Winter Feeding Research Articles

Cascading effects of moose (Alces alces) management on birds

AbstractLarge herbivores often have key functions in their ecosystems, and may affect ecosystem processes with cascading effects on other animals. The mechanisms often involve relocations of resources of various kinds, including reduction in resource availability following foraging and increase in resources from animal excreta. As large herbivore populations in Europe generally are intensely managed, management activities may interact with the activities of the herbivores themselves in the effect on other ecosystem components. We investigated the effects of moose (Alces alces) winter browsing, together with the effect of net nutrient input via supplementary winter feeding of moose on functional composition and species richness of birds in a boreal forest. Supplementary feeding stations for moose had a net zero effect on bird species richness and abundance, because negative effects of moose browsing were balanced by positive effects of nutrient input. Sites with a similar browsing intensity as at feeding stations but without nutrient input had lower abundance and species richness than feeding stations. Functional groups of bird species showed differing responses: birds nesting at or below browsing height were negatively affected by moose browsing, whereas species nesting above the browsing zone were positively affected by moose browsing. Insect‐eating species responded negatively to moose browsing on birch but positively to nutrient input at feeding stations, whereas seed‐eating species responded positively to birch browsing and negatively to feeding stations. This study showed that both high levels of cervid activity and human management interventions influence bird communities.

Migration Pathways, Behavioural Thermoregulation and Overwintering Grounds of Blue Sharks in the Northwest Atlantic

The blue shark Prionace glauca is the most abundant large pelagic shark in the Atlantic Ocean. Although recaptures of tagged sharks have shown that the species is highly migratory, migration pathways towards the overwintering grounds remain poorly understood. We used archival satellite pop-up tags to track 23 blue sharks over a mean period of 88 days as they departed the coastal waters of North America in the autumn. Within 1–2 days of entering the Gulf Stream (median date of 21 Oct), all sharks initiated a striking diel vertical migration, taking them from a mean nighttime depth of 74 m to a mean depth of 412 m during the day as they appeared to pursue vertically migrating squid and fish prey. Although functionally blind at depth, calculations suggest that there would be a ∼2.5-fold thermoregulatory advantage to swimming and feeding in the markedly cooler deep waters, even if there was any reduced foraging success associated with the extreme depth. Noting that the Gulf Stream current speeds are reduced at depth, we used a detailed circulation model of the North Atlantic to examine the influence of the diving behaviour on the advection experienced by the sharks. However, there was no indication that the shark diving resulted in a significant modification of their net migratory pathway. The relative abundance of deep-diving sharks, swordfish, and sperm whales in the Gulf Stream and adjacent waters suggests that it may serve as a key winter feeding ground for large pelagic predators in the North Atlantic.

Widespread Mitochondrial Disease in North American Bison

AbstractNorth American bison have rebounded from near-extinction in the nineteenth century but from such small inbred founding populations that once-rare deleterious nuclear gene alleles and mitochondrial haplotypes are now at high frequencies. The initial bottleneck was compounded by decades of unnatural selection affecting bison conservation genomics and undercutting restoration initiatives. The genomics era began in late 2010 for bison and sister species yak with the release of 102 whole mitochondrial genomes, displacing earlier control region and microsatellite data not extending to coding regions. This allows detection of both sporadic and sub-clade level mutations in mitochondrially encoded proteins and tRNAs by comparative genomics methods: deleterious mutations in both cytochrome b (V98A) and ATP6 (I60N) occur within a single common bison haplotype. Since similar mutations in human and dog cause clinical impairment of mitochondrial oxidative phosphorylation, these bison are predicted to be significantly impaired in aerobic capacity, disrupting highly evolved cold tolerance, winter feeding behaviors, escape from predators and competition for breeding. Because Yellowstone National Park bison are subjected to genetically uninformed culls and surplus animals used to seed new conservation herds, mutational status has significant implications. Continuing take of the remaining bison with wildtype mitochondria may recapitulate errors of nineteenth century bison stewardship bringing bison conservation to the point of no return.

