). Das Wasserinput umfasst den direkten Wassereinsatz und den indirekten Wassereinsatz, z.B. für zugekaufte Futtermittel. Die Ermittlung der Wasserproduktivität wird vor allem bei der Bewertung von landwirtschaftlichen Maßnahmen zur Verbesserung des Niederschlags- und technischen Wassereinsatzes in der Tier- und Pflanzenproduktion benötigt. Zur Steigerung der Wasserproduktivität und auch um die Umweltwirkungen der Tierhaltungssysteme zu verringern, bedarf es einheitlicher Methoden. Im Jahr 2019 hat die Food and Agriculture Organization of the United Nations (FAO) mit dem Livestock Environmental Assessment and Performance (LEAP) Partnership Richtlinien für die Bewertung der Wassernutzung in Tierproduktionssystemen und zugehöriger Lieferketten veröffentlicht. Zielsetzung ist die Ermittlung der Wasserflüsse auf betrieblicher Ebene, um einerseits die Wasserproduktivität zu ermitteln und andererseits den Beitrag der Tierhaltung zu einer möglichen Wasserknappheit zu bewerten. In dieser kumulativen Dissertationen werden die Ergebnisse der ersten Anwendung dieser Leitlinien der FAO in landwirtschaftliche Betriebe in Brasilien vorgestellt. In referierten Fachzeitschriften wurden bereits drei Originalarbeiten veröffentlicht. Im Rahmen der drei Veröffentlichungen wurde die Wasserproduktivität wurde für 115 Betriebe (Schweine-, Geflügel- und Milchviehbetriebe) im Einzugsgebiet des Lajeado Tacongava in Südbrasilien berechnet, wobei die Auswirkungen der Viehzucht auf die Wasserknappheit bewertet wurden. Die Ergebnisse der ersten und zweiten bereits veröffentlichten Originalarbeiten zeigen den großen Einfluss von Futtermitteln auf die Wasserproduktivität tierischer Erzeugnisse. Die Ergebnisse unterstreichen daher die Notwendigkeit einer engen Zusammenarbeit zwischen Pflanzenproduktion und Tierhaltung. Die Niederschlagswasserproduktivität der Futterproduktion muss verbessert werden, um das Management der Tierernährung zu optimieren. Darüber kann eine höhere Wasserproduktivität der Tierhaltung insgesamt erreicht werden. In Milchviehbetrieben zeigen die Ergebnisse, dass die Wasserproduktivität direkt von den Indikatoren für eine höhere Milchproduktivität des Betriebs abhängt, unabhängig von der Art des Produktionssystems, und unterstreichen die Bedeutung der Bewertung dieses Indikators WP auf Betriebsebene. Die dritte Veröffentlichung standen die Umweltauswirkungen der Wassernutzung der Tierhaltung im Fokus. Die Bewertung der Auswirkungen der Wassernutzung ergab eine geringe Wasserknappheit im untersuchten Wassereinzugsgebiet. Die Wasserknappheit ist nicht alarmierend, selbst bei den Szenarien mit geringerer Verfügbarkeit von Wasser. Die Produktion von Schweinen wies den größten „Fußabdruck der Wasserknappheit“ im Wassereinzugsgebiet auf, gefolgt von der Milch- und Geflügelproduktion. Diese Dissertation trägt dazu bei, das Wissen über die Wasserflüsse, die Wasserproduktivität der Schweine- und Geflügelproduktion und die Milchproduktion in verschiedenen Produktionssystemen auf betrieblicher Ebene zu erweitern. Es sind die ersten Berechnungen der Wasserproduktivität dieser Tierproduktionssysteme in brasilianischen Betrieben und die erste Bewertung der Auswirkungen der Wasserknappheit in der Tierproduktion in einem brasilianischen Einzugsgebiet. Zudem wurde das Land Brasilien damit in die internationale wissenschaftliche Diskussion zu diesem Thema eingeführt. Die LEAP-Richtlinien der FAO wurden in dieser ersten Studie in Brasilien erfolgreich angewandt. Auf der Grundlage der Ergebnisse wird eine breite Anwendung der Leitlinien empfohlen, um die Berechnung von zuverlässigen und vergleichbaren Ergebnissen zu gewährleisten und die Entscheidungsfindung von Regierung, Wirtschaft und Gesellschaft im Hinblick auf eine resiliente und nachhaltige landwirtschaftliche Produktionssysteme zu unterstützen. / Water shortages caused by persistent