M.I. Endres

Comparison of microbial fermentation in the rumen of dairy cows and dual flow continuous culture

Four ruminal and duodenal cannulated lactating dairy cows and four dual flow continuous culture fermenters were used in a replicated 4 × 4 Latin square to compare fermentation and microbial ecology of in vivo and in vitro systems. Diets contained 32% maize silage, 19.8% alfalfa-grass hay, and 48.2% concentrate, and were arranged in a 2 × 2 factorial with two levels of non-fibrous carbohydrate (40%, 25%) and two levels of ruminally degradable intake protein (12%, 9%). Concentrations of viable bacteria were greater (P = 0.01) in vitro compared with in vivo, averaging 5.04 × 109 and 2.75 × 109 cells per ml, respectively. Cellulolytic bacterial concentrations (cells per ml) were lower (P = 0.04) in vitro (4.09 × 107) compared with in vivo (6.15 × 107), but concentrations of proteolytic and amylolytic bacteria were similar (P > 0.1). Protozoal concentrations (cells per ml) were greater (P = 0.0001) in vivo (3.72 × 105) compared with in vitro (2.8). Digestion of neutral detergent fiber (NDF) and total non-structural carbohydrate (TNC) exhibited square × NFC interactions (P < 0.002), and comparison of these interaction means revealed that the difference in NDF and TNC digestion between ruminal and in vitro fermentations occurred only for the 40% NFC diets. Mean TNC digestion was 87.6, 61.7, 60.9, and 60.4% whereas NDF digestion was 33.8, 55.9, 57.6, and 58.4% for the in vitro-40% NFC, in vitro-25% NFC, in vivo-25% NFC, and in vivo-40% NFC treatments, respectively. These data suggest that the continuous culture system had difficulty simulating digestion of high TNC diets. Other differences between fermentation in continuous culture and in vivo can be attributed mainly to lack of absorption from the fermenters, defaunation of the in vitro system, and endogenous protein contamination in vivo.

Animal welfare in cross-ventilated, compost-bedded pack, and naturally ventilated dairy barns in the upper Midwest

The objective of this cohort study was to investigate animal welfare in 2 newer dairy housing options in the upper Midwest, cross-ventilated freestall barns (CV) and compost-bedded-pack barns (CB), compared with conventional, naturally ventilated freestall barns (NV). The study was conducted on 18 commercial dairy farms, 6 of each housing type, in Minnesota and eastern South Dakota. The primary breed in all farms was Holstein; 1 CV and 1 NV herd had approximately 30% Jersey-Holstein crossbreds. All freestall herds used sand for bedding. Farms were visited 4 times (once in each season) between January and November 2008, and approximately 93% of all animals in each pen were visually scored on each visit. Outcome-based measurements of welfare (locomotion, hock lesions, body condition score, hygiene, respiration rates, mortality, and mastitis prevalence) were collected on each farm. Lameness prevalence (proportion of cows with locomotion score ≥3 on a 1 to 5 scale, where 1=normal and 5=severely lame) in CB barns (4.4%) was lower than that in NV (15.9%) and CV (13.1%) barns. Lameness prevalence was similar between CV and NV barns. Hock lesion prevalence (proportion of cows with a lesion score ≥2 on a 1 to 3 scale, where 1=normal, 2=hair loss, and 3=swelling) was lower in CB barns (3.8%) than in CV (31.2%) and NV barns (23.9%). Hygiene scores (1 to 5 scale, where 1=clean and 5=very dirty) were higher for CB (3.18) than CV (2.83) and NV (2.77) barns, with no differences between CV and NV barns. Body condition scores, respiration rates, mastitis prevalence, culling, and mortality rates did not differ among housing systems. The CV and NV barns were evaluated using the cow comfort index (proportion of cows lying down in a stall divided by all animals touching a stall) and the stall usage index (proportion of cows lying divided by all animals in the pen not eating). The CV barns tended to have greater cow comfort index (85.9%) than the NV barns (81.4%) and had greater stall usage index (76.8% and 71.5%, respectively). Dairy cattle housed in CB barns had reduced lameness and hock lesions compared with those housed in freestall barns and had no adverse associations with body condition, respiration rates, mastitis prevalence, culling, or mortality. When comparing the 2 freestall housing options, CV barns had improved cow comfort indices compared with NV barns. Although cows in CB barns had better feet and leg health, as indicated by the reduced lameness and hock lesion prevalence, acquiring bedding and managing the bedded pack could limit their use.