Winter-feeding systems for gestating sheep I. Effects on pre- and postpartum ewe performance and lamb progeny preweaning performance1

Mature pregnant crossbred ewes (n = 90) were used in a randomized complete block design and assigned to 1 of 3 winter-feeding systems differing in primary feed source: haylage (HL), limit-fed corn (CN), or limit-fed dried distillers grains (DDGS). Effects of these winter-feeding strategies on ewe and lamb performance were determined. Diets were formulated to meet or exceed NRC (1985) nutrient requirements during gestation and were fed from about d 60 of gestation until parturition. All ewes were fed a common diet postpartum. Every 2 wk during gestation, BW and BCS were collected and diets were adjusted to maintain similar BW gain for ewes fed CN and DDGS vs. HL. At 80 and 122 d of gestation, jugular blood samples were collected at 0, 3, 6, and 9 h postfeeding to measure plasma glucose, insulin, NEFA, and blood urea nitrogen concentrations. At birth, 6 lambs per treatment were killed to measure body composition. At 28 ± 2 d postpartum, milk yield was measured. Lambs were weaned at 61 ± 4 d of age. During mid gestation (d 60 to 115), BW gain of ewes was similar among treatments; however, at d 115 of gestation ewes fed HL had a smaller (P = 0.04) BCS than ewes fed DDGS or CN. Plasma glucose concentrations were greater (P ≤ 0.004) in ewes fed CN than in those fed HL or DDGS just before feeding on d 80 and 122 of gestation, whereas ewes fed DDGS vs. CN or HL had greater (P ≤ 0.04) plasma insulin concentrations at 3 h postfeeding. At parturition, ewe BW was greatest for DDGS, least for HL, and intermediate for CN (P ≤ 0.003). Ewes fed CN and DDGS had greater BCS at parturition than those fed HL, but by weaning, ewes fed DDGS had greater BCS (P ≤ 0.05) than those fed CN or HL. Birth BW tended (P = 0.09) to be heavier for lambs from ewes fed CN and DDGS than from those fed HL prepartum, but there was no difference (P = 0.19) due to ewe gestation diet on lamb BW at weaning. At birth, lamb muscle, bone, organ, and fat measures were not affected (P > 0.13) by treatment. Ewe milk production and lamb preweaning ADG were also similar (P > 0.44) among treatments. Prepartum dam winter feed source did not have detrimental effects on pre- or postpartum ewe performance, but altered prepartum maternal nutrient supply during gestation, which affected birth weight but not preweaning growth or mortality.

Effects of Winter Feeding of Channel Catfish on Production in Multibatch Systems

AbstractMost channel catfish Ictalurus punctatus are produced in multibatch production systems, but winter feeding studies typically have used single‐batch systems. Winter feeding studies that reflect commercial production practices are needed. Two pond studies (winters of 2005–2006 [study 1] and 2006–2007 [study 2]) were conducted in ten 0.10‐ha ponds; fish in five ponds received feed, whereas fish in the five remaining ponds did not. Ponds were stocked with sub‐market‐sized (<0.57 kg) channel catfish at a rate of 2,957 kg/ha and market‐sized fish (>0.57 kg) at 986 kg/ha. Net yield (kg/ha) in both treatment and control ponds was negative over both winters. The decrease in net yield of fish was significantly less in ponds that received feed than in those that did not receive feed in study 2; the decrease in net yield did not differ between treatments in study 1, which had a colder winter and fewer feeding days than study 2. There was no significant difference in mean weight at harvest for market‐sized fish in fed and unfed treatments, but sub‐market‐sized fish in the fed treatment were significantly larger than those in the unfed treatment. A disease challenge conducted in aquaria showed that mortality after exposure to Edwardsiella ictaluri was significantly higher for unfed fish than for fed fish. Six concrete vats were used to measure feed consumption during the winter of 2007–2008. Channel catfish continued to feed at temperatures as low as 7°C. The amount of feed consumed (expressed as a percentage of body weight) was similar to published recommendations, but fish continued to consume feed daily at lower temperatures than previously assumed. Additional research is needed to determine an optimal frequency of winter feeding.Received February 23, 2010; accepted July 24, 2010