and severe droughts and changes in rainfall patterns are expected to be more frequent and intense due to climate change, increasing water competition and posing food production at risk. Therefore, sustainable and resilient food systems are needed to meet the demand of a growing population. Plant production and animal husbandry account for 72% of the water withdrawn worldwide. Most water consumed in livestock production is for animal feed production. Water is also needed to provide drinking water and to clean and cool the stables. In this context, increasing agriculture and livestock water productivity (WP) is crucial, along with integrated management and governance of water resources. WP describes the ratio of output (e.g. kg milk) to water input (e.g. m³ evapotranspiration). Water input includes direct (e.g. water intake) and indirect (e.g., water for purchased feed) water use. WP calculations are used primarily in evaluating agricultural measures to improve rainfall and technical WP in livestock and crop production. Consistent methods are needed to increase WP and also to reduce the water-related environmental impact of livestock systems. Recently, the Food and Agriculture Organization of the United Nations (FAO), through the Livestock Environmental Assessment and Performance (LEAP) Partnership, launched reference guidelines for assessing water use in livestock production systems and supply chains. The FAO LEAP guidelines aim to understand the water flows on a farm scale and evaluate the contribution of livestock activities to water scarcity, supporting the identification of opportunities to reduce the potential water use impacts in this sector. This cumulative thesis presents the results of the first application of the FAO LEAP guidelines on farms located in Brazil. Three original publications were published in peer-reviewed journals. The WP was calculated based on primary data collected on 115 farms (pig, poultry and dairy) located within the Lajeado Tacongava watershed in southern Brazil, where the water scarcity impact associated with livestock production was assessed. The results of the first two original papers published show the high influence of feed production on the WP of animal products. Therefore, the results emphasize the need for close cooperation between feed production and livestock production to improve WP. Rainfall WP of feed production can be improved to optimize animal nutrition management. In addition, higher livestock WP can be achieved. In dairy farms, results indicate that WP is directly dependent on dairy productivity indicators of the farm, regardless the type of production system, and reinforce the importance of assessing this indicator on a farm scale. In the third publication, the environmental impact of water use in livestock production was investigated. The water scarcity impact assessment demonstrated a low water scarcity in the watershed and it is not alarming even in the driest water flow scenarios. Pig production presented the highest water scarcity footprint in the watershed, followed by dairy farming and poultry production. This dissertation contributes to the advancement of knowledge on the water flows, WP of pig, poultry and milk produced under different production systems on farm scale, which are the first WP benchmarks for these animal production systems in Brazilian farms. It also introduced Brazil to the international scientific discussion on this topic. Some suggestions of potential improvements for the guidelines are presented in this study. The FAO LEAP guidelines were successfully applied in its first study in Brazil. Based on the results of this study, the guidelines’ widespread use is recommended to ensure reliable and comparable results to support government, business and society decision-making toward a more resilient and sustainable food supply chain.

