Effect of water restriction on feeding and metabolism in dairy cows

Modeling the effect of ambient temperature on reticulorumen temperature, and drinking and eating behaviors of late-lactation dairy cows during colder seasons

Dairy cows may suffer thermal stress during the colder seasons especially due to their open-air housing systems. Free water temperature (FWT) and feed temperature (FT) are dependent on ambient temperature (AT) and can be critical for maintaining body and reticulorumen temperature (RT) in cold conditions. The objective of this study was to determine the effects of FWT and FT on RT fluctuations, and of AT on RT and drinking and eating behaviors in late-lactation cows during cold exposure. Data were collected from 16 multiparous lactating cows for four 6-d periods during the autumn and winter seasons. The cows (224 ± 36 days in milk; mean ± SD) had an average milk yield (MY) of 24.8 ± 4.97 kg/d and RT of 38.84 ± 0.163 °C. Daily average AT ranged from 4.38 to 17.25 °C. The effects of the temperature and amount of the ingested water or feed on RT change and recovery time, and the effect of the daily AT on RT, feed and water intake, and drinking, eating, and rumination behaviors were analyzed using the generalized additive mixed model framework. Reticulorumen temperature change and recovery time were affected by FWT (+0.0596 °C/°C and -1.27 min/°C, respectively), but not by FT. The amount of the ingested free water and feed affected RT change (-0.108 °C/kg drink size and -0.150 °C/kg meal size, respectively), and RT recovery time (+2.13 min/kg drink size and + 3.71 min/kg meal size, respectively). Colder AT decreased RT by 0.0151 °C/°C between 9.91 and 17.25 °C AT. Cows increased DM intake (DMI) by 0.365 kg/d per 1 °C drop in AT below 10.63 °C, but with no increase in MY. In fact, MY:DMI decreased by 0.0106/°C as AT dropped from 17.25 to 4.38 °C. Free water intake (FWI) was reduced by 0.0856 FWI:DMI/°C as AT decreased from 17.25 to 8.27 °C. Cold exposure influenced animal behavior with fewer drink and meal bouts (-0.432 and -0.290 bouts/d, respectively), larger drink sizes (+0.100 kg/bout), and shorter rumination time (-5.31 min/d) per 1 °C decrease in AT from 17.25 °C to 8.77, 12.53, 4.38, and 10.32 °C, respectively. In conclusion, exposure to low AT increased feed intake, reduced water intake, and changes in eating, drinking and rumination behaviors of dairy cows in late lactation. Additionally, the consequences of cold exposure on cows may be aggravated by ingestion of feed and free water at temperatures lower than the body, potentially impacting feed efficiency due to the extra energetic cost of thermoregulation.

Long-term impacts of 48-h water and feed deprivation on blood and performance responses of grazing Bos indicus Nellore heifers

The study investigated the effects of 48-h water and feed deprivation on blood and the performance of grazing Nellore (Bos indicus) heifers. Twenty-four Nellore heifers (initial body weight [BW] = 238 ± 10 kg; age = 16 ± 2 mo), were ranked by initial BW and age and randomly assigned to one of the two treatments: (1) grazing animals with free access to pasture, water, and mineral-mix (CON; n = 12), or (2) the same grazing conditions but deprived of pasture, water, and mineral-mix for 48 h (DPR; n = 12). The paddocks consisted of Urochloa brizantha cv. Marandu, using a continuous and fixed stocking rate. The experiment lasted 225 d, with the first 14 d considered as the adaptation period (days -14 to -1) and the subsequent 211 d as the evaluation period (days 0 to 211). From days 0 to 2, treatments were applied by keeping the DPR heifers in pens and reintegrating them into the experimental area after a 48-h water and feed deprivation. Individual full BW was recorded on days -14, -13, -1, before (day 0) and after (day 2) treatment application, and on days 6, 11, 12, 41, 42, 210, and 211. Blood samples were collected in the morning on days 0, 2, 6, 12, and 211. A treatment effect was detected (P < 0.001) for shrink BW from days 0 to 2, which was greater (P < 0.001) in DPR vs. CON heifers. Subsequently, DPR animals were lighter (P < 0.001) compared with CON heifers by the end of the deprivation period (day 2). From days 4 to 211, DPR was lighter (P < 0.001) compared with CON heifers after treatment application and for the entire experimental period. In the first 10 d after treatment application (days 2 to 12), DPR heifers showed a partial compensatory average daily gain (ADG; P < 0.001) compared with CON heifers, while no significant differences were observed in ADG between the treatments from days 12 to 42 and 42 to 211 (P > 0.420). Overall ADG (days 2 to 211) was greater (P < 0.001) for DPR vs. CON heifers. All serum variables, except AST, were higher (P < 0.001) in DPR than in CON heifers on day 2 after treatment application. Our study demonstrates that grazing Nellore heifers subjected to 48-h water and feed deprivation experienced significant alterations in their blood metabolites and BW immediately after the stressful event. Although the deprived heifers partially compensated for their BW loss in the early days post-deprivation, they remained 12 kg lighter than the non-deprived animals throughout the production cycle.

Developing models to predict feces and urine excretion in Japanese Black fattening steer by multiple regression analysis

The objective of this study was to develop models for predicting the amount of feces and urine excreted by Japanese Black fattening steer using a dataset of 119 digestion trials for a total of 46 animals. Correlation analysis was used to analyze the relationships between feces and urine excretion and feed intake, feed digestibility, and nitrogen balance. Multiple regression analysis was conducted to develop models for predicting the amount of feces and urine excreted using the explanatory variables selected from various animal and dietary parameters based on P-value (<0.10) and variance inflation factor (<3.0). Resultingly, dry matter intake was a primary predictor of feces excreted. The prediction equation for the amount of feces excretion as a function of body weight, dry matter intake, and calculated total digestible nutrients fits the data well (adjusted coefficient of determination [adj R2 ] = 0.519, root mean square error = 1.57). Furthermore, the nitrogen content in the urine was the primary predictor of the urine excretion amount. Thus, the prediction equation for the amount of urine excreted using the nitrogen content in urine yielded a highly accurate model (adj R2  = 0.813, root mean square error = 4.12).

Dairy Cattle Rumen Bolus Developments with Special Regard to the Applicable Artificial Intelligence (AI) Methods

It is a well-known worldwide trend to increase the number of animals on dairy farms and to reduce human labor costs. At the same time, there is a growing need to ensure economical animal husbandry and animal welfare. One way to resolve the two conflicting demands is to continuously monitor the animals. In this article, rumen bolus sensor techniques are reviewed, as they can provide lifelong monitoring due to their implementation. The applied sensory modalities are reviewed also using data transmission and data-processing techniques. During the processing of the literature, we have given priority to artificial intelligence methods, the application of which can represent a significant development in this field. Recommendations are also given regarding the applicable hardware and data analysis technologies. Data processing is executed on at least four levels from measurement to integrated analysis. We concluded that significant results can be achieved in this field only if the modern tools of computer science and intelligent data analysis are used at all levels.

