M.M. Schutz

An Interdisciplinary Review of Body Condition Scoring for Dairy Cattle

Abstract In this review, methods for assessing energy reserves, the role of assigning BCS in dairy management, and the impact of varying BCS on animal productivity, health, and reproduction are explored from a whole-system viewpoint. The usefulness, validity, and precision of BCS for assessing body energy reserves are well documented. Generally, BCS decrease in early lactation as cows partition energy from body reserves to support milk production, and they then begin to increase throughout the remainder of lactation. Excessive loss of energy reserves during early lactation, generally associated with cows of higher BCS at calving, often results in impaired health and reproductive performance. Among diseases, the most consistent relationship has been an increased incidence of ketosis for cows with higher BCS at calving. Although published results have varied, either high or low BCS has also been related to greater incidences of metritis, retained placenta, milk fever, lameness, cystic ovaries, dystocia, displaced abomasum, and mastitis. Losses in BCS or the actual BCS are associated with various fertility measures including days to first ovulation, days to first estrus, days to first service, first service conception rate, number of services, calving interval, and embryonic losses. Patterns of BCS change within lactation are under genetic control indicating potential for inclusion of BCS in genetic evaluations. Concerns about subjectivity and the time required for scoring have limited the use of BCS in daily management. An automated BCS might provide a more objective, less time-consuming means of estimating energy reserves in dairy cattle.

The effect of mitochondrial DNA on milk production and health of dairy cattle

Maternal lineage effects, probably indicative of mitochondrial DNA (mtDNA) differences, may be important for milk production and reproductive success in dairy cattle (Bos taurus). Sequence variation of mtDNA in 36 maternal lineages of dairy cattle was studied with animal models to assess effects on milk production and reproductive traits. Cattle within maternal lineages defined by registered pedigrees were assumed to be uniform for the nucleotide sequences examined. Sequence polymorphisms of bovine mtDNA were shown to be associated with milk production, reproduction, and health costs incurred. One particular base-pair substitution was associated with additional production of 842 kg milk and 37 kg milk fat per cow per lactation. Another single base-pair substitution was associated with a decrease of 36 days and one unsuccessful breeding between successive calvings. Effects of this size are economically important and have broad implications in genetic selection of dairy cattle.

Potential for estimation of body condition scores in dairy cattle from digital images.

Body condition scoring, an indirect measure of the level of subcutaneous fat in dairy cattle, has been widely adopted for research and field assessment or for management purposes on farms. The feasibility of utilizing digital images to determine body condition score (BCS) was assessed for lactating dairy cows at the Scottish Agricultural College Crichton Royal Farm. Two measures of BCS were obtained by using the primary systems utilized in the United Kingdom (UK-BCS) and the United States (USBCS). Means were 2.12 (+/-0.35) and 2.89 (+/-0.40), modes were 2.25 and 2.75, and ranges were 1.0 to 3.5 and 1.5 to 4.5 for the UKBCS (n = 2,346) and USBCS (n = 2,571), respectively. Up to 23 anatomical points were manually identified on images captured automatically as cows passed through a weigh station. Points around the hooks were easier to identify on images than points around pins and the tailhead. All identifiable points were used to define and formulate measures describing the cows contour. For both BCS systems, hook angle, posterior hook angle, and tailhead depression were significant predictors of BCS. When the full data set testing only the angles around the hooks was used, 100% of predicted BCS were within 0.50 points of actual USBCS and 92.79% were within 0.25 points; and 99.87% of predicted BCS were within 0.50 points of actual UKBCS and 89.95% were within 0.25 points. In a reduced data set considering only observations in which the tailhead depression angle was available, adding the tailhead depression to models did not improve model predictions. The relationships of the calculated angles with USBCS were stronger than those with UKBCS. This research demonstrates the potential for using digital images for assessing BCS. Future efforts should explore ways to automate this process by using a larger number of animals to predict scores accurately for cows across all levels of body condition.

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.

