Dags in Sheep Grazing Temperate Pastures: Causes and Consequences of Faecal Adhesion to Wool

Dags are the accumulation of faeces on wool in the perianal (breech) region of sheep and are a common problem in sheep fed good quality ryegrass based pastures in New Zealand. Their removal, or prevention, is costly but the consequences of doing nothing are severe. There is a high correlation between dags and flystrike (development of maggots) on sheep with dags, and dags reduce fleece value, live-weight gain and reproductive performance. Information summarised here suggests a range of factors contribute to the incidence of dags: lush (high quality) feeds, high voluntary feed intakes, presence of parasites in the gastro-intestinal tract, ingestion of parasite larvae, ingestion of fungal endophyte and a genetic predisposition to loose faeces. Faecal co elements, dry ground roughage, gums, detergent, serum, lanolin and water and measuring effects on adhesion. Other tests included measurement of faecal form, wool type and diet. Pelleted faeces did not adhere to wool, but interference with faecal form (e.g. mixing faeces) appeared to increase adhesion. It was concluded that faecal form was the most important factor affecting the incidence of dags and although conditions resulting in soft gooey faeces would facilitate their development, the chemical composition of faeces and of pasture were not the principal causes of dag formation. Factors associated with a high incidence of dags may increase the rate of digesta passage through the large intestine and/or alter intestinal function to affect faecal form and the adhesion of faeces to wool

Screening Fresh Forages for Protein Degradation and Nutritive Value

A method has been developed to prepare fresh forages for in sacco and in vitro incubation by freezing and mincing to achieve a particle size distribution of dry matter (DM) similar to in vivo conditions. The method is described and data presented to indicate losses of nitrogen (N) during in sacco digestion and net yield of ammonia from proteolysis in vitro for 22 fresh and conserved forages. Grasses, legumes and herbs were evaluated, with fractional degradation rates of forages ranging from 0.07h-1 with tall fescue (Festuca arundinacea) to 0.24 h-1 with chicory (Cichorium intybus). Degradation of protein to ammonia in vitro over 24 h was highest with white clover (Trifolium repens) and about 20% of the nitrogen (N) released during degradation was incorporated into microbial N. These data will assist formulation of forage based total mixed rations for high producing ruminants

Benefits of condensed tannins in forage legumes fed to ruminants:Importance of structure, concentration, and diet composition

Condensed tannins (CTs) account for up to 20% of the dry matter in forage legumes used as ruminant feeds. Beneficial animal responses to CTs have included improved growth, milk and wool production, fertility, and reduced methane emissions and ammonia volatilization from dung or urine. Most important is the ability of such forages to combat the effects of gastrointestinal parasitic nematodes. Inconsistent animal responses to CTs were initially attributed to concentration in the diet, but recent research has highlighted the importance of their molecular structures, as well as concentration, and also the composition of the diet containing the CTs. The importance of CT structural traits cannot be underestimated. Interdisciplinary research is the key to unraveling the relationships between CT traits and bioactivities and will enable future on-farm exploitation of these natural plant compounds. Research is also needed to provide plant breeders with guidelines and screening tools to optimize CT traits, in both the forage and the whole diet. In addition, improvements are needed in the competitiveness and agronomic traits of CT-containing legumes and our understanding of options for their inclusion in ruminant diets. Farmers need varieties that are competitive in mixed swards and have predictable bioactivities. This review covers recent results from multidisciplinary research on sainfoin (Onobrychis Mill. spp.) and provides an overview of current developments with several other tanniniferous forages. Tannin chemistry is now being linked with agronomy, plant breeding, animal nutrition, and parasitology. The past decade has yielded considerable progress but also generated more questions — an enviable consequence of new knowledge

Benefits of Condensed Tannins in Forage Legumes Fed to Ruminants: Importance of Structure, Concentration, and Diet Composition

Condensed tannins (CTs) account for up to 20% of the dry matter in forage legumes used as ruminant feeds. Beneficial animal responses to CTs have included improved growth, milk and wool production, fertility, and reduced methane emissions and ammonia volatilization from dung or urine. Most important is the ability of such forages to combat the effects of gastrointestinal parasitic nematodes. Inconsistent animal responses to CTs were initially attributed to concentration in the diet, but recent research has highlighted the importance of their molecular structures, as well as concentration, and also the composition of the diet containing the CTs. The importance of CT structural traits cannot be underestimated. Interdisciplinary research is the key to unraveling the relationships between CT traits and bioactivities and will enable future on-farm exploitation of these natural plant compounds. Research is also needed to provide plant breeders with guidelines and screening tools to optimize CT traits, in both the forage and the whole diet. In addition, improvements are needed in the competitiveness and agronomic traits of CT-containing legumes and our understanding of options for their inclusion in ruminant diets. Farmers need varieties that are competitive in mixed swards and have predictable bioactivities. This review covers recent results from multidisciplinary research on sainfoin (Onobrychis Mill. spp.) and provides an overview of current developments with several other tanniniferous forages. Tannin chemistry is now being linked with agronomy, plant breeding, animal nutrition, and parasitology. The past decade has yielded considerable progress but also generated more questions-an enviable consequence of new knowledge