Association between stall surface and some animal welfare measurements in freestall dairy herds using recycled manure solids for bedding

The objective of this cross-sectional study was to investigate the association between stall surface and some animal welfare measurements in upper Midwest US dairy operations using recycled manure solids as bedding material. The study included 34 dairy operations with herd sizes ranging from 130 to 3,700 lactating cows. Forty-five percent of the herds had mattresses and 55% had deep-bedded stalls. Farms were visited once between July and October 2009. At the time of visit, at least 50% of the cows in each lactating pen were scored for locomotion, hygiene, and hock lesions. On-farm herd records were collected for the entire year and used to investigate mortality, culling, milk production, and mastitis incidence. Stall surface was associated with lameness and hock lesion prevalence. Lameness prevalence (locomotion score ≥ 3 on a 1 to 5 scale) was lower in deep-bedded freestalls (14.4%) than freestalls with mattresses (19.8%). Severe lameness prevalence (locomotion score ≥ 4) was also lower for cows housed in deep-bedded freestalls (3.6%) than for cows housed in freestalls with mattresses (5.9%). In addition, the prevalence of hock lesions (hock lesion scores ≥ 2 on a 1 to 3 scale, with 1=no lesion, 2=hair loss or mild lesion, and 3=swelling or severe lesion) and severe hock lesions (hock lesion score=3) was lower in herds with deep-bedded freestalls (49.4%; 6.4%) than in herds with mattresses (67.3%; 13.2%). Herd turnover rates were not associated with stall surface; however, the percentage of removals due to voluntary (low milk production, disposition, and dairy) and involuntary (death, illness, injury, and reproductive) reasons was different between deep-bedded and mattress-based freestalls. Voluntary removals averaged 16% of all herd removals in deep-bedded herds, whereas in mattress herds, these removals were 8%. Other welfare measurements such as cow hygiene, mortality rate, mastitis incidence, and milk production were not associated with stall surface.

Compost Dairy Barn Layout and Management Recommendations

Compost barns are a loose housing system that provides excellent cow comfort for dairy cows. Producer experience with well-managed compost barns in Minnesota has generally been positive. Cows are relatively clean, very comfortable, have fewer lameness problems, and in some cases had lower somatic cell counts (SCC) after moving to a compost barn from tie-stall or freestall barns. Current design and management recommendations are based on dairy producer experiences. Compost barns have a concrete feed alley, a bedded pack resting area that is stirred two times a day, and a 1.2-m (4-ft) high wall surrounding the pack. The wall that separates the pack and feed alley has walkways to allow cow and equipment access to the stirred pack area. The stirred pack is sized to provide a minimum stirred bedded pack area of 7.4 m2/cow (80 ft2/cow). Producers use dry fine wood shavings or sawdust for bedding. Fresh bedding is added when the bedded pack becomes moist enough to stick to the cows. The pack is stirred (aerated) at least two times each day to a producer recommended depth of 25 to 30 cm (10 to 12 in.). Stirring aerates and mixes manure and urine on the surface into the pack to provide a fresh surface for cows to lie down on. The pack can provide manure storage for 6 to 12 months. Excellent pack management and pre-milking cow preparation procedures are required. Research on compost barns is needed.

Characterization of peripartum rumination and activity of cows diagnosed with metabolic and uterine diseases