Heat stress develops with increased total-tract gut permeability, and dietary organic acid and pure botanical supplementation partly restores lactation performance in Holstein dairy cows

To evaluate the effects of heat stress (HS) conditions and dietary organic acid and pure botanical (OA/PB) supplementation on gut permeability and milk production, we enrolled 46 multiparous Holstein cows [208 ± 4.65 dry matter intake (DMI; mean ± SD), 3.0 ± 0.42 lactation, 122 ± 4.92 d pregnant, and 39.2 ± 0.26 kg of milk yield] in a study with a completely randomized design. Cows were assigned to 1 of 4 groups: thermoneutral conditions (TN-Con, n = 12), HS conditions (HS-Con, n = 12), thermoneutral conditions pair-fed to HS-Con (TN-PF, n = 12), or HS supplemented with OA/PB [75 mg/kg of body weight (BW); 25% citric acid, 16.7% sorbic acid, 1.7% thymol, 1.0% vanillin, and 55.6% triglyceride; HS-OAPB, n = 10]. Supplements were delivered twice daily by top-dress; all cows not supplemented with OA/PB received an equivalent amount of the triglyceride used for microencapsulation of the OA/PB supplement as a top-dress. Cows were maintained in thermoneutrality [temperature-humidity index (THI) = 68] during a 7-d acclimation and covariate period. Thereafter, cows remained in thermoneutral conditions or were moved to HS conditions (THI: diurnal change 74 to 82) for 14 d. Cows were milked twice daily. Clinical assessments and BW were recorded, blood was sampled, and gastrointestinal permeability measurements were repeatedly evaluated. The mixed model included fixed effects of treatment, time, and their interaction. Rectal and skin temperatures and respiration rates were greater in HS-Con and HS-OAPB relative to TN-Con. Dry matter intake, water intake, and yields of energy-corrected milk (ECM), protein, and lactose were lower in HS-Con relative to HS-OAPB. Nitrogen efficiency was improved in HS-OAPB relative to HS-Con. Compared with TN-Con and TN-PF, milk yield and ECM were lower in HS-Con cows. Total-tract gastrointestinal permeability measured at d 3 of treatment was greater in HS-Con relative to TN-Con or TN-PF. Plasma total fatty acid concentrations were reduced, whereas insulin concentrations were increased in HS-Con relative to TN-PF. We conclude that exposure to a heat-stress environment increases total-tract gastrointestinal permeability. This study highlights important mechanisms that might account for milk production losses caused by heat stress, independent of changes in DMI. Our observations also suggest that dietary supplementation of OA/PB is a means to partly restore ECM production and improve nitrogen efficiency in dairy cattle experiencing heat stress.

A review on water intake in dairy cattle: associated factors, management practices, and corresponding effects

In this changing climate scenario, the availability of potable water has become scarce for both humans and animals in many parts of the world. Continuous supply of water is crucial for animals' life as well as different body and sanitary maintenance needs. Water availability has a direct and indirect role in clenching thirst, feeding, cleaning of animals and their environment, and other dairy operations. Water intake by dairy animals is affected by several factors including body weight of animals, genetic makeup, dry matter intake, mineral content of feed offered, milk productivity, environmental conditions, and water temperature. Behavioral patterns of dairy animals are adversely affected by restriction of water supply to them. Researchers have recommended that ad libitum water supply should be assured to the farm animals to avoid any negative effect on their health and performances. In the recent years, there is growing interest in quantifying the effects of restricted water supply to dairy animals. Many studies have demonstrated that the availability of potable water for animals will be a great challenge soon. Therefore, the present review paper has been formulated to gain better understanding of the factors affecting water intake in dairy animals and management strategies to ensure availability of water resources essential for their health, production, and well-being.

Characterization of body composition and liver epigenetic markers during periods of negative energy balance and subsequent compensatory growth in postpubertal beef bulls

This study aimed to characterize the effects of dietary restriction and subsequent re-alimentation on body composition and hepatic gene expression of epigenetic markers of DNA methylation, RNA m6A methylation, and histone acetylation in the liver of postpubertal beef bulls. Twelve Angus × Hereford crossbred bulls (n = 6, 23 ± 0.55 mo [young bulls], 558 ± 6.1 kg; and n = 6, 47 ± 1.2 mo [mature bulls], 740 ± 30.5 kg) were submitted to two dietary regimes per offering of the same hay: low plane of nutrition (90 d) and compensatory growth (90 d). Each animal acted as its own control and were fed Beardless wheat (Triticum aestivum) hay and mineral mix during the trial. Statistical analyses were performed using SAS 9.4 following a pre-post repeated measures design. Bulls in negative energy balance (NEB) decreased (P < 0.001) empty body weight (EBW; 23.1% [-139.1 kg]), empty body fat (EBF; 39.8% [-85.4 kg]), and empty body protein (EBP; 14.9% [-13.5 kg]) and fully recovered at the end of the trial. Body fat accounted for 77.1% of daily changes in body energy status, whereas body protein accounted for only 22.9% (P < 0.001). Relative abundance of epigenetic markers transcripts was analyzed via qPCR. Bulls at NEB tended (P ≤ 0.097) to increase gene expression of epigenetic markers of RNA m6A methylation (METTL14, VIRMA, and WTAP) and increased (P ≤ 0.050) the gene expression of epigenetic markers of DNA methylation (DNMT3A) and histone-acetylation (SIRT3 and SIRT7). Young bulls had a tendency (P ≤ 0.072) of higher RNA m6A methylation, VIRMA, and WTAP than mature bulls. Effect of diet × age interaction was not detected (P ≥ 0.137) for METTL14, VIRMA, WTAP, DNMT3A, SIRT3, or SIRT7. Younger bulls tended to have greater RNA m6A methylation levels than mature bulls, indicating that, while contemporaneously fed the same diet during periods of undernourishment followed by compensatory growth, age has an impact on this epigenetic mechanism. In conclusion, metabolic status seems to carry a greater impact on regulating bovine hepatic epigenetic mechanisms that modulate gene transcription, such as DNA methylation and histone acetylation, than on epigenetic mechanisms that regulate gene translation, such as RNA m6A methylation. During periods of undernourishment followed by compensatory growth, body fat pools appear to change more dynamically and are easily detected having a greater impact on epigenetic markers that modulate hepatic gene transcription rather than translation.

Sperm DNA 5-methyl cytosine and RNA N6-methyladenosine methylation are differently affected during periods of body weight losses and body weight gain of young and mature breeding bulls

