Forage Consumption Research Articles

Increasing home-grown forage consumption and profit in non-irrigated dairy systems. 3. Intake, milk production and composition, bodyweight and body condition score

This paper reports the performance [intake, milk production, bodyweight and body condition score (BCS)] of cows managed under two feeding systems over 4 years (June 2005–May 2009) in south-west Victoria, Australia. The feeding systems were ‘Ryegrass Max’ (RM) a well managed perennial ryegrass pasture-based system stocked at 2.2 cows/ha, and a ‘Complementary Forage’ (CF) system based on perennial ryegrass, tall fescue and a double crop of winter-sown cereal and summer-sown brassica crops stocked at 2.82 cows/ha. There were no significant differences in milk production per lactation between feeding systems, with an average of 543 and 553 kg milk solids per cow (1246 and 1642 kg milk solids per ha) produced in the RM and CF systems, respectively. These production levels were 20.9 and 10.8% above pre-experimental model targets, respectively. The bodyweight and BCS of multiparous cows were not significantly different between the two feeding systems; however, bodyweight of heifers in early lactation declined more rapidly in the CF compared with RM feeding system. Over the 4-year study in the RM system pasture comprised 60% of total DM consumed (grazed + conserved), with 26% of the ration being concentrate and the balance being purchased hay supplements. In the CF system, home-grown forage contributed 57.9% of total DM consumed of which 46.6% was pasture (grazed + conserved) and 11.3% was from the double cropping system. These levels of home-grown forage consumption were lower than those predicted by the pre-experimental modelling, leading to higher than predicted levels of purchased concentrates and conserved forages being fed. The lower than expected levels of consumption of the forages produced in the double cropping system reflected both the low intake potential and moderate nutritive value of cereal silage, and the failure of establishment and subsequent low DM yields from the summer brassica crop. Further work is required to determine the risk of implementing CF in rain-fed dairy systems reflecting uncertainties in forage management planning and nutrient delivery to support high levels of milk production.

Increasing home-grown forage consumption and profit in non-irrigated dairy systems. 4. Economic performance

The profitability of dairy farm systems in southern Australia is closely related to the amount of pasture grown and consumed on-farm by dairy cows. However, there are doubts regarding the extent to which gains in feed supply from perennial ryegrass pasture can continue to support productivity growth in the industry. A farmlet experiment was conducted in south-western Victoria for 4 years (June 2005–May 2009), comparing a production system based on the use of forage species that complement perennial ryegrass in their seasonal growth pattern (‘Complementary Forages’, or CF) with a well managed system solely based on perennial ryegrass pasture (‘Ryegrass Max’, or RM). The forage base in CF included perennial ryegrass with a double-cropping rotation of winter cereal grown for whole-crop silage, followed by a summer brassica for grazing on 15% of farmlet area, a summer-active pasture based on tall fescue (on average 20% of farmlet area), perennial ryegrass oversown with short-rotation ryegrasses (average 16% of farmlet area) and summer brassica crops used in the process of pasture renovation (average 5% of farmlet area). The stocking rate was 2.2 and 2.8 cows/ha on RM and CF, respectively. Both systems were profitable over the 4 years of the experiment, with the modified internal rate of return over 4 years being 14.4% and 14.7% for the RM and CF farmlets, respectively. The coefficient of variation (%) of annual operating profit over 4 years was higher for the CF farmlet (56% and 63% for RM and CF, respectively). A severe drought in one of the 4 years exposed the more highly stocked CF system to greater supplementary feed costs and business risk. By comparison, the RM system performed consistently well across different seasons and in the face of a range of milk prices. The very small gain in profit from CF, plus the associated higher risk, makes it difficult to endorse a substantial change away from the traditional RM feed supply to greater reliance on summer-grown forages on non-irrigated dairy farms in southern Australia, as implemented in this experiment.