The objectives of the current experiment were to characterize the correlation among total serum Ca, nonesterified fatty acids (NEFA), β-hydroxybutyrate (BHBA), and haptoglobin concentrations and daily rumination time (DRT) and activity of periparturient cows and to determine the association between periparturient events and peripartum DRT and activity. Holstein animals (nulliparous = 77, parous = 219) were enrolled in the experiment approximately 21 d before expected calving date. Cows were fitted with individual Heat Rumination Long Distance collars (HRLD, SCR Engineers Ltd., Netanya, Israel) from enrollment until approximately 21 ± 3 d postpartum. Blood samples collected weekly from enrollment to 21 d postpartum were used to determine concentrations of NEFA, BHBA, and haptoglobin. Blood samples collected within 72 h after calving were used to determine total serum Ca concentration. Subclinical ketosis was characterized by BHBA > 1,000 µmol/L in any sample, and subclinical hypocalcemia was characterized by Ca < 8.55 ng/dL within 72 h after calving. Cows were examined 1, 7 ± 3, and 14 ± 3 d postpartum for diagnosis of retained fetal membrane and metritis. Total Ca (r = 0.15), NEFA (r = -0.27), and haptoglobin (r = -0.18) concentrations were weakly correlated with DRT. Concentration of BHBA (r = -0.14) was weakly correlated with activity. Postpartum DRT was reduced among cows that delivered twins compared with cows that delivered singletons (437.9 ± 4.8 vs. 385.9 ± 17.1 min/d). Prepartum (465.8 ± 4.1 vs 430.8 ± 14.9 arbitrary units) and postpartum (536.5 ± 5.5 vs. 480.3 ± 19.4 arbitrary units) activity were reduced among cows that delivered twins compared with cows that delivered singletons. Delivery of stillborn calves was associated with reduced DRT prepartum (478.0 ± 5.9 vs. 417.0 ± 23.4 min/d) and postpartum (437.2 ± 4.8 vs. 386.5 ± 19.3 min/d). On the other hand, cows delivering stillborn calves had increased activity prepartum compared with cows delivering live calves (499.3 ± 16.2 vs. 461.3 ± 4.1 arbitrary unit). Occurrence of retained fetal membrane tended to and was associated with reduced prepartum (444.3 ± 11.0 vs. 466.5 ± 4.3 arbitrary unit) and postpartum (488.2 ± 14.5 vs. 538.8 ± 5.7 arbitrary unit) activity, respectively. Cows diagnosed with metritis had reduced postpartum DRT (415.9 ± 10.1 vs. 441.0 ± 5.2 min/d) and activity (512.5 ± 11.5 vs. 539.2 ± 6.0 arbitrary unit). Postpartum activity was reduced among cows that were diagnosed with subclinical ketosis (502.20 ± 16.5 vs. 536.6 ± 6.2 arbitrary unit). Although differences in DRT and activity between populations of cows that developed periparturient diseases and healthy cows were observed, further experiments are necessary to determine how DRT and activity data may be used to precociously diagnose individuals that will develop such periparturient diseases.

Management and characteristics of recycled manure solids used for bedding in Midwest freestall dairy herds.

Interest in using recycled manure solids (RMS) as a bedding material for dairy cows has grown in the US Midwest. Cost of common bedding materials has increased in recent years and availability has decreased. Information regarding the composition of RMS and its use as a bedding material for dairy cows in the Midwest is very limited. The objectives of this study were to characterize RMS as a bedding material, observe bedding management practices, document methods of obtaining RMS, and describe housing facilities. We visited 38 Midwest dairy operations bedding freestalls with RMS to collect data. Methods of obtaining RMS for bedding included separation of anaerobic digested manure, separation of raw manure, and separation of raw manure followed by mechanical drum-composting for 18 to 24 h. Average bedding moisture of unused RMS was 72.4% with a pH of 9.16. Unused samples contained (on a dry basis) 1.4% N, 44.9% C, 32.7C:N ratio, 0.44% P, 0.70% K, 76.5% neutral detergent fiber, 9.4% ash, 4.4% nonfiber carbohydrates, and 1.1% fat. Moisture was lowest for drum-composted solids before and after use as freestall bedding. After use in the stalls, digested solids had lower neutral detergent fiber content (70.5%) than drum-composted (75.0%) and separated raw (73.1%) solids. Total N content was greater in digested solids (2.0%) than in separated raw (1.7%) solids. Total bacterial populations in unused bedding were greatest in separated raw manure solids but were similar between digested and drum-composted manure solids. Drum-composted manure solids had no coliform bacteria before use as freestall bedding. After use as bedding, digested manure solids had lower total bacteria counts compared with drum-composted and separated raw manure solids, which had similar counts. Used bedding samples of digested solids contained fewer environmental streptococci than drum-composted and separated raw solids and had reduced Bacillus counts compared with separated raw solids. Coliform counts were similar for all 3 bedding sources. Addition of a mechanical blower post-separation and use of a shelter for storage were associated with reduced fresh-bedding moisture but not associated with bacterial counts. This was the first survey of herds using RMS for bedding in the Midwest. We learned that RMS was being used successfully as a source of bedding for dairy cows. For most farms in the study, somatic cell count was comparable to the average in the region and not excessively high.