Winter feeding - changing labour requirements and productivity

Current winter feeding practice using a daily grazing duration to ration feed is based on the sheep industry of the 1960s to the 1980s when per head performance was much lower than today. This study investigated the impact of changing from a 1-day grazing duration to a 4-day grazing duration during winter on subsequent productivity. Ewe condition score and liveweight, tailing percentages, and tailing and weaning weights of lambs, as well as the incidence of vaginal prolapse in ewes at lambing were recorded over several years on a total of seven farms. Spring pasture growth and botanical composition was measured on one farm. Results suggest 4-day shifting had little impact on vaginal prolapse but did result in more settled sheep, easier winter shifting regime, and less pasture damage, leading to improved pasture production in early spring (P

PORÓWNANIE SKŁADU KWASÓW TŁUSZCZOWYCH ZAWARTYCH W TŁUSZCZU MLEKA KLACZY I KRÓW

The objective of the study was to assess the composition of fatty acids (FA) in the mare's milk fat and to compare them with the composition of FA in the cow's milk fat, with a focus on the FA appearing essential in human nutrition. The research material consisted of 10 mare's milk samples and 10 cow's milk samples taken from the milk of the animals during the winter and summer feeding periods, in the Mazovia region. In each sample, the fatty matter content was determined using a Rose-Gottlieb method, as was the composition of FA using a gas chromatography. The analysis of FA composition in the mare's milk showed a high content of saturated FA: caprylic C8:0, capric C10:0,lauric C12:0. The unsaturated FA of the mare's milk were represented mainly by the linoleic acid C18:2 9c12c and the alpha linolenic acid C18:3 9c12c15c. The cow's milk was characterized by the higher content of the following saturated FA: butyric acid C4:0, caproic acid C6:0, and stearic acid C10:0, as well as by a significantly lower content of polyunsaturated FA: linolenic and alpha linolenic acid. The content of FA in the milk of those two animal species was characterized by the high season-dependent variation

The Interaction of Migratory Birds and Domestic Poultry and Its Role in Sustaining Avian Influenza

We investigate the role of migratory birds in the spread of H5N1 avian influenza, focusing on the interaction of a migratory bird species with nonmigratory poultry. The model is of patch type and is derived with the aid of reaction-advection equations for the migratory birds in the air along the flyways. Poultry may reside at some or all of the four patches of the model, which consist of the breeding patch for the migratory birds, their winter feeding patch, and two stopover patches where birds rest and refuel on their migration. Outward and return migratory routes can be different. The equations for the migratory birds contain time delays which represent the flight times for migratory birds along particular sectors. Delays also appear in the model coefficients via quantities which represent flight survival probabilities for the various sectors. We establish results on positivity, boundedness, global asymptotic stability of the disease-free equilibrium, and the persistence of infection. We also discuss extensions of the model to include the seasonality of the migration phenomenon. Numerical simulations support the analytical findings; here we used data on H5N1 infected ducks in the Poyang Lake region of China.

The influence of supplementation with haylage, haylage plus soybean meal or haylage plus corn dried distillers’ grains with solubles on the performance of wintering pregnant beef cows fed wheat straw

Fourteen pens containing a total of 53 individually fed, multiparous, pregnant, crossbred beef cows were used to investigate feeding of free-choice haylage or supplemention programs for cows fed wheat straw. Dietary treatments for the 112-d feeding period were: free choice haylage (pens = 2, cows = 7; 100% Haylage), haylage offered at 0.7% body weight (BW) plus free choice straw (pens = 3, cows = 11; 0.7% Haylage), haylage offered at 1% of BW plus free choice straw (pens = 3, cows = 12; 1% Haylage), haylage offered at 0.5% BW plus soybean meal and free choice straw (pens = 3, cows = 12; Haylage + SBM), and haylage offered at 0.5% BW plus corn dried distillers’ grains plus solubles and free choice access to straw [pens = 3, cows = 11; Haylage + dried distillers’ grains with solubles (DDGS)]. The non-straw component of Haylage + SBM and Haylage + DDGS was formulated to provide equal amounts of N (relative to BW) to that of 1% Haylage. Total dry matter intake (DMI) was greater (P ≤ 0.01) in cows receiving 100% Haylage vs. other treatments and 1% Haylage, Haylage + SBM, and Haylage + DDGS vs. 0.7% Haylage. Straw DMI was greater (P < 0.001) in cows receiving Haylage + SBM and Haylage + DDGS vs. 1% Haylage. Average daily gain was greater (P ≤ 0.002) in cows receiving 100% Haylage vs. other treatments, 1% Haylage, Haylage + SBM, and Haylage + DDGS vs. 0.7% Haylage, and Haylage + SBM and Haylage + DDGS vs. 1% Haylage. These data indicate that feeding wheat straw supplemented with haylage or haylage plus SBM or DDGS may be an acceptable alternative to free-choice haylage to minimize winter feed costs and that supplementation with Haylage plus SBM or Haylage plus DDGS results in increased straw DMI and ADG when compared to supplementation with haylage alone.