Aiming to characterize the effects of nutritional status on epigenetic markers, such as DNA 5-methyl cytosine (mC) methylation and RNA N6-methyladenosine (m6A) methylation, of bovine sperm, 12 Angus × Hereford crossbred breeding bulls were submitted to nutritional changes for a period of 180 d: no change in body weight (BW) (phase 1 = 12 d), BW loss (phase 2 = 78 d), and BW gain (phase 3 = 90 d) in a repeated measures design. Animals were fed Beardless wheat (Triticum aestivum) hay and mineral mix. Statistical analyses were performed using SAS 9.4 (SAS Inst., Cary, NC). Higher levels of RNA m6A (P = 0.004) and DNA methylation (P = 0.007) of spermatic cells were observed at phase 2 compared with phase 1. In phase 3, sperm RNA m6A methylation levels continued to be higher (P = 0.004), whereas the DNA of sperm cells was similar (P = 0.426) compared with phase 1. Growing bulls had a tendency (P = 0.109) of higher RNA m6A methylation levels than mature bulls. Phase 2 altered scrotal circumference (P < 0.001), sperm volume (P = 0.007), sperm total motility (P = 0.004), sperm progressive motility (P = 0.004), total sperm count (P = 0.049), normal sperm (P < 0.001), abnormal sperm (P < 0.001), primary sperm defects (P = 0.039), and secondary sperm defects (P < 0.001). In phase 3, bulls had scrotal circumference, sperm volume, sperm motility, sperm progressive motility, total sperm count, normal and abnormal spermatozoa, and primary and secondary spermatozoa defects similar to phase 1 (P > 0.05). Serum concentrations of insulin-like growth factor-1 and leptin decreased during phase 2 (P = 0.010), while no differences (P > 0.05) were detected between phases 3 and 1; growing bulls tended (P = 0.102) to present higher leptin levels than mature bulls. Specific for mature bulls, DNA methylation was positively correlated with leptin concentration (0.569, P = 0.021), whereas for young bulls, DNA methylation was positively correlated with abnormal spermatozoa (0.824, P = 0.006), primary spermatozoa defect (0.711, P = 0.032), and secondary spermatozoa defect (0.661, P = 0.052) and negatively correlated with normal spermatozoa (-0.824, P = 0.006), total sperm count (-0.702, P = 0.035), and sperm concentration (-0.846, P = 0.004). There was no significant correlation (P > 0.05) between RNA m6A and hormones and semen traits. In conclusion, the nutritional status of breeding bulls alters epigenetic markers, such as DNA methylation and RNA m6A methylation, in sperm, and the impact of change seems to be age dependent. These markers may serve as biomarkers of sperm quality and fertility of bulls in the future. Detrimental effects on sperm production and seminal quality are observed at periods and places when and where environmental and nutritional limitations are a year-round reality and may carry hidden players that may influence a lifetime of underperformance.

Environmental variables responsible for Zebu cattle thermal comfort acquisition

The aim of this study was to estimate, using data mining, which microclimate and behavioral variables affect the behavior of animals to seek shaded or sunny areas. The experiment was carried out between January and May 2016 in an integrated crop-livestock-forest system. In this system, we defined two different areas: shaded and sunny. Microclimatic variables (At, BGt, RH, and WS) were measured in each area on 4 consecutive days per month. With these variables, we determined the bioclimatic indicators (THI, BGHI, HLI, MRT, RTL, and ETI). In addition, we calculated the absolute difference (Δ) by subtracting the value recorded in shaded areas from the value recorded in sunny areas for all microclimatic variables and bioclimatic indicators, except for WS. The behaviors (grazing, ruminating, and other activities), posture (standing or lying), and use of areas (shaded or sunny) of 38 Zebu cattle were recorded on 2 consecutive days per month. The data mining technique was applied for analysis in a classification task. The model correctly classified 76% of the instances with a Kappa statistic of 0.51 after features selection from the database. The ΔBGt was the most important feature in the model to classify the decision of Zebu cattle to seek another area or remain in a determined area. The model was built with seven classification rules, being one simple rule, composed of the interaction between ΔBGt and rumination; and other more complex rules, composed of the interactions among the ΔBGt, WS, and rumination. The preference of Zebu cattle to seek or remain in shaded or sunny areas was influenced by eight features: rumination, drinking water, WS, ΔBGt, MRT in shade, BGHI in sun, ΔBGHI, and HLI in sun.

Dairy Heifer Motivation for Access to a Shaded Area

We used an operant conditioning paradigm to test the motivation of non-pregnant dairy heifers to access shade during the summer and autumn months (January to June) in southern Brazil. Dairy heifers (n = 18) were trained to push a weighted gate to access either an experimental area containing both a shaded (simple tree shade and shade cloth) and unshaded area (WITH SHADE) or an experimental area with no shade (BARREN). The latency to push the weighted gate, and the maximum weight pushed by each heifer, were recorded in both the summer and the autumn. Temperature and humidity were recorded continuously for the duration of the study and were used to calculate the heat index. The maximum weight pushed to enter the WITH SHADE area was greater in summer than in autumn, and was inversely related to the latency to push the weighted gate. Heifers refused to work for access to the BARREN environment. As expected, both the maximum ambient temperatures and heat index were higher in summer than in autumn, and also higher in the non-shaded areas than under the shade in both seasons. Heifers of higher social rank displaced other heifers more often, and spent more time in the shaded areas, particularly in the area with trees plus a shade cloth, than the intermediate and subordinate heifers. We conclude that shade is an important and valued resource for heifers reared on pasture-based systems in sub-tropical environments, particularly during the hot summer months.

Invited review: Freedom from thirst-Do dairy cows and calves have sufficient access to drinking water?

The importance of drinking water for production and animal welfare is widely recognized, but surveys and animal welfare assessment schemes suggest that many dairy calves and dairy cows do not have sufficient access. Limit milk-fed calves drink more water than calves fed milk ad libitum, but ad libitum milk-fed calves also require access to drinking water, as milk does not meet the animal's requirement for water. At hot ambient temperatures and when calves are sick, access to water is especially important and should be provided at all times. Many young calves do not have access to water throughout 24 h, and whether healthy young calves require free access to water at all times, or from which age, is not clear and requires further study. Dairy cow free water intake (FWI) is largely determined by milk yield, and high-yielding dairy cows may drink up 100 L of water per day. Dry matter, crude protein, and salt content of feed, as well as ambient temperature, have considerable effects on dairy cow water intake. Deprivation of water affects meal patterning for the cow, as well as increased subsequent rate of drinking and compensatory water intake. Although dairy cow ad libitum water intake may exceed the water provision necessary to maintain production, offering water for ad libitum intake may be necessary to safe guard animal welfare. Cattle are suction drinkers that prefer to drink from large open water surfaces, and Holstein dairy cows can drink at a rate of up to 24 L/min. Research on the effect of design and placement of water troughs for indoor-housed dairy cows on their drinking behavior and water intake is limited. Access to a water source at pasture increases the time cows spend there, and access to shade reduces water requirements during periods of warm weather. In both indoor and pastured cattle, there is a lack of knowledge about the effect of stocking of water troughs on competition, drinking behavior, and intake in dairy cows. Studies on the effect of available water trough length and placement, and of the number of cows being able to drink from the same trough of a given dimension, are needed to evaluate current recommendations.

Effects of Heated Drinking Water on the Growth Performance and Rumen Functionality of Fattening Charolaise Beef Cattle in Winter

Simple Summary

Efficiency has been a major metric for measuring the production performances and profitability of zootechny, especially in beef cattle farming, even in terms of environmental sustainability. More efficient beef cattle farming should include a decrease in total feed consumption, equal or greater production performance and lower methane emissions and manure excretion. In fact, the rumen is the keystone of cattle efficiency. Strategies to maintain the rumen’s stability while enhancing its functionality can be drivers of better overall efficiency. Besides the feeds used and nutritional management, drinking water—specifically, its temperature—can alter and modulate the ruminal environment, due to the high sensitivity of the ruminal microbiota. Drinking heated water kept at a constant temperature can lead to enhanced production efficiency, due to better rumen stability and increased viability of ruminal bacteria.

