S.D. Eicher

Influence of milk yield, stage of lactation, and body condition on dairy cattle lying behaviour measured using an automated activity monitoring sensor

Time spent lying by lactating Holstein-Friesian cows of varying body condition scores (BCS) and milk yield was measured using an animal activity monitor. A 3-week average BCS was calculated for each cow; and in total, 84 cows were selected with 28 cows each among three BCS categories (Thin: BCS<2.75; Moderate: 2.75 > or = BCS<3.25; Heavy: BCS> or = 3.25) and two stage of lactation categories (<150 days in milk or >150 days in milk). Cows were kept in two management systems: parlour/freestall (n=60) or automated milking system/freestall (n=24). Behaviour was recorded for 5.3+/-0.1 d for each cow. Production levels were considered using a 28-d rolling average of daily milk production. Cows that exhibited clinical lameness before or during the observation period were excluded from analyses. For cows exhibiting oestrus, the day prior to, day of, and day following breeding were removed. The final analysis included 77 cows (408 d of observation). A mixed model was fitted to describe average daily hours spent lying. Results demonstrated that lying time increased as days in milk (DIM) increased (P=0.05). Variables that were tested but not significant (P>0.05) were BCS category, parity category (1 or 2) and 28-d rolling average daily milk production. Although a numerical trend for increasing hours spent lying with increasing BCS was observed, after accounting for other factors in the mixed model, BCS did not significantly impact lying time. Continued investigation of these management factors that impact lying time and bouts, using new technologies, more cows, and more herds will help dairy owners better manage facilities and cow movements to optimize this essential behaviour.

Dietary L-arginine supplementation attenuates lipopolysaccharide-induced inflammatory response in broiler chickens.

In the present study, two experiments were conducted to investigate the effect of dietary L-arginine (Arg) supplementation on the inflammatory response and innate immunity of broiler chickens. Expt 1 was designed as a 2 × 3 factorial arrangement (n 8 cages/treatment; n 6 birds/cage) with three dietary Arg concentrations (1.05, 1.42 and 1.90%) and two immune treatments (injection of lipopolysaccharide (LPS) or saline) given at an interval of 48 h between 14 and 21 d of age. In Expt 2, correlation between dietary Arg concentration (0.99, 1.39, 1.76, 2.13 or 2.53%) and percentage of circulating B cells (percentage of circulating lymphocytes) was determined. In Expt 1, LPS injection decreased body-weight gain and feed intake and increased feed conversion ratio of the challenged broilers (14-21 d; P< 0.05). LPS injection suppressed (P< 0.05) the percentages of splenic CD11+ and B cells (percentages of splenic lymphocytes) and phagocytic activity of splenic heterophils and macrophages; Arg supplementation linearly decreased the percentages of CD11+, CD14+ and B cells in the spleen (P< 0.10). LPS injection increased (P< 0.05) the expression of IL-1β and IL-6 mRNA in the spleen and caecal tonsils. Arginine supplementation decreased (P< 0.05) the expression of IL-1β, Toll-like receptor 4 (TLR4) and PPAR-γ mRNA in the spleen and IL-1β, IL-10, TLR4 and NF-κB mRNA in the caecal tonsils. In Expt 2, increasing dietary Arg concentrations linearly and quadratically reduced the percentage of circulating B cells (P< 0.01). Collectively, Arg supplementation attenuated the overexpression of pro-inflammatory cytokines probably through the suppression of the TLR4 pathway and CD14+ cell percentage. Furthermore, excessive Arg supplementation (1.76%) suppressed the percentages of circulating and splenic B cells.

