Free-stall Barn Research Articles

Prediction of free-stall occupancy rate in dairycattle barns through fuzzy sets

The goal of this study was to develop a fuzzy model to predict the occupancy rate of free-stalls facilities of dairy cattle, aiding to optimize the design of projects. The following input variables were defined for the development of the fuzzy system: dry bulb temperature (Tdb, °C), wet bulb temperature (Twb, °C) and black globe temperature (Tbg, °C). Based on the input variables, the fuzzy system predicts the occupancy rate (OR, %) of dairy cattle in free-stall barns. For the model validation, data collecting were conducted on the facilities of the Intensive System of Milk Production (SIPL), in the Dairy Cattle National Research Center (CNPGL) of Embrapa. The OR values, estimated by the fuzzy system, presented values of average standard deviation of 3.93%, indicating low rate of errors in the simulation. Simulated and measured results were statistically equal (P>0.05, t Test). After validating the proposed model, the average percentage of correct answers for the simulated data was 89.7%. Therefore, the fuzzy system developed for the occupancy rate prediction of free-stalls facilities for dairy cattle allowed a realistic prediction of stalls occupancy rate, allowing the planning and design of free-stall barns.

Associations of cow-level factors, frequency of feed delivery, and standing and lying behaviour of dairy cows milked in an automatic system

Deming, J. A., Bergeron, R., Leslie, K. E. and DeVries, T. J. 2013. Associations of cow-level factors, frequency of feed delivery, and standing and lying behaviour of dairy cows milked in an automatic system. Can. J. Anim. Sci. 93: 427–433. The objectives of this observational study were to quantify the standing and lying behaviour of dairy cows milked in an automatic milking system (AMS) and determine associations of this behaviour with cow-level factors (parity, stage of lactation, production, lameness) and feeding management (frequency of feed delivery). Ninety lactating Holstein cows (178±83 d in milk (DIM); parity: 2.1±1.9), kept in a free-stall barn in one of two pens, each with a free-traffic AMS, were monitored for a period of 70 d. To vary feeding management, in two consecutive 35-d periods, cows in each pen were delivered a total mixed ration (TMR), in a random order, once daily (at 0730) or twice daily (at 0730 and 1730). During the last 7 d of each period, standing and lying behaviour were recorded with data loggers, while milking information was recorded by the AMS. Cows were lameness (gait) scored twice each period. Cows lay down for 10.9±2.0 h d−1, produced an average of 34.7±8.7 kg d−1of milk, and milked 2.6±0.6 times per day. Cows spent more time standing after milking (P=0.04) when fed once daily compared with twice daily. Lying duration tended to increase (P=0.06) when feed was delivered twice daily. Milk yield (P<0.001) and lying bout frequency (P=0.05) were negatively associated with DIM, while lying bout length (P=0.005) and total duration of lying (P=0.01) were positively associated with DIM. Cows with higher gait scores milked less frequently (P=0.04), and spent more time lying per day (P=0.008) and tended to have more lying bouts per day (P=0.06). Overall, the results of this observational study suggest that the standing and lying behaviour of AMS-milked cows may be influenced by feed delivery frequency, but are more consistently associated with stage of lactation and lameness.

Fan cooling of the resting area in a free stalls dairy barn

This summer study evaluated the effect of providing additional fans (cooling) in the resting area within a free-stall dairy barn that had fans and sprinklers in the feeding area and paddock availability. Thirty cows were divided into two homogenous groups and kept in two pens: one had the resting area equipped with two fans (FAN) while no fans were added to the other resting area (CON). Microclimatic parameters, rectal temperature (RT), breathing rate (BR), milk yield, and milk pH traits were recorded. Time budgeting and the behaviour of the cows (time spent in the feeding area, standing and lying in other areas) were also recorded using digital video technology. Two slight-to-moderate heat waves were observed. During the hottest period the daily maximum temperature recorded was 33.5 °C and the daily maximum THI was 81.6. During this period, the BR and RT increased only slightly in both groups, with lower BR (n.s.) in FAN compared with CON. Milk yield was better maintained (n.s.) in FAN compared with CON during the hottest period. The FAN cows showed a greater (P<0.05) lying time in the free stalls (9.5 and 8.6 h/day in FAN and CON, respectively), whereas CON cows made greater (P<0.05) use of the paddock during evening and late evening hours. Consequently, the total daily lying time was 13.5 h/day in both groups. In conclusion, the results suggest that using fans in the resting area improves cow comfort, which increases use of the resting area. The lying time results also suggest that the benefits of providing ventilation in the resting area might be more evident in barns where there is no paddock.