<p dir="ltr">Heat stress is one of the leading welfare concerns for modern swine production globally. Swine are especially susceptible as the species has inactive sudoriferous glands and, as a result, these animals thermoregulate mainly through behaviors such as wallowing and rooting up cooler patches of ground. In commercial settings, access to open ground or wallowing pits would present a threat to the animals’ health in the form of a vector for diseases and parasites. This puts aspects of swine welfare in direct conflict with one another, while public legislature and consumer pressures increasingly call for approaches to animal welfare that encompass all aspects of welfare to be considered. Efforts towards improved welfare are also crucial to the environmental and economical sustainability for producers and consumers. Previous genetic selection tactics used in swine herds focused intensely on a few traits and have led to modern animals being highly productive but also more environmentally sensitive. Intensely selected animals have energy margins that are narrower and more devoted to higher production leaving less accommodations for resilience in moments of stress. Since swine behaviorally thermoregulate, the use of behavior studies combined with those of genetics is one possible way to effectively identify heritable aspects of climatic resilience into future herds while still improving production traits. The primary objectives of this thesis were to develop an ethogram that can be used to base phenotypes of behavior; calculate the variance components of the behavior traits; correlate these components with those of maternal productivity and heat tolerance; and finally explore the genetic background of the behavior traits based on the identification of genomic markers significantly associated with them. Data was collected on 1,678 Landrace × Large White sows from a commercial swine herd in North Carolina. The data comprised information on climatic factors, litter performance, and behavior during a standardized human handling procedure in the summer of 2021. These animals were genotyped using the PorcineSNP50K Bead Chip (Illumina, San Diego, CA, USA). These studies describe the development of an ethogram for use on lactating sows in a commercial setting in order to create the novel behavior traits of Responsiveness Score (RS), Vocalization Score (VS), and Shave Time (ST). The genetic variance components were then estimated, and heritabilities found to be 0.17 ± 0.05 for RS, 0.15 ± 0.05 for VS, and 0.10 ± 0.05. These novel behavior traits had low genetic correlations with traits of maternal performance and heat stress resilience. Genome-wide association studies were then performed, and 19 genomic markers were significantly associated with the three behavior traits. However, only one region located on chromosome 3 harbors a candidate gene that may play a role in heat stress resilience. Although the novel behavior traits explored in this study are heritable, they were not found to be viable indicator traits for heat stress resilience due to their low genetic correlations with direct indicators of heat tolerance in lactating sows. It is important that additional phenotypic records of behaviors related to welfare are generated in the future to better map their polygenic nature. </p>

Despite the importance of a high white clover (Trifolium repens) content in temperate pastoral systems in terms of livestock performance and nitrogen fixation, the proportion of white clover in grass-clover pastures is often low (<20%). This thesis examined in two experiments whether the white clover content of pastures could be improved by sowing white clover with alternative grass species to diploid perennial ryegrass (Lolium perenne L.). In a pasture experiment, DM production, pasture composition and morphology of grass-clover mixtures was measured over the establishment year (January 2007 to January 2008) where white clover was sown in fine mixtures with diploid perennial ryegrass, tetraploid perennial ryegrass, timothy (Phleum pratense L.) and cocksfoot (Dactylis glomerata L.). Pastures were irrigated and rotationally grazed with on-off grazing with Coopworth ewe hoggets. Total annual DM production of pasture was more than 20% higher in tetraploid (12521 kg DM ha⁻¹) and diploid (11733 kg DM ha⁻¹) perennial ryegrass than timothy (9751 kg DM ha⁻¹) and cocksfoot (9654 kg DM ha⁻¹). However, timothy (5936 kg DM ha⁻¹) and cocksfoot (5311 kg DM ha⁻¹) had more than four times higher white clover annual DM production than tetraploid (1310 kg DM ha⁻¹) and diploid (818 kg DM ha⁻¹) ryegrass. Pasture growth rate at the first three harvests in autumn was significantly greater in tetraploid and diploid ryegrass than timothy and cocksfoot. Timothy and cocksfoot had a higher proportion of white clover than tetraploid and diploid perennial ryegrass throughout the entire year. This was due to more and larger white clover plants in timothy and cocksfoot plots. In a grazing preference experiment, the partial preference of sheep for white clover offered in combination with the same grass species as in the pasture experiment was measured in five grazing tests in May, September, October, November and December 2007. Pastures were sown in January 2007. Paired plots (grass and clover both 4.2 m x 10 m) were grazed by three Coopworth ewe hoggets between 9am and 5pm, and preference was recorded by decline in pasture mass and visual scan sampling for grazing time. Grazing preference for clover was generally low throughout these tests (e.g. average apparent DM intake from clover = 47%; average grazing time from clover = 44%). Several explanations are proposed for this low preference including a high N content and intake rate of the grass relative to the clover. No significant differences were found among the grass treatments in total grass grazing time, total clover grazing time, ruminating time, the proportion of grazing time on clover, selective coefficient for clover and DM intake percentage from clover at any date. There was no significant change in overall sward surface height (SSH) decline among grass treatments throughout all the tests except December 2007 when the overall SSH decline for cocksfoot was significantly lower than the other species. The study indicated that the rapid growth rate of perennial ryegrass in the early phase of pasture establishment, rather than differences in partial preference, was the key factor limiting white clover content in the mixed swards relative to cocksfoot and timothy pastures. It is concluded that high clover-containing pastures capable of delivering high per head performance can be established through the use of slow establishing pasture species such as timothy and cocksfoot.

