Feeding Indoors Research Articles

Comparison of Three Feeding Regimens on Blood Fatty Acids Metabolites of Wujumqin Sheep in Inner Mongolia.

Simple SummaryThe traditional sheep feeding system in Inner Mongolia, based on pasture grazing, is gradually transforming into a semi-grazing plus supplementation or feedlot approach, as grassland ecological protection becomes increasingly important. The fatty acid composition of the animals’ tissues changes with transformation of the feeding system. However, the changes to blood fatty acid metabolites in sheep as a result of alterations to the feeding regimen are unknown. In this study, pasture feeding, pasture feeding plus corn supplementation, and barn feeding were carried out to explore the effects of feeding regimens on blood fatty acid composition and metabolic pathways of sheep using a metabolomic approach. The results revealed that compared to grazing, concentrate supplement feeding regimens, including either grazing plus supplements or feeding indoors, down-regulated blood n-3 PUFA biosynthesis and up-regulated blood inflammatory compound metabolism by n-6 PUFA. These data suggest that under different feeding regimens, an appropriate ratio of n-6/n-3 PUFA in ruminant diets will contribute to increasingly high-quality animal production and improved immunocompetence.Feeding regimens influence the fatty acid composition of animal-derived products. However, there is limited information on the effect of feeding regimens on the blood fatty acid composition and metabolic pathways of ruminant animals. In this study, 30 Wujumqin sheep were randomly assigned to three groups, PF (pasture feeding), PSF (pasture feeding plus corn supplementation) and BF (barn feeding), to examine the effects of feeding regimens on blood fatty acid composition and metabolic pathways through a metabolomic approach. The results showed that the BF sheep had increased serum n-6 polyunsaturated fatty acids levels, while the PF and PSF sheep had increased serum n-3 PUFA levels. Compared to the BF and PSF sheep that were fed ground corn, the PF sheep that only ate natural grass had up-regulated serum DHA levels. Meanwhile, blood metabolites from linoleic acid and arachidonic acid, including pro-inflammatory products (20-HETE, LTs, TX etc.) and anti-inflammatory products (LXB4, DHETs, HPETEs etc.) were elevated in the BF group. It was found that, compared to grazing, concentrate supplement feeding regimens, including either grazing plus supplements or feeding indoors, down-regulated blood n-3 PUFA biosynthesis and up-regulated the blood inflammatory compound metabolism by n-6 PUFA.

Feeding cows with hay, silage, or fresh herbage on pasture or indoors affects sensory properties and chemical composition of milk and cheese

In European countries, silage-free feeding is an ancient tradition and has a particularly positive reputation among consumers. In the present study, we compared grass-based forages from the same plot conserved as hay or silage or fed fresh either on pasture or indoors, and we evaluated the differences in sensory properties of milk and uncooked pressed cheese. All herbage from the first cut of a grassland dominated by perennial ryegrass was harvested on the same day and preserved either as hay or silage. The first regrowth of the same plot was used for strip grazing or green feeding indoors. Balanced by breed, 24 Montbéliarde and 24 Holstein cows were allocated to the 4 treatments. Apart from the forages, the late-lactation cows received 3 kg/d of dry matter from concentrate. After 2 wk of dietary adaptation, the bulk milk of 3 subgroups, each with 4 cows, was collected. Part of the milk was pasteurized, and part was left raw and partly transformed to small-sized Cantal-type cheese ripened for 9 wk. Milk and cheese underwent descriptive sensory analysis by a trained sensory panel, as well as analyses of physicochemical traits. Volatile organic compounds of the cheeses were also analyzed. Raw and pasteurized milk from hay-fed cows had less intense odors of cooked milk, cream, and barnyard than milk from grazing cows, whereby the effect of pasteurization did not differ between herbage utilization methods. Cheeses obtained from cows fed fresh herbage (grazing and indoors) were clearly yellower than cheeses from silage- and hay-fed cows, which coincided with the color intensity perceived by the panelists. Moreover, cheeses from cows fed fresh herbage had more intense barnyard and dry fruit flavors, were perceived as creamier and having less lactic odor, and exhibited more fat exudation than those from cows fed conserved herbage. Only a few differences were observed in milk and cheeses from hay-fed compared with silage-fed cows, and those differences were far less pronounced than those of milk and cheeses from cows fed fresh herbage. In conclusion, the present study did not substantiate assumptions of clear sensory differences of milk and uncooked pressed cheese from hay-fed compared with silage-fed cows. For the first time, this study reports that the global flavor intensity of cheeses from indoor green-fed cows is similar to that of cheeses derived from cows fed conserved forages, whereas cheeses from grazing cows have the greatest global flavor intensity.