Increasing home-grown forage consumption and profit in non-irrigated dairy systems. 1. Rationale, systems design and management

The profitability of dairy businesses in southern Australia is closely related to the amount of feed consumed from perennial ryegrass-dominant pasture. Historically, the dairy industry has relied on improvements in pasture productivity and utilisation to support profitable increases in stocking rate and milk production per hectare. However, doubts surround the extent to which the industry can continue to rely on perennial ryegrass technology to provide the necessary productivity improvements required into the future. This paper describes the design and management of a dairy systems experiment at Terang in south-west Victoria (780-mm average annual rainfall) conducted over four lactations (June 2005–March 2009) to compare the production and profitability of two forage base options for non-irrigated dairy farms. These options were represented by two self-contained farmlets each milking 36 mixed-age, autumn-calving Holstein-Friesian cows at peak: (1) well managed perennial ryegrass pasture (‘Ryegrass Max’, or ‘RM’); and (2) perennial ryegrass plus complementary forages (‘CF’) including 15% of farmlet area under double cropping with annual species (winter cereal grown for silage followed by summer brassica for grazing on the same land) and an average of 25% of farmlet area in perennial pasture based on tall fescue for improved late spring–early summer feed supply. The design of these systems was informed by farming systems models (DairyMod, UDDER and Redsky), which were used to estimate the effects of introducing different forage options on farm profitability. The design of the CF system was selected based on modelled profitability increases assuming that all forage components could be managed to optimise forage production and be effectively integrated to optimise milk production per cow. Using the historical ‘average’ pasture growth curve for the Terang district and a mean milk price of $3.71 per kg milk solids, the models estimated that the return on assets of the RM and CF systems would be 9.4 and 15.0%, respectively. The objectives of the experiment described here were to test whether or not such differences in profitability could be achieved in practice, and to determine the risks associated with including complementary forages on a substantial proportion of the effective farm area. Key results of the experiment are presented in subsequent papers.

Increasing home-grown forage consumption and profit in non-irrigated dairy systems. 2. Forage harvested

A dairy farmlet experiment was conducted at Terang in south-west Victoria, Australia, over 4 years to test the hypothesis that a 30% increase in forage harvested per ha could be achieved in a production system that incorporated a range of Complementary Forages with perennial ryegrass (CF) compared with a well managed perennial ryegrass-only farmlet (‘Ryegrass Max’, RM). The CF farmlet included perennial ryegrass pasture (44% of the farmlet area on average over 4 years), but also incorporated oversowing perennial ryegrass with short-term ryegrasses (average 16% of farmlet area) to increase winter growth, tall fescue-based pasture (average 20% of farmlet area) to increase production in the late spring–summer period, a double cropping rotation (15% of farmlet area) based on winter cereal for silage production followed by summer brassica crops for grazing, and summer crops used in the pasture renovation process (average 5% of farmlet area). The RM and CF farmlets were stocked at 2.2 and 2.82 June-calving cows/ha, respectively and average annual nitrogen (N) fertiliser application rates (pasture only) were 141 and 153 kg N/ha, respectively. The total amount of forage harvested per year was generally less than predicted from pre-experimental modelling of both farmlets. However, the proposed target of a 30% increase in home-grown forage harvest per ha in the CF system compared with RM was exceeded in 2005–06 (+33%), with 21, 16 and 11% higher forage harvest achieved in CF in 2006–07, 2007–08 and 2008–09, respectively (average for all 4 years = 20%). Annual forage harvested in RM ranged between 6.5 and 8.9 t DM/ha compared with 7.9–10.3 t DM/ha in CF. Approximately two-thirds of the increased forage harvest in CF came from higher rates of pasture consumption per ha and one-third from the double cropping component of the system, although the performance of the double crop (mean annual production of 11.5 t DM/ha) was well below the expected 20 t DM/ha based on pre-experimental modelling. The higher per-hectare pasture harvest rates in CF were primarily due to increased perennial ryegrass pasture consumption achieved through higher stocking rates and efficient responses to higher N inputs from both higher fertiliser rates and additional supplementary feeding. In CF, the DM harvested from pastures oversown with short-term ryegrasses was lower than perennial ryegrass, while tall fescue-based pastures were similar to perennial ryegrass. Poor spring rainfall in 2006–07 and 2008–09 likely contributed to the lower than expected DM yields of tall fescue-based pasture and the summer crops within the double cropping component. Home-grown forage harvest rates can be increased by 11–33% above what is currently achieved by best industry practice with perennial ryegrass-only pastures using complementary forages but perennial ryegrass will remain a key component of the forage base for dairy production in southern Australia.

