Lick Block Research Articles

Ruminant Lick Blocks, Particularly in China: A Review

A lick block (LB) is a solidified mixture of molasses, urea, minerals, filler, coagulant and binder that is supplemented to livestock mainly in relatively extensive rearing systems. It provides nutrients, such as soluble sugars, proteins, minerals and vitamins to balance dietary intake and can improve rumen fermentation and facilitate digestion and absorption of nutrients. These supplements improve livestock production, reproduction and carcass quality. In addition, LB can partially replace concentrate, serve as a delivery vehicle for additives such as enzymes and drugs and mediate the distribution of grazing livestock. This paper classifies and analyzes representative research; discusses the types, ingredients and current status of the utilization of LB; and systematically reviews the processing technology, quality assessment, influencing factors of intake, action mechanism and application. This review can provide a basis for the development, popularization and application of novel LB products.

The effect of molasses nitrate lick blocks on supplement intake, bodyweight, condition score, blood methaemoglobin concentration and herd scale methane emissions in Bos indicus cows grazing poor quality forage

Context The Australian government has approved a greenhouse gas (GHG) offset method that requires cattle to consume nitrate in the form of a lick block. Field studies demonstrating the effectiveness of this methodology have not been previously reported. Aims This experiment was conducted to determine the effects on productivity and health when nitrate lick blocks were provided as a supplement to grazing beef cattle. We hypothesised that beef cattle given access to nitrate lick blocks would have similar productivity compared with cattle offered urea lick blocks. Methods Bos indicus breeding cows (n = 76) grazed a 467-ha paddock near Charters Towers, Queensland, between May and November 2014. A two-way remote automatic drafting system enabled allocation of cattle to different treatments while grazing in a common paddock. Treatments were 30% urea lick blocks (30U), or molasses nitrate lick blocks (MNB). At monthly intervals liveweight (LW), body condition score (BCS), and blood methaemoglobin concentration were recorded. Estimates of individual supplement intake were made on three separate occasions using a lithium marker technique. Results Mean daily supplement intake (±s.e.m.) of 30U (122 ± 13 g) was greater (P < 0.001) than MNB (67 ± 8 g). Lesser MNB intake was associated with greater variability for individual supplement intake, a greater proportion of non-consumers of supplement during July (P < 0.05) and reduced voluntary supplement intake until October (P < 0.001). Increasing MNB consumption during October and November was accompanied by elevated blood methaemoglobin concentration (P < 0.001). It was estimated that cattle offered MNB had insufficient supplementary nitrogen intake throughout the study to resolve rumen degradable nitrogen deficiency from grazed forage. Consequently, cattle provided access to MNB demonstrated conceptus free liveweight loss and lesser BCS compared with cattle treated with 30U (P < 0.001). Conclusion Nitrate lick blocks were ineffective as a dual-purpose non-protein nitrogen supplement and methane mitigant for beef cattle grazing poor quality forage. Further field experiments are required to determine if there may be situations where this GHG offset methodology is efficacious. Implications Caution is advised in implementing GHG mitigation methods that involve the use of nitrate lick blocks.

Effective incorporation of xylanase and phytase in lick blocks for grazing livestock

The addition of feed enzymes to livestock diets has contributed to significant increases in productivity over recent decades. The use of enzymes has been the most common in systems where enzyme delivery and diets can be easily managed, such as for poultry and pigs. Lick blocks supplement the forage diets of ruminants with nitrogen and minerals but not enzymes, due in part to concerns that block manufacturing temperatures would lead to unacceptable levels of enzyme degradation. The nutritional value of low quality pasture could be improved using enzyme supplemented lick blocks if enzymes remain active at the high lick block manufacturing temperatures. The aim of this study was to determine the extent of xylanase and phytase activity survival when exposed to the production of hot poured lick blocks. Lick block formulations and methods of manufacturing vary, so two enzyme containing molasses-based lick blocks were produced, one at 60°C and another at 100°C. The results showed that both the xylanase and phytase enzymes have high levels of survival at 60°C. In the 100°C lick block, the phytase displayed a half-life of ~10 min, whereas the xylanase retained 90% of the original activity after 30 min of exposure. The inherent thermostability of the enzymes were critical factors for enzyme survival and the enzymes were more stable in the lick blocks than in solution. The results indicate that it should be possible to add enzymes to lick blocks manufactured at elevated temperatures to enhance low quality pasture and thereby aid ruminant digestion and production.