The nutritive characteristics of maize silage and maize silage/grass rations for cattle : a thesis presented in partial fulfilment of the requirements for the degree of Master of Agricultural Science in Animal Science at Massey University, 1973

An experiment was conducted to investigate some of the nutritional properties of maize silage, when fed to rising two year old monozygous twin Jersey and Jersey cross cattle, housed indoors. In a preliminary experiment, silages made from maize harvested with two types of harvester were evaluated in terms of digestibility, rate of passage, and the extent of kernel loss in the faeces. Fine chop (conventional) silage (mean particle size 1.24 cm) and coarse chop silage (2.20 cm) were each fed to six animals at restricted levels of intake. The mean retention times of the fine (44.6 hours) and coarse (49.0 hours) chop silages were significantly different (P<0.01) but differences between DM digestibilities (62.7 and 65.1% respectively) were not significant. Undigested faecal kernel loss from both silages was negligible. Intakes of the fine chop silage were slightly higher than those of the coarse chop, but this may have been due to its higher dry matter content. In the main experiment maize silage and grass (ryegrass/clover (MP), and Tama (Ta) in separate trials), in the ratios of 100:0 (t1), 80:20 (t2), 45:55 (t3) and 0:100 (t4), were fed ad lib to four groups of four cattle. The experimental layout was a balanced incomplete block design, and the main parameters measured were digestibility and voluntary intake. Digestibilities rose as the proportion of grass in the rations increased. Approximate OM digestibilities for t2, t3 and t4 were 68.0, 73.0 and 82.0% respectively, however silage (t1) digestibilities were low, and declined from 65.4 to 57.2% over the duration of the experiment (8 weeks). In most instances, comparisons between t3 (or t4) and t1 were highly significant (P<O.01). Voluntary intakes of cattle fed the mixed rations were significantly greater than those of animals fed silage (P<0.05) or grass alone, and responses to the t3 ration were greatest when the Tama was used. When Tama was offered the DM intakes (g/kg BW.75) for t1, t2, t3 and t4 were 95.9, 107.0, 122.3 and 88.9, respectively, and when MP was fed corresponding values were 84.3, 102.1, 108.8 and 101.6. Digestible DM intakes (g/kg BW.75) of the cattle fed silage (51.7) were 27% below those of the cattle fed grass alone (66.5 for both grasses). Intakes of t2 (64.8 (MP), 68.4 (Ta)) were similar to those of t4, whereas t3 resulted in much higher intakes, particularly when Tama was fed (70.8 (MP), 80.7 (Ta)). All comparisons between t1 and the mixed rations were highly significant (P<0.01) and the t1 - t4 comparisons were significant at P<0.025. The results were discussed, and it was concluded that small amounts of fresh pasture can overcome the protein deficiencies of maize silage, and lead to intakes of digestible DM which are similar to those of cattle fed grass alone. Higher levels of grass supplementation resulted in very high intakes

Feeding lucerne silage to beef cattle at three allowances and four feeding frequencies affects circadian patterns of methane emissions, but not emissions per unit of intake

Abstract. The objective of this study was to determine the circadian variation in methane (CH 4 ) emissions from cattle fed lucerne silage at different feeding levels and feeding frequencies, to assist with interpretation of short &apos;snapshot&apos; CH 4 measurements used for predicting daily emissions. Eight Hereford · Friesian heifers (initially 20 months of age) were used in five consecutive periods (P1-5) of 14 days with CH 4 emissions measured using respiration chambers for two consecutive days at the end of each period. Feed was restricted to intakes of~6, 8, 8, 8 and 11 AE 1.3 (ad libitum) kg lucerne silage dry matter (DM), fed in 2, 2, 3, 4 or ad libitum (refilled twice daily) meals per day in P1-5, respectively. Daily CH 4 production (g/day) was lower in P1 than in P2-4 (P &lt; 0.05), which were lower than in P5 (P &lt; 0.05), but CH 4 yield (24.3 AE 1.23 g/kg DM) was unaffected by treatment. Among the five periods, CH 4 emission rate (g/h) before feeding ranged from 1.8 to 6.5 g/h, time to peak CH 4 production after start of feeding ranged from 19 to 40 min and peak CH 4 production rate ranged from 11.1 to 17.5 g/h. The range in hourly CH 4 emission rates during the day decreased with increasing feed intake level, but was unaffected by feeding frequency. In summary, the circadian pattern of CH 4 emissions was affected by feed allowance and feeding frequency, and variation in CH 4 emission rate was reduced with increasing intake, without affecting average daily yield (g CH 4 /kg DM intake)