Stochastic simulation using @Risk for dairy business investment decisions

Purpose - The purpose of this paper is to develop a dynamic, stochastic, mechanistic simulation model of a dairy business to evaluate the cost and benefit streams coinciding with technology investments. The model was constructed to embody the biological and economical complexities of a dairy farm system within a partial budgeting framework. A primary objective was to establish a flexible, user-friendly, farm-specific, decision-making tool for dairy producers or their advisers and technology manufacturers. Design/methodology/approach - The basic deterministic model was created in Microsoft Excel (Microsoft, Seattle, Washington). The @Risk add-in (Palisade Corporation, Ithaca, New York) for Excel was employed to account for the stochastic nature of key variables within a Monte Carlo simulation. Net present value was the primary metric used to assess the economic profitability of investments. The model was composed of a series of modules, which synergistically provide the necessary inputs for profitability analysis. Estimates of biological relationships within the model were obtained from the literature in an attempt to represent an average or typical US dairy. Technology benefits were appraised from the resulting impact on disease incidence, disease impact, and reproductive performance. In this paper, the model structure and methodology were described in detail. Findings - Examples of the utility of examining the influence of stochastic input and output prices on the costs of culling, days open, and disease were examined. Each of these parameters was highly sensitive to stochastic prices and deterministic inputs. Originality/value - Decision support tools, such as this one, that are designed to investigate dairy business decisions may benefit dairy producers.

Immunological, Physiological, and Behavioral Effects of Salmonella enterica Carriage and Shedding in Experimentally Infected Finishing Pigs

Finishing pigs infected with Salmonella pose significant food safety risks by carrying the pathogen into abattoirs. This study was conducted to determine the dynamics of Salmonella infection in finishing pigs, and associated immunological, physiological, and behavioral alterations, by longitudinally comparing infected to noninfected pigs during 6 weeks postinfection (p.i.). Bacteriological data revealed that all inoculated pigs started shedding Salmonella within 2 h p.i., and persistently shed the bacteria up to the end of the study. Ileal and cecal contents, as well as mesenteric lymph node samples, were all positive throughout the study, containing 3-4 log(10) cfu/g of Salmonella at 24 h p.i., and 4-5 log(10) cfu/g of Salmonella up to 4 weeks p.i. Levels of Salmonella dropped markedly (p < 0.05) in all samples at 5 weeks p.i. There was no difference between groups for blood cell counts. Tumor necrosis factor-α was greater (p < 0.05) in infected pigs: (1) in the mesenteric lymph nodes by 48 h p.i.; (2) at 24 h and 3 weeks p.i. in the ileum; and (3) in the cecum and spleen at 3 weeks p.i. Interleukin-12, interleukin-1 and its antagonist, and a porcine-specific antimicrobial peptide RNA expression in tissues changed over time, but were not different between groups. Infected pigs spent more time in ventral recumbency, standing, and sitting than controls (p < 0.01). Infected pigs were also more active (p < 0.01), and approached a novel object more quickly than control pigs (p < 0.05). No treatment differences were detected for rectal temperature or plasma cortisol (p > 0.10). This study shows that finishing pigs can carry high levels of Salmonella for up to 4 weeks p.i. in the gastrointestinal contents and mesenteric lymph nodes, shedding high levels of the bacteria without developing clinical symptoms, but developing an immune response throughout the intestinal tract. Moreover, subtle behavioral changes measured as postures were detected, and therefore warrant additional investigation.

Assessing the potential value for an automated dairy cattle body condition scoring system through stochastic simulation

Purpose - Automated body condition scoring (BCS) through extraction of information from digital images has been demonstrated to be feasible; and commercial technologies are being developed. The primary objective of this research was to identify the factors that influence the potential profitability of investing in an automated BCS system. Design/methodology/approach - An expert opinion survey was conducted to provide estimates for potential improvements associated with technology adoption. A stochastic simulation model of a dairy system, designed to assist dairy producers with investment decisions for precision dairy farming technologies was utilized to perform a net present value (NPV) analysis. Benefits of technology adoption were estimated through assessment of the impact of BCS on the incidence of ketosis, milk fever, and metritis, conception rate at first service, and energy efficiency. Findings - Improvements in reproductive performance had the largest influence on revenues followed by energy efficiency and then by disease reduction. The impact of disease reduction was less than anticipated because the ideal BCS indicated by experts resulted in a simulated increase in the proportion of cows with BCS at calving 3.50. The estimates for disease risks and conception rates, obtained from literature, however, suggested that this increase would result in increased disease incidence. Stochastic variables that had the most influence on NPV were: variable cost increases after technology adoption; the odds ratios for ketosis and milk fever incidence and conception rates at first service associated with varying BCS ranges; uncertainty of the impact of ketosis, milk fever, and metritis on days open, unrealized milk, veterinary costs, labor, and discarded milk; and the change in the percentage of cows with BCS at calving 3.25 before and after technology adoption. The deterministic inputs impacting NPV were herd size, management level, and level of milk production. Investment in this technology may be profitable but results were very herd-specific. A simulation modeling a deterministic 25 percent decrease in the percentage of cows with BCS at calving =3.25 demonstrated a positive NPV in 86.6 percent of 1,000 iterations. Originality/value - This investment decision can be analyzed with input of herd-specific values using this model.