Evaluación de la rentabilidad y competitividad de los sistemas de producción de ovinos en la región de Libres, Puebla

Con el objetivo de evaluar el grado en que los sistemas de producción de ovinos son competitivos y presentan ventajas comparativas, se entrevistaron a 139 productores, y se dio seguimiento a seis rebaños de tres sistemas de producción durante siete meses, en la región de Libres, Puebla. Se registró información de costos, infraestructura, actividad agrícola, mano de obra, producción y venta de ovinos. Para determinar la rentabilidad y la competitividad se utilizó la Matriz de Análisis de Política. El sistema de producción con alimentación en corral fue el más rentable y competitivo de acuerdo con los indicadores de rentabilidad privada, Relación del Costo Privado, Coeficiente de Rentabilidad Privada y la Relación del Costo-Beneficio Privado. El costo de los factores de producción fue mayor en el sistema de producción de corderos en pastoreo y fue el de menor competitividad. La Relación Costo-Beneficio Social indicó ineficiencia para reemplazar las importaciones. La producción de ovinos tuvo una estructura de mercado oligopsónica, producto de las deficiencias institucionales y ausencia de políticas de protección. Los productores utilizaron como criterio de venta el peso adulto, aunque la venta de los corderos inició entre los 30 y 90 días. Es recomendable realizar el análisis de la función de producción, para determinar la viabilidad de la venta de cordero destetado, como una opción para aumentar las ganancias de los productores y la competitividad de estos sistemas.

Maternal grazing on stubble and Mediterranean shrubland improves meat lipid profile in light lambs fed on concentrates

Concentrates-fed lamb meat is often associated with an unfavourable lipid profile (high levels of saturated and/or n-6 polyunsaturated fatty acids; SFA and PUFA). For this reason, Spanish sheep producers from Mediterranean areas are turning to traditional grazing by ewes to obtain healthier lamb meat. The objective of this research was to determine the effects of maternal grazing on the fatty acid (FA) composition of weaned lamb meat. The ewes (Segureña breed) were allocated to two different rearing systems during pregnancy (5 months) and lactation (45 days): (i) feeding indoors on barley grain and lucerne pellets; (ii) grazing on cereal stubble, fallow land and seasonal pastures consisting of Mediterranean shrubs, herbs and trees. Two groups of 20 autumn and spring lambs were sampled. The lambs were weaned at 13.1±0.9 kg and 45.0±4.1 days age and fed on grain-based concentrates until they reached 24.8±2.1 kg live weight (light lambs slaughtered at 98.3±3.6 days of age). The FA content was determined in the intramuscular loin fat by gas chromatography using a flame ionization detector. The ewe diet did not affect the levels of the main lamb FAs (C18:1c+t, C16:0 and C18:2c), and so did not provide any additional reduction in fat saturation. Saturated fatty acids represented around 40% of total FAs determined in the meat. Ewe grazing acted as an n-3 PUFA-promoting diet, providing a lamb meat with a lower n-6/n-3 ratio. Spring lamb meat had higher proportions of n-3 PUFA (C18:3n-3, C20:5, C22:5 and C22:6) and conjugated linoleic acid (C18:2c9t11+c11t9) to the detriment of the n-6 PUFAs (C20:4, C20:2 and C22:4), while autumn lamb meat also had higher levels of C18:3n-3 and C18:3n-6, and lower level of C20:4, which points to little seasonal differences. The n-6/n-3 ratio achieved by ewe grazing fell from 8.2 to 4.1 (Spring) and from 7.6 to 5.5 (Autumn), values which are close to those recommended in human diet for good cardiovascular health. These n-6/n-3 reductions were associated with lower levels of total PUFA and C20:4n-6. Our research concluded that grazing on stubble and Mediterranean shrubland by ewes, a sustainable rearing practice involving local agro resources, contributed to obtaining weaned lamb meat with a more favourable lipid profile and so can be recommended to sheep farmers.