Suitability of group-level oral fluid sampling in ruminant populations for lumpy skin disease virus detection

The geographic expansion of Lumpy skin disease (LSD) from the near East into the European Union highlighted again the need for appropriate disease detection tools applicable to animal host populations where access to individual animals is difficult. This is of particular importance considering that the clinical manifestation of LSD is often mild making early disease detection challenging under the above-mentioned conditions. Building on positive experiences of group-level oral fluid sampling for pathogen detection as it is known to work for swine herds and wild boar, the concept was transferred to ruminants. Two groups of six cattle were infected experimentally with Lumpy skin disease virus (LSDV) under controlled conditions. Blood as well as oropharyngeal and nasal swab samples were collected at regular intervals. Group samples were obtained by placing cotton gauze around a salt lick block provided commonly as dietary supplement. Pieces of the gauze with visible signs of manipulation were tested in parallel to samples obtained from individual animals. Genome load analysis by qPCR technology revealed LSDV detection window starting from day 2 post infection until day 28 post infection, the end of the animal trial. At the individual level, detection periods varied between animals and type of sample and included intermitted detection. The accumulative character of the alternative sampling method makes it suitable to detect LSDV DNA at group-level even at times of the infection where a selective sampling of individuals from a group – as normally done in LSD surveillance – would have most likely failed in the detection.

62 Immunomodulation of Supplemental Omega-3 Fatty Acids in Horses Delivered Via a Commercially Available Molasses Lick Block.

62 Immunomodulation of Supplemental Omega-3 Fatty Acids in Horses Delivered Via a Commercially Available Molasses Lick Block.

Dietary supplements during the cold season increase rumen microbial abundance and improve rumen epithelium development in Tibetan sheep.

Livestock on the Qinghai-Tibetan Plateau are faced with extreme harsh winters and are often in negative energy balance during this period. Dietary supplementation can improve growth performance of Tibetan sheep and, consequently, we hypothesized that it would also increase microbial abundance and rumen epithelium development. To test this hypothesis, we examined the effect of feed supplementation during the cold season on rumen microbes, fermentation, epithelium development, and absorptive capability in Tibetan sheep. Eighteen 1-yr-old ewes (BW = 29.4 ± 1.79, kg) were offered oat hay ad libitum for 60 d and divided randomly into three groups: 1) no supplement; control group (CON); 2) urea-molasses lick block supplement (BS); and 3) concentrate feed supplement (CS). The ADG of CS ewes (143.3, g/d) was greater (P < 0.05) than BS ewes (87.9, g/d), which was greater (P < 0.05) than CON ewes (44.5, g/d). Serum concentrations of GH, IGF-1, and IGF-2 in the CS and BS groups were greater than in the CON group (P < 0.05). Greater relative abundance of protozoa, Ruminococcus albus, Fibrobacter succinogenes, Streptococcus bovis, and Ruminobacter amylophilus was observed in the CS and BS groups than in the CON group (P < 0.05), and relative abundances of rumen fungi, Butyrivibrio fibrisolvens, and Prevotella ruminicola in the CS group were greater than in the BS and CON groups (P < 0.05). Ruminal total VFA, ammonia, and microbial protein concentrations in the CS and BS groups were greater than in the CON group (P < 0.05), and in the CS group were greater than in the BS group (P < 0.05). Ruminal papillae width and surface area in the CS and BS groups were greater than in the CON group (P < 0.05), while in the CS group were greater than in the BS group (P < 0.05). The mRNA expressions of IGFBP5, NHE1 (sodium/hydrogen antiporter, isoform 1), DRA (downregulated in adenoma), and Na+/K+-ATPase (sodium/potassium ATPase pump) in ruminal epithelium were greater in the CS and BS groups than in the CON group (P < 0.05), and in the CS group was greater than in the BS group (P < 0.05), while NHE3 (sodium/hydrogen antiporter, isoform 3), MCT1 (monocarboxylate transporter 1), and MCT4 (monocarboxylate transporter 4) mRNA expressions in the CS group were greater than in the BS and CON groups (P < 0.05). It was concluded that supplementing Tibetan sheep during the cold season increases rumen microbial abundance and improves fermentation parameters, rumen epithelium development, and absorptive capability.