Dry period length in Montbéliarde cows and its association with selected production and functional characteristics

Abstract. The study evaluated the effects of selected factors (dry period number, milk yield in standard lactation and length of full lactation) on the length of dry periods. The effect of dry period length on milk yield and composition, the frequency of milk samples with different somatic cell counts (SCC) and the course of lactation were also analysed. The study included 491 cycles (dry period and lactation) and 4 998 results of test-day milking conducted in a herd of 230 Montbéliarde cows. The cows were kept in a free-stall barn and fed total mixed rations (TMR). The average length of the dry period was found to be 85 days. The first dry period was 34-45 days longer than subsequent ones, which may have been due to the cows becoming acclimated after having been brought to the farm as in calf heifers. Increasing milk yield in standard lactation was accompanied by significantly shorter dry periods. The most beneficial dry periods in terms of milk yield were those lasting 22-41 days. The lowest yield was noted in lactations preceded by a dry period reduced to 0-21 days. However, this milk contained the most fat, protein and dry matter and the SCC did not exceed 400 000 cells/ml in 73.3 % of cases. The decrease in daily milk yield from its peak in the 2nd month to the 10th month after calving was smallest in cows with dry periods of 57-84 days, which may suggest that lactations in these cows were the most persistent.

Effect of relocation and sire lineage on behaviour and milk yield of dairy cows

Abstract. The objective of the present study was to analyse the maintenance behaviour of cows after shift from tie-stall barn to free-stall barn. The activities were analysed in relation to the time of moving of the cows. Forty-one Holstein cows were used. Cows were observed for three 24-h (first, second and tenth day) periods after moving into the new barn with free-stall housing. The shortest times of lying and ruminating were recorded at the first day after relocation (336.3 min, 628.0 min, 756.1 min, P&lt;0.001; 318.0 min, 325.0 min, 440.5 min, P&lt;0.001). The longest time was recorded for the duration of standing (1 103.7 min, 811.9 min, 683.9 min, P&lt;0.001). The period’s number of lying and ruminating were the lowest at the first day and highest at the tenth day after relocation (7.34, 14.07, 16.34, 14.32, 15.75, 18.58, P&lt;0.001). The opposite trend was found in the period’s number of feeding and standing (17.46, 12.73, 9.54 and 24.93, 18.19 and 12.41; P&lt;0.001). Sires progeny was significantly manifested in times of total lying, standing (P&lt;0.05) and feeding (P&lt;0.01) as well as in the number of lying periods (P&lt;0.05). Cows produced significantly less milk at the first day after removing than the last day before (23.76 kg vs. 30.97 kg, P&lt;0.001). Milk yield returned towards basal levels at the 13th day (31.82 kg). Milk production was different among sires.

An automatic system for the detection of dairy cows lying behaviour in free-stall barns

In this paper, a method for the automatic detection of dairy cow lying behaviour in free-stall barns is proposed. A computer visionbased system (CVBS) composed of a video-recording system and a cow lying behaviour detector based on the Viola Jones algorithm was developed. The CVBS performance was tested in a head-to-head free stall barn. Two classifiers were implemented in the software component of the CVBS to obtain the cow lying behaviour detector. The CVBS was validated by comparing its detection results with those generated from visual recognition. This comparison allowed the following accuracy indices to be calculated: the branching factor (BF), the miss factor (MF), the sensitivity, and the quality percentage (QP). The MF value of approximately 0.09 showed that the CVBS missed one cow every 11 well detected cows. Conversely, the BF value of approximately 0.08 indicated that one false positive was detected every 13 well detected cows. The high value of approximately 0.92 obtained for the sensitivity index and that obtained for QP of about 0.85 revealed the ability of the proposed system to detect cows lying in the stalls.