Comparison of Reticular and Rectal Core Body Temperatures in Lactating Dairy Cows

The Phase IV Cattle Temperature Monitoring System (CTMS; Phase IV Engineering Inc., Boulder, CO) marketed by MaGiiX (MaGiiX Inc., Post Falls, ID) uses a passive bolus equipped with a temperature sensor, a panel reader placed at a parlor entrance or exit to query the bolus, and a software package to collect, analyze, and view data. The biologically inert bolus resides in the cows reticulum and is queried each time the cow passes the reader. Reticular temperature (RETT) and rectal temperature (RECT) were recorded simultaneously in the milking parlor exit lane in 4 consecutive milkings in each of 4 seasons, totaling 16 measurements per cow. The RETT were obtained by using the phase IV CTMS, whereas the RECT were obtained manually with a GLA M750 thermometer (GLA Agricultural Electronics, San Luis Obispo, CA). Data were edited to remove RETT likely to have been affected by a recent drinking bout. For the 2,042 observations used in analyses, means (+/-SD) were 39.28 (+/-0.41), 38.83 (+/-0.36), and 0.45 (+/-0.33) for RETT, RECT, and the difference between RETT and RECT, respectively. The RETT and RECT were strongly correlated (r = 0.645). The relationship between RETT and RECT varied by season, milking, housing system, and parity. Because dairy producers and veterinarians are accustomed to viewing rectal temperatures, equations to adjust reticular temperatures to a rectal-based scale may increase the utility of the phase IV CTMS. The resulting conversion equations were RECT = 19.23 + 0.496(RETT) for the a.m. milking and RECT = 15.88 + 0.587(RETT) for the p.m. milking.

Impact of Intake Water Temperatures on Reticular Temperatures of Lactating Dairy Cows

Automatic temperature recording may allow early detection of disease, estrus, heat stress, and the onset of calving. The phase IV Cattle Temperature Monitoring System (MaGiiX Inc., Post Falls, ID) utilizes a passive bolus equipped with a temperature sensor, a stationary panel reader to query the bolus, and software to collect, analyze, and display data. One potential limitation to collection of reticular temperatures is the effect of water temperature and consumption on recorded temperatures. Two replicated 3 x 3 Latin square experiments were conducted at the Purdue Dairy Research and Education Center to assess the impact of water intake on reticular temperatures using the Cattle Temperature Monitoring System. Nine high-producing, mid-lactation, second-parity cows with low somatic cell counts were selected. Before administering a water treatment, access to feed and water was restricted for at least 2 h. Baseline reticular temperatures were established from measurements before water intake. In experiment 1, treatments were 25.2 kg of hot water (34.3 degrees C +/- 1.0), warm water (18.2 degrees C +/- 0.4), or cold water (7.6 degrees C +/- 0.4). In experiment 2, treatments were 18.9 kg of body-temperature water (38.9 degrees C +/- 0.2), cold water (5.1 degrees C +/- 0.4), or control (no water). Following water intake, reticular temperatures were collected for 3 h. In experiment 1, an initial dramatic decrease in reticular temperature was observed followed by a gradual increase toward baseline. Least squares means for maximum drop in temperature were 8.5 +/- 0.5, 6.9 +/- 0.5, and 2.2 +/- 0.5 degrees C for cold, warm, and hot water treatments, respectively. Yet at 3 h, reticular temperatures did not return to the baseline. In experiment 2, control cows remained within the baseline confidence interval through the observation period, and cows receiving body temperature water experienced an initial decrease in temperature (0.4 +/- 0.2 degrees C) with a return to within the baseline confidence interval within 15 min. Cows receiving cold water did not return to within the baseline confidence interval after a large decrease of 9.2 +/- 0.2 degrees C during the 3-h observational period. Moreover, a regression analysis of continued ascent in temperatures predicted that temperatures would return to baseline within 3.5 h. These results demonstrate that, when cows consume large quantities of cold water, the effect of water intake is sizable and sustained. The value of reticular temperatures for daily monitoring in a production setting hinges largely on the implications of this impact.

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.

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.

Effects of rubber flooring during the first 2 lactations on production, locomotion, hoof health, immune functions, and stress1

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 pains 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.