Special considerations for ruminally-cannulated animals

International audienc

Sheep numbers required for dry matter digestibility evaluations when fed fresh perennial ryegrass or forage rape

Research trials with fresh forages often require accurate and precise measurement of digestibility and variation in digestion between individuals, and the duration of measurement periods needs to be established to ensure reliable data are obtained. The variation is likely to be greater when freshly harvested feeds are given, such as perennial ryegrass (Lolium perenne L.) and forage rape (Brassica napus L.), because the nutrient composition changes over time and in response to weather conditions. Daily feed intake and faeces output data from a digestibility trial with these forages were used to calculate the effects of differing lengths of the measurement period and differing numbers of sheep, on the precision of digestibility, with a view towards development of a protocol. Sixteen lambs aged 8 months and weighing 33 kg at the commencement of the trial were fed either perennial ryegrass or forage rape (8/treatment group) over 2 periods with 35 d between measurements. They had been acclimatised to the diets, having grazed them for 42 d prior to 11 days of indoor measurements. The sheep numbers required for a digestibility trial with different combinations of acclimatisation and measurement period lengths were subsequently calculated for 3 levels of imposed precision upon the estimate of mean dry matter (DM) digestibility. It is recommended that if the standard error of the mean for digestibility is equal to or higher than 5 g/kg DM, and if sheep are already used to a fresh perennial ryegrass or forage rape diet, then a minimum of 6 animals are needed and 4 acclimatisation days being fed individually in metabolic crates followed by 7 days of measurement

A Nutritional Investigation of Major Feed Types and Feed Rations Used in Medium-Scale Dairy Production Systems in Sri Lanka

In this paper, the nutritional quality, digestibility, and chemical composition of major feed types as well as the use of those feeds in rations by medium-scale dairy farmers in the Kurunegala district of Sri Lanka were studied. Nine dairy farms were visited fortnightly over a five-month period to identify the feeds that were commonly used. All farms operated under a stall-feeding system in which a manually mixed ration (MMR) was fed 2&ndash;3 times daily. Four forages were identified: Guinea grass ecotype A (Panicum maximum), called Guinea grass; Hybrid Napier CO-3 (Pennisetum purpureum &times; Pennisetum americanum), called CO-3 grass; Gliricidia (Gliricidia sepium); and maize stover (Zea mays L.), along with three other supplementary feeds (maize silage, barley distillers&rsquo; by-products, and commercially formulated cattle feed). These feeds were subjected to proximate analysis and in vitro digestibility analysis. The metabolisable energy (ME) of the forages ranged from 7.5&ndash;10.0 MJ/kg dry matter (DM), with the ME of Guinea grass and CO-3 grass (7.5 and 8.0 MJ/kg DM, respectively) being lower than that of Gliricidia (10.0 MJ/kg DM). The neutral detergent fibre (NDF) concentration of both Guinea grass and CO-3 grass (both 72% DM) was much higher than that of Gliricidia (47% DM). Crude protein (CP) was higher in Gliricidia (17.5% DM) than in either Guinea grass or CO-3 grass (8.0 and 8.8% DM, respectively). The ME of the supplementary feeds varied between 11.0 and 12.8 MJ/kg DM, while CP varied between 15.0 and 24.0% DM. The daily ME intake of cows was consistently 10% lower than their calculated daily energy requirement; for dry cows, the mean intake was 90 MJ/cow/day supplied vs. 101 MJ required, while for cows in early lactation the mean intake was 126 MJ/cow/day supplied vs. 140 MJ required. The average CP intake of lactating cows (13.5% DM) was inadequate (requirements: 16 to 17.5% DM), while the average CP intake of dry cows (11.8% DM) was satisfactory (requirements: 11 to 12% DM). The current study shows that the majority of the feed types used in these medium-scale dairy farms provide insufficient ME or CP to meet the nutritional requirements of either lactating or dry cows irrespective of the quantity of feed provided