Increasing home-grown forage consumption and profit in non-irrigated dairy systems. 4. Economic performance

Increasing home-grown forage consumption and profit in non-irrigated dairy systems. 4. Economic performance

Ungulate-adapted forest management: effects of slash treatment at harvest on forage availability and use

Forest management strongly influences the interactions between ungulates and their food resources. Different ungulate-adapted measures have been proposed in forestry to improve forage availability or to reduce browsing damage. However, the potential and feasibility of such measures are inadequately known. We studied the effects of harvest timing and slash treatment in final felling and commercial thinning on the availability of Scots pine Pinus sylvestris forage and its use by ungulates during winter in the Swedish boreal forests. Pellet group counts showed that moose (Alces alces) was the dominating species using the post-harvest stands. Under conventional slash treatment, final felling stands held on average 226 kg pine forage ha−1 after harvesting and commercial thinning stands 137 kg ha−1. Ungulate-adapted slash treatment increased the available forage biomass by 20 %, but had no significant effect on consumption of forage by ungulates. Time since harvest had the strongest effect on forage consumption; for example, under conventional slash treatment, there was a tenfold increase in consumption (3 vs. 33 kg ha−1) following final felling as exposure time increased from 2–3 to 4–5 months. Consumption was higher in thinned stands than in final felling stands for the first 3 months but not later. To increase ungulate use of the forage made available at harvest, pine-dominated stands should be harvested in the late autumn or early in the winter.

Quantitative characterization of the nutrition of the free-living horse (Equus caballus) on Vodnyi Island (Manych-Gudilo Lake)

The nutritional value of plant fodder, daily consumption, and digestibility of forage were assessed in an isolated group of free-living (wild) horses inhabiting the pastures of Vodnyi Island during different seasons of 2010–2011. The digestibility was determined by the proportion between inert food components (silicon, lignin) in the diet and the feces. The daily intake of food was calculated according to the weight of the daily feces and digestibility of food. Daily food consumption of the free-living horses during the snowless period is from 8 to 14 kg/ind. and 16 kg/ind. (dry weight) during the winter period. Food digestibility changes from 49 to 54% per year; the mean digestibility is 52%. The daily metabolic energy intake during the snowy period of the year (130.7 MJ/ind.) is almost twofold higher than in spring (67.4 MJ/ind.). In all the seasons, it exceeds the requirements for energy. The free-living horses of Vodnyi Island have parameters of digestibility and consumption of forage similar to other horses.

The Effects of Some Aditives on Production Performances in Laying Hens

Normal 0 21 false false false MicrosoftInternetExplorer4 The research was performed on 108 laying hens, Isa-Brown hybrid, divided in four groups, 27 heads/group. Prebiotic Actigen was supplemented in total mixed ratio (TMR) in group 1E using a proportion of 0.06%, prebiotic Bio-Mos in proportion of 0.1% (group 2E) and organic Se (Sel-Plex) in proportion of 0.04% (group 3E). The trial developed within 6 weeks, first laying stage (33 weeks - 39 weeks of age), respectively. The laying hens were individually weighted, in the beginning and in the end of the trial. During trial, the following issues were studied: evolution of body weight, laying intensity, average weight of eggs and forage consumption by egg. The use of prebiotics (Bio-Mos and Actigen) and organic selenium (Sel-Plex) in the mentioned doses determined an increase of laying intensity and average weight of eggs and reducing the feed conversion ratio for an egg, as compared to the control group (C). The results obtained confirm the favourable influence of prebiotics and organic selenium on the main production and consumption indices of laying hens in the first laying stage.

Do the large termite mounds of Macrotermes concentrate micronutrients in addition to macronutrients in nutrient-poor African savannas?

The influence of soil organisms on the availability of nutrients to other biota within ecosystems can be context-dependent. Fungus-culturing termites, for example, are known to concentrate nutrients by building large mounds in nutrient-poor savannas, but several factors determine the nutritional value of the mounds – whether by geophagy or consumption of forage – for large herbivores. Such factors include the limitations of the local edaphic environment and the degree of nutritional enrichment of plants growing on these mounds. We investigated, in nutrient-poor miombo vegetation in Zimbabwe, how the surrounding soils and maturity of the mounds affected concentrations of macro- and micronutrients in mounds and the woody plant foliage growing on them. All macro- and micronutrients save ammonium, extractable P, Zn and Se were enriched in large mounds relative to matrix soils, but none was significantly enriched in incipient mounds, suggesting that the full nutritional value of mounds is only expressed in large mounds. Concentrations of macronutrients, other than extractable P, in large mounds varied independently of concentrations in the matrix of surrounding topsoils. However, six (Mo, Cu, Fe, Zn, Se and Mn) of the nine micronutrient elements tested showed correlation with surrounding topsoils. Although foliar concentrations of N and P in mound species of woody plants did not differ significantly from those of matrix species, they reached maxima in mound species (5.7% for N and 0.4% for P, exceeding maxima of 4.3% and 0.24% in matrix species). Similarly, foliar concentrations of 75% of the micronutrients tested did not differ between mound and matrix species; but mound species contained maxima for 75% of these elements. Since herbivory is affected by soil nutrients, herbivores might meet their nutrient requirements in this nutrient-poor system by including mound plant species in their diets.