Dairy cow preference for different types of outdoor access

Dairy cows display a partial preference for being outside, but little is known about what aspects of the outdoor environment are important to cows. The primary aim of this study was to test the preference of lactating dairy cattle for pasture versus an outdoor sand pack during the night. A secondary aim was to determine whether feeding and perching behavior changed when cows were provided outdoor access. A third objective was to investigate how the lying behavior of cows changed when given access to different outdoor areas. Ninety-six lactating pregnant cows were assigned to 8 groups of 12 animals each. After a baseline phase of 2 d in which cows were kept inside the freestall barn, cows were habituated to the outdoor areas by providing them access to each of the 2 options for 24 h. Cows were then given access, in random order by group, to either the pasture (pasture phase) or the sand pack (sand phase). As we tested the 2 outdoor options using space allowances consistent with what would be practical on commercial dairy farms, the space provided on pasture was larger (21,000 m2) than that provided on the sand pack (144 m2). Cows were tested at night (for 2 nights in each condition), from 2000 h until morning milking at approximately 0800 h, as preference to be outdoors is strongest at this time. During the next 3 nights cows were given access to both outside options simultaneously (choice phase). Feeding and perching behaviors were recorded when cows were indoors during the day and night periods. Lying behavior was automatically recorded by HOBO data loggers (Onset, Bourne, MA). Cows spent more time outside in the pasture phase (90.0 ± 5.9%) compared with the sand phase (44.4 ± 6.3%). When provided simultaneous access to both options, cows spent more time on pasture than on the sand pack (90.5 ± 2.6% vs. 0.8 ± 0.5%, respectively). Time spent feeding indoors during the day did not change regardless of what type of outdoor access was provided, but there was a decline in perching during the day when cows were provided access to either outdoor option at night. Lying time in the pasture phase was lower than in the baseline or sand phase. During the nighttime, lying time outside was not different between the sand (55.4 ± 7.9%) and pasture (52.0 ± 7.4%) phases. In summary, cows spent a considerable amount of time outside during the night when given the opportunity and showed a preference for a large pasture versus a small sand pack as an outdoor area.

Investigating associations between biting time in the malaria vector Anopheles arabiensis Patton and single nucleotide polymorphisms in circadian clock genes: support for sub-structure among An. arabiensis in the Kilombero valley of Tanzania.

BackgroundThere is growing evidence that the widespread use of Long-Lasting Insecticidal Nets (LLINs) is prompting malaria vectors to shift their biting towards times and places where people are not protected, such as earlier in the evening and/or outdoors. It is uncertain whether these behavioural shifts are due to phenotypic plasticity and/or ecological changes within vector communities that favour more exophilic species, or involve genetic factors within vector species to limit their contact with LLINs. Possibly variation in the time and location of mosquito biting has a genetic basis, but as yet this phenomenon has received little investigation. Here we used a candidate gene approach to investigate whether polymorphisms in selected circadian clock genes could explain variation in the time and location of feeding (indoors versus outside) within a natural population of the major African malaria vector Anopheles arabiensis.MethodsHost-seeking An. arabiensis were collected from two villages (Lupiro and Sagamaganga) in Tanzania by Human Landing Catch (HLC) technique. Mosquitoes were classified into phenotypes of “early” (7 pm–10 pm) or “late” biting (4 am –7 am), and host-seeking indoors or outdoors. In these samples we genotyped 34 coding SNPs in 8 clock genes (PER, TIM, CLK, CYC, PDP1, VRI, CRY1, and CRY2), and tested for associations between these SNPs and biting phenotypes. SNPs in 8 mitochondrial genes (ATP6, ATP8, COX1, COX2, COX3, ND3, ND5 and CYTB) were also genotyped to test population subdivision within An. arabiensis.ResultsThe candidate clock genes exhibited polymorphism within An. arabiensis, but it was unrelated to variation in the timing and location of their biting activity. However, there was evidence of strong genetic structure within An. arabiensis populations in association with the TIM, which was unrelated to geographic distance. Substructure within An. arabiensis was also detected using mitochondrial markers.ConclusionsThe variable timing and location of biting in An. arabiensis could not be linked to candidate clock genes that are known to influence behaviour in other Diptera. This finding does not rule out the possibility of a genetic basis to biting behaviour in this malaria vector, but suggests these are complex phenotypes that require more intensive ecological, neuronal and genomic analyses to understand.Electronic supplementary materialThe online version of this article (doi:10.1186/s13071-016-1394-8) contains supplementary material, which is available to authorized users.