Genetic resources in Trifolium and their utilization in plant breeding

Clovers (Trifoliumspecies) are a large and widespread genus of legumes. Recent work supports the Mediterranean origin of the genus in the Early Miocene period, and centres of diversity for clovers occur in the Eastern Mediterranean, East Africa and South America. A number of clovers are of agricultural importance as forage species in grassland agriculture around the world, particularly in temperate areas. White clover (Trifolium repensL.) is the most important legume of grazed pastures, and red clover (T. pratense) is widely cut and conserved as a winter feed. We consider the current state of collected resources in clovers, which have been collated in the most important databases. These are European Internet Search Catalogue (EURISCO), germplasm resources information network and system-wide information network for genetic resources together with the collection held at AgResearch, New Zealand. In total, collections have been made of 204 species with 48 species having more than 100 accessions in these databases. As expected, the majority of accessions are of the agriculturally important species. The geographical origin of collected material is outlined and, for the major species, accessions are broken down according to their status, e.g. wild population, breeders' lines. We then describe some of the ways in which genetic resources of white and red clovers and their relatives have been used in the breeding of these species. These include introgression of stress tolerance traits, targetting improvements in resource use efficiency and increasing seed yield.

Italian ryegrass silage in winter feeding of organic dairy cows: forage intake, milk yield and composition

Organic milk production aims at efficient use of home-grown feeds, especially forages, to minimise the quantity of purchased feeds. In conventional agriculture, Italian ryegrass (Lolium multiflorum Lam.) is known for its high energy content and palatability, and the aim of the present study was to examine its suitability as feed for organic dairy cows. Therefore a feeding trial was conducted comparing a diet including 50% (of silage dry matter (DM)) of Italian ryegrass silage with a control diet based on grass/clover silage (a mixture of the second cut from permanent grassland and the second cut from a perennial clovergrass ley) alone. Inclusion of Italian ryegrass silage in the diet increased forage intake significantly (14.5 vs 13.4 kg DM in the control group) and concentrate intake did not differ, but milk yield was slightly lower (20.3 vs 21.0 kg) owing to the low energy and protein concentration of Italian ryegrass silage. Italian ryegrass was indeed found to be highly palatable, confirming in principle its suitability as feed for organic dairy cows. However, higher energy and protein concentrations in this forage would be necessary to translate the high intakes of Italian ryegrass silage into improved milk production as well.

Cross-infection of gastrointestinal nematodes between winter corralled semi-domesticated reindeer (Rangifer tarandus tarandus) and sheep (Ovis aries)

The increasing number of sheep (Ovis aries) in the reindeer (Rangifer tarandus tarandus) herding area in North Finland and supplementary winter feeding of reindeer in corrals shared with sheep causes potential for cross-infection of gastrointestinal nematodes between reindeer and sheep. The aim of this study was to elucidate this potential. The study included 46 animals, of which 12 reindeer and 8 sheep had shared a corral. Twelve reindeer had no known contact with sheep. Both reindeer groups shared free ranging areas with wild moose (Alces alces). Two moose were included in this study, as were 12 sheep which had no contact with other ruminants. After slaughter in September-November abomasa and proximal small intestines were collected and examined for gastrointestinal nematodes. The parasites were collected, counted and identified. Following species were found in reindeer: Ostertagia gruehneri, Ostertagia arctica, Spiculopteragia dagestanica, Nematodirus tarandi, Nematodirella longissimespiculata and Bunostomum trigonocephalum. Sheep were infected with Teladorsagia circumcincta, Teladorsagia trifurcata, Ostertagia gruehneri, Ostertagia arctica, Nematodirus filicollis and Nematodirus spathiger. Spiculopteragia dagestanica and Ostertagia gruehneri were identified in moose. Ostertagia gruehneri, which is considered to be a reindeer parasite, was only found in the sheep that had shared a corral with reindeer. These sheep were not found to be infected with other abomasal nematodes. The reindeer that had shared a corral with sheep were not infected with nematodes usually having sheep as their primary host.