The effect of floor surface on dairy cow immune function and locomotion score

This study evaluated the effect of 2 dairy cow housing systems on cow locomotion, immune status, and expression of genes associated with lameness during the dry and periparturient periods. Cows were assigned to freestall housing with either rubber (RUB; n = 13) or concrete (CON; n = 14) at the feed-bunk and alley immediately after their first calving, and managed on this system during all subsequent lactations. At dry off, cows were moved to a straw bedded-pack dry cow pen, and remained there until about 2 d before subsequent calving. To investigate whether greater exposure to RUB or CON increased the differences between cows on each treatment, cows at the end of either their first (n = 16) or second (n = 11) lactations were included in the experiment. Locomotion scores and blood samples were obtained at -60 (beginning of the dry period), -30, 0 (after calving), +10 and +18 d relative to calving. Leukocyte counts were obtained by using an automated cell counter. Phagocytic activity, and cells positive for CD14 and CD18 expression were measured by flow cytometry using labeled microbeads and antibodies. Expression of tachikinin 1(TAC1), histamine receptor 1 (H1), and metalloproteinase (MMP)13 in blood leukocytes was estimated using quantitative real-time PCR. Treatment effects were determined using a repeated measures model. Provision of rubber flooring did not improve dairy cow locomotion during the subsequent study period. However, time relative to calving had an effect on locomotion score and speed, which were worst on d 0, probably because of the discomfort associated with calving. An interaction occurred between treatment and time for neutrophil and lymphocyte counts. The RUB cows had greater neutrophil and lesser lymphocyte numbers postpartum than CON. These cows also had more cells positive for CD14 postpartum compared with prepartum. Moreover, RUB cows showed upregulation of MMP13 and TAC1 compared with CON. These genes are associated with lameness and pain detection respectively. Greater neutrophil to lymphocyte ratios and CD14 expression are associated with physiological stress or with activated immunity. Rubber flooring is associated with an increase in activity and standing. This may have resulted in indications of physiological stress and upregulation of genes associated with lameness and pain for RUB cows. However, this study did not take into account the long-term effects of concrete or rubber flooring; for instance, occurrence of lameness or survivability within the herd.

Lairage during transport of eighteen-kilogram pigs has an impact on innate immunity and commensal bacteria diversity in the intestines