Winter Activity and Aboveground Hybridization Between the Two Biotypes of the West Nile Virus Vector Culex pipiens.

Culex (Cx.) pipiens mosquitoes are important vectors of West Nile virus (WNV). In Europe, the species Cx. pipiens consists of two biotypes, pipiens and molestus, which are morphologically identical, but differ in behavior. Typical behavior of the molestus biotype is the ability to remain active during winter, whereas the pipiens biotype enters diapause. The current paradigm is that the two biotypes occur sympatrically in southern Europe, but occur in isolated above- and belowground populations in northern Europe. In northern Europe, hybridization between biotypes is considered to be low because of the barrier that exists between typical habitats. Data on the occurrence of the biotypes and hybrids in northern Europe, however, are scarce, because identification to the level of biotype is often not performed. Our objective was to clarify the distribution of the Cx. pipiens biotypes and to determine hybridization rates in The Netherlands. Cx. pipiens mosquitoes were collected using three different approaches. First, traps were deployed randomly throughout The Netherlands during the summers of 2011 and 2012 (active surveillance). Second, using a web-based reporting platform and media campaign, Dutch citizens were asked to send dead mosquitoes to our laboratory during the winter and summer of 2014 (passive surveillance). Third, larvae and adults were collected during the summer of 2014 from aboveground locations in Amsterdam to identify molestus larval habitats. Real-time PCR was used for identification to the level of biotype. We found that biotype molestus and hybrids were feeding indoors during winter and summer in The Netherlands and that hybridization rates ranged between 6% and 15%. Larval habitats of biotype molestus were found to occur aboveground. The high percentage of hybridization has implications for assessing the risk of WNV transmission, because hybrids are thought to have ideal characteristics for bridging WNV between birds and humans.

Current trends in British dairy management regimens

This paper presents a summary of results from a 2012 survey that investigated feeding and housing management regimens currently adopted by dairy farmers in Britain. Responses from 863 farms provide a snapshot of dairy industry structure and a description of the range of management systems currently in operation. Outcomes highlight a diversity of management practices, showing that 31% of farms maintained a traditional grazing system with no forage feeding indoors during the summer, whereas 38% of farmers indicated that all their milking cows received some feeding indoors during the summer. A system of housing dairy cows for 24h/d while they are lactating was implemented by 8% of farms, whereas 1% of farms did not house their cows at any time of the year. Statistical analyses were carried out on 3 distinct groups identified from survey responses: (1) farmers who did not undertake any indoor feeding during the summer; (2) farmers who fed all their milking cows indoors during the summer; and (3) farmers who continuously housed their cows for 24h/d while lactating. Results showed a significant relationship between management type and herd size, and between management type and breed type; on average, herd sizes were larger within systems that feed indoors. No significant relationship was found between management type and farm location when classified by estimated grassland productivity. The results indicate that traditional all-summer grazing is no longer the predominant system adopted by dairy farmers and that other systems such as all-year-round indoor feeding and continuous housing are becoming more prevalent in Britain.