Dystocia in Friesian cows and its effects on postpartum reproductive performance and milk production

A total of 1,243 records for 585 dairy Friesian cows from 1997–2004 were used to study the factors affecting dystocia and its effects on reproductive performance and milk production. The overall incidence of dystocia was 6.9%. The percentage of dystocia decreased with increasing live body weight, age, and parity of cows (P < 0.05); however, it increased with increasing birth weight of calves (P < 0.05). The highest percentage of dystocia was detected in winter season, but the least percentage was in summer season (P < 0.05). The percentage of incidence of dystocia was significantly (P < 0.05) higher with winter feeding compared to summer ration (8.2% vs. 5.1%). The percentage of incidence of dystocia was significantly (P < 0.05) higher with twinning than single calving (15.5% vs. 6.5%), while not significantly affected by the sex of born calves. Incidence of dystocia had adverse effects on reproductive performance and milk yield. The service interval, service period, days open, and calving interval were significantly (P < 0.05) longer in cows afflicted with dystocia compared to normal cows. The conception rate was lower (P < 0.05), but the number of service per conception was higher (P < 0.05) in cows afflicted with dystocia compared to normal cows (60.5% vs. 73.0% and 3.4 vs. 2.7, respectively). Average daily milk yield was lower (P < 0.05) by 1 kg for cows with incidence of dystocia compared to normal cows.

Winter feeding leads to a shifted phenology in the browntail moth Euproctis chrysorrhoea on the evergreen strawberry tree Arbutus unedo

1 The browntail moth Euproctis chrysorrhoea is a highly polyphagous univoltine forest pest. Although its young larvae usually overwinter in diapause from early autumn to the beginning of spring, winter larval feeding has been reported when this species feeds on the evergreen woody shrub strawberry tree Arbutus unedo. 2 The present study investigated life-history traits of four populations of E. chrysorrhoea feeding on A. unedo, including phenology of the different life stages, larval feeding activity and diapause incidence. By modelling the relationship between larval size and host plant leaf persistence, elevation and mean annual temperature, we also studied larval development in ten populations of this species sampled from a range of geographical locations in Spain, from both A. unedo and deciduous hosts. 3 The results obtained revealed that on A. unedo, E. chrysorrhoea phenology has shifted: from October to March, A. unedo larvae doubled their size, whereas, on deciduous Ulmus minor and Quercus faginea, larval size did not change. General linear models demonstrated that such differences were not related to environmental variables. We also found that on A. unedo larval feeding was arrested for 2 months, with this period representing a true diapause. 4 The results obtained in the present study suggest that E. chrysorrhoea populations are phenologically adapted to their local host plants, and that the presence of foliage is a key element in the phenological shift reported on A. unedo. These results may have implications with respect to the formation of E. chrysorrhoea host races.

Effect of water temperature on gut transit time, digestive enzyme activity and nutrient digestibility in yellowtail kingfish ( Seriola lalandi)

