Comparisons of recycled manure solids and wood shavings/sawdust as bedding material -implications for animal welfare, herd health, milk quality and bedding costs in Swedish dairy herds

Increasing shortages and costs of common bedding materials have led dairy farmers in Sweden to consider using recycled manure solids (RMS), which are readily available and low-cost, as an alternative bedding material. The main risks are effects on udder health and milk quality, but RMS could also affect animal welfare and claw health. The advantages and disadvantages of using RMS bedding have not been fully investigated, and findings in other countries cannot be directly applied to Swedish conditions and climate. This observational cross-sectional study investigated the use of RMS as bedding regarding associations with certain aspects of animal welfare, herd health, milk quality, and bedding costs in Swedish dairy herds. Thirty-four dairy farms using RMS or wood shavings/sawdust (each n = 17) were compared. Each farm was visited 2 times during the housing period 2020-2021, once in October-December and once in March-May. Dairy barns were observed, animal welfare was assessed, and free-stall dimensions were measured. Farm owners were interviewed about housing system characteristics, herd performance, and herd management. Data on milk production and herd health were obtained from the Swedish official milk recording scheme for the indoor period October-March. The prevalence of claw disorders and abnormal claw conformation were collected from the national claw health database for the period, October-May. On each farm visit, composite samples of unused bedding outside the barn and used bedding material from the free stalls, respectively, were taken for total bacterial count and dry matter analysis. Samples of bulk tank milk for determination of total bacterial count were taken in connection to the visits. In addition, samples of unused and used bedding material and manure from alleys for analysis of 3 Treponema species associated with digital dermatitis (DD) were gathered and analyzed. Total bacterial count was significantly higher in unused (8.50 log10 cfu/g) and used RMS bedding (9.75 log10 cfu/g) than in wood shavings/sawdust (used 4.74; unused 8.63 log10 cfu/g), but there were no significant differences in bulk milk total bacterial count (median 4.07 versus 3.89 log10 cfu/mL) or somatic cell count (median 243,800 versus 229,200 cells /mL). The aspects of animal welfare that were assessed did not differ significantly between the 2 bedding systems, while the prevalence of total claw disorders (25.9 versus 38.0% of trimmed cows), dermatitis (6.9 versus 16.2% of trimmed cows) and sole ulcers (2.0 versus 4.0% of trimmed cows) were significantly lower in the RMS herds. Treponema spp. were not detected in unused RMS material, but all RMS herds had presence of DD recorded at foot trimming. An economic assessment based on the interview results and price level from winter 2021 revealed that the costs of RMS bedding varied with amount of RMS produced. Thus, RMS is a potential alternative bedding material for dairy cows in Sweden and can be a profitable option for large dairy herds. However, the high level of total bacteria in the material requires attention to bedding and milking routines as well as regular monitoring of herd health.

Genetic evaluations and genome-wide association studies for specific digital dermatitis diagnoses in dairy cows considering genotype x housing system interactions

The present study aimed to use detailed phenotyping for the claw disorder digital dermatitis (DD) considering specific DD stages in 2 housing systems (conventional cubicle barns = CON and compost bedded pack barns = CBPB) to infer possible genotype x housing system interactions. The DD-stages included 2,980 observations for the 3 traits DD-sick, DD-acute and DD-chronic from 1,311 Holstein-Friesian and 399 Fleckvieh-Simmental cows. Selection of the 5 CBPB and 5 CON herds was based on a specific protocol to achieve a high level of herd similarity with regard to climate, feeding, milking system and location, but with pronounced housing system differences. Five other farms had "a mixed system" with 2 sub-herds, one representing CBPB and the other one CON. 899 cows (1530 observations) represented the CBPB system, and 811 cows (1450 observations) the CON system. The average disease prevalence was 20.47% for DD-sick, 13.88% for DD-acute and 5.34% for DD-chronic, with a higher prevalence in CON than in CBPB. After quality control of 50K genotypes, 38,495 SNPs from 926 cows remained for the ongoing genomic analyses. Genetic parameters for DD-sick, DD-acute and DD-chronic were estimated by applying single-step approaches for single-trait repeatability animal models considering the whole data set, and separately for the CON and CBPB subsets. Genetic correlations between same DD traits from different housing systems, and between DD-sick, DD-chronic and DD-acute, were estimated via bivariate animal models. Heritabilities based on the whole data set were 0.16 for DD-sick, 0.14 for DD-acute and 0.11 for DD-chronic. A slight increase of heritabilities and genetic variances was observed in CON compared with the "well-being" CBPB system, indicating a stronger genetic differentiation of diseases in a more challenging environment. Genetic correlations between same DD traits recorded in CON or CBPB were close to 0.80, disproving obvious genotype x housing system interactions. Genetic correlations among DD-sick, DD-acute and DD-chronic ranged from 0.58 to 0.81. SNP main effects and SNP x housing system interaction effects were estimated simultaneously via GWAS considering only the phenotypes from genotyped cows. Ongoing annotations of potential candidate genes focused on chromosomal segments 100 kb upstream and downstream from the significantly associated candidate SNP. GWAS for main effects indicated heterogeneous Manhattan plots for especially for DD-acute and DD-chronic, indicating particularities in disease pathogenesis. Nevertheless, a few shared annotated potential candidate genes, i.e., METTL25, AFF3, PRKG1 and TENM4 for DD-sick and DD-acute, were identified. These genes have direct or indirect effects on disease resistance or immunology. For the SNP x housing system interaction, the annotated genes ASXL1 and NOL4L on BTA 13 were relevant for DD-sick and DD-acute. Overall, the very similar genetic parameters for same traits in different environments and negligible genotype x housing system interactions indicate only minor effects on genetic evaluations for DD due to housing system particularities.