Consistently high estimates for the proportion of human exposure to malaria vector populations occurring indoors in rural Africa

Background Insecticide-treated nets (ITNs) and indoor residual spraying (IRS) are highly effective tools for controlling malaria transmission in Africa because the most important vectors, from the Anopheles gambiae complex and the A. funestus group, usually prefer biting humans indoors at night.Methods Matched surveys of mosquito and human behaviour from six rural sites in Burkina Faso, Tanzania, Zambia, and Kenya, with ITN use ranging from 0.2% to 82.5%, were used to calculate the proportion of human exposure to An. gambiae sensu lato and An. funestus s.l. that occurs indoors (πi), as an indicator of the upper limit of personal protection that indoor vector control measures can provide. This quantity was also estimated through use of a simplified binary analysis (πiB) so that the proportions of mosquitoes caught indoors (Pi), and between the first and last hours at which most people are indoors (Pfl) could also be calculated as underlying indicators of feeding by mosquitoes indoors or at night, respectively.Results The vast majority of human exposure to Anopheles bites occurred indoors ( = 0.79–1.00). Neither An. gambiae s.l. nor An. funestus s.l. strongly preferred feeding indoors (Pi = 0.40–0.63 and 0.22–0.69, respectively), but they overwhelmingly preferred feeding at times when most humans were indoors (Pfl = 0.78–1.00 and 0.86–1.00, respectively).Conclusions These quantitative summaries of behavioural interactions between humans and mosquitoes constitute a remarkably consistent benchmark with which future observations of vector behaviour can be compared. Longitudinal monitoring of these quantities is vital to evaluate the effectiveness of ITNs and IRS and the need for complementary measures that target vectors outdoors.

Consistently high baseline estimates for the proportion of human exposure to rural African malaria vector populations that occurred indoors

Background Insecticide treated nets (ITNs) and indoor residual spraying (IRS) are highly effective options for controlling malaria transmission in Africa because the most important vectors, which are from the Anopheles gambiae complex and the An. funestus group, prefer biting humans who are indoors at night. It is feared that sustained large scale use of ITNs and IRS can cause these vectors to shift biting in place and time where ITNs and IRS are not effective. Materials and methods Matched surveys of mosquito and human behavior from six rural sites in Burkina Faso, Tanzania, Zambia, and Kenya with ITN coverage ranging from 0.2% to 82.5% were used to calculate the proportion of human exposure to Anopheles gambiae sensu lato and An. funestus s.l. that occurs indoors (πi) as an indicator of the maximum level of personal protection that ITN use can provide. The proportion of mosquitoes caught indoors (Pi )a nd between the first and last hours when most people are indoors (Pfl) were also calculated as underlying indicators of vector preference for feeding indoors or at night, respectively. Results The vast majority of human exposure to Anopheles bites occurred indoors (πi = 0.90-1.00). Neither An. gambiae s.l. nor An. funestus s.l. strongly preferred feeding indoors (Pi = 0.46-0.63 and 0.22-0.72, respectively) but they overwhelmingly preferred feeding at times when most humans were indoors (Pfl = 0.84-1.00 and 0.93-0.99, respectively). Conclusions These quantitative summaries of behavioral interactions between humans and mosquitoes establish baseline values against which behaviour observed in residual vector populations exposed to high ITN or IRS coverage can be compared. Longitudinal monitoring of these quantities is vital to evaluate the effectiveness of ITNs and IRS and to evaluate the need for development of complementary measures targeting the outdoor-biting vectors.

Novel Vectors of Malaria Parasite in the Western Highlands of Kenya

To the Editor: The primary malaria control techniques, indoor application of residual insecticides and insecticide-treated bed nets, are used on the basis of previously assumed key characteristics of behaviors of vectors of malaria parasites, i.e., resting and feeding indoors (1). Any deviation from the typical activities of a species related to exophagy (feeding outdoors) and exophily (living and resting indoors) (2) or to population replacement, followed by increased outdoor biting or resting (3), may undermine malaria control efforts. Identification of mosquitoes that transmit malaria parasites has, for the most part, relied on the use of outdated morphologic keys (4,5) and, more recently, species-diagnostic PCR (6). Cryptic species or subpopulations that exhibit divergent behaviors (7) may be responsible for maintaining malaria parasite transmission, and without adequate discriminatory techniques, these vectors may be misidentified and their key behavioral differences overlooked.