Alternative Bedding Materials for Compost Bedded Pack Barns in Minnesota: A Descriptive Study

Bedding availability for compost bedded pack barns is a concern for dairy producers who use this type of daily stirred bedded pack housing system. The material most commonly used in these barns is sawdust. The objective of this study was to describe management practices of dairy operations utilizing alternative bedding materials for partial or total replacement of sawdust in their compost barns. This study was conducted on six Minnesota dairy farms having compost bedded packs. Bedding materials used on these farms included: sawdust, wood chips, flax straw, wheat straw, oat hulls, strawdust, and soybean straw. Each farm was visited four times, once each season between January 2008 and November 2008. Replicated samples of the bedded pack material were collected during winter and summer. Samples were analyzed for dry matter, carbon, nitrogen, C:N ratios, ammonium, nitrate, pH, and bacterial counts. Temperatures of each pack were measured seasonally at various depths. Cows were scored for hygiene (1=clean, 5=dirty), body condition (1=thin, 5=obese), and locomotion (1=normal, 5=severely lame), and hock lesions were observed. Aerial ammonia and hydrogen sulfide concentrations, air velocity, and light intensity were measured each season. Overall average aerial ammonia was 3.92 ppm and hydrogen sulfide was 22.8 ppb across all farms and season. Average light intensity was 3,250 lux and air velocity was 0.81 m/s. Bedding pack material averaged 15.8% for total C, 0.93% for total N, 17.8 for C:N ratio, 37.3% for dry matter, 8.83 for pH, 4.25 mg/kg for nitrate, 955 mg/kg for ammonium, 15 g/kg for total potassium, 2.8 g/kg for total phosphorus, 8.5 dS/m for EC, 31.7°C for pack temperature, 7.6°C for outside temperature, and 9.42 million cfu/mL for total bacterial counts in the bedding. Based on these results and our observations, it appears that any of the bedding materials evaluated in this study used to substitute or partially substitute for sawdust can work well in compost dairy barns if the pack is consistently well managed by tilling twice daily, providing proper ventilation to keep surface of pack dry, and adding new material when it is visually adhering to the cows.

Feeding management and characteristics of rations for high-producing dairy cows in freestall herds

The objectives of this cross-sectional observational study were to 1) describe the feeding management and characteristics of rations for high-producing Holstein cows housed in freestall barns in Minnesota, 2) evaluate ration change over time, and 3) investigate herd-level risk factors for ration change. Each of 50 randomly selected freestall dairy herds was visited once during the study. Samples of TMR were collected from the high-production group feed bunk to represent the initial ration as delivered to the cows, 3 additional samples were collected every 2 to 3h after feed delivery, and the accumulated orts were cleaned out of the feed bunk. Feeding management practices and TMR formulation were also collected at the time of visit. Seventy percent of herds fed once daily, 22% fed twice daily, and 8% fed 3 times daily. Frequency of feed push-up was 5.4+/-2.3 times daily. Linear feed bunk space per cow was 0.45+/-0.11m. Sixty-two percent of the farms had 3-row pens and 38% had 2-row pens. Linear feed bunk space per cow was greater in 2-row pens (0.56 m/cow) than in 3-row pens (0.39 m/cow). Post and rail was the most common type of feed barrier; it was used by 60% of the herds. Headlocks were used by 28% of the herds, combination of post and rail with headlocks was used by 8%, and diagonal bars were used by 4%. Water trough linear space was 4.6+/-2.1 cm/cow. Estimated dry matter intake was 24.3 kg/cow per day. The forage content of the formulated ration was 52% of the ration DM, and corn silage was the most commonly used forage. The NDF content of the analyzed ration was greater than the NDF content of the formulated ration (30.6 and 29.8%, respectively). In contrast, the CP content was lower (17.5 and 17.9%, respectively). Some feeding management practices (e.g., feeding frequency) were associated with ration NDF content change over time. This association may be minimized by implementing ration and management changes.

Prepartum stocking density: effects on metabolic, health, reproductive, and productive responses.

