A better understanding of how livestock respond to weather is essential to enable farming to adapt to a changing climate. Climate change is mainly expected to impact dairy cattle through heat stress and an increase in the frequency of extreme weather events. We investigated the effects of weather on milk yield and composition (fat and protein content) in an experimental dairy herd in Scotland over 21 years. Holstein Friesian cows were either housed indoors in winter and grazed over the summer or were continuously housed. Milk yield was measured daily, resulting in 762 786 test day records from 1369 individuals, and fat and protein percentage were sampled once a week, giving 89 331 records from 1220 cows/trait. The relative influence of 11 weather elements, measured from local outdoor weather stations, and two indices of temperature and humidity (THI), indicators of heat stress, were compared using separate maximum likelihood models for each element or index. Models containing a direct measure of temperature (dry bulb, wet bulb, grass or soil temperature) or a THI provided the best fits to milk yield and fat data; wind speed and the number of hours of sunshine were most important in explaining protein content. Weather elements summarised across a week's timescale from the test day usually explained milk yield and fat content better than shorter-scale (3 day, test day, test day −1) metrics. Then, examining a subset of key weather variables using restricted maximum likelihood, we found that THI, wind speed and the number of hours of sunshine influenced milk yield and composition. The shape and magnitude of these effects depended on whether animals were inside or outside on the test day. The milk yield of cows outdoors was lower at the extremes of THI than at average values, and the highest yields were obtained when THI, recorded at 0900 h, was 55 units. Cows indoors decreased milk yield as THI increased. Fat content was lower at higher THIs than at intermediate THIs in both environments. Protein content decreased as THI increased in animals kept indoors and outdoors, and the rate of decrease was greater when animals were outside than when they were inside. Moderate wind speeds appeared to alleviate heat stress. These results show that milk yield and composition are impacted at the upper extreme of THI under conditions currently experienced in Scotland, where animals have so far experienced little pressure to adapt to heat stress.Keywords: climate change, fat percentage, heat stress, protein percentage, THI ImplicationsClimate change is expected to bring about drier, hotter summers and an increased frequency of extreme weather events across Europe. Here we show that milk yield and quality decline at the upper extremes of temperature and humidity even under conditions currently experienced in Scotland. We identify the values of temperature and humidity, and of other weather elements, at which performance begins to decrease. These estimates could be used in conjunction with climate projections to help policy makers un...
International audienceOur understanding of fundamental organismal biology has been disproportionately influenced by studies of a relatively small number of ‘model’ species extensively studied in captivity. Laboratory populations of model species are commonly subject to a number of forms of past and current selection that may affect experimental outcomes. Here, we examine these processes and their outcomes in one of the most widely used vertebrate species in the laboratory – the zebra finch (Taeniopygia guttata). This important model species is used for research across a broad range of fields, partly due to the ease with which it can be bred in captivity. However despite this perceived amenability, we demonstrate extensive variation in the success with which different laboratories and studies bred their subjects, and overall only 64% of all females that were given the opportunity, bred successfully in the laboratory. We identify and review several environmental, husbandry, life-history and behavioural factors that potentially contribute to this variation. The variation in reproductive success across individuals could lead to biases in experimental outcomes and drive some of the heterogeneity in research outcomes across studies. The zebra finch remains an excellent captive animal system and our aim is to sharpen the insight that future studies of this species can provide, both to our understanding of this species and also with respect to the reproduction of captive animals more widely. We hope to improve systematic reporting methods and that further investigation of the issues we raise will lead both to advances in our fundamental understanding of avian reproduction as well as to improvements in future welfare and experimental efficiency