Effect of supplements during the cold season on the reproductive system in prepubertal Tibetan sheep ewes.

We examined the development of the reproductive system in prepubertal Tibetan sheep ewes when fed only oat hay (CON) or supplemented with either lick blocks (BS) or concentrate feed (CS) during the cold season. The average daily gain of the CS ewes was greater than that of the BS ewes (P<0.05), which was greater than that of the CON ewes. The same pattern was observed in the number of ovarian follicles (P<0.001), that is, CS>BS>CON. Serum concentrations of gonadotropin-releasing hormone, follicle-stimulating hormone, luteotrophic hormone, estradiol and progesterone in the CS and BS groups were higher than in the CON group (P<0.05). The messenger RNA (mRNA) expression of KiSS-1, GPR54 (G protein-coupled receptor 54), ERα (estradiol receptor α) in the hypothalamic anteroventral periventricular area of the CS group were higher than in both the BS and CON groups (P<0.05), while the BS group was higher than in the CON group (P<0.05). Similar differences among groups were observed for gonadotropin-releasing hormone receptor mRNA expression in the pituitary, follicle-stimulating hormone receptor and luteinizing hormone receptor mRNA expression in the ovary. These results indicated that the KiSS1/GPR54 system was more active with nutrition or trace mineral supplementation during the cold season. The system stimulated the hypothalamic-pituitary-gonadal axis and enhanced folliclar development in prepubertal Tibetan sheep ewes. We concluded that energy, protein and trace minerals supplements could improve the reproductive performance of Tibetan sheep on the Qinghai-Tibetan plateau.

Effect of various antiparasitic treatments on the economic value of production in a sheep flock

Our objective was to compare the effects of a conventional antiparasitic chemical drug and a lick block containing plant-based compounds on the economic value of lambs. Ewes and their new-born offspring were allocated among three treatments: a group receiving standard drenching with an albendazole-containing drug, a group supplied with a lick block containing essential oils from 10 plant species having antiparasitic properties, and a control group that was not dewormed. During the experiment, all lambs were given periodic birth weighings at 28, 56, 70 and 100 days of age. The results obtained were the basis for the estimation of the economic value of lambs reared in particular experimental groups of the observed animals. The average price earned for slaughter material in each weight standard was used to calculate the differences between the groups. The current prices were made available by the Regional Association of Sheep and Goat Breeders in Lublin. All lambs (live at 56, 70, 100 and 120 days) were included in calculations of the average value of the animals. In the case of lambs falling within the standard 0 to 12 kg, a value for 0 PLN per kilogram was assumed because of the lack of sales potential. At 56 days, the value of the lambs in the group receiving feed with the addition of essential oils was 11.90% higher than that of the lambs from control group. At 70, 100 and 120 days, the value of those lambs was higher than that of the lambs from control group by 21.13%, 4.99% and 5.51%, respectively. The value of the lambs from the group receiving standard drenching with an albendazole-containing drug was similar to that of the lambs from the undewormed group. The results of the research indicate that it is beneficial to use natural substances in the prevention of parasitic invasion. The use of natural methods to reduce parasitic infestations will reduce the application of chemicals, which is extremely important due to the increasing resistance of parasites and the preferences of consumers, who search for products free of harmful residues of medicinal substances.