Target product profiles for protecting against outdoor malaria transmission

BackgroundLong-lasting insecticidal nets (LLINs) and indoor residual sprays (IRS) have decimated malaria transmission by killing indoor-feeding mosquitoes. However, complete elimination of malaria transmission with these proven methods is confounded by vectors that evade pesticide contact by feeding outdoors.MethodsFor any assumed level of indoor coverage and personal protective efficacy with insecticidal products, process-explicit malaria transmission models suggest that insecticides that repel mosquitoes will achieve less impact upon transmission than those that kill them outright. Here such models are extended to explore how outdoor use of products containing either contact toxins or spatial repellents might augment or attenuate impact of high indoor coverage of LLINs relying primarily upon contact toxicity.ResultsLLIN impact could be dramatically enhanced by high coverage with spatial repellents conferring near-complete personal protection, but only if combined indoor use of both measures can be avoided where vectors persist that prefer feeding indoors upon humans. While very high levels of coverage and efficacy will be required for spatial repellents to substantially augment the impact of LLINs or IRS, these ambitious targets may well be at least as practically achievable as the lower requirements for equivalent impact using contact insecticides.ConclusionsVapour-phase repellents may be more acceptable, practical and effective than contact insecticides for preventing outdoor malaria transmission because they need not be applied to skin or clothing and may protect multiple occupants of spaces outside of treatable structures such as nets or houses.

Effect of feeding system on unsaturated fatty acid level in milk of dairy cows

AbstractIn recent years, consumer attitudes toward fat of animal origin have changed owing to findings that some milk fatty acids (FAs) are positive for human health, especially conjugated linolenic acid andn-3 FAs. Accordingly, the manipulation of the fat content and FA composition of cows’ milk via nutritional strategies has been an important target for the dairy industry in many countries. Twenty commercial Holstein–Friesian dairy herds of Asturias (northern Spain) with 1106 dairy cows were examined in order to evaluate milk FA profiles under different management systems. These herds were divided into three groups according to management: (1) indoor herds: cows feeding indoors, (2) mixed herds: indoor management system but with at least 6 h of grazing outdoors and (3) outdoor herds: cows allowed 6–18 h of grazing per day. Milk from the indoor herds exhibited the highest concentration of fat (3.57%;P⩽0.01), protein (3.14%;P⩽0.001), lactose (4.76%;P⩽0.01) and urea (29.4 mg dl−1;P⩽0.01). The milk of outdoor herds had a lower (P⩽0.05) content of short-chain FAs than that of the indoor and mixed herds (10.89 versus 11.52 and 11.35 g 100 g−1FA). The milk of the indoor herds had higher concentrations of saturated fatty acids (SFA) (67.56 g 100 g−1FA;P⩽0.001) and palmitic and palmitoleic acids (30.16 and 1.82 g 100 g−1FA, respectively), while that of the mixed and outdoors herds had higher concentrations of unsaturated fatty acids (UFA) (34.58 g 100 g−1FA;P⩽0.001) and long-chain FAs, especially stearic (13.89 g 100 g−1FA;P⩽0.01), vaccenic (2.77 g 100 g−1FA;P⩽0.001), conjugated linoleic (0.92 g 100 g−1FA;P⩽0.001) and linolenic (0.42 g 100 g−1FA;P⩽0.001) acids. Results from this study suggest that the incorporation of forage and pasture in the diet of dairy cows can improve the FA profile of milk.

Efficacy of the botanical repellents geraniol, linalool, and citronella against mosquitoes

We determined the degree of personal protection provided by citronella, linalool, and geraniol in the form of commercially available candles or diffusers, both indoors and outdoors. Under the uniform conditions of the experiments, all substances repelled significantly more mosquitoes than the unprotected control. Furthermore, the repellents tested were more active when in the form of a continuous release diffuser than in candle form. All candles were 88 g containing 5% of the active ingredient and all diffusers contained 20 g of 100% active ingredient. Indoors, the repellency rate of citronella candles was only 14% while the repellency rate of citronella diffusers was 68%. The repellency of geraniol candles was 50% while the diffusers provided a repellency rate of 97%. No linalool candles were available for study but linalool diffusers repelled mosquitoes by 93%. Outdoors, citronella diffusers placed 6 m from mosquito traps repelled female mosquitoes by 22%, linalool repelled females by 58%, and geraniol repelled females by 75%. Trap catches were significantly reduced again when diffusers were placed 3 m from the traps. We concluded that geraniol had significantly more repellent activity than citronella or linalool in both indoor and outdoor settings.