Abstract

The effects of heated drinking water on growth performance and rumen functionality in fattening beef cattle during winter were evaluated. Newly received Charolaise bulls (n = 224) were allocated to two experimental groups: (i) water at room temperature (RTW) (weight 408 ± 34 kg); (ii) constantly heated water (25 °C) (HW) (weight 405 ± 38 kg). Growth performances, feed intake, feed conversion rate, water intake and carcass characteristics were evaluated. Internal reticuloruminal wireless boluses were used to collect rumen pH and temperature values every 10 min. Bodyweight was not affected by the water temperature, but the overall average daily gain (ADG) was significantly higher in the HW group (1.486 vs. 1.438 kg/head/day in the RTW; p = 0.047). Dry matter intake was significantly higher in the HW group (p = 0.001), even though the final feed conversion rate (FCR) was not influenced. There was also a tendency for better cold carcass weight (CCW) and carcass yield (CY) in the HW group. Drinking heated water reduced the time (min/day) during which the ruminal pH was below pH 5.8 or 5.5, and the time during which the temperature was lower than 37 or 39 °C (p < 0.001). The use of heated drinking water is a plausible a strategy for enhancing ruminal stability and the overall production efficiency in fattening beef cattle, which will lead to both better growth performance and higher ruminal stability.

Feed digestibility, digesta passage and faecal microbial biomass in desert-adapted goats exposed to mild water restriction

In arid and semi-arid environments, extensively managed ruminants regularly experience drinking water shortage, especially in the dry season. The present study therefore investigated the effects of mild drinking water restriction on feed intake, feed digestibility, solid digesta passage and composition of faeces including faecal microbial biomass. A feeding trial was conducted in Oman, during the dry summer months. Nine adult male Batinah goats were subjected to three watering regimes in a 3 × 3 Latin Square design. Treatments were (1) water offered ad libitum (100%, W100); (2) water restricted to 85% ad libitum consumption (W85); and (3) water restricted to 70% ad libitum consumption (W70). Animals were offered Rhodes grass hay and whole barley grains (1:1 ratio) at 1.3 times maintenance energy requirements. Each of the three experimental periods comprised 16 days of adaptation and 8 days of measurements. During the latter, feed offered and refused as well as faeces were sampled and quantified. Gastrointestinal digesta passage was determined using ytterbium-labelled Rhodes grass hay. Ergosterol and amino sugars were used as markers for faecal microbial biomass, that is the sum of fungi and bacteria. Water restriction had no effect on feed intake and digesta passage. However, feed dry matter, organic matter and fibre digestibility increased (p < 0.05) in W70 compared with W85, and the excreted amount of faecal dry matter, organic matter, nitrogen and neutral detergent fibre decreased (p < 0.05) in W70 compared with W85. Even though water restriction did not affect total faecal microbial biomass carbon (C) concentration, that of fungal biomass C increased (p < 0.05) in W70 compared with W85. Therefore, mild water restriction seems unproblematic from a physiological and nutrient utilization perspective as it increases feed digestibility without compromising feed intake.

Effect of Different Watering Regimes in Summer Season on Water Intake, Feed Intake, and Milk Production of Marecha She-camel (Camelus dromedarius)

Simple Summary

Camel livestock is a significant sector of agriculture in Pakistan. Punjab Marecha is the camel breed more diffuse for their production characteristics. In fact, this camel breed is well adapted to the desert ecosystem, tolerating elevated temperatures and dehydration. This study aimed to evaluate the effect of water deprivation on milk production performance in Marecha camels during the summer. Twelve she-camels in the early lactation stage were included. After seven days, camels were divided into three groups: Group 1 (G1) having access to water once a day, Group 2 (G2) having access once every 4 days, and Group 3 (G3) having access once every 6 days. Milk production and daily dry matter were decreased in camels deprived of water for 6 days. The results of the current study suggest that the camel is a productive animal even when subjected to water deprivation; however, its feed intake and milk production are decreased.

Abstract

Twelve lactating healthy Marecha she-camels in the early lactation stage during the summer at Camel Breeding and Research Station Rakh-Mahni (Pakistan) were included. All animals were fed with Medicago sativa and Cicer arientinum ad libitum and divided into three groups in relation to the access to water, after a period of seven days of adaptation to experimental conditions. Group 1 (G1) was considered as control having access to water once every day; Group 2 (G2) had access once every 4 days, while Group 3 (G3) had access once every 6 days. The duration of the study was 60 days with an adaptation period to experimental conditions of 7 days before the onset of the study. Dry matter intake (DMI) was calculated on a dry matter basis. On average the ambient temperature and relative humidity during the trial were 39–41 °C and 55–63%, respectively. The DMI, water intake, milk production, and body weight changes were affected (p < 0.001) during various watering regimes. The mean values of water intake were found to be 82.94 ± 1.34 L higher in G3 than G1 and G2.

Beef Cattle on Pasture Have Better Performance When Supplied With Water Trough Than Pond

The behavior and performance of steers on pasture regarding water availability in troughs or in ponds were compared. Eight paddocks were randomly allocated to one treatment: POND (~30 m of diameter) or TROUGH (water trough, 120 cm diameter and 60 cm high and 500 L capacity). Eight groups of six beef steers were randomly assigned to one of the paddocks. The first 10 days were considered for animal habituation. Animals were individually weighed (days 0, 30, 60, and 90). Beginning in the day after each weighing on days 30 (Month 1), 60 (Month 2), and 90 (Month 3), behavior and animal distribution in the paddock were recorded by direct visual observation in three periods of 4 consecutive days. Water temperature and fecal and herbage DM were also recorded in these periods. Water intake was measured during 16 random days in the troughs. Data were analyzed using Generalized Linear Mixed Models, with treatment and period as fixed effects. TROUGH steers gained more weight (0.44 vs. 0.34 kg/day/animal; P ≤ 0.007) during the experiment and were heavier than the others at the end of the study (P ≤ 0.05). POND steers spent more time drinking water, but TROUGH steers increased the number of drinking events throughout the study (P ≤ 0.05), suggesting an adaptation for the new type of water source. Both treatments increased grazing time throughout the study, but not ruminating time (P ≤ 0.05). Walking time differed between treatments in all periods of behavior observation (P ≤ 0.05). Events of animal licking and ingesting salt of POND steers reduced throughout the study (P ≤ 0.05). The number of drinking events of TROUGH steers increased throughout the study, and drinking events were longer for POND steers than TROUGH steers (P ≤ 0.05). TROUGH steers spent more time on pasture on Month 2 (P ≤ 0.05). Period collection did not affect the water intake of TROUGH treatment (P > 0.05). This study demonstrates that water available in troughs rather than ponds for steers on pasture has positive effects on their weight gain and affects cattle behavior.

Proxy Measures and Novel Strategies for Estimating Nitrogen Utilisation Efficiency in Dairy Cattle

Simple Summary

Dairy cow diets contain nitrogen, mostly in the form of protein. However, dietary nitrogen is used with a low efficiency for milk production, and much of the unused nitrogen is converted to urea and excreted in urine and faeces (manure). Nitrogen within manure can then be lost to the environment, and this is a particular issue when dairy cows are offered diets containing excess dietary protein. As a result, there is increasing pressure on the dairy sector to improve the efficiency with which dairy cows utilise dietary nitrogen. While nitrogen utilisation efficiency can be measured accurately on research farms, this is more difficult on commercial farms. For that reason, there is much interest in developing low-cost and easy-to-use proximate measures that can provide accurate estimates of nitrogen utilisation. This review examines a number of proximate analyses that are already used as indicators of nitrogen use efficiency in dairy cows (e.g., blood urea and milk urea), and a number of more novel measures that may have potential for use in the future (including analysis of milk, blood, urine, breath, and predictions of intake). These ‘proxy’ measurements can be used to improve feeding management and might be used to monitor adherence to legislation.