Vitamin A deficiency in Bos indicus heifers fed a wheat straw diet cannot be corrected with algae lick blocks or intramuscular injectable retinyl palmitate treatments

Serum and liver retinol concentrations and blood β-carotene concentrations were studied in 30 Bos indicus heifers rendered deficient of vitamin A over 180 days and then given treatments of access to algae-based lick blocks (n = 10), injectable retinyl palmitate and molasses-based lick blocks (n = 10), or a negative control given access to molasses-based lick blocks only (n = 10). All heifers became deficient in blood and liver vitamin A, as well as blood β-carotene by 180 days. There was no treatment effect on bodyweight (P = 0.347). However, a highly significant effect of time (P = 0.001) was detected where all heifers achieved an average daily gain of 0.74 kg/day throughout the depletion phase of the study but lost 0.150 kg/day during the repletion phase. The concentrations of serum and liver retinol and blood β-carotene were not different between treatment groups (P = 0.362, P = 0.535 and P = 0.839) during the depletion or repletion phases of the study. All heifers continued to be rendered deficient in the concentrations of serum and liver retinol and blood β-carotene throughout the experiment demonstrating a highly significant effect of time (P = 0.001). Injectable retinyl palmitate (818 100 IU retinol) or access to algal lick blocks (4180 IU retinol) did not elevate blood or liver retinol concentrations in heifers rendered deficient of vitamin A. It is speculated that the protein-deficient diet fed to the heifers had an adverse effect on the blood retinol transport proteins.

An evaluation of carbon offset supplementation options for beef production systems on coastal speargrass in central Queensland, Australia

In 2014, the Australian Government implemented the Emissions Reduction Fund to offer incentives for businesses to reduce greenhouse gas (GHG) emissions by following approved methods. Beef cattle businesses in northern Australia can participate by applying the ‘reducing GHG emissions by feeding nitrates to beef cattle’ methodology and the ‘beef cattle herd management’ methods. The nitrate (NO3) method requires that each baseline area must demonstrate a history of urea use. Projects earn Australian carbon credit units (ACCU) for reducing enteric methane emissions by substituting NO3 for urea at the same amount of fed nitrogen. NO3 must be fed in the form of a lick block because most operations do not have labour or equipment to manage daily supplementation. NO3 concentrations, after a 2-week adaptation period, must not exceed 50 g NO3/adult animal equivalent per day or 7 g NO3/kg dry matter intake per day to reduce the risk of NO3 toxicity. There is also a ‘beef cattle herd management’ method, approved in 2015, that covers activities that improve the herd emission intensity (emissions per unit of product sold) through change in the diet or management. The present study was conducted to compare the required ACCU or supplement prices for a 2% return on capital when feeding a low or high supplement concentration to breeding stock of either (1) urea, (2) three different forms of NO3 or (3) cottonseed meal (CSM), at N concentrations equivalent to 25 or 50 g urea/animal equivalent, to fasten steer entry to a feedlot (backgrounding), in a typical breeder herd on the coastal speargrass land types in central Queensland. Monte Carlo simulations were run using the software @risk, with probability functions used for (1) urea, NO3 and CSM prices, (2) GHG mitigation, (3) livestock prices and (4) carbon price. Increasing the weight of steers at a set turnoff month by feeding CSM was found to be the most cost-effective option, with or without including the offset income. The required ACCU prices for a 2% return on capital were an order of magnitude higher than were indicative carbon prices in 2015 for the three forms of NO3. The likely costs of participating in ERF projects would reduce the return on capital for all mitigation options.