There is little evidence that the productivity of New Zealand beef herds has improved over time. Data from the NZ Meat and Wool Board’s Economic Service (2006) suggest that the average national calving percentage has declined over the last two decades. During the same period cattle carcass weights have increased but so too has the average cow live-weight which has resulted in increased maintenance costs of the cow herds. It is unclear whether production efficiency in the industry has improved or declined over time. The aim of this research was to develop means of improving productivity in commercial beef herds through practical methods of performance recording. The objectives were firstly to establish current management practices in commercial herds and secondly to develop an objective system for cow selection and culling which would have practical application in commercial herds. Beef management survey Ninety two commercial beef producers with more than 100 breeding cows from the greater Canterbury region of New Zealand were surveyed. Pasture control was the main reason given for owning a beef herd. Size and conformation were the main selection criteria for choosing replacement heifers and bulls. Over 80% of herds retained their own heifers as replacements and >60% mated yearling heifers to first calve at two years of age. Fertility was poor in the surveyed herds. In-calf rates at pregnancy testing averaged 88% for maiden heifers, 92% for rising second calvers and 93% for mixed age (m.a.) cows. There was no significant difference between in-calf rates of maiden heifers mated to first calve at two or three years of age; nor was there any significant difference between the re-breeding success of the two groups. Heifers mated at least one week earlier than m.a. cows, achieved a re-breeding success 4.7% greater (P<.01) than those mated at the same time. Reasons for cows not weaning a calf included wet dry (9.3% of pregnant cows wintered), pregnancy tested not-in-calf (7.4%) and dam death (2.6%). Only 87.9% of pregnant females wintered weaned a calf (89.4% of m.a. cows and 84.9% of heifers). Reasons why cows exited the herds included diagnosed empty (37.2% of all exits), involuntary culls (25.4%), sold wet dry (16.2%), deaths (13.1%) and poor calf production (5.1%). Vaccination was infrequent with clostridial vaccines the most common in m.a. cows (15.2%) and in calves (40.7%); vaccination against Leptospirosis was much less common. Very few of the surveyed farms used any system of performance recording; as a result there was very little performance-based selection or culling practiced. Evaluation of alternative measures of cow productivity Data from four performance recording beef herds were used to compare alternative measures of cow productivity with the industry standard which is calf weaning weight adjusted for sex (SOC) and age of calf and age of dam (AOD), i.e. the “200 day weight.” None of the alternative measures evaluated required knowledge of calving date and all were relatively easily obtainable in extensively managed beef herds. The assessment of cows was based not on their estimated breeding values but instead on their most probable producing ability which, as the sum of all of the permanent, repeatable aspects of the calf-rearing ability of the cow, explains considerably more of the variance of weaning weight than does breeding value alone. SOC and AOD-adjusted marking weight, weaning weight and average daily gain (ADG) between marking and weaning were the traits mostly highly correlated with the 200d wt of calves (r = 0.68, 0.90 and 0.74. respectively). An Extensively- Grazed-Cow-Weaning-Index of these three indicator traits was found to be more highly correlated than any of the individual traits on their own (r = 0.94). Index weights for the three indicator traits were calculated within each herd and then those within-herd index weights were regressed on readily obtainable herd descriptive variables to obtain a regression equation that could predict index weights for any herd. When the model was applied to data from two additional herd years not included in the original model, the EGCW Index was highly correlated with the 200d weights (r>0.90). Performance-based culling of previously unselected commercial beef herds based on the EGCW Index will result in improved productivity due to the moderately high repeatability of calf weaning weight. Objective data from extensively grazed commercial herds will also make possible the use of commercial herd data in genetic evaluations of herd sires.