Abstract

The efficiency with which dairy cows convert dietary nitrogen (N) to milk N is generally low (typically 25%). As a result, much of the N consumed is excreted in manure, from which N can be lost to the environment. Therefore there is increasing pressure to reduce N excretion and improve N use efficiency (NUE) on dairy farms. However, assessing N excretion and NUE on farms is difficult, thus the need to develop proximate measures that can provide accurate estimates of nitrogen utilisation. This review examines a number of these proximate measures. While a strong relationship exists between blood urea N and urinary N excretion, blood sampling is an invasive technique unsuitable for regular herd monitoring. Milk urea N (MUN) can be measured non-invasively, and while strong relationships exist between dietary crude protein and MUN, and MUN and urinary N excretion, the technique has limitations. Direct prediction of NUE using mid-infrared analysis of milk has real potential, while techniques such as near-infrared spectroscopy analysis of faeces and manure have received little attention. Similarly, techniques such as nitrogen isotope analysis, nuclear magnetic resonance spectroscopy of urine, and breath ammonia analysis may all offer potential in the future, but much research is still required.

Resilience of Lambs to Limited Water Availability without Compromising Their Production Performance

Water scarcity is a common phenomenon in arid and semi-arid regions, which could have tremendous effects on livestock production. This study aimed to determine the level of water restriction that lambs fed on a pelleted diet can tolerate without compromising their production performance. A total of 24 male Najdi lambs were housed individually and randomly allocated into three equal groups, namely ad libitum water intake, 33% water-intake restriction, and 67% water-intake restriction. Dry-matter intake, feed conversion ratio, and average daily gain were decreased (p < 0.05) with the increasing level of water restriction. Water restriction had also reduced (p < 0.05) nutrient digestibility. The water-conserving ability of the water-restricted lambs was manifested by the production of concentrated and lower (p < 0.05) quantities of urine and feces. Meanwhile, serum osmolality and concentrations of albumin, total protein, urea-N, glucose, and non-esterified fatty acids were increased (p < 0.05) with the increasing levels of water restriction. It is surprising that lambs subjected to 67% water restriction retained more (p < 0.05) nitrogen relative to intake and had better (p < 0.05) efficiency of nitrogen utilization. It was strongly evident that lambs could tolerate water-intake restriction of up to 33% without compromising their production performance.

Invited review: Physiological and behavioral effects of heat stress in dairy cows

Animal welfare can be negatively affected when dairy cattle experience heat stress. Managing heat stress has become more of a challenge than ever before, due to the increasing number of production animals with increased milk yield, and therefore greater metabolic activity. Environmental temperatures have increased by 1.0°C since the 1800s and are expected to continue to increase by another 1.5°C between 2030 and 2052. Heat stress affects production, reproduction, nutrition, health, and welfare. Means exist to monitor and evaluate heat stress in dairy cattle, as well as different ways to abate heat, all with varying levels of effectiveness. This paper is a summary and compilation of information on dairy cattle heat stress over the years.

Water turnover among human populations: Effects of environment and lifestyle

OBJECTIVES

To discuss the environmental and lifestyle determinants of water balance in humans and identify the gaps in current research regarding water use across populations.

METHODS

We investigated intraspecific variation in water turnover by comparing data derived from a large number of human populations measured using either dietary survey or isotope tracking. We also used published data from a broad sample of mammalian species to identify the interspecific relationship between body mass and water turnover.

RESULTS

Water facilitates nearly all physiological tasks and water turnover is strongly related to body size among mammals (r2=0.90). Within humans, however, the effect of body size is small. Instead, water intake and turnover vary with lifestyle and environmental conditions. Notably, despite living physically active lives in conditions that should increase water demands, the available measures of water intake and turnover among small-scale farming and pastoralist communities are broadly similar to those in less active, industrialized populations.

CONCLUSIONS

More work is required to better understand the environmental, behavioral, and cultural determinants of water turnover in humans living across a variety of ecosystems and lifestyles. The results of such work are made more vital by the climate crisis, which threatens the water security of millions around the globe.

Developing and evaluating threshold-based algorithms to detect drinking behavior in dairy cows using reticulorumen temperature

In this study, we assessed for the first time the use of a reticuloruminal temperature bolus and a thresholding method to detect drinking events and investigated different factors that can affect drinking behavior. First, we validated the detection of drinking events using 16 cows that received a reticuloruminal bolus. For this, we collected continuous drinking behavior data for 4 d using video recordings and ambient and water temperature for the same 4 d. After all the data were synchronized, we performed 2 threshold algorithms: a general-fixed threshold and a cow-day specific threshold algorithm. In the general-fixed threshold, a positive test was considered if the temperature of any cow fell below a fixed threshold; in the cow-day specific threshold, a positive test was considered when the temperature of specific cows fell below the threshold value deviations around the mean temperature of the cow for that day. The former was evaluated using a threshold varying between 35.7 and 39.5°C, and the latter using the formula μ-n10σ, where µ = mean of the temperature of each cow for one day, n = 1, 2, …, 20, and σ = standard deviation of the temperature of each cow on that day. The performance of the validation of detection using each of the threshold types was computed using different metrics, including overall accuracy, precision, recall (also known as sensitivity), F-score, positive predictive value, negative predictive value, false discovery rate, false omission rate, and Cohen's kappa statistic. The findings of the first study showed that the cow-day specific threshold of n = 10 performed better (true positives = 466; false positives = 167; false negatives = 165; true negatives = 8,416) than using a general-fixed threshold of 38.1°C (true positives = 449; false positives = 181; false negatives = 182; true negatives = 8,402). With the information gained in this first study, we investigated the different factors associated with temperature drop characteristics per cow: number of drops, mean amplitude of the drop, and mean recovery time. For this, we used data from 54 cows collected for almost 1 yr to build a mixed-effect multilevel model that included days in milk, parity, average monthly milk production, and ambient temperature as explanatory variables. Cow characteristics and ambient temperature had significant effects on drinking events. Our results provide a platform for automated monitoring of drinking behavior, which has potential value in prediction of health and welfare in dairy cattle.

The relationship between the number of consecutive days with heat stress and milk production of Holstein dairy cows raised in a humid continental climate

Heat stress is known to affect performance of dairy cows experiencing prolonged periods of high temperature and relative humidity. Less is known about its effects in cooler climates. The goals of the present study were to determine the prevalence of days susceptible to cause mild heat stress in dairy cows living in a humid continental climate and to investigate the relationship between the number of consecutive days of mild heat stress and milk, fat, protein, and lactose production. A 6-yr data set (2010-2015) containing 606,031 milk analysis records for 34,360 Holstein dairy cows at different parities was matched with the corresponding daily maximum temperature-humidity index. Exposure to heat stress conditions was divided into 5 categories corresponding to 0, 1 to 2, 3 to 4, 5 to 6, and 7 to 8 consecutive days before milk test date. On average, cows were exposed to heat stress conditions for 135.8 ± 5.9 d/yr in Southwest Quebec and 95.3 ± 10.2 d/yr in Eastern Quebec. Cows experiencing heat stress conditions produced on average less fat, protein, and energy-corrected milk and lower fat and protein concentrations. The decrease in milk fat reached 6% for category 7 to 8 exposure of cows in parity 3 or more. The association between exposure category and milk yield and lactose yield and concentration was weak. Heat stress lowered milk fat and protein production but had little effect on milk volume output. Further research is necessary to better understand the mechanism underlying the effects of sporadic low- to medium-intensity heat stress on dairy productivity.