Proboscideans and paleoenvironments of the Pleistocene Great Lakes: landscape, vegetation, and stable isotopes

In this study, we review the history of proboscideans in the Great Lakes region (Ontario and western New York) in the context of local glacial and vegetational histories. Further, we investigate mammoth (Mammuthus) and mastodon (Mammut) environmental niche partitioning using stable isotope analysis of bone and dentin collagen (δ13Ccol, δ15Ncol) and structural carbonate in tooth enamel bioapatite (δ13Csc, δ18Osc), and demonstrate that stable isotopes can be used to identify non-locals among museum specimens with no contextual records. New radiocarbon dates suggest that Ontario mastodons lived in tundra-like environments as well as their more common spruce forest habitat. Local Ontario/New York mammoths and mastodons consumed 100% C3-plant diets and drank low-18O waters, consistent with colder-than-modern climates and proximity to glacial meltwater sources. Mammoths and mastodons occupied distinct environmental niches, characterized by different oxygen- and nitrogen-isotope compositions and geographical locations. This suggests that direct competition for resources was not a major factor in their local extinction. We suggest that both mammoths and mastodons obtained water from sources formed primarily from precipitation rather than glacial meltwater. We describe how high δ15N values in mammoths could have been caused by a combination of preferences for dry environments, consumption of low-nutrient forage (particularly stems and stalks), coprophagy, geophagy, and dung fertilization. We argue that low δ15N values in mastodons could have been caused by consumption of trees and shrubs (including nitrogen-fixing taxa) and a preference for recently deglaciated landscapes and/or spruce environments. Finally, we raise the possibility that mastodons contributed to the spruce-pine transition by browsing directly on spruce trees.

Arsenic toxicosis in sheep: The first report from Iran

Arsenic contamination of groundwater has been previously reported in Ghopuz, a village located in the Northwest of Iran. Samples were taken from consuming and irrigation water and plants of the region for chemical analysis. A seven-year old ewe, which had lived in and fed a lifelong at the same place, with clinical signs such as weakness, wasting and inappropriate integument was necropsied. Grossly, buccal erosion, stomatitis, cutaneous ulcers and serous atrophy of fat deposits were observed. Rumen contents, wool and several tissue samples were obtained for toxicological and histopathological examinations. Mean arsenic concentration in the spring water, irrigation water and grass/algae were 70.11, 48.74 and 141.85 ppb (µg/kg), respectively. Arsenic levels were 486.73, 247.94, 127.92, 125.97 and 231.24 ppb in wool, skin, rumen contents, liver and kidney, respectively. Microscopic study revealed hyperemia and heavy parasitic infestation of the abomasal wall. Hyperemia and regeneration of renal tubule epithelia were observed in kidneys and hyperkeratosis, suppurative deep dermatitis and paniculitis were found in skin. Periacinar fibrosis and a poorly differentiated cholangiocarcinoma were seen in liver. In pancreas, reduced cell density of islands of Langerhans was noticeable. In the central nervous system, perineuronal and perivascular edema, ischemic changes in gray matter neurons, and microcavitation of white matter were present. Our findings confirmed chronic arsenic toxicosis in small ruminants in this region. It can be concluded that long-term consumption of arsenic contamined water and forage may be associated with chronic arsenic poisoning in domestic animals and human beings, with consequent neoplastic disease and induction of diabetes in this region.