Gait Analysis in Walking and Trotting Dairy Cows on Different Flooring Types with Novel Mobile Pressure Sensors and Inertial Sensors

Mechanical overburdening is a major risk factor that provokes non-infectious claw diseases. Moreover, lameness-causing lesions often remain undetected and untreated. Therefore, prevention of claw tissue overburdening is of interest, especially by analyzing harmful effects within dairy cows’ housing environment. However, objective “on-cow” methods for bovine gait analysis are underdeveloped. The purpose of the study was to apply an innovative mobile pressure sensor system attached at the claws to perform pedobarometric gait analysis. A further goal was the supplementation with accelerative data, generated simultaneously by use of two inertial measurement units (IMUs), attached at metatarsal level. IMU data were analyzed with an automatic step detection algorithm. Gait analysis was performed in ten dairy cows, walking and trotting on concrete flooring and rubber mats. In addition to the basic applicability of the sensor systems and with the aid of the automatic step detection algorithm for gait analysis in cows, we were able to determine the impact of the gait and flooring type on kinematic and kinetic parameters. For pressure sensor output, concrete was associated with significantly (p < 0.001) higher maximum and average pressure values and a significantly smaller contact area, compared to rubber mats. In contrast to walking, trotting led to a significantly higher force, especially under the medial claw. Further, IMU-derived parameters were significantly influenced by the gait. The described sensor systems are useful tools for detailed gait analysis in dairy cows. They allow the investigation of factors which may affect claw health negatively.

[Improvement of claw health of cattle in Switzerland]

INTRODUCTION

The modern technique of cattle hoof care was founded by E. Toussaint Raven in 1977. Environmental risk factors on cattle claws altered in the past 43 years. The change from free ranging to indoor housing, the intensified feeding and the breeding towards traits of high performance have significantly increased the mechanical and chemical stress on the claws. In modern free-stalls, dairy cows are required to walk on hard flooring to feed, drink and get milked. Good hoof health is a basic requirement for cattle welfare. Professional and regular hoof trimming is still considered the most effective measure to promote hoof health in dairy cattle. In order to meet today's requirements and to promote claw health, the Swiss Hoof Trimmers Association (SKV), in collaboration with the Vetsuisse faculties, Universities of Berne and Zurich, and the Bovine Health Service (RGD, Bern) developed and described the Swiss technique of functional claw trimming. The aim was to establish a consistent method, which takes into account the size and bodyweight of the modern cow, the anatomical and physiological characteristics of their claws and includes adaptations counteracting very relevant diseases such as digital dermatitis. The result is a workflow described and illustrated with coloured pictures and consisting of five individual steps based on the technique of E. Toussaint Raven, Additionally, the upcoming Swiss national resource project on long-term improvement of claw health is presented in some detail. The key point of this project is the electronic documentation of clinical findings by the trained professional claw trimmers. This data will later (i) be used to assess the foot health of Swiss cows, (ii) allow to determine the prevalence of foot diseases of cattle in Switzerland and (iii) to monitor the effect of the implementation of foot health concepts. The aim of this work is to combine the findings from science and the practical experience of hoof trimmers in one method, to standardize the applied hoof care in Switzerland and to adapt it to today's hoof health requirements.