The objectives of the current experiment were to determine the effects of 2 prepartum stocking densities on milk yield, concentration of metabolites during the peripartum period, and health and reproductive parameters of dairy cows. Jersey cows enrolled in the experiment at 254±3 d of gestation were balanced for parity (nulliparous vs. parous) and previous lactation projected 305-d mature equivalent milk yield (parous) and assigned to 1 of 2 treatments: 80% headlock stocking density (80SD; 38 animals/48 headlocks) and 100% headlock stocking density (100SD; 48 animals/48 headlocks). The number of experimental units was 8 (4 replicates and 2 pens/treatment per replicate). In total, 154 nulliparous and 184 parous animals were enrolled in the 80SD treatment and 186 nulliparous and 232 parous animals were enrolled in the 100SD treatment. At the start of each replicate, treatments were switched within pen. Cows were milked thrice daily and monthly milk yield, fat and protein content, and somatic cell count data were recorded up to 155 d postpartum. Plasma nonesterified fatty acid concentration was measured weekly, from -18±3 to 17±3 d relative to calving, and plasma β-hydroxybutyrate was measured weekly, from 1±2 to 17±3 d relative to calving. Cows were examined 1, 4±1, 7±1, 10±1, and 13±1 d relative to calving for diagnosis of uterine diseases. Blood was sampled for determination of progesterone concentration and resumption of ovarian cycles 35±3 and 45±3 d relative to calving. Average headlock (74.1±0.4 vs. 94.5±0.3%) and stall (80.8±0.4 vs. 103.1±0.4%) stocking density was lower for the 80SD treatment compared with the 100SD treatment. Treatment did not affect incidence of retained fetal membranes (80SD=5.1, 100SD=7.8%), metritis (80SD=21.2, 100SD=16.7%), acute metritis (80SD=9.9, 100SD=9.4%), and vaginal purulent discharge (80SD=5.8, 100SD=7.9%). Concentrations of nonesterified fatty acids (80SD=251.5±6.1, 100SD=245.9±5.6μmol/L) and β-hydroxybutyrate (80SD=508.2±14.3, 100SD=490.9±13.6μmol/L) were not different between treatments. Treatment had no effect on percentage of cows removed from the herd on the first 60 d postpartum (80SD=6.1, 100SD=5.1%) and on rate of removal from the herd up to 305 d postpartum 80SD=referent, 100SD [adjusted hazard ratio (95% confidence interval)]=1.02 (0.75, 1.38). Percentages of cows pregnant to first (80SD=41.9, 100SD=48.4%) and second (80SD=49.3, 100SD=42.0%) postpartum AI were not different between treatments. Finally, treatment did not affect energy-corrected milk yield up to 155 d postpartum (80SD=33.8±0.5, 100SD=33.4±0.5kg/d). In herds with weekly or twice weekly movement of new cows to the prepartum pen and separate housing of nulliparous and parous animals, a target stocking density of 100% of headlocks on the day of movement is not expected to affect health, metabolic, reproductive, and productive parameters.

Effect of stocking density on social, feeding, and lying behavior of prepartum dairy animals

The objectives of this study were to determine the effects of prepartum stocking density on social, lying, and feeding behavior of dairy animals and to investigate the relationship between social rank and stocking density. In total, 756 Jersey animals were enrolled in the study approximately 4 wk before expected calving date. This study used 8 experimental units (4 replicates × 2 pens/treatment per replicate), and at each replicate, one pen each of nulliparous and parous (primiparous and multiparous) animals per treatment was enrolled. The 2 treatments were 80% stocking density (80D, 38 animals per pen; each pen with 48 headlocks and 44 stalls) and 100% stocking density (100D, 48 animals per pen). Parous animals were housed separately from nulliparous animals. Animals at 254±3d of gestation were balanced for parity (parous vs. nulliparous) and projected 305-d mature-equivalent milk yield (only parous animals) and randomly assigned to either 80D or 100D. Displacements from the feed bunk were measured for 3h after fresh feed delivery on d 2, 5, and 7 of each week. Feeding behavior was measured for 24-h periods (using 10-min video scan sampling) on d 2, 5, and 7 on wk 1 of every replicate and d 2 and 5 for the following 4 wk. A displacement index (proportion of successful displacements from the feed bunk relative to all displacements the animal was involved in) was calculated for each animal and used to categorize animals into ranking categories of high, middle, and low. Seventy nulliparous and 64 parous focal animals in the 80D treatment and 89 nulliparous and 74 parous focal animals in the 100D were used to describe lying behavior (measured with data loggers). Animals housed at 80D had fewer daily displacements from the feed bunk than those housed at 100D (15.2±1.0 vs. 21.3±1.0 per day). Daily feeding times differed between nulliparous and parous animals at the 2 stocking densities. Nulliparous 80D animals spent 12.4±5.0 fewer minutes per day feeding than nulliparous 100D animals, whereas 100D parous animals tended to spend 7.6±4.5 fewer minutes per day feeding than 80D parous animals. The 2 treatments were not different in the number of lying bouts or lying-bout duration; lying time was longer for 100D on d -33, -29, and -26 and shorter on d -7, -5, and 0 than 80D. The interaction between treatment, parity, and social rank was associated with lying and feeding times. In summary, animals in the 80D treatment had a lower number of displacements from the feed bunk and spent more time lying down near parturition than 100D animals, and 80D nulliparous animals had reduced daily feeding time compared with 100D nulliparous animals. Although these results showed some potential behavior benefits of a prepartum stocking density of 80% compared with 100%, observed changes were small. However, greater stocking density cannot be recommended; more research is needed to evaluate the effects of stocking densities greater than 100% and with other breeds of cattle besides Jersey.