Effect of dietary phosphorus concentration and phytate-phosphorus on environmentally-relevant phosphorus excretion in horses

Effect of dietary phosphorus concentration and phytate-phosphorus on environmentally-relevant phosphorus excretion in horses

COMPETITION AND FACILITATION BETWEEN PRAIRIE DOGS AND LIVESTOCK

All photographs by David Augustine. Black-tailed prairie dog on a colony in the Conata Basin of Buffalo Gap National Grassland, South Dakota, USA. Cattle grazing on a black-tailed prairie dog colony at the Buffalo Gap National Grassland, which is adjacent to the Badlands National Park visible in the background. Cattle grazing on a black-tailed prairie dog colony at the Pawnee National Grassland, Colorado. In the Great Plains of North America, black-tailed prairie dogs are often thought to compete with cattle for forage. We examined how prairie dogs affect the amount and quality of forage growing on their colonies in Colorado and South Dakota. At a site experiencing below-average rainfall, forage both on and off colonies was so short and sparse that cattle were likely to be limited by the rate at which they could consume forage, rather than the rate at which they could digest it. In contrast, at sites experiencing above-average rainfall, forage both on and off colonies was tall and dense enough for cattle to be limited by digestion rather than the rate of forage consumption. Overall, our findings show prairie dogs can both enhance and suppress the weight gains of cattle depending on local weather conditions and the proportion of a pasture that is occupied by prairie dogs. Cattle grazing off of a black-tailed prairie dog colony at the Buffalo Gap National Grassland, South Dakota, with Badlands National Park as the backdrop. These photographs illustrate the article “Competition and facilitation between a native and a domestic herbivore: trade-offs between forage quantity and quality,” by David J. Augustine and Tim L. Springer, scheduled for publication in Ecological Applications 23(4), June 2013.

Physiological effects of diet mixing on consumer fitness: a meta‐analysis

The degree of dietary generalism among consumers has important consequences for population, community, and ecosystem processes, yet the effects on consumer fitness of mixing food types have not been examined comprehensively. We conducted a meta-analysis of 161 peer-reviewed studies reporting 493 experimental manipulations of prey diversity to test whether diet mixing enhances consumer fitness based on the intrinsic nutritional quality of foods and consumer physiology. Averaged across studies, mixed diets conferred significantly higher fitness than the average of single-species diets, but not the best single prey species. More than half of individual experiments, however, showed maximal growth and reproduction on mixed diets, consistent with the predicted benefits of a balanced diet. Mixed diets including chemically defended prey were no better than the average prey type, opposing the prediction that a diverse diet dilutes toxins. Finally, mixed-model analysis showed that the effect of diet mixing was stronger for herbivores than for higher trophic levels. The generally weak evidence for the nutritional benefits of diet mixing in these primarily laboratory experiments suggests that diet generalism is not strongly favored by the inherent physiological benefits of mixing food types, but is more likely driven by ecological and environmental influences on consumer foraging.

Land-use change in southern Sweden: Before and after decoupling

Rural land-use in the European Union (EU) is strongly influenced by the Common Agricultural Policy (CAP) because it directly affects the relative profitability of different land-use options. Since 2000, the CAP has been heavily reformed. In particular, in Sweden, the 2003 CAP reform was followed by substantial shifts in agricultural land allocation. However, this land-use change has barely been studied empirically beyond the net changes of land-use categories. In order to better understand the transformation of the land-use system, all transitions between land-use categories and changes within existing categories need to be considered. This article presents an analysis of agricultural land-use change between 2002 and 2010 in a landscape in southern Sweden. The inter-category land transitions were identified and quantified by using a spatially explicit field-level resolution dataset. The intra-category change of utilization intensity was assessed for grasslands by using standard yields and forage consumption estimates. Substantial shifts in chains of connected inter-category land transitions were found between cereals, temporary grasses, permanent pastures and fallow lands. The grassland utilization analysis showed a growing gap between grassland area and forage consumption. These results indicate concentration of agricultural production to better quality land and a growing number of land-idling farms in the region. The CAP single farm payment scheme is discussed in the light of these findings.