Impact of 24-h feed, water, or feed and water deprivation on feed intake, metabolic, and inflammatory responses in beef heifers

This experiment investigated the effects of 24-h feed or water deprivation on hay intake, metabolic, and inflammatory responses in growing beef heifers. Forty Angus × Hereford heifers were ranked by initial BW (275 ± 6 kg) and age (278 ± 6 d) and randomly allocated to 20 drylot pens (2 heifers/pen). Pens were randomly assigned to 1 of 5 squares (4 × 4; 4 pens/square; a total of 8 animals per square), that were run simultaneously with each containing 4 experimental periods of 17 d each (day -6 to 10). From day -5 to 0 of each period, pens were offered alfalfa-grass hay ad libitum + 454 g of dried distillers grains with solubles (as-fed basis) per heifer daily. On day 0 of each period, pens received 1 of 4 treatments: 1) feed and water deprivation for 24 h (FWD), 2) feed deprivation for 24 h, but regular access to water (FD), 3) water deprivation for 24 h, but regular access to feed (WD), or 4) regular access to feed and water (CON). Treatments were concurrently applied from day 0 to 1. Heifer full BW was collected on day -6 and -5, before (day 0) and after (day 1) treatment application, and on day 3, 6, 9, and 10 of each period. Hay DMI was recorded daily from day -5 to 10. Blood samples were collected on day -5, 0, 1, 3, 6, and 10 of each experimental period. Following treatment application on day 1, BW loss was greater, and BW was less (P < 0.01) in WD, FWD, and FD compared with CON heifers, and similar (P = 0.64) among FWD and FD heifers. No treatment effects were detected (P ≥ 0.21) for final BW and overall ADG. Plasma cortisol concentrations were greater (P < 0.01) in FD and FWD vs. WD and CON on day 1, whereas FD had greater (P < 0.01) plasma cortisol concentration vs. CON, WD, and FWD on day 6 and 10. Serum NEFA concentration was greater (P < 0.01) in FD and FWD vs. WD and CON on day 1, and greater (P < 0.01) in WD vs. CON heifers on day 1. No treatment effects were detected (P = 0.53) for plasma haptoglobin concentration. Plasma ceruloplasmin concentration was greater (P < 0.01) in FD and FWD vs. CON on day 1, and greater (P < 0.01) in FD vs. CON and WD on day 3 and 6. Collectively, feed or water deprivation for 24 h did not impact feed intake and BW gain, whereas metabolic results suggest that feed deprivation stimulates cortisol, NEFA, and ceruloplasmin responses in growing beef heifers.

Readily Available Water Access is Associated with Greater Milk Production in Grazing Dairy Herds

Simple Summary

In Santa Catarina, Brazil, most milk is produced on small-scale farms that utilize grazing as the main form of nutrition; however, the farms differ in how they provide water for their herds, with some herds not providing access to drinking water while on pasture and other herds having unrestricted access to water. In this study, we assessed the milk production on farms that differ in the way drinking water is provided to the herd. Herds with unrestricted access to drinking water produced more milk than herds that had restricted access to drinking water, regardless of the main breed of the herd, and amount of concentrate offered per cow per day. Simple changes in water management practices may positively impact milk production.

Abstract

In this cross-sectional study, we measured the association between water provision and milk production on intensively managed small-scale grazing dairy herds. Farms (n = 53) were categorized according to water provision as follows: (1) Restricted—cows did not have access to a water trough while on pasture; and (2) Unrestricted—cows had free access to a water trough while on pasture. Herd main breed and feeding practices were included in a model to assess the effect of water provision category on farm average milk yield/cow/d. The effect of pasture condition and environmental variables on milk production were also assessed, however were not retained on the final model. Herds provided with unrestricted access to drinking water produced on average 1.7 L more milk per cow/d (p = 0.03) than herds with restricted access to drinking water. Predominantly Holstein herds produced 2.8 L more milk per cow/d (p < 0.01) than non-Holstein herds. Each extra kg of concentrate offered per day increased milk yield by 1.1 L/cow/d (p < 0.01). In conclusion, providing free access to drinking water while grazing was associated with greater milk production.

Effect of niacin supplementation in long-distance transported steer calves

Long-distance transportation has negative impacts on production and health in cattle. Feed and water are routinely deprived from cattle during transportation. We investigated whether niacin supplementation could improve niacin nutrition and mitigate the adverse effect of transportation with feed and water deprivation in steer calves. We also studied the adverse effect of feed and water deprivation in nontransported steer calves. Twelve calves were assigned to feed and water deprivation for 2 days, or full access to feed and water in experiment 1. Ten calves were assigned to 2-day transportation with feed and water deprivation, or the transportation with feed and water deprivation, but with supplementation of rumen-protected niacin at 100 g/day per head in experiment 2. Bodyweight was measured and blood was collected for 32 days in each experiment. Feed and water deprivation temporarily decreased serum glucose concentrations and bodyweight gain. Transportation with deprivation of feed and water caused a temporal decrease in bodyweight gain and serum albumin concentration, and a continuous decrease in serum glucose and total cholesterol concentrations, which was suppressed by niacin supplementation. Niacin supplementation increased blood niacin concentration. These results suggest that niacin supplementation mitigates adverse effects of transportation with feed and water deprivation in steer calves.

The effect of water restriction on physiological and blood parameters in lactating dairy cows reared under Mediterranean climate

OBJECTIVE

This study was conducted to evaluate the effect of water restriction (WR) on physiological and blood parameters in lactating dairy cows reared under Mediterranean climate.

METHODS

The trial lasted 16 days preceded by two weeks of adaptation to the experimental condition in spring 2014 on 6 dairy cows in mid-lactation. These cows were allowed water ad libitum for 4 days (W100) (hydration period), then split into 2 groups, one group has received 25% and the other 50% of water compared to their mean water consumption during the hydration period; then rehydrated for 4 days. Feed intake and physiological parameters: respiratory rate (RR), heart rate (HR), and rectal temperature (RT) were recorded twice a day. Blood was collected once a day and analyzed for serum concentration of glucose (Glc), triglycerides (TG), cholesterol (Chol), urea (Ur), creatinine (Crea), and total protein (TP) by enzymatic colorimetric method and cortisol (Cort) by radioimmunoassay.

RESULTS

Total dry matter intake (TDMI) was affected by WR. A decrease in TDMI was observed in WR groups compared to W100 group (effect, group, period, day, group×day, period× day: p<0.001). Also, WR resulted in a significant increase in RR, HR, RT in WR groups than in W100 group (effect, group: p<0.001). In addition, an increase in the serum concentration of Glc, TG, Chol, Ur, Crea, TP, and Cort was noted in WR groups (effect, group, period, day: p<0.001).

CONCLUSION

This study has shown the ability of cows raised in a Mediterranean climate to cope with different levels of WR and thus reach a new equilibrium. As result, elucidates the important role of water as a limiting factor for livestock in environments with low water availability.

Smallholder farmers' attitudes toward the provision of drinking water for dairy cows in Kagera, Tanzania

Agriculture's large share of Tanzanian GDP and the large percentage of rural poor engaged in the sector make it a focus for many development projects that see it as an area of attention for reducing rural poverty. This paper uses a case of the Kamachumu community, where a dairy cow loan project was implemented using the heifer-in-trust (HIT) model. This study finds that productivity is limited by how the cows are being managed, particularly with many animals not having ad lib access to drinking water. The paper explores reasons why farmers do or do not provide their cows with unlimited access to drinking water. The study concludes that there are many barriers farmers face, including water accessibility, education and training, infrastructure, simple negligence, and security. These results suggest an increase in extension services and national and local livestock policies that consider the specific realities of small-scale dairy farmers.