Influence of feed delivery frequency on behavioural activity of dairy cows in freestall barns

Research on feeding management in more competitive free-stall settings indicates that frequency of delivery of fresh feed stimulates feed bunk attendance and can affect other aspects of cows’ time budgets apart from feeding such as time spent standing vs. lying down. The objective of this study was to examine how the frequency of feed delivery affects the behavior in two farms, one with a conventional and one with automatic milking system (AMS). The feeding frequency was varied from two to three times per day in the conventional dairy farm; one to two times per day in the AMS farm. The experiment was carried out in two different seasons. All behaviours of the cows were monitored in continuous by video recording. As expected, behavioral indices have been significantly affected by environmental conditions both in conventional farm and AMS farm. The variation in the frequency of feed delivery seems to affect the cow behavioural activity only in a limited way and modify only slightly the daily averages of the time spent in different activities mainly increasing the time cows spend standing (+4- 5%).

An automatic system for the detection of dairy cows lying behaviour in free-stall barns

In this paper, a method for the automatic detection of dairy cow lying behaviour in free-stall barns is proposed. A computer visionbased system (CVBS) composed of a video-recording system and a cow lying behaviour detector based on the Viola Jones algorithm was developed. The CVBS performance was tested in a head-to-head free stall barn. Two classifiers were implemented in the software component of the CVBS to obtain the cow lying behaviour detector. The CVBS was validated by comparing its detection results with those generated from visual recognition. This comparison allowed the following accuracy indices to be calculated: the branching factor (BF), the miss factor (MF), the sensitivity, and the quality percentage (QP). The MF value of approximately 0.09 showed that the CVBS missed one cow every 11 well detected cows. Conversely, the BF value of approximately 0.08 indicated that one false positive was detected every 13 well detected cows. The high value of approximately 0.92 obtained for the sensitivity index and that obtained for QP of about 0.85 revealed the ability of the proposed system to detect cows lying in the stalls.

Influence of feed delivery frequency on behavioural activity of dairy cows in freestall barns

Research on feeding management in more competitive free-stall settings indicates that frequency of delivery of fresh feed stimulates feed bunk attendance and can affect other aspects of cows’ time budgets apart from feeding such as time spent standing vs. lying down. The objective of this study was to examine how the frequency of feed delivery affects the behavior in two farms, one with a conventional and one with automatic milking system (AMS). The feeding frequency was varied from two to three times per day in the conventional dairy farm; one to two times per day in the AMS farm. The experiment was carried out in two different seasons. All behaviours of the cows were monitored in continuous by video recording. As expected, behavioral indices have been significantly affected by environmental conditions both in conventional farm and AMS farm. The variation in the frequency of feed delivery seems to affect the cow behavioural activity only in a limited way and modify only slightly the daily averages of the time spent in different activities mainly increasing the time cows spend standing (+4- 5%).

Forecasting Heat Stress in Dairy Cattle in Selected Barn Zones with the Help of Thi and Thiadj Indexes / Prognozowanie Stresu Cieplnego U Bydła Mlecznego W Wybranych Strefach Obory Za Pomocą Wskaźników Thi I Thiadj

Abstract The paper presents the influence of temperature, relative air humidity, air movement velocity and solar radiation on forecasting the risk of heat stress in dairy cows in a free-stall barn during hot weather seasons. THI and adjusted THI indexes were calculated for the periods in which the air temperature exceeded 28°C in the barn, and when it reached 25°C. Based on the THI values obtained during the heat, which ranged from 63 to 83, the occurrence of heat stress in cattle was stated. Heat stress also caused a decrease in milk yield, from about 22 kg to about 18 kg in the technological group. The calculated THIadj values (83 to 90), taking into account the solar radiation and air movement velocity, indicated also the occurrence of health-threatening conditions for cattle. On the fourth day of heat the maximum daily value of THI in the first measurement point was 83 with THIadj of 90, while in the second point THI was 82 and THIadj was 87. This indicated the occurrence of significant differences in microclimatic conditions in the occupied zone of the same technological group. The influence of investigated microclimate factors on the formation of THIadj in the researched zone of the barn was stated. No proper method of its determination was also stated. The analysis of the impact of air movement velocity on THIadj value (P&lt;0.05) and the solar radiation (P&lt;0.05) demonstrated the importance of these parameters in forecasting heat stress in cows in the barn.