Context‐dependent planktivory: interacting effects of turbidity and predation risk on adaptive foraging

By shaping species interactions, adaptive phenotypic plasticity can profoundly influence ecosystems. Predicting such outcomes has proven difficult, however, owing in part to the dependence of plasticity on the environmental context. Of particular relevance are environmental factors that affect sensory performance in organisms in ways that alter the tradeoffs associated with adaptive phenotypic responses. We explored the influence of turbidity, which simultaneously and differentially affects the sensory performance of consumers at multiple trophic levels, on the indirect effect of a top predator (piscivorous fish) on a basal prey resource (zooplankton) that is mediated through changes in the plastic foraging behavior of an intermediate consumer (zooplanktivorous fish). We first generated theoretical predictions of the adaptive foraging response of a zooplanktivore across wide gradients of turbidity and predation risk by a piscivore. Our model predicted that predation risk can change the negative relationship between intermediate consumer foraging and turbidity into a humped‐shaped (unimodal) one in which foraging is low in both clear and highly turbid conditions due to foraging‐related risk and visual constraints, respectively. Consequently, the positive trait‐mediated indirect effect (TMIE) of the top predator on the basal resource is predicted to peak at low turbidity and decline thereafter until it reaches an asymptote of zero at intermediate turbidity levels (when foraging equals that which is predicted when the top predator is absent). We used field observations and a laboratory experiment to test our model predictions. In support, we found humped‐shaped relationships between planktivory and turbidity for several zooplanktivorous fishes from diverse freshwater ecosystems with predation risk. Further, our experiment demonstrated that predation risk reduced zooplanktivory by yellow perch (Perca flavescens) at a low turbidity, but had no effect on consumption at an intermediate turbidity. Together, our theoretical and empirical findings show how the environmental context can govern the strength of TMIEs by influencing consumer sensory performance and how these effects can become realized in nature over wide environmental gradients. Additionally, our hump‐shaped foraging curve represents an important departure from the conventional view of turbidity's effect on planktivorous fishes, thus potentially requiring a reconceptualization of turbidity's impact on aquatic food‐web interactions.

Fatty acid composition of meat and estimated indices of lipid metabolism in different poultry genotypes reared under organic system

According to EC regulation 889/08, different European countries should draw up a list of slow-growing strains adapted to an organic system, and in the meantime, provide this information to operators and the European Union commission. Thus, the aim of the present work was to evaluate the effect of poultry genotype on fatty acid composition and lipid indices of poultry meat. Six poultry genotypes (100 birds each), each with a different growth rate (slow-growing: Leghorn, Ancona, Cornish×Leghorn; medium-growing: Kabir, Naked neck; fast-growing: Ross), were reared under an organic system. Breast meat fatness, fatty acid composition, and indices were largely related to genotype, as slow-growing strains had higher elongase, thioesterase, and Δ5/Δ6 desaturase indices accompanied by a lower Δ9. Differences in the fatty acid profiles were observed by varying contents of total saturated fatty acids, with a higher value seen in Leghorn chickens and a lower value seen in commercial lines. On the contrary, Leghorn and Ancona chickens exhibited higher amounts of stearic acid and total polyunsaturated fatty acids compared with commercial genotypes, both in the total content and in the different fractions (total n-3 and total n-6). Despite the increased consumption of fresh forage, the lower linolenic acid in meat of the slow-growing strain could be explained by the higher conversion of this fatty acid to its long-chain derivatives.

Postweaning performance of heifers fed starter with and without hay during the milk-feeding period

This study assessed the carryover effects of providing forage during the milk-feeding period on postweaning feed intake and growth of heifers. At 11wk of age, heifers previously (3 to 77d of age) reared on starter (n=8) or starter plus grass hay (n=8) were switched to a single diet consisting of restricted amounts of concentrate [60% of the starter required to support daily body weight (BW) gain of 800g] with ad libitum access to coarsely chopped orchardgrass hay. Feed intake and growth were measured from 11 to 18wk of age. Starter dry matter (DM) intake averaged 2.14±0.15kg/d for both treatments. Forage consumption and total (starter plus hay) DM, neutral detergent fiber, crude protein, and metabolizable energy intakes were greater in heifers previously fed forage compared with those provided no forage. Initial and final BW were similar for the 2 treatments (108.2±9.1 and 149.6±9.3kg, respectively). Overall average daily gain in heifers previously fed starter alone (0.92±0.05,kg/d) tended to be greater than those previously fed starter plus hay (0.79±0.06,kg/d). Total DM intake (starter plus hay) was lower in heifers previously fed starter alone than those fed starter plus hay (3.55±0.13 vs. 4.08±0.15kg/d, respectively). Feed efficiency (BW gain/DM intake) after switching to a common diet was greater in calves previously fed starter alone than in those previously fed starter plus hay (0.26±0.01 vs. 0.19±0.01, respectively). However, heifers provided access to hay had a smaller body barrel (an indicator of gut fill) at 15wk (127.7±1.7 vs. 134.3±2.7cm) and 17wk (132.4±1.9 vs. 141.0±2.2cm) of age and had greater blood β-hydroxybutyrate (0.22±0.04 vs. 0.32±0.04mmol/L) compared with heifers that did not have access to hay earlier in life. These results indicate that provision of hay early in life promotes forage intake when heifers are switched to a high forage diet. However, greater feed consumption did not translate into live BW gain. Higher feed efficiency after switching to a common diet in heifers previously fed starter alone compared with those fed starter plus hay must be viewed with caution because intestinal content likely varied between treatment groups.