Supplementation of Solid Ex-Decanter on Performance of Cattle Fed Palm Fruit By-Products

The objective of this study was to evaluate the potential of palm fruit by-products as feed supplement to increase weaned calves performance. Solid ex-decanter were combined with multi mineral and utilized as feed supplement fo form a lick block. Ten weaned calves 6 months old (122.34 ± 20.25 kg) were randomly categorized into 2 groups. Control weaned calves receive no Solid Ex-Decanter Multi-Nutrient Block (SEDMB) supplementation and treated calf were given continuously. The experiment was conducted at rural farmin areas in Darmasraya and calves feed total mix ratio formulated with palm fruuit by product based. Measured parameter were daily weight gain (DWG), body condition score (BCS) feed consumption, feed conversion, in vivo dry matter and organic matter digestibility. The treatment were significanly different (p 0.05) on feed consumption, dry matter and organic matter digestibility. SEDMB supplementation on weaned calves performance of Simbrah Breed showed the effectiveness of feed consumption. Keywords: Solid ex-decanter, calves, supplement, palm fruit by-products.

Use of a nutritional lick block and higher feeding levels to reduce aggression and provide enrichment for sows in groups

Animal Production Science (continuing Australian Journal of Experimental Agriculture) publishes original research into applied agriculture including animal production, animal-plant interactions, pasture and fodder crops, field crops, extension and horticulture

Effect of various antiparasitic treatments on lamb growth and mortality

Our objective was to compare the effects of a conventional anti-parasitic chemical drug and a lick block containing plant-based compounds on lamb growth and mortality. Ewes and their new-born offspring were allocated among three treatments: a group receiving standard drenching with an albendazole containing drug, a group supplied with a lick block containing essential oils from 10 plant species having anti-parasitic properties and a control group that was not dewormed. Lamb growth was evaluated as daily gain at various time periods between birth and 120 days-of-age. Lamb mortality was monitored in all groups. At the end of the fattening period, lamb meatiness and fatness were assessed by in vivo ultrasound measurement. Parasite infection of lambs at 28, 42, 56, 70, 100 and 120 days-of-age was assessed by examination of feces for parasite oocytes. Results established that the lick block, as did the chemical agent, effectively reduced coccidian invasion in lambs. It should be noted, however, that parasite infection in the experimental animals was relatively low, which allowed the use of moderately strong preparations as compared to conventional anti-parasitic drugs. The lick block treatment also had a beneficial effect on growth and body development of the lambs. Results suggest the need for further research on prophylaxis strategies with plant-origin anti-parasitic substances. Moreover, the provision of anti-parasitic substances in enriched lick blocks could be beneficial in optimal timing of treatments and for preventing weight gain declines after conventional drenching.

Intake of selected minerals on commercial dairy herds in central and northern England in comparison with requirements

SUMMARYOverfeeding minerals to dairy herds will raise diet cost, increase their excretion into the environment and for minerals such as copper (Cu) can lead to poisoning and cow death. In contrast, underfeeding may compromise cow performance, health and fertility. Despite this, the level of mineral intake on commercial dairy units is poorly documented. To determine the mineral intake on commercial dairy herds in central and northern England over the winter of 2011/12 and compare these to recommended levels, samples of compound feed, forage mix, supplementary sources (including lick blocks, rumen boluses, free access minerals and drenches) and drinking water were collected from 50 herds over the winter feeding period and analysed for 10 macro and trace minerals. For cows in early lactation the mean dietary concentration of phosphorus (P) was 4·5 g/kg dry matter (DM) (s.d. 0·70), 0·1 g/kg DM below UK requirements, and for calcium (Ca) was 10·2 g/kg DM (s.d. 2·94), 5·9 g/kg DM above requirements. Trace mineral concentrations were also in excess of requirements in early lactation, with a mean dietary Cu concentration of 28 mg/kg DM (s.d. 9·85), approximately 18 mg/kg DM above UK requirements, with 32 of the 50 herds feeding above the UK industry recommended maximum of 20 mg/kg DM and 6 above the EU limit of 40 mg/kg DM. Dietary mineral concentrations were generally lower in late lactation but still higher than requirements. The forage mix (including supplementary feeds and minerals) contributed the greatest amount of minerals, with percentile ranges (10th–90th) of 2·1–4·4 g/kg diet DM for P, 1·4–3·2 g/kg diet DM for magnesium (Mg) and 5·3–25·0 mg/kg diet DM for Cu. Compounds fed in the milking parlour supplied (10th–90th percentile) 0·0–1·4 g P g/kg diet DM, 0·0–1·2 g Mg/kg diet DM and 0·0–11·6 mg Cu/kg diet DM. For the upper 90th percentile of dairy herds, water supplied proportionally 0·08 of Ca requirements recommended in early lactation in the UK, whilst supplementary mineral sources supplied up to 0·64 of Cu and 0·43 of zinc (Zn) requirements. High dietary concentrations of Cu were not justified by the presence of the dietary antagonist molybdenum (Mo), with no relationship between the two minerals in early or late lactation diets. In conclusion, most dairy herds were feeding excess amounts of minerals over the winter feeding period when compared to UK or other national recommended guidelines, with the implications of a higher diet cost and negative impact on the environment and animal health.