A key goal for livestock science is to ensure that food production meets the needs of an increasing global population. Climate change may heighten this challenge through increases in mean temperatures and in the intensity, duration, and spatial distribution of extreme weather events, such as heat waves. Under high ambient temperatures, livestock are expected to decrease dry matter intake (DMI) to reduce their metabolic heat production. High yielding dairy cows require high DMI to support their levels of milk production, but this may increase susceptibility to heat stress. Here, we tested how feed intake and the rate of converting dry matter to milk (feed efficiency, FE) vary in response to natural fluctuations in weather conditions in a housed experimental herd of lactating Holstein Friesians in the United Kingdom. Cows belonged to 2 lines: those selected for high genetic merit for milk traits (select) and those at the UK average (control). We predicted that (1) feed intake and FE would vary with an index of temperature and humidity (THI), wind speed, and the number of hours of sunshine, and that (2) the effects of (1) would depend on the cows' genetic merit. Animals received a mixed ration, available ad libitum, from automatic feed measurement gates. Using >73,000 daily feed intake and FE records from 328 cows over 8 yr, we found that select cows produced more fat- and protein-corrected milk, and had higher DMI and FE than controls. Cows of both lines decreased DMI and fat- and protein-corrected milk but, importantly, increased FE as THI increased. This suggests that improvements in the efficiency of converting feed to milk may partially offset the costs of reduced milk yield owing to a warmer climate, at least under conditions of mild heat stress. The rate of increase in FE with THI was steeper in select cows than in controls, which raises the possibility that select cows use more effective coping tactics. This is, to our knowledge, the first longitudinal study on the effects of weather on FE. Understanding how weather influences feed intake and efficiency can help us to develop management and selection practices that optimize productivity under unfavorable weather conditions. This will be an important aspect of climate resilience in future.
This study was conducted in the state of Minas Gerais, Brazil, on a sandy loam soil low in fertility and a pH of 5.1. The mean monthly rainfall ranged from near zero during the 5‐ to 6‐month winter dry season and up to 330 mm in the mid‐summer wet season. The percentages of dry matter, crude protein, cellulose, crude fiber, and in vitro digestibility were determined on six tropical grass species: Melinis minutiflora Beauv., Digitaria decumbens Stent., Pennisetum purpureum Schum., Pennisetum clandestinum Hochst, Cynodon dactylon Pers., and Panicum maximum Jacq. var. Gongylodes Doell. Samples were taken with advancing age every 4 weeks beginning at the outset of the wet summer seasons in each of 2 years, 1964 and 1965, and each sampling period continued for 36 weeks. Lime, N, P, and K were applied as a basal application. In addition, N was applied each year at the rates of 0, 100, and 200 kg/ha. The increase in dry matter percentage was linear over time with an increase of 21.2 to 51.4% for all grasses. P. purpureum had the lowest dry matter percentage and C. dactylon the highest. Application of N fertilizer resulted in decreased dry matter percentage during the early growth stages but not at the more mature stages. The crude fiber percentage increased with age and the in vitro cellulose digestibility decreased. The cellulose percentage of three of the grasses increased with age while the other three remained almost constant during the sampling period.
Hill, Davina L., Pillay, Neville and Schradin, Carsten (2015) Alternative reproductive tactics in female striped mice: heavier females are more likely to breed solitarily than communally. Journal of Animal Ecology, 84 (6). pp. 1497-1508.Downloaded from: http://insight.cumbria.ac.uk/id/eprint/2543/ Usage of any items from the University of Cumbria's institutional repository 'Insight' must conform to the following fair usage guidelines.Any item and its associated metadata held in the University of Cumbria's institutional repository Insight (unless stated otherwise on the metadata record) may be copied, displayed or performed, and stored in line with the JISC fair dealing guidelines (available here) for educational and not-for-profit activities provided that• the authors, title and full bibliographic details of the item are cited clearly when any part of the work is referred to verbally or in the written form• a hyperlink/URL to the original Insight record of that item is included in any citations of the work • the content is not changed in any way• all files required for usage of the item are kept together with the main item file. You may not• sell any part of an item• refer to any part of an item without citation • amend any item or contextualise it in a way that will impugn the creator's reputation• remove or alter the copyright statement on an item.The full policy can be found here. Alternatively contact the University of Cumbria Repository Editor by emailing insight@cumbria.ac.uk.
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