Performance and behaviour at milking after relocation and housing change of dairy cows

The hypothesis that relocation of cows with a housing change temporarily decreases their milk production and affects cows&amp;rsquo; behaviour in the milking parlour has been proved. Forty-one Holstein cows on the 1&lt;sup&gt;st&lt;/sup&gt; and 2&lt;sup&gt;nd&lt;/sup&gt; lactation were relocated from the tie-stall barn into the free-stall barn. Cows were milked in a 2 &amp;times; 5 herringbone parlour twice a day. Individual milk yields, order, and used parlour side were recorded electronically during 50 (milk) or 22 (order and side) milking sessions. Milk yield after cows&amp;rsquo; relocation (23.76&amp;nbsp;kg) significantly decreased if compared to that reached on the day preceding relocation (30.97 kg; P &amp;lt; 0.001). Milk production approached the level of the last day on days 3 and 4 (30.72 and 30.72 kg, respectively) after relocation. Milk yield exceeded that before relocation on day 13 (31.82 kg). There were significant differences between parities during the whole observation period except for the first day after relocation &amp;ndash; cows on the 2&lt;sup&gt;nd&lt;/sup&gt; parity yielded more (P &amp;lt; 0.001). Multiparous cows entered the parlour earlier than primiparous, equally during morning and evening milkings (P &amp;lt; 0.01). Generally a left-side preference was found in the observed cows, while it was more prominent in primiparous than in multiparous cows during evening milkings (P &amp;lt; 0.05). Relationships between milking order and milk performance were on days 5&amp;ndash;11 negative and significant (P &amp;lt; 0.01). We may conclude that although temporarily, relocation with housing and milking changes significantly affected the milk yield. &amp;nbsp;

The effect of low and high barn temperatures on behaviour and performance of Holstein dairy cows

The experiment was carried out at the University Training Farm in Žabčice (the Czech Republic; location 49°0’51.081”N, 16°36’14.848”E, 179 m.a.s.l) over the period of one year (1st July to 30th June). The assessment of temperature impact was based on data from 16 hottest days (H) and 16 coldest days (L). The experimental group consisted of 70 cows in various stage of lactation (30d–210d) and parity (1–8). The cows were housed in a section (one quarter) of a free-stall barn with 77 stalls in three rows. Row A was located peripherally, close to the side wall, row B was in the middle and row C was situated centrally, close to the feed table. The cows were observed weekly on the same day at 9.00 a.m. The microclimate characteristics were recorded daily: temperature in hot (H) resp. cold (L) period was in average 27.1°C resp. – 1.47 °C, and relative humidity 54.4 % resp. 77.3 %, and THI 75 resp. 33.Behaviour was described by a number of cows standing or lying down, number of cows lying down on their left or right side and row preference (A, B, C) in the resting area. Cow Comfort Index (CCI – a number of cows lying down at given time) was calculated. A total of 1587 observations were analysed. A number of cows lying down (922) was significantly higher than that of standing cows (665). Milk production was significantly higher in hot (H) period (by 1.0–1.7 kg). There was an interaction in milk production between period and standing. In H period the standing cows produced more milk, in L period vice versa. The cows with non-significant tendency towards left-side laterality produced more milk (by 1.2 kg). No interaction was found between period and laterality for milk production. All the observed parameters significantly differed between rows A, B and C. Row A was the most preferred, the cows preferring it were young (low number of lactation) with greatest milk production. The cows in row C had the lowest milk production and were in late lactation. The interaction was found between period and row affected number of lactation (P &lt; 0.01) and number of cows (P &lt; 0.05). In H period the row A was preferred by older cows (high number of lactation), while in L period it was preferred by younger cows. The cows in H period used row C less while in L period they preferred it.