RETRACTED: Benefits of different urea supplementation methods on the production performances of Merino sheep

The impact of urea supplementation of sheep feed was examined in two experiments. In Experiment 1, 48 8-month-old Merino wethers were randomised into three groups by liveweight and each group was fed one of three diets: (1) untreated oaten chaff hay; (2) hay treated with urea in-paddock (pre-experiment); or (3) hay treated with a 2% urea solution using a feed mixer. In Experiment 2, 48 4-month-old Merino ewes were randomised into three groups and each group received one of the following roughages: (1) untreated oaten chaff hay, (2) hay treated with a 2% urea solution in a feed mixer, or (3) a 20 kg urea lick block. Both experiments lasted 40 days, and sheep liveweight (kg), average feed intake (g/day), average daily gain (ADG) and body condition score (BCS) were recorded. Ruminal fluid and blood samples were collected on days 20 and 40 from animals in Experiment 1. Sheep supplemented with additional urea had a greater average dry matter (DM) intake (Experiment 1, P = 0.038; Experiment 2, P = 0.001), ADG (Experiment 1, P = 0.043; Experiment 2, P = 0.041) and average final liveweight (Experiment 1, P = 0.048), compared to sheep receiving no additional supplementary urea. On both days 20 and 40 in Experiment 1, blood analyses revealed that urea supplemented sheep had elevated levels of urea, creatine kinase and total protein (P <0.05). Urea supplementation most likely influenced blood urea and total protein concentrations, as supplemented sheep had an increased crude protein intake (through increased feed intake of urea treated roughage with a higher crude protein percentage). By providing additional urea, the DM intake of sheep in both experiments was increased and offers a practical strategy when providing supplementation to sheep. The practice can benefit sheep production by increasing the nutritional value and digestibility of low energy crop stubbles, when fed over dry summer months to help maintain BCS.

Effects of supplementary urea‑minerals lick block on the kinetics of fibre digestion, nutrient digestibility and nitrogen utilization of low quality roughages

Three yearling lambs with a rumen cannula were used to investigate the effects of supplementation with an urea-minerals lick block (ULB) on the kinetics of ruminal fibre digestion, nutrient digestibility and nitrogen (N) utilization of rice straw (RS), ammonia bicarbonate (AB)treated RS (ABRS) and hay prepared from natural pasture. The digestibility of dry matter and organic matter of RS increased by 13.1% and 12.7% (P<0.05) when the diet was supplemented with ULB, and approached to that of ABRS, indicating that the effect of ULB on digestibility of RS is similar to that of AB treatment. The digestibility of ABRS was slightly improved by the ULB feeding. Nitrogen retention was highest in lambs fed on ABRS alone, followed by hay with ULB, and was lowest in animals fed on RS with ULB. However, both the amount and proportion of N retention to N intake were enhanced by ULB supplementation to lambs fed on hay. The proportion of N retained to N digested decreased due to ULB supplementation to lambs fed on RS or ABRS. Supplementing ULB did not greatly influence the rumen degradation of either dry matter or crude protein in each of the three diets. RS and hay had similar values in the potential extent of digestion (PED) and digestion rate of PED (kd) of fibrous materials, but the discrete lag time for RS was lower than that for hay. The AB treatment significantly increased the PED (P<0.05) and kd (P<0.05) of RS. Neither the PED nor kd for RS and ABRS was influenced by ULB supplementation, but the kd for hay significantly increased due to ULB. The lag time for hay was also shortened by the ULB feeding. The ULB improved the digestion of fibre in the rumen of lambs fed on low quality roughage. It is inferred that while ULB is effective in increasing nutrient digestibility of low quality roughages by improving ruminal fibre digestion. A synchronized supply of N and energy to rumen microbes should be considered to improve the efficiency of N utilization when the basal diet is ammoniated straw.