Effect of protein supplementation on tropical grass hay utilization by beef steers drinking saline water

An experiment was conducted to assess the impact of increasing levels of supplemental soybean meal (SBM; 45.7% CP) in cattle consuming tropical grass hay (Panicum maximum cultivar Gatton; 7.0% CP and 81.8% NDF) and drinking low salt water (LS) or high salt water (HS). Six ruminally fistulated beef steers (BW = 375 ± 43 kg) were used in a 6-treatment, 4-period crossover experiment. Treatments were arranged as a 2 × 3 factorial, with 2 levels salt in the water (LS and HS: 786 and 6,473 mg/kg of total dissolved solids [TDS], respectively) and 3 levels of SBM (0, 0.2, and 0.4% BW/d). After 15 d of adaptation to treatments, periods consisted of 5 d for intake and digestibility determination, 1 d for monitoring ruminal fermentation, 1 d for ruminal evacuation, and 1 d for blood sampling. Supplemental SBM × water quality interactions were significant (P < 0.05) for most measures of intake, except for total tract digestible OM intake (P = 0.38) and total tract digestible NDF intake (TTDNDFI; P = 0.32). At greater levels of SBM, forage OM intake, NDF intake, and water intake seemed to reach a plateau in LS while this was not observed in HS. Total tract digestible OM intake increased linearly (P = 0.01) and TTDNDFI tended to increase (P = 0.09) in response to increased SBM. Digestibility of OM and NDF were not affected by treatment (P > 0.21). Passage rate of acid detergent insoluble ash linearly increased (P < 0.01) in response to SBM, although it was not affected by water quality (P = 0.98). Total VFA concentrations and ruminal pH were not affected (P > 0.60 and P > 0.31, respectively) by treatment. Ruminal ammonia N levels were linearly increased by SBM supplementation (P < 0.01) but were not affected by water quality (P = 0.25). However, ruminal ammonia tended (P = 0.09) to be greater in HS at 0.2% of SBM supplementation. No interaction was observed for plasma urea N (PUN; P = 0.20). Plasma urea N was affected by SBM supplementation (P = 0.05) and water quality (P < 0.01). However, PUN did not differ for 0.4% SBM supplementation (P = 0.30) either at LS or HS treatments. In conclusion, a high level of SBM supplementation (0.4% BW) counteracted the detrimental effect of high TDS in drinking water on low-quality forage consumption by cattle.

Diet effects on urine composition of cattle and N2O emissions

Ruminant production contributes to emissions of nitrogen (N) to the environment, principally ammonia (NH3), nitrous oxide (N2O) and di-nitrogen (N2) to air, nitrate (NO3 -) to groundwater and particulate N to surface waters. Variation in dietary N intake will particularly affect excretion of urinary N, which is much more vulnerable to losses than is faecal N. Our objective is to review dietary effects on the level and form of N excreted in cattle urine, as well as its consequences for emissions of N2O. The quantity of N excreted in urine varies widely. Urinary N excretion, in particular that of urea N, is decreased upon reduction of dietary N intake or an increase in the supply of energy to the rumen microorganisms and to the host animal itself. Most of the N in urine (from 50% to well over 90%) is present in the form of urea. Other nitrogenous components include purine derivatives (PD), hippuric acid, creatine and creatinine. Excretion of PD is related to rumen microbial protein synthesis, and that of hippuric acid to dietary concentration of degradable phenolic acids. The N concentration of cattle urine ranges from 3 to 20 g/l. High-dietary mineral levels increase urine volume and lead to reduced urinary N concentration as well as reduced urea concentration in plasma and milk. In lactating dairy cattle, variation in urine volume affects the relationship between milk urea and urinary N excretion, which hampers the use of milk urea as an accurate indicator of urinary N excretion. Following its deposition in pastures or in animal houses, ubiquitous microorganisms in soil and waters transform urinary N components into ammonium (NH4 +), and thereafter into NO3 - and ultimately in N2 accompanied with the release of N2O. Urinary hippuric acid, creatine and creatinine decompose more slowly than urea. Hippuric acid may act as a natural inhibitor of N2O emissions, but inhibition conditions have not been defined properly yet. Environmental and soil conditions at the site of urine deposition or manure application strongly influence N2O release. Major dietary strategies to mitigating N2O emission from cattle operations include reducing dietary N content or increasing energy content, and increasing dietary mineral content to increase urine volume. For further reduction of N2O emission, an integrated animal nutrition and excreta management approach is required.

Plasma leptin, glucose and non-esterified fatty acid variations in dromedary camels exposed to prolonged periods of underfeeding or dehydration

The involvement of plasma leptin in the adaptation of dromedary camels to harsh conditions such as food or water shortages was studied through 2 experiments. In experiment 1, fourteen female camels were either fed at 68% of maintenance energy requirements (MER) during 112d (n=4) or overfed at 134% of MER during the first 56d and then underfed at 17% of MER the next 56d (OV-UN, n=5), or underfed and then overfed for the same durations and energy intake levels (UN-OV, n=5). Weekly plasma samples showed that leptin, glucose and non-esterified fatty acid (NEFA) concentrations were significantly modulated by energy intake level. NEFA increased sharply but transiently in underfed camels of the UN-OV or OV-UN groups, whereas glucose and leptin concentrations decreased with underfeeding and increased with overfeeding with more significant effects in camels that were previously overfed or underfed, respectively. In experiment 2 twelve female camels were either normally watered (n=6) or dehydrated (n=6) during 23d and then rehydrated during 4d. Dehydration specifically increased blood hematocrit, plasma NEFA and glucose whereas leptin decreased slightly. For both experiments, leptinemia was positively related to hump adipocyte volume. Taken together these results provide new data for a better understanding of lipid and energy metabolism in camels.

Induced metabolic disturbance and growth depression in rabbits infected with Eimeria coecicola

Eimeria coecicola causes intestinal coccidiosis in rabbits and, thereby, enormous economic losses in rabbit farms. This study aimed to investigate the effect of intestinal coccidial infection, E. coecicola on metabolic status and growth of rabbits. Animals were allocated into two groups with eight rabbits each; one group was orally inoculated with saline and served as control while the other group was orally inoculated with 5 × 10(4) sporulated oocysts. On day 7 postinfection, fecal expulsion of E. coecicola oocysts is maximal (1.2 × 10(6) oocyst/g feces) and rabbits have lost approximately 23% of their weight. Infection induced a severe depletion in plasma growth hormone level. In addition, the energy metabolic status was significantly (P ≤ 0.05) altered by the infection as, both blood glucose and total lipid levels were significantly elevated with mutual depletion in carbohydrate stores in liver sections. Also, the thyroid-stimulating hormone and cortisol concentrations were raised as a consequence of the infection. Moreover, protein status was affected by the infection as both liver and plasma total proteins were significantly decreased with concurrent disturbance in the blood protein electrophoretic pattern and duplication of blood urea nitrogen concentration. Finally, the infection induced plasma electrolyte imbalance as indicated by a significant decrease in sodium, potassium, calcium, phosphorus, ferrous, and selenium ions. Our data suggested that the intestinal coccidial infection of rabbits with E. coecicola has serious effects on rabbit growth and metabolism and could disrupt endocrine and electrolyte homeostasis.