Inicialmente, foram analisados dados peso-idade do nascimento até 100 meses de idade, de vacas de quatro grupos genéticos (G): Nelore (NEL), ½Canchim + ½Nelore (CN), ½Angus + ½Nelore (AN) e ½Simental + ½Nelore (SN), pertencentes a Embrapa Pecuária Sudeste, São Carlos. Os animais considerados neste estudo nasceram de 1998 a 2001 (Ano), na primavera e outono (EP), e foram criados em sistema de produção intensiva, recebendo três níveis de suplementação pós-desmama (M): 0, 1,5; 3,0 kg/animal/dia de concentrado. O objetivo neste estudo foi comparar diferentes modelos não-lineares para estimar o crescimento, e avaliar a influência de efeitos de ambiente e grupo genético sobre os parâmetros estimados. Os modelos não-lineares: Brody, Gompertz, Logístico, Von Bertalanffy e Richards foram ajustados por mínimos quadrados ordinários e ponderados, considerando a variância normal e ponderada pelo inverso dos pesos em diferentes períodos. Foi usado o procedimento NLIN do SAS. Os modelos Brody e Von Bertalanffy convergiram para todos os G, havendo, entretanto, leve superioridade do Brody ponderado. Na comparação do ajuste dos modelos considerando o uso do inverso da variância os modelos mostraram-se mais adequado. As estimativas dos parâmetros peso assintótico (A) e taxa de maturidade (k) do modelo de Brody ponderado foram analisadas por meio de modelo que, além do efeito médio global, incluiu os efeitos de G, M, EP e as interações entre estes efeitos. Houve diferenças significativas das curvas de crescimento médias para os G. Na análise individual dos parâmetros A e k estimados através do modelo Brody ponderado, verificou-se que A foi influenciado (P<0,05) por G e EP e k foi influenciado (P<0,05) por M, fornecidos aos animais durante quatro meses após desmama. Melhorias no manejo alimentar resultaram em menor variação na forma das curvas de crescimentos e em altas taxas de maturidade. Na segunda parte, verificou-se a qualidade do modelo Brody, ponderado pelo inverso das variâncias dos pesos, quanto ao ajuste peso-idade como também a influência das estimativas do peso à maturidade (A) e da taxa de maturidade (k) sobre características produtivas das vacas NEL, CN, AN e SN. Foram organizados 10 grupos contemporâneos (GC), com concatenação dos efeitos Ano-EP-M para cada G. Utilizando-se um modelo misto com efeitos de G e GC, foi incluído, alternadamente covariáveis linear e quadrática de A e k, na análise das características produtivas: peso à desmama dos bezerros (PD); número (ND8) e kg (KD8) de bezerros desmamados em até 8 anos de permanência da vaca no rebanho; relação PD/peso da vaca ao parto (PD_PVP); relação PD/peso da vaca à desmama do bezerro (PD_PVD); relação PD/unidade metabólica da vaca (PV0,75) à desmama do bezerro (PDW). Houve diferença significativa (P<0,05) da curva de crescimento entre os grupos genéticos (G) e também entre os grupos de contemporâneos (GC) dentro de G. Verificou-se que estas características foram, em geral, influenciadas (P<0,01) tanto pelos efeitos linear e quadrático de A quanto pelos efeitos linear e quadrático de k. / Initially, were analyzed weight-age data from birth to 100 months of age from cows of four genetic groups (G): Nellore (NEL), ½Nellore + ½Canchim (CN), ½Angus +½Nellore (AN) and ½Simmental + ½Nellore (SN), of a experiment carried out at Embrapa Southeast Cattle Research Center, State of São Paulo, Brazil. The animals considered in this study were born from 1998 to 2001 (Year) in spring and fall (EP), and were managed in intensive production system and submitted to three of levels of supplementation post-weaning (M): 0, 1.5 and 3.0 kg/animal/day of concentrate. The objective of this study was to compare different nonlinear models to fitted growth curves, of beef cattle females, and to evaluate of environmental and genetic group effects on the estimated parameters. The nonlinear models: Brody, Gompertz, Logistic, Von Bertalanffy and Richards were fitted by ordinary least squares and weighted by the inverse of the variances of the weights in different periods. It was used the NLIN procedure of SAS. The parameters asymptotic weight (A) and maturing rate (k) obtained from model of Brody were analyzed by a mixed linear model that, besides the overall mean effect, included