Release of cell contents and comminution of particles of perennial ryegrass herbage during ingestion by dairy cows fed indoors or grazing

AbstractThe effect of feeding indoors fresh perennial ryegrass vs. grazing on ingestive behaviour, release of cell contents and comminution of particles during ingestion, as well as on gas production of ingested boli fermented in vitro, was studied. Indoor feeding and grazing were compared using four dairy cows according to a triple reversal design with six periods. Chemical and morphological composition of the ingested herbage was similar for both indoor feeding and grazing treatments. The intake rate was markedly higher indoors compared with grazing [52·1 vs. 22·9 g dry matter (DM) min−1] with heavier boli and less saliva added per gram of DM intake. The proportions of intracellular nitrogen and chlorophyll released during mastication after ingestion of herbage fed indoors were lower, and the median size of the particles in the boli was larger (5·97 vs. 4·44 mm) compared with grazing. As a result, the rate of gas production in vitro was also lower for herbage fed indoors compared with grazing (0·423 vs. 0·469 mL min−1 g−1 incubated DM). Indoor feeding or grazing may have limited consequences in vivo on the kinetics of availability of nutrients for micro‐organisms in the rumen, because the consequences of the more extensive physical damage suffered by herbage ingested at grazing could be compensated by a lower intake rate.

Indoor and outdoor mass production of the diatom Chaetoceros muelleri in a mexican commercial hatchery

In tropical and subtropical countries, hatcheries may produce microalgae for larval feeding either indoors, which is supposed to improve the quality and reliability of production but has a higher cost, or they may use outdoor cultures at a lower cost, but with a high seasonal variability. In this paper, we compare the cell concentrations and the organic biomass yields and composition of indoor and outdoor mass cultures of the diatom Chaetoceros muelleri obtained in four seasons in a commercial hatchery of the state of Sonora, in the Mexican northwest. Cell yields were better outdoors in spring and fall but lower in winter, whereas in summer they were similar indoors and outdoors. Organic biomass production was higher in spring and summer and tended to be lower, but not significantly different, in winter. Indoors, the percentage of proteins was significantly higher during spring, but it was lower in fall and winter. In summer, there was no difference between outdoors and indoors. Carbohydrates were higher indoors in summer, when lipids were higher outdoors, whereas in winter they were higher indoors. The organic biomass production ranged from 22.5 to 45.7 g/m 3/d indoors, with a mean estimated cost of US$ 176.67 and 75.88 per kg of total biomass. Outdoors, the mean production varied from 29.0 to 69.7 g/m 3/d in winter and spring, respectively, at a mean annual cost of US$ 50.36 per kg.

Production of healthier goat milk. Use of a concentrate supplemented with a “protected” fat rich in PUFA

In order to obtain healthier goat milk as far as its fat composition is concerned, milk production and composition trials were carried out with Granadina goats kept in semi-extensive breeding conditions. The animals were feeding indoors with a concentrate supplemented or not with 7% of fat conveniently protected against the action of rumen, which had 35% of polyunsaturated fatty acids (PUFA). The amount of milk produced was higher (p < 0.05) with consumption of the fat supplemented concentrate. At the same time, and although there was no difference in the milk concentration of fat and protein nitrogen (p > 0.05), the corresponding yields were higher for consumption of the fat supplemented concentrate. As for the composition of milk fat, the use of the supplemented concentrate resulted in fat with a higher (p < 0.05) concentration of PUFA and a lower (p < 0.05) concentration of stearic acid. At the same time, the concentration of medium chain triglycerides, which is the specific nutritional value particular to goats' milk, was the same whichever concentrate was consumed.