Long distance transportation may affect the health of pigs; thus, adding a rest stop (lairage) during long journeys may improve their well-being. The objective of this study was to determine whether a mid-journey lairage influenced swine innate immunity and intestinal microbial populations after a 16-h transport. Four replications were conducted, 1 in each of 4 seasons. Eighteen-kilogram pigs were housed in 16 pens (13 to 16 pigs/pen) with 8 pens/treatment. Lairage pigs were transported for 8 h, given a rest with food and water for 8 h, then transported for an additional 8 h. Continuous pigs were continuously transported for 16 h. Jugular blood samples and intestinal tissue and contents were collected from 16 pigs (8/treatment) on d 1, 3, 7, and 14 posttransport. Hematocrit and white blood cell counts were determined and neutrophil cell functions, including phagocytosis/oxidative burst and phagocytosis of latex beads and leukocyte phenotypic cell markers (CD14 and CD18), were analyzed using flow cytometry. Expression of toll-like receptors 2, 4, and 5; IL-8 (a cytokine that is a chemoattractant for neutrophils); CCL20 (a chemokine that is a chemoattractant for dendritic cells); and the antimicrobial peptide PR39 were determined from ileal and jejunal total RNA. Denaturing gradient gel electrophoresis was used to determine shifts in intestinal microbial populations. Total white blood cell and granulocyte counts in continuous pigs were greater (P < 0.01) on d 1 than in lairage pigs. Phagocytosis of microbeads was greater in continuous (P < 0.05) than in lairage pigs on d 7. Expression of IL-8 in jejunum was greater (P < 0.05) for continuous than for lairage pigs on d 1. Expression of CCL20 in the ileum was greater (P < 0.05) on d 14 for the continuous pigs. Expression of PR39 was greatest (P < 0.05) in the jejunum of lairage pigs on d 3. Lairage pigs had a greater (P < 0.05) variation in microbial populations (lower similarity coefficient) in the jejunum contents on d 1 and 7, in the cecum contents and tissue on d 3, and in the jejunum contents and tissue on d 14. However, continuous pigs had greater (P < 0.05) variation in the ileal tissues on d 14. This study indicates that adding a lairage to an extended transport alters immune functions, receptor, cytokine and chemokine expression, and gut microbiota compared with pigs transported for 16 h without lairage.

Yeast cell-wall products containing β-glucan plus ascorbic acid affect neonatal Bos taurus calf leukocytes and growth after a transport stressor

The objectives were to ascertain whether a yeast cell-wall derivative that was 1.8% beta-glucan in combination with ascorbyl-2-polyphosphate could improve innate immunity and mediate transportation stress in neonatal calves, and to compare the 1.8% beta-glucan yeast cell-wall derivative with a more purified yeast cell-wall derivative (70% beta-glucan). Treatments were 1) an unsupplemented control (CNT); 2) 113 g of a 1.8% (approximately 2%) beta-glucan derivative of yeast cell walls plus 250 mg of l-ascorbic acid phosphate (BG2); or 3) 150 mg of a purified beta-glucan fraction from yeast cell walls (approximately 70% beta-glucan) plus 250 mg/feeding of l-ascorbic acid phosphate (BG70). Calves (n = 39) were transported for 4 h, placed in outdoor hutches, and randomly assigned to treatments. Treatments (mixed with a milk replacer) were individually fed twice daily for 28 d. Calves were offered calf starter, free choice, throughout the study. Weekly starter intake and BW were measured, and fecal samples were collected for Salmonella Typhimurium and Escherichia coli O157:H7 PCR analysis. Blood was collected immediately before transport (d 0) and on d 3, 7, 10, 14, 21, and 28 after transport. Starter intake and DMI were less (P < 0.05) at d 28 for the BG2 and BG70 treatments compared with the CNT treatment. Hematocrit percentages increased (P = 0.002) throughout the experiment. White blood cell counts (treatment x time interaction, P = 0.066) were less for the calves supplemented with BG70 than for those supplemented with BG2 (P = 0.01) or for CNT calves (P = 0.04) on d 28. Granulocyte counts changed (P = 0.04) throughout the experiment. A trend (P = 0.077) for a treatment x time interaction was detected for peripheral blood mononuclear cell counts (PBMC). Counts of PBMC were greater (P = 0.006) for the BG2 treatment compared with the CNT treatment on d 3. Calves given the BG70 supplement had fewer PBMC than those given the BG2 supplement on d 21 (P = 0.03) and 28 (P = 0.05). Fibrinogen concentrations were affected only by time (P = 0.002). Time effects were detected for phagocytosis (P = 0.005), oxidative burst (P < 0.001), expression of cluster of differentiation 18 (P = 0.001), and increased cluster of differentiation 18 (P = 0.006). Phagocytosis was less (P = 0.05) for calves in the BG70 group than for those in the CNT group. Percentage of calves positive for E. coli O157:H7 was greatest (P <or= 0.05) for those in the BG2 group on d 7 compared with those in the other treatments. The BG2 and BG70 supplements both increased feed intake, but only the BG2 supplement increased E. coli shedding on d 7, and the BG2 and BG70 supplements varied in modulating immune functions, indicating differences in yeast extract function.