Temperature, Humidity and Air Movement Variations Inside a Free-Stall Barn During Heavy Frost / Zróżnicowanie warunków cieplno-wilgotnościowych i ruchu powietrza w oborze wolnostanowiskowej podczas silnych mrozów

Abstract The paper presents results of research on the variability of temperature, humidity and air movement in selected areas of a free-stall barn during heavy frost. The study revealed the occurrence of unfavourable factors influencing microclimate in the barn. Some areas of the barn suffered from draughts, some were excessively exposed to sun or too shaded, which resulted in significant temperature and relative humidity fluctuations during the day as well as changes in air movement velocity. All these factors exerted an impact on cattle welfare. The conclusion points out the need to determine zones in the barn characterized by clearly different microclimatic conditions. In the studied example, these conditions were influenced by weather changes and depended on the orientation of the building to cardinal points as well as wall construction materials.

Rumination time during the summer season and its relationships with metabolic conditions and milk production

The main objective of this experiment was to monitor the rumination pattern during the summer season in lactating dairy cows and to investigate its relationships with metabolic conditions and physiological markers of heat stress. The study was carried out in an experimental freestall barn located near Piacenza, Italy (45°01′N, 9°40′E; 68m above sea level), and involved 21 Italian Friesian cows (11 primiparous and 10 multiparous) during the summer season. Rumination time (RT) was recorded by using an automatic system and data were calculated and summarized in 2-h intervals. Microclimatic conditions (temperature and relative humidity) inside the barn were recorded during the trial, and the temperature-humidity index (THI) was calculated. Breathing rates and rectal temperatures were recorded following stable meteorological periods characterized by lower and higher temperatures. At the same times, blood samples were collected to assess biochemical variables related to energy, protein, and mineral metabolism, as well as markers of inflammatory conditions and enzyme activity. Daily milk yield, body weight, nutritional condition, and health status were also recorded. The average RT was 501min/d, with no significant differences between primiparous and multiparous cows. According to the microclimatic conditions and physiological markers of heat stress, the cows suffered mild to moderate heat stress during the summer. A negative relationship between daily maximum THI and RT was observed (r=−0.32), with a reduction of 2.2min of RT for every daily maximum THI unit over the threshold of daily maximum THI of 76. Most of the rumination occurred during the night (on average the nighttime RT was 63.2% of daytime and nighttime RT); moreover, the proportion of nighttime RT slightly but significantly increased as THI increased. Rumination time throughout the trial was negatively related to breathing rate and positively related to milk yield. Daily maximum THI was negatively correlated with plasma glucose (r=−0.52) and positively correlated with plasma β-hydroxybutyric acid (r=0.26). Values of plasma β-hydroxybutyric acid were positively related to RT through the trial. Our results indicate that hot conditions negatively affect RT and modify its daily pattern. The relationship between RT and the physiological markers used in our trial support the use of RT as a marker of heat stress.

Use of residual feed intake in Holsteins during early lactation shows potential to improve feed efficiency through genetic selection1

Improved feed efficiency is a primary goal in dairy production to reduce feed costs and negative impacts of production on the environment. Estimates for efficiency of feed conversion to milk production based on residual feed intake (RFI) in dairy cattle are limited, primarily due to a lack of individual feed intake measurements for lactating cows. Feed intake was measured in Holstein cows during the first 90 d of lactation to estimate the heritability and repeatability of RFI, minimum test duration for evaluating RFI in early lactation, and its association with other production traits. Data were obtained from 453 lactations (214 heifers and 239 multiparous cows) from 292 individual cows from September 2007 to December 2011. Cows were housed in a free-stall barn and monitored for individual daily feed consumption using the GrowSafe 4000 System (GrowSafe Systems, Ltd., Airdrie, AB, Canada). Animals were fed a total mixed ration 3 times daily, milked twice daily, and weighed every 10 to 14 d. Milk yield was measured at each milking. Feed DM percentage was measured daily, and nutrient composition was analyzed from a weekly composite. Milk composition was analyzed weekly, alternating between morning and evening milking periods. Estimates of RFI were determined as the difference between actual energy intake and predicted intake based on a linear model with fixed effects of parity (1, 2, ≥ 3) and regressions on metabolic BW, ADG, and energy-corrected milk yield. Heritability was estimated to be moderate (0.36 ± 0.06), and repeatability was estimated at 0.56 across lactations. A test period through 53 d in milk (DIM) explained 81% of the variation provided by a test through 90 DIM. Multiple regression analysis indicated that high efficiency was associated with less time feeding per day and slower feeding rate, which may contribute to differences in RFI among cows. The heritability and repeatability of RFI suggest an opportunity to improve feed efficiency through genetic selection, which could reduce feed costs, manure output, and greenhouse gas emissions associated with dairy production.