A genome-wide association study for susceptibility and infectivity of Holstein Friesian dairy cattle to digital dermatitis

Selection and breeding can be used to fight transmission of infectious diseases in livestock. The prevalence in a population depends on the susceptibility and infectivity of the animals. Knowledge on the genetic background of those traits would facilitate efficient selection for lower disease prevalence. We investigated the genetic background of host susceptibility and infectivity for digital dermatitis (DD), an endemic infectious claw disease in dairy cattle, with a genome-wide association study (GWAS), using either a simple linear mixed model or a generalized linear mixed model based on epidemiological theory. In total, 1,513 Holstein-Friesian cows of 12 Dutch dairy farms were scored for DD infection status and class (M0 to M4.1) every 2 wk for 11 times; 1,401 of these cows were genotyped with a 75k SNP chip. We performed a GWAS with a linear mixed model on 10 host disease status traits, and with a generalized linear mixed model with a complementary log-log link function (GLMM) on the probability that a cow would get infected between 2 scorings. With the GLMM, we fitted SNP effects for host susceptibility and host infectivity, while taking the variation in exposure of the susceptible cow to infectious herd mates into account. With the linear model we detected 4 suggestive SNP (false discovery rate < 0.20), 2 for the fraction of observations a cow had an active lesion on chromosomes 1 and 14, one for the fraction of observations a cow had an M2 lesion on at least one claw on chromosome 1 (the same SNP as for the fraction of observations with an active lesion), and one for the fraction of observations a cow had an M4.1 lesion on at least one claw on chromosome 10. Heritability estimates ranged from 0.09 to 0.37. With the GLMM we did not detect significant nor suggestive SNP. The SNP effects on disease status analyzed with the linear model had a correlation coefficient of only 0.70 with SNP effects on susceptibility of the GLMM, indicating that both models capture partly different effects. Because the GLMM better accounts for the epidemiological mechanisms determining individual disease status and for the distribution of the y-variable, results of the GLMM may be more reliable, despite the absence of suggestive associations. We expect that with an extended GLMM that better accounts for the full genetic variation in infectivity via the environment, the accuracy of SNP effects may increase.

Genomic analysis of claw lesions in Holstein cows: Opportunities for genomic selection, quantitative trait locus detection, and gene identification

Claw lesions are the third most important health issue in dairy cattle, after mastitis and reproductive disorders, and genomic selection is a key component for long-term improvement of claw health. The objectives of this study were to assess the feasibility of a genomic evaluation for claw health in French Holstein cows, explore possibilities to increase evaluation accuracy, and gain a better understanding of the genetic determinism of claw health traits. The data set consisted of 48,685 trimmed Holstein cows, including 9,646 that were genotyped; 478 genotyped sires were also used. Seven claw lesion traits were evaluated using BLUP, genomic BLUP, BayesC, and single-step genomic BLUP, and the accuracies obtained using these approaches were measured through a validation study. The BayesC approach was used to detect quantitative trait locus (QTL) regions associated with the 7 individual traits (digital dermatitis, heel horn erosion, interdigital hyperplasia, sole hemorrhage circumscribed, sole hemorrhage diffused, sole ulcer, and white line fissure) based on their Bayes factor. Annotated genes on these regions were reported. Genomic evaluation approaches generally did not allow for greater accuracies than BLUP, except for single-step genomic BLUP. Accuracies were moderate, but best and worst validation animals were correctly discriminated and showed significant differences in lesion frequencies. A total of 192 QTL regions were identified, including 13 with major evidence or involved for 2 of the traits. A high number of genes were present on these regions, and several had functions associated with the immune system. In particular, the EPYC gene is located close to a major evidence QTL for resistance to digital dermatitis that is also a QTL for interdigital hyperplasia (on chromosome 5, around 20.9 MB) and has been associated with Ehlers-Danlos syndrome in cattle. Genomic selection can be used to improve resistance to individual claw lesions, and several possibilities exist to improve accuracies of genomic evaluations.

Effects of supplementing organic microminerals and methionine during the rearing phase of replacement gilts on lameness, growth, and body composition