Effects of prepartum milking on postpartum reproduction, udder health and production performance in first-calf dairy heifers

Postpartum production performance of dairy heifers may be enhanced by prepartum milking by alleviating the stress of the periparturient period. The objective of this study was to determine the impact of prepartum milking of dairy heifers on postpartum reproduction, udder health, milk production and other associated production characteristics. Pregnant heifers (Holstein, n=21; Jersey n=10) were assigned to either a prepartum milked (premilked, n=15) or control (n=16) group. Premilked heifers were milked twice daily starting 3 weeks prior to anticipated calving dates, and milk yield recorded at each milking. All heifers were evaluated on days 21, 14 and 7 before calving, and udder oedema scores and milk conductivity readings were recorded. Following calving, measurements were taken twice weekly to assess udder oedema, milk conductivity (indicative of udder infection), and reproductive health, which included palpation for uterine tone and uterine position, vaginal electrical impedance (VEI) and the quantification of cross-sectional area of the uterine horns (uterine difference) by transrectal ultrasonography. Uterine tone, uterine position, uterine difference, and VEI did not differ (P>0.10) with treatment. Overall, up to week six inclusive, postpartum premilked heifers had lower (P<0.01) udder oedema scores than control heifers and up to week five inclusive, had lower (P<0.01) milk conductivity readings (indicative of fewer incidences of udder infections) than control heifers. The premilked heifers of both breeds produced more milk (P<0.01) at calving and more milk overall from calving to day 60 postpartum than the control heifers. In summary, udder health and milk production were improved post calving in premilked heifers compared with controls. However, no overt differences in reproductive characteristics were observed between the premilked and control heifers.

Effect of group size on behavior, health, production, and welfare of veal calves.

The objective of this study was to investigate the effect of group size on behavior, growth, health, and welfare of veal calves. Holstein-Friesian bull calves (n=168; 44±3 d of age) were assigned randomly to 1 of 3 treatments of group housing with 2, 4, or 8 calves per pen. The pens used for housing were 3 by 1.20 m (2 calves per pen), 3 by 2.40 m (4 calves per pen), and 3 by 4.80 m (8 calves per pen), supplying a total pen space allowance of 1.82 m2/calf, regardless of pen size. Behavior was recorded from video data throughout the day from 0700 to 1900 h during a single day each month for 5 mo using scan sampling every 5 min within 30-min observation sessions. On d 0, 1, 5, 14, 42, and 70 after grouping, continuous focal sampling around feeding time (30-min intervals before, during, and after feeding) focused on oral and aggressive behaviors. Calves housed in large groups (4 or 8 calves per pen) showed more (P≤0.001) conspecific contact, walking, and standing and less (P<0.001) manipulation of objects, self-licking, and lying when compared to calves housed in small groups (2 calves per pen). Group size had no effect on play behavior (P=0.11) throughout the experiment. During feeding times group size had no (P≥0.07) effect on any behavioral patterns except for duration of conspecific contact (P<0.01). Aggression at feeding time was not (P>0.23) affected by treatment. Group size treatments were similar for hip height change (P=0.41) and heart girth change (P=0.18) over the duration of the experiment; however, both hip height and heart girth increased (P=0.001) with calf age. During mo 1, calves in groups of 8 or 4 coughed more than calves in groups of 2 whereas calves in groups of 8 coughed more than calves in groups of 4 or 2 in mo 2 (treatment×month, P=0.03). Furthermore, during mo 4, calves in groups of 8 had less nasal discharge than calves in groups of 2 or 4 (treatment×month, P=0.02). Ocular discharge, ears, and fecal scores did not differ (P≥0.05) among treatments. Plasma cortisol was not (P≥0.37) affected by group size. The number of veal calves in a group when given the same space did not affect production and physiological indicators of welfare but had a transient effect on health during the 5-mo finishing period. If increased play and social contact and decreased aggression are considered as primary indicators of welfare, group size did not alter calf welfare.