A computer vision-based system for the automatic detection of lying behaviour of dairy cows in free-stall barns

A computer vision-based system for the automatic detection of dairy cow lying behaviour in free-stall barns is proposed. The system is composed of a multi-camera video-recording system and a software component which executes a cow lying behaviour detector model using the Viola–Jones algorithm. A method to carry out the training, testing and validation phase of the modelled cow lying behaviour detector is described. The performance of the system was tested in an area of a head-to-head free-stall barn where a group of 15 Holstein dairy cows was housed. A multi-camera video-recording system was installed to obtain panoramic top-view images of the area under study. Since the Viola–Jones algorithm was not invariant to the rotation of the cow images, two classifiers were modelled, one for each row of stalls located in the barn. These two classifiers were implemented in the software component of the system in order to perform the lying behaviour detection. The system was validated by comparing its detection results with those generated from visual recognition. The ability of the system to detect cow lying behaviour was confirmed by the high value of its sensitivity, which was approximately 92%. Conversely, the value of the branching factor which was approximately 0.08 indicated that one false positive was detected for every 13 well detected cows. These results suggest that the system proposed in this study could be used for the calculation of the cow lying index which is widely used to investigate cow lying behaviour in free-stall barns. ► To model the cow lying behaviour detector image enhancement was not required. ► In the training phase FPR cas of the order of 10 −7 and TPR cas of 0.90 were achieved. ► The testing phase proved detector ability even when noise affected camera images. ► The cow lying behaviour detector provided a sensitivity of 92% and a BF of 0.08. ► CVBS can be used to compute cow lying index.

Effects of rubber flooring during the first 2 lactations on production, locomotion, hoof health, immune functions, and stress

Some housing systems on dairy farms can result in long-term chronic pain. The effects of acute pain on immunity have been explored, but chronic pain’s influence on immune responses is still poorly understood. Therefore, the objective of this research was to determine chronic effects of flooring on immune responses and production in freestall housing for dairy cows. Thirty heifers were studied from before calving as first-calf heifers until d 180 of their second lactation. Treatments were rubber (Kraiburg; Agromatic Inc., Fond du Lac, WI) flooring or concrete with diamond grooves in a freestall barn, each in 2 quadrants of the barn. Heifers entered the treatments after calving, so the system was dynamic and each cow was considered an experimental unit. At the end of the first lactation, cows were housed in a bedded pack barn with pasture access until calving was imminent. At that time, they returned to their assigned treatment, but not necessarily into the same quadrant. Production, reproduction, cortisol, acute-phase proteins, and health data were recorded throughout lactation 1, locomotion was scored weekly, and hoof scoring and care was conducted on d 60 and 180 of lactations 1 and 2, and quantitative real-time-PCR of blood leukocytes was analyzed in mid lactation of lactation 1. Mature-equivalent milk fat, milk protein, and protein percentages during the first lactation were greater for cows on the rubber flooring. Hoof and leg therapy treatments per cow were fewer for rubber floor-housed cows. Locomotion scores were less for cows housed on rubber during the second lactation. White blood cell counts were less for cows housed on rubber, and caused by greater lymphocyte counts for cows housed on concrete. The possibility of chronic inflammation was substantiated by less IL-1β and more IL-1 receptor antagonists for cows housed on rubber at d 150 in the second lactation. Cortisol and acute-phase proteins did not differ between the treatments. Interferon-γ, IL-12, the modulator of tissue reconstruction (B-cell-transforming growth factor 1), and pain-modulating neurokinin (tachykinin 1) were not different at d 105. These data show indicators of chronic inflammation for cows housed on the concrete flooring compared with those housed on rubber. Implications for the use of rubber flooring in freestall barns are broader than just lameness and may affect many aspects of cow physiology and production.