Lameness is a primary reason for culling and mortality within a sow herd. This study evaluated the impact of feeding organic trace minerals and methionine (Met) to growing gilts (134 d) on lameness, performance, body composition and claw health (to first parity), productivity (to second parity), and reproductive performance through 2 parities. Young gilts (28.8 ± 8.8 kg of body weight [BW], n = 360) were BW blocked (10 gilts/pen) and randomly allotted to 1 of 4 dietary treatments: control (CON, basal diet); CON plus organic minerals (MIN, at 10, 20, and 50 mg/kg of Cu, Mn, and Zn, respectively; Aplomotec Plus, Tecnología & Vitaminas, S.L, Alforja, Spain); additional Met (MET, at 102% Met: Lys); and MET plus MIN (MM). Feed was provided ad libitum. Lameness, BW, and body composition were measured 7 times during rearing, at gilt service, day 109 of gestation, and first weaning. Gilts fed the MM diet had lower average daily feed intake (5.1%) and final BW (2.1%) than CON gilts (P < 0.05), whereas MIN and MET were intermediate and not different from each other. Similarly, final backfat (BF) was greatest in CON (P < 0.05), whereas CON and MIN increased final loin depth compared with MM (P < 0.05) with MET not being different. During rearing, 7.7% of all gilts presented lameness, which appeared between 106.8 and 129.7 kg BW confidence interval. Gilts that had been or were lame had reduced BW and average daily gain compared with never lame gilts (P < 0.05). Lameness during rearing was highest (P < 0.01) in gilts fed CON diet (14.8%), with no differences amongst MIN (2.0%), MET (5.3%), or MM (6.5%). In the sow herd, 21% of sows showed lameness and 24% of those were associated with claw lesions. At weaning, gilts fed CON diet had highest (P < 0.01) prevalence of lameness (20.8%) with no differences amongst MIN (6.5%), MET (11.1%), or MM (7.6%). Over the first 2 parities, 27.3% of gilts were culled. On farm, lameness was associated with 0.7 more stillborn piglets (P < 0.10), 1 mm more BF loss in first lactation (P < 0.05), and increased weaning-to-estrus by 3 d (P < 0.05). In conclusion, lameness during rearing was decreased by supplementing organic trace minerals, methionine, and their combination, which also reduced lameness during lactation.

Foot and leg conformation traits have a small effect on genomic predictions of claw disorders in Norwegian Red cows

The aim of this study was to evaluate whether the predictive correlation of genomic breeding values (GEBV) for claw disorders increased by including genetically correlated traits as additional information in the analyses. Predictive correlations of GEBV for claw disorders were calculated based on claw disorders only and by analyzing claw disorders together with genetically correlated foot and leg conformation traits. The claw disorders analyzed were corkscrew claw (CSC); infectious claw disorder, including dermatitis, heel horn erosion, and interdigital phlegmon; and laminitis-related claw disorder, including sole ulcer, white line disorder, and hemorrhage of sole and white line. The foot and leg conformation traits included were hoof quality, foot angle, rear leg rear view new, and rear leg rear view old. The data consisted of 183,728 daughters with claw health records and 421,319 daughters with foot and leg conformation scores. A 25K/54K single nucleotide polymorphism (SNP) data set containing 48,249 SNP was available for the analyses. The number of genotyped sires with daughter information in the analyses was 1,093 including claw disorders and 3,111 including claw disorders and foot and leg conformation traits. Predictive correlations of GEBV for CSC, infectious claw disorder, and laminitis-related claw disorder were calculated from a 10-fold cross-validation and from an additional validation set including the youngest sires. Only sires having daughters with claw health records were in the validation sets, thus increasing the reference population when adding foot and leg conformation traits. The results showed marginal improvement in the predictive correlation of GEBV for CSC when including hoof quality and foot angle, both in 10-fold cross-validation (from 0.35 to 0.37) and in the validation including the youngest sires (from 0.38 to 0.49). For infectious claw disorder and laminitis-related claw disorder, including foot and leg conformation traits had no effect on the predictive correlation of GEBV. Claw disorders are novel traits with a limited amount of historical data and, therefore, a small reference population. Increasing the reference population by including sires with daughter information on foot and leg conformation traits had small effect on the predictive correlation of GEBV. However, the small increase in predictive correlation of GEBV for CSC shows a possible gain when including moderate to high genetically correlated traits.

Lameness and foot lesions in Swiss dairy cows: I. Prevalence

Prevalences of foot lesions and lameness were recorded in 1'449 Swiss dairy cows during routine claw-trimming on 78 farms from June 2010 until February 2011. Lameness was present in 14.8 % of cows and on 80.8 % of investigated farms. Highest prevalences were seen for widened white line (80.7 %/100 %), signalling foot lesion (65.6 %/98.7 %), heel-horn erosion (34.2 %/88.5 %), digital dermatitis complex (29.1 %/73.1 %), severe hemorrhages (27.9 %/87.2 %), and Rusterholz' sole ulcers (11.5 %/74.4 %) at cow and herd level, respectively. Lower prevalences were found for subclinical laminitis (5.4 %/47.4 %), chronic laminitis (3.3 %/25.6 %), white line disease (4.7 %/42.3 %), double soles (2.6 %/33.3 %), interdigital hyperplasia (3.1 %/33.3 %), sole ulcers (0.4 %/6.4 %), toe infections caused by faulty claw-trimming (3.9 %/39.7 %) and by injury (0.1 %/2.6 %), deep lacerations (0.4 %/6.4 %), and interdigital phlegmona (0.1 %/1.3 %). Lameness and foot lesions were shown to represent important health problems of dairy cows under the conditions of the typical grass-based production system in Switzerland. Digital dermatitis has developed to the most relevant foot disease with a high impact on welfare of Swiss dairy cows within the past 10 years.