the effects of G, M, EP, and the interactions among these effects. The Brody and Von Bertalanffy models converged for all genetic groups, although slight superiority of the weighted Brody. Comparing the goodness of fit of these models, the use of the inverse of variances showed more efficient than the adjust of the models considering normal variances. Individual analysis of A and k estimated the model weighted Brody, the A parameter was influenced (P <0.05) by genetic group and season of birth and k was influenced (P <0 05) for levels of supplementation to the animals. Improvements in feeding supplementation resulted in less variation in the shape of growth curves and rates of maturity. In the second part of the work, it was evaluated the goodness of the Brody model, weighted by the inverse variance weights, in the adjust of weight-age data, and also analyzed the influence of the maturity weight (A) and maturing rate (k) estimates for traits cows productivity. Were organized 10 contemporary groups (CG) with concatenation of effects Year- EP-M for each G. Considering a mixed model with effects of G and CG (10 contemporaneous groups organized by concatenation Year-EP-M effects), linear and quadratic covariate effects of A and k, were added, alternately, for the analysis of the following traits: weaning weight of calve (WW), number (NW8) and kg (KW8) of calves weaned over 8 years of the cow in the herd; WW/weight of the cow at calving (WW_WC); WW/cow weight at weaning of calf (WW_WWC); and WW/metabolic unit of the cow (PV0,75) at weaning of the calf (MW). There was significant difference (P<0.05) of the growth curve among the genetic groups and also among contemporary groups within G. It was found that the production traits were, in general, influenced (P<0.01) by both linear and quadratic effects of A and k.

The cost of lamb mortality caused by cold exposure has been estimated at approximately 40 million dollars per year. This value is probably conservative as it does not include the cost due to the reduction in productivity in hypothermic lambs that manage to survive or the cost of reduced selection potential incurred by fewer lambs surviving until selection. The objectives of this research was to investigate whether sire-line variation exists in neonatal lamb cold tolerance and whether polymorphism in the β₃ adrenergic receptor gene can be used as a genetic marker for lamb cold tolerance and lean muscle growth. The influence of the climate, birthweight, age of dam at lambing, gender and birth rank on neonatal lamb cold tolerance was also analysed. Neonatal lamb mortality due to cold exposure was analysed in four field trials that used neonatal lamb morality from cold exposure as a predictor of neonatal lamb cold tolerance. Sire-line variation in neonatal lamb morality was observed in all trials, though it appeared that this effect was largely mediated through sire-line variation in lamb birth weight. Variation in lamb birth weight between birth rank classed was also found to be responsible for the influence of birth rank on neonatal lamb mortality due to cold exposure. The age of dam at lambing and the lamb gender was not observed to influence neonatal lamb mortality due to cold exposure. The sires from the cold tolerance study and the progeny of the lean muscle growth study were genotyped for the β₃ adrenergic receptor locus. Other studies have found evidence that a major gene exists in the catecholamine stimulation of brown adipose thermogenesis and evidence that the β₃-AR gene is a likely candidate. However, this hypothesis and the hypothesis that polymorphism in the β₃-AR gene is also linked to lean muscle growth in lambs was not confirmed in this study. So while it appears that the results were confounded by experimental design, there is evidence that influence of polymorphism in the ovine β₃ AR gene on neonatal lamb mortality and/or lean muscle growth is not sufficient to be considered a major gene effect. The implications of this experiment on the sheep industry and sheep farmers in general are huge. While completely eliminating lamb deaths due to inadequate cold tolerance is impossible, this study shows that large gains in lamb survival could be possible through selective breeding.