A Survey of Particulate Matter on California Dairy Farms

Over the past 30 yr, individual California dairy operations have grown in size; however, little is known about the distribution and determinants of particulate matter (PM) concentrations on these dairies. Elevated exposure to PM is associated with respiratory and cardiovascular health effects, particularly in occupational settings. The purpose of this study was to quantify the concentrations of PM and all inhalable PM (0-100 µm) on California dairies. Samplers were placed at various locations (e.g., milking parlor, grain storage area, drylot corral, and freestall barns) on 13 different dairies to collect PM and all inhalable PM during the 2008 summer months. The PM and all inhalable PM concentrations varied between different areas on a dairy and from dairy to dairy. Geometric mean concentrations for PM and inhalable PM were 24 µg m (range, 2-116 µg m) and 332 μg m (range, 74-1690 µg m). A key variable for explaining variation in PM concentrations with a mixed effects model was regional background ambient concentrations of PM No significant differences were observed in mean concentrations between upwind and downwind fence line concentrations (adjusted geometric mean ratio [AGMR] = 0.7; 95% CI, 0.4-1.3), although significant differences were found between upwind and central location mean values (AGMR = 0.5; 95% CI, 0.3-0.8; < 0.01). These results indicate dairy PM sources and, thus, elevated occupational exposure. Covariates, such as the age of the dairy and number of cows in the freestall barn and drylot corral, were important variables in explaining PM concentration variability. Levels of PM were lower compared with dairies in other U.S. states and other countries.

Integrating maize and triticale in grass/clover based dairy systems: examining yields and autumn soil nitrate levels

To establish N-efficient crop rotations with perennial ryegrass/white clover, maize and triticale, a 9-year field experiment was executed on an organic experimental farm in the Netherlands. Crop rotations with different levels of slurry (dairy effluent from the free-stall barn, average dry matter content of 7%) application were tested for dry matter (DM) yield, N yield, soil mineral N in autumn, soil organic matter and soil organic N. Maize cropping and slurry application both increased annual DM yield. However, the second year of grass/ clover following maize, maize itself and slurry applications each resulted in higher soil mineral N in autumn, increasing the risk of nitrate leaching losses. A rotation of 4 years of grass/clover, 2 years of maize and 1 year of triticale resulted in relatively high average annual DM production (12 t DM/ha/year) for Dutch conditions, with a higher potential N leaching loss in 2 out of 7 years. Keywords: crop rotation, grass clover, maize, triticale, N efficiency, soil mineral N

Einsatz einer Klauenwaschanlage unter Beurteilung der Reinigungswirkung, des Tierverhaltens und der Waschwasserqualität

Only limited scientific information on the efficiency of claw cleaning systems for dairy cows is currently available. For this reason, this investigation aimed to test the devio AG's claw hygiene system regarding its cleaning effect as well as its impact on the cow traffic and the quality of its washing water. During the first of two investigative phases of this controlled study, main water was used to clean the claws, while in the second phase a biozide was additionally applied. Every 4 weeks the hind claws of approximately 55 dairy cows (German Fleckvieh breed) were evaluated and their degree of soiling classified into four categories. In addition to the system's cleaning effect, its effect on cow traffic was investigated using video recordings and the quality of the recycled washing water was tested using bacteriological sampling. In the second investigation phase, claw cleanliness in the treatment group was significantly higher than in the control group. However, there was no significant difference between the two groups during the first investigation phase. The video analysis showed, that after a short period of adaptation, there was undisturbed cow traffic. Within one week of installing the claw hygiene system, the length of stay in the system increased from a mean of 23 s to 32 s and the time the cows spent waiting in front of the system was reduced from a mean of 3 min 51 s to 2 min 20 s. Water analysis revealed an increasing bacterial count from initially 1.2 × 10⁶ to 7.3 × 10⁷ CFU/ml. The undisturbed cow traffic allows the easy integration of the claw cleaning system into a free-stall barn. The improvement of claw cleanliness can make a positive contribution to claw hygiene. However, the increasing bacterial contamination of the washing water gives cause for concern in terms of infections being passed between cows when using this system.