Effect of lamb growth rate and growth pattern on carcass fat levels

AbstractA total of 252 lambs was subjected to two contrasting growth rates (high and low) for 7 weeks commencing at 6 weeks of age, factorially arranged with two contrasting growth rates (high and low) from 13 weeks to slaughter. Growth rate was controlled either by weaning lambs at 6 weeks and feeding indoors throughout on differing levels of a concentrate diet (84 lambs in experiment 1) or by grazing at differing sward heights up to weaning at 13 weeks after which weaned lambs were grazed at differing sward heights and where necessary housed from early October and offered differing levels of concentrate and silage (168 lambs in experiment 2). Lamb slaughter weights on each growth rate treatment covered the range 40 to 48 kg live weight.Increasing the growth rate between 6 and 13 weeks from 213 to 320 glday in experiment 1 and from 191 to 291 g/day in experiment 2 did not significantly affect the fat depth measured at various locations throughout the carcass, the weight of perinephric and retroperitoneal fat, fat grade or the total lipid content of soft tissue dissected from the shoulder joint when lambs were taken to slaughter weights. Increasing the growth rate between 13 weeks and slaughter from 136 to 338 g/day in experiment 1 and from 99 to 146 g/day in experiment 2 significantly increased the depth of carcass fat and fat grade but, though lipid content of the tissue in the shoulder also increased, this difference was not significant.Carcass fat depth, perinephric and retroperitoneal fat, fat grade and lipid content of the shoulder tissue increased as slaughter weight increased. The effect of carcass weight on carcass fat was greater on the high plane of feeding from 13 weeks than on the low plane. For example, mean fat depth increased by 0·52 mm/kg increase in carcass weight on the high plane compared with 0·13 mm/kg on the low plane.Comparing the effect of plane of feeding and carcass weight on carcass fat depth the high finishing plane of feeding had an effect equivalent to an increase of 3·8 kg carcass weight. The equivalent figure for the depth of tissue over the 12th rib was 2·8 kg while in relation to fat grade the effect was smaller at 1·0 kg carcass weight.

Comportamiento de anopheles (Kerteszia) ledidotus zavortink, 1973 y su discriminación como posible vector de malaria en el departamento del Tolima Colombia (1)

Entomological studies were made of a focus of P. vivax malaria in the municipalities of Cunday, Villarrica, Dolores, Prado and Purificación, Departament of Tolima, during april 1981 to may 1983. Of 2.209 anopheline mosquitoes collected from human bait all were of the subgenus Kerteszia, 99.5% of which were An. (K) lepidotus and the remainder An. (K). boliviensis. Therefore, it was concluded that An. lepidotusis the vector in this focus; this in the first report of this species being incriminated as a malaria vector in Colombia. Earlier observations in this focus had incriminated An. boliviensis due to taxonomic confusion which has been only clarified in the last 10 years. Highest An lepidotus densities occurred during January to June and peak An lepidotus density proceeded peak malaria cases by about 2 months. An. lepidotus was found to be highly exophagic (3. 7 times more human biting activity outdoors than indoors) and exophilic (92% of those feeding indoors left the house whiteout resting). Human biting is almost totally diurnal with peak biting activity between 15:00 and 18:00 hours. No evidence was found of irritability or physiological resistance to DDT. Implications of the above results in relation to malaria control measures are discussed and the present known distribution of An. lepidotus in Colombia is given.

Biochemical, Serological and Haematological Changes Associated with Infections of Calves with the Nematode Parasite, Ostertagia Ostertagi

(1) Blood and abomasal contents have been analysed from about 80 cattle with natural and experimental infections with Ostertagia ostertagi , and also parasite-free calves. (2) Heavy infections resulted in serum albumin levels falling to 1.3 to 1.6 g./100 ml. Anthelmintic treatment followed by heavy concentrate feeding indoors resulted in rapid increases in serum albumin. (3) Packed cell volume estimations support the view that haemoncentration is associated with the fall in albumin level in early infection and that haemodilution occurs as albumin rises after treatment. (4) Heavy infections were characterized by high pH and low pepsin concentrations in the abomasum at slaughter and these changes were evident, to a lesser degree, in moderate infections. These changes suggest that gastric function must be markedly reduced in heavy infections.