Uso de la diversidad forrajera tropical en combinaciones pareadas de leñosas forrajeras como indicador de preferencia para su inclusión en el diseño de sistemas silvopastoriles en zonas secas

Los efectos del cambio climático frente a la disponibilidad de alimento bovino en zonas secas es una gran limitante, como innovación se seleccionaron diez forrajes leñosos en la zona seca de Rivas (Nicaragua); dentro de las cuales existen diferencias funcionales (nutricionales, físicas y fenológicas) que muestran la variabilidad entre las leñosas tales como leguminosas sin espinas (Albizia niopoides, Gliricidia sepium, Leucaena leucocephala, Samanea saman); leguminosas con espinas (Acacia farnesiana, Mimosa pigra) y leñosas no leguminosas (Moringa oleifera, Brosimum alicastrum, Cordia dentata y Guazuma ulmifolia). Estas representan parte de la diversidad forrajera tropical de zonas secas con alta posibilidad de integrarlas en el diseño de sistemas silvopastoriles como estrategias de alimentación bovina. Son pocos los estudios desarrollados en donde se combinan especies forrajeras para determinar la preferencia de los bovinos en pruebas controladas de cafetería, la primera, como una prueba corta se usó la metodología de pruebas de cafetería con leñosas pareadas, en donde se integra el tiempo efectivo de consumo como factor de medición. Para esto se utilizó forraje de ramas delgadas <1,0 cm de diferentes individuos seleccionados de cada especie leñosa. Se utilizaron 5 vacas en producción con similares características, las cuales antes y después de las pruebas permanecieron con alimento y agua disponible. Se dispusieron atados en parejas de leñosas de acuerdo al orden de aleatorización. Se realizaron 225 combinaciones; 45 combinaciones por vaca (aleatorio) 25 combinaciones diarias (orden aleatorio); 3 minutos por evento; (75 minutos prueba/día); tiempo total de la prueba 11,25 horas; número de especies 10 y número días de prueba 9. Se evaluó el tiempo de consumo de cada leñosa, número de bocados/especie, y se obtuvo el consumo por diferencia de forraje ofrecido y rechazado. Estos resultados reflejan mayor preferencia y consumo de forraje, influenciado por la combinación de especies que presentan diferencias en sus rasgos físicos, nutricionales y fenológicos contrastantes que favorecen un mayor grado de preferencia cuando son ofrecidas individualemte. Lo anterior es explicado por razones asociadas a la integración de efectos nutricionales de la combinación como efectos sinérgicos a nivel digestivo de los componentes de la combinación de leñosas o con un incremento en la palatabilidad y consumo de las especies.

Current Trends in Dairy Cattle Farming in the Mediterranean Region of Turkey

This study assesses the current status of dairy cattle farming in Burdur province, an important region for milk production in Turkey. The study involved 677 enterprises and found that the mean number of cattle per farm was 11.3 and the number of milk cows per farm was 5.9. The estimated amount of concentrated feed consumed was 7.0 ± 2.3 kg/cattle/day; forage consumption was 9.1 ± 5.2 kg/cattle/day; the weaning age for calves was 87.4 ± 13.2 days; average milk yield was 18.7 ± 5.0 l/day; average drying-off time was 6.7 ± 0.5 months; and average age of first insemination was 17.0 ± 1.0 months. Of the 677 enterprises studied, 27.2% used free-stall barns, 20.9% used closed free-stall barns, and 51.9% used tie-stall barns. The mean size of tie-stall barns was 78 ± 51 m2. Milking was performed using portable milking machines in most enterprises (93%). Nearly all (96%) enterprises lacked any form-based recording system and received no regular veterinary treatment. This study provides important new survey data on dairy cattle breeding in Turkey.