Free-choice consumption of mineral lick blocks by fattening lambs fed ad libitum alfalfa hay and concentrates with different trace mineral content

The objective of this study was to evaluate the ability of lambs to regulate intake of mineral lick blocks (MLBs) with different trace mineral content when alfalfa hay and concentrates, also with a different trace mineral content, were available to lambs for ad libitum consumption. Twelve 4-month-old purebred Karagouniko lambs were divided into three groups, pen housed individually, and fed unchopped alfalfa hay and concentrates ad libitum. The three concentrates used consisted of a basal concentrate food supplemented (TM+) or not (TM−) with trace elements and a vitamin premix. This basal food of the third group (3TM) was supplemented with a premix in which the trace minerals added were three times the amount of the control group, TM+. The experiment lasted 66 days. The first 31 days were used as an adaptation period, and from the 32nd day two different MLBs were put in each pen. One of the MLBs was white in colour while the other was light pink and had a three-fold greater trace mineral content compared to the white one. Two weeks following the introduction of the MLBs (adaptation period), the behaviour of lambs was video recorded for 48 h per week for 3 weeks. Food and water intake and MLB consumption were recorded regularly and the Cu and Zn concentrations were determined in the blood plasma and the liver of the lambs. The average daily MLB intake, the number of visits to the MLBs, and the time spent by the lambs licking the MLBs were higher for the group TM− and lower for the 3TM group. However, the daily mineral intake from the ingested MLB represented only a very small proportion of the total mineral intake of the animals. The differences among the groups in plasma and liver Cu and Zn concentrations represented the quantities ingested via the diet rather the MLBs. In conclusion, the results of this experiment did not show clearly that the lambs could regulate the intake of MLB because they failed to exhibit a ‘mineral wisdom’ related to their physiological needs and mineral status.

Salt block consumption by high yielding dairy cows fed rations with different amounts of NaCl

The effect of different NaCl contents in the rations for dairy cows on salt lick block (99% NaCl) intake was studied and the intake of 5 different commercial blocks was evaluated. After mixing, the ration containing 60% roughage (whole crop silage and grass silage) and 40% concentrates (maize ear ground, soya bean meal and compound feed) was offered, to two groups each of 32 cows. The only difference in rations between the two groups was that either no NaCl (low salt:LS) or 0.8% NaCl (high salt:HS) was added to the compound feed resulting in Na +-contents in the rations of 1.0 and 1.7 g per kg dry matter, respectively. Five commercial hardened salt blocks were offered under the same conditions to both groups. Cows on LS consumed significantly more from the lick blocks than cows on HS (34 versus 24 g per cow per day) whereas no differences in DM-intake and milk yield were observed. This suggests a nutritional need for NaCl when dairy cows were fed rations containing from just enough (1.0 g/kg DM) to an adequate (1.7 g/kg DM) supply of Na +. Significant differences in lick block intake were observed between blocks related to hardness and/or palatability. Although nearly all the cows used the lick blocks, block intake varied highly between cows from both groups from nearly 0 to max. 70 g per cow per day.

Effect of levels of concentrate with lick block on nutritive values of some roughages

Effect of levels of concentrate with lick block on nutritive values of some roughages

Feeding rice straw supplemented with urea-molasses lick block to lactating cows in Bhutan

Feeding rice straw supplemented with urea-molasses lick block to lactating cows in Bhutan