Dairy cows welfare quality in tie-stall housing system with or without access to exercise

Background

Tie-stall housing of dairy cows is used extensively worldwide, despite of the welfare concerns regarding the restriction of voluntary movement and limitation of expression of the cows’ natural behaviour. The aim of this study was to compare the welfare quality of dairy cows kept in two types of tie-stall housing systems: with regular outdoor exercise and without access to exercise. In addition, the study investigated the relationship between different welfare measures of dairy cows kept in tie-stalls.

Methods

3,192 lactating cows were assessed using the Welfare Quality® assessment protocol for cattle in 80 commercial dairy farms, half of the farms providing outdoor access for the animals to exercise. The descriptive statistical indicators were determined for the assessed measures and for the welfare criteria and principle scores. The data obtained in the two housing types were compared and the correlation coefficients were calculated between the different welfare measures.

Results

The significant differences found between the two housing systems for the majority of the animal based measures indicate the positive effect of exercise on the welfare of tethered cows. Many of the animal welfare parameters correlated with each other. For the farms allowing the cows’ turnout in a paddock, pasture or both, the mean scores for the welfare criteria and principles were higher than for the farms with permanent tethering of the cows, except the criteria absence of prolonged hunger and expression of social behaviours. The lowest scores were obtained for the criterion positive emotional state, in both housing systems. With regard to the overall classification, none of the farms were considered excellent. In the not classified category were only farms with all-year-round tethering of the animals and in the enhanced category only farms where the cows had outdoor access.

Conclusions

The welfare quality of the investigated dairy cows was significantly better in the tie-stall farms which allow exercise for cows (paddocks, pasture or both) than in those which do not. In the light of our results we consider that dairy cattle welfare is not necessarily poor in tie-stall housing systems, its quality depending on the management practices.

Cow and herd variation in milk urea nitrogen concentrations in lactating dairy cattle

Milk urea nitrogen (MUN) is correlated with N balance, N intake, and dietary N content, and thus is a good indicator of proper feeding management with respect to protein. It is commonly used to monitor feeding programs to achieve environmental goals; however, genetic diversity also exists among cows. It was hypothesized that phenotypic diversity among cows could bias feed management decisions when monitoring tools do not consider genetic diversity associated with MUN. The objective of the work was to evaluate the effect of cow and herd variation on MUN. Data from 2 previously published research trials and a field trial were subjected to multivariate regression analyses using a mixed model. Analyses of the research trial data showed that MUN concentrations could be predicted equally well from diet composition, milk yield, and milk components regardless of whether dry matter intake was included in the regression model. This indicated that cow and herd variation could be accurately estimated from field trial data when feed intake was not known. Milk urea N was correlated with dietary protein and neutral detergent fiber content, milk yield, milk protein content, and days in milk for both data sets. Cow was a highly significant determinant of MUN regardless of the data set used, and herd trended to significance for the field trial data. When all other variables were held constant, a percentage unit change in dietary protein concentration resulted in a 1.1mg/dL change in MUN. Least squares means estimates of MUN concentrations across herds ranged from a low of 13.6 mg/dL to a high of 17.3 mg/dL. If the observed MUN for the high herd were caused solely by high crude protein feeding, then the herd would have to reduce dietary protein to a concentration of 12.8% of dry matter to achieve a MUN concentration of 12 mg/dL, likely resulting in lost milk production. If the observed phenotypic variation is due to genetic differences among cows, genetic choices could result in herds that exceed target values for MUN when adhering to best management practices, which is consistent with the trend for differences in MUN among herds.

Invited review: associations between variables of routine herd data and dairy cattle welfare indicators

As farm animal welfare is high on the political and societal agendas of many countries, considerable pressure exists to establish audit programs in which farm animal welfare is routinely monitored. On-farm assessment of animal welfare, however, is time-consuming and costly. A promising strategy to monitor animal welfare more efficiently is to first estimate the level of animal welfare on a farm based on routine herd data that are available in national databases. It is not currently known which variables of routine herd data (VRHD) are associated with dairy cattle welfare indicators (WI). Our aim was to identify VRHD that are associated with WI in a literature review. The 27 VRHD used in this review included the main types of data that are currently collected in national herd databases of developed countries, and related to identification and registration, management, milk production, and reproduction of dairy herds. The 34 WI used in this review were based on the Welfare Quality Assessment Protocol for Cattle. The search yielded associations in 146 studies. Twenty-three VRHD were associated with 16 WI. The VRHD that related to milk yield, culling, and reproduction were associated with the largest number of WI. Few associations were found for WI that referred to behavioral aspects of animal welfare, nonspecific disease symptoms, or resources-based indicators. For 18 WI, associations with VRHD were not significant (n=5 WI) or no studies were found that investigated associations with VRHD (n=13 WI). It was concluded that many VRHD have potential to estimate the level of animal welfare on dairy farms. As strengths of associations were not considered in this review, however, the true value of these VRHD should be further explored. Moreover, associations found at the animal level and in an experimental setting might not appear at the farm level and in common practice and should be investigated. Cross-sectional studies using integrated welfare scores at the farm level are needed to more accurately determine the potential of VRHD to estimate levels of animal welfare on dairy farms.

Milk production and feeding behavior in the camel (Camelus dromedarius) during 4 watering regimens

Camels survive and produce milk during recurrent prolonged hot and dry periods. The objective was to evaluate how different watering intervals affected milk production and feeding. Eight lactating camels (Camelus dromedarius) were recruited and subjected to 4 watering regimens in a Latin square design experiment performed at Haramaya University in Ethiopia. Each regimen lasted 16 d with 5 d of daily watering between periods: water was offered at 1,315 h once daily (W1); on d 4, 8, 12, and 16 (W4); on d 8 and 16 (W8); and on d 16 (W16). One camel became sick in the second period and its results were excluded. Camels were kept in a pen with minimal shade and a noon temperature of 30.9±0.1°C. They had free access to hay and were offered 2 kg of concentrates 3 times daily. At noon on d 1, 4, 8, 12, and 16, a blood sample was taken from the jugular vein before watering. All calves were kept together in a separate pen. Morning and afternoon calves stimulated milk let-down before the camels were hand-milked, after which the calves suckled, emptying the udder. Camels maintained the milk volume during water deprivation for about 1 wk, but they produced less milk during the second week during W16. Morning milk osmolality increased from 315±3 on d 1 to 333±3 mosm/kg on d 4 during W4 and from 321±3 on d 1 to 342±3 mosm/kg on d 8 during W8. After watering at 1315 h, milk osmolality decreased to 316±3 and 323±3 mosm/kg, respectively, the same afternoon and then increased during recurrent water deprivation to 338±3 (W4) and 347±3 mosm/kg (W8) on d 16, respectively. During W16, osmolality increased from 318±3 to 336±3 mosm/kg during the first 4 d of water deprivation, but during the remaining 12 d the further rise in osmolality was not higher compared with that on d 4. The change in milk osmolality was linearly correlated to plasma osmolality (r=0.8), but milk lactose content did not increase. Contrary to widespread belief, camels did not dilute their milk when dehydrated. Instead milk osmolality increased in parallel to blood osmolality. This study provides further support to earlier observations on camels' adaptation to their environment.