Yellowtail kingfish ( Seriola lalandi) are farmed in sea cages in South Australian waters and exposed to seasonal variations in water temperature. The temperature variations, ranging from 10 to 24 °C, influence feed intake and on-farm feeding practices. Sub-adult yellowtail kingfish are fed twice daily in summer while feeding in winter may be reduced to once every second day. Lower winter water temperatures increase gut transit times which may lead to a condition known as winter syndrome. This syndrome causes an enteritis response in yellowtail kingfish and reduces farm productivity. The impact of water temperature on gut transit time, nutrient digestibility and protease and lipase enzyme activities in yellowtail kingfish (2.12 ±0.03 and 2.77 ± 0.03 kg live weight in summer and winter respectively) was investigated at summer and winter water temperatures; 20.8 ± 0.4 °C and 12.6 ± 0.1 °C respectively, using observations made on dissected fish and detection of the passage of dietary markers. Water temperature had a significant effect on gut transit time, with visual observations demonstrating that at summer water temperatures it takes 12–16 h for all digesta to be voided from the fish compared to 36–48 h at winter temperatures. Temperature did not have a significant effect on the dietary nutrient apparent digestibility coefficients (ADC, %) although there was a numerical tendency for nutrient ADC to be higher in the posterior intestine at summer water temperatures: 46% vs. 35% for dry matter; 70% vs. 67% for protein; 66% vs. 58% for fat; and 70% vs. 63% for energy. Nutrient digestibility did not differ significantly between the anterior and posterior intestinal sections; however, the ADC values were consistently higher in posterior intestine. Protease activity was significantly higher in the posterior intestine and there was also a numerical, but not significant, increase in protease and lipase activities in the anterior section of the intestine during winter. Lipase activity was significantly higher in the anterior intestine during summer, when compared to the posterior section, and numerically higher in this section during winter. In winter it was found that a greater proportion of nutrient digestion occurred in the stomach, pyloric caeca and anterior intestine when compared to summer. This was thought to be due to the slower gut motility and higher enzyme activities observed during winter. Even though gut transit time was slower in winter, the lower water temperature also resulted in nutrient digestibility that was numerically lower.

Comparison of Corn Coproducts and Corn Residue Bales with Alfalfa Mixed Hay on Beef Cow-Calf Performance, Lactation, and Feed Costs

Two experiments were conducted to evaluate the effects of a winter feeding strategy on the performance, lactation, reproduction, and feed costs of springcalving, lactating beef cows. In Exp. 1, Angus (n = 66) and Simmental (n = 70) cows were allotted to 1 of 4 treatments: 1) distillers dried grains with solubles (DDGS) and free-choice corn residue bales; 2) corn bran and DDGS and freechoice corn residue bales; 3) corn bran and high-protein distillers dried grains and free-choice corn residue bales; or 4) free-choice alfalfa mixed hay. In Exp. 2, Angus (n = 72) and Simmental (n = 92) cows were allotted to 1 of 4 treatments: 1) free-choice corn residue bale and 6.5 kg DDGS; 2) 6.4 kg ground corn residue bale and 6.5 kg DDGS; 3) 4.5 kg ground corn residue bale and 7.5 kg DDGS; and 4) free-choice alfalfa mixed hay. In both experiments, cows with free-choice hay intake lost more BW than cows fed coproduct and corn residue bales, but there were no differences in milk production or calf ADG. Three-year average price data were used to calculate feed costs (corn residue, $55/ton; DDGS, $124.71/ ton; and hay, $131.67/ton). In Exp. 2, the hay diet was more expensive than the 3 DDGS and corn residue diets ($2.50 vs. $1.44/cow∙per day, respectively). Machinery costs were also considered for each diet with herd sizes from 50 to 300 cows. Herd size dictated which winter feeding strategy was the least expensive. Feeding corn coproducts with corn residue bales can result in acceptable performance and reduced feed costs compared with traditional hay diets.

Winter Feed Estimator: A Practical Tool for the Beef Cow-Calf Producer

AN244, a 3-page fact sheet by Mark Warren, Ed Jennings, and Matt Hersom, provides a simple approach for estimating dry matter feed requirements of the beef herd and then converting those requirements into an estimate of required hay or silage round rolls. Published by the UF Department of Animal Science, June 2010. AN244/AN244: Winter Feed Estimator: A Practical Tool for the Beef Cow-Calf Producer (ufl.edu)

Evaluation of NRC (2000) model energy requirement and DMI equation accuracy and precision for wintering beef cows in western Canada

Three years of winter feeding trials using 90 Angus cows (15 pens of six cows) fed typical western Canadian wintering diets formulated to stage of pregnancy were used to evaluate National Research Council (NRC 2000) energy requirement and dry matter intake (DMI) equation accuracy and precision. Data collection included pen DMI, individual cow weights, body condition scores, calving dates and weights, and daily environmental temperature. Diet energy density was estimated from nutrient analysis of composited weekly feed samples. Equation evaluations compared observed and predicted DMI and conceptus corrected average daily gain (ADG) for the second and third trimesters using regression, means comparison, concordance correlation coefficient (CCC), and total deviation index (TDI) methods. Across all 3 yr, second trimester DMI was over-predicted (P &lt; 0.01) with low precision (CCC = 0.24, TDI90 = n/a) using actual environmental conditions, but not (P = 0.34) when assuming thermal neutral (TN) conditions, although precision remained low (CCC = 0.25, TDI90 = 1.91 kg d-1). Third trimester DMI over the 3 yr was also over-predicted (P &lt; 0.01) with low precision (CCC = 0.12, TDI90 = 1.57 kg d-1) using actual environmental conditions, but was largely under-predicted (P &lt; 0.01) with lower precision (CCC = -0.01, TDI90 = 2.34 kg d-1) when assuming TN conditions. Across all 3 yr, second trimester ADG was largely under-predicted (P &lt; 0.01) with low precision (CCC = 0.50, TDI90 = 0.58 kg) using actual environmental conditions, but over-predicted (P &lt; 0.01) with similar precision (CCC = 0.51, TDI90 = 0.50 kg) when assuming TN conditions. Third trimester ADG predictions using actual environmental conditions were inaccurate (P &lt; 0.01) with low precision (CCC = 0.20, TDI90 = 0.38 kg) using actual conditions and lower precision (CCC = -0.01, TDI90 = n/a) when assuming TN conditions where ADG was over-predicted (P &lt; 0.01). These results indicate a lack of accuracy and precision with the current NRC (2000) model energy requirement and DMI equations that was not addressed by assuming TN conditions. Future research should be targeted at alternate DMI equations and refinements to maintenance and gain requirements.Key words: NRC evaluation, nutrient requirements, wintering beef cows

Transfer of Sulfamethazine from Contaminated Beeswax to Honey

A liquid chromatographic tandem mass spectrometric method for the determination of sulfa drugs in beeswax was developed. When performing residue control on beeswax intended for the fabrication of wax foundations, residues of sulfonamides were found. A migration test was set up to study whether sulfonamide-containing beeswax could lead to the contamination of honey. The higher the concentration of sulfamethazine doped in the wax, the higher was the concentration of sulfamethazine found in the honey. The maximum transfer was 15.6, 56.9, and 29.5% of the initial amount spiked in the wax foundation. In a second experiment, the percentage of sulfamethazine migrating from medicated winter feed to beeswax in relation to the concentration in the syrup and the contact time was studied. The maximum transfer of sulfamethazine from medicated sucrose syrup to beeswax was 3.1%.

Scavenging Makes Cougars Susceptible to Snaring at Wolf Bait Stations

Abstract:In western Canada it is illegal to trap or snare cougars (Puma concolor), but cougars are sometimes caught accidentally in snares placed near carrion baits, a technique commonly used by trappers to harvest wolves (Canis lupus). We studied cougar foraging ecology and survival in west‐central Alberta to estimate the propensity for cougars to scavenge, their susceptibility to snaring at trapper bait stations, and the implications these have for managing cougar populations. During 2005–2008, we used data from visits to 3,407 Global Positioning System (GPS) location clusters and &gt;400 km of snow tracking of 44 cougars to locate foraging events and calculate scavenging rates. We identified 83 instances of scavenging, and 64% of monitored cougars scavenged at least once. Scavenging rates were higher in winter (0.12 events/week) than in summer (0.04 events/week), reflecting seasonal variation in carrion availability. Individual cougars scavenged at different rates, and winter feeding on carrion occupied up to 50% of total carcass handling time for some cougars. Based on these results we conclude that cougars are facultative scavengers. A propensity to scavenge made cougars susceptible to snaring causing high annual mortality in radiocollared cougars (0.11, 95% CI = 0.03–0.21). Provincial cougar mortality data demonstrate that snaring has increased dramatically as a mortality source in Alberta over the last 2 decades. Mortalities of radiocollared cougars during our study were 100% human caused and the addition of snaring mortality to already high hunting mortality resulted in low annual survival (0.67, 95% CI = 0.53–0.81). Our study is one of the first to identify population‐level consequences for nontarget animals killed unintentionally by indiscriminate harvest techniques in a terrestrial ecosystem. Maintaining sustainable cougar harvest where snaring at carrion baits is permitted may require flexible hunting quotas capable of accommodating high cougar snaring mortalities in some years.