Cull Cows Research Articles

Alternative treatment of bovine mastitis

The treatment of mastitis is based mainly on the use of antibiotics. However, in recent times, an increase in resistance phenomena and the presence of residues in milk and their derivatives has been reported. Few studies have focused on the treatment of mastitis by homeopathy elsewhere or in Algeria. The objective of this current study aimed to clarify in particular the interest of homeopathy in the treatment of mastitis. The study was carried out on two dairy farms on a total of 14 cows located in Laghouat region (southern Algeria). Before the start of the experiment, a tolerance test was performed on two cull cows free from any apparent infection (except mastitis). Local and general reactions were noted at specific times. A total of 31 mammary quarters received 4 intramammary injections of a homeopathic preparation containing several natural products every 12h over 48h. A clinical examination and an analysis of the milk samples on D0, D7 and D14 were performed on all cows and the conclusion was made on the day 14. Data showed a very good tolerance to the homeopathic preparation and a 75% cure rate of the clinical mastitis. An improvement with a decrease in CMT score was also noted. In addition, healing rates of 51.85% for subclinical mastitis on D7 and 59.29% on D14 were also reported. Ultimately, homeopathy could, in some cases, represent an alternative to antibiotic therapy and bring an advantage to breeders. Further investigations should be performed in the future.

Survival analysis of dairy cows in the Netherlands under altering agricultural policy

Culling of underperforming dairy cows by replacement heifers is a fundamental part of Dutch dairy farm management. Changes in national agricultural policies can influence farmers’ culling decisions. The objective of this study was to analyse the relevancy of cow-level risk factors for survival of Dutch dairy cows under perturbations due to national policy changes related to the -milk quota abolishment of 2015 and the phosphate regulations since 2017. For this purpose, an accelerated failure time model was fitted on-longitudinal dairy cows’ data at national level covering the period 2009−2019. The associated cow-level risk factors for culling such as lactation value (relative production level), parity number, rolling average of inseminations over all parities, very high fat-protein ratio (highFPR) and very low fat-protein ratio (lowFPR) in early lactation, test-day somatic cell count, were fitted in the model. Along with these, a factor representing three target policy periods, namely Milk Quota period (MQ), Post-Milk Quota period (PMQ) and Phosphate regulation period (PH) were fitted. The mean survival age for all producing cows was 441 weeks overall. The predicted median survival time for the policy periods MQ, PMQ and PH were 273 weeks, 271 weeks and 256 weeks, respectively. Risk factors such as lactation value, parity and highFPR, rolling average of inseminations over all parities were positively associated with survival time in all three policy periods. Risk factors such as test-day somatic cell count and lowFPR were negatively associated with survival time in all three policy periods. In conclusion, this study demonstrated the differences in survival of Dutch dairy cows in response to changing agricultural policy. The association of cow-level risk factors for culling was consistent across the three evaluated policy periods.

Invited Review: The welfare of cull dairy cows

ABSTRACT Purpose The purpose of this invited review was to identify and discuss (a) the welfare issues that can occur when cull dairy cows are sent for slaughter, (b) factors that can affect the occurrence and severity of these issues and how they relate to on-farm management decisions, (c) measures that can mitigate these issues, and (d) proposals to improve the welfare of cull dairy cows. Sources Peer-reviewed literature, book chapters, reports, and guidance documents were sources of information. Synthesis Severe welfare issues occur when some cull dairy cows that are not fit for the intended journey are transported to slaughter. These issues are even greater if compromised cows are sent to slaughter via an auction market. The decision to send a cull cow to slaughter needs to be made before the cow becomes unfit for the likely journey. If a cow becomes unfit for transport, it should be euthanized on the farm. Some cull cows arrive at slaughter plants and are observed at markets with distended udders, severe lameness, and disease. The numbers of cows with these severe welfare issues could be reduced by improved on-farm decision making about when and how to manage cows with health issues, when to euthanize sick or injured cows, and when a cow is fit for transport and for sale at a market. Dairy producers need to understand the welfare implications of how they manage their cull dairy cows, and that some changes in their management practices are required. Conclusions and Applications This review identified that research on the assessment of the fitness of cull dairy cows for transport and on the factors that influence their welfare during transport and marketing are required. Research about how to motivate dairy producers to incorporate the welfare implications of their management of cull cows into their culling decisions and how to increase their use of industry recommendations about the care of cull cows are priorities.

Carcass and Primal Composition Predictions Using Camera Vision Systems (CVS) and Dual-Energy X-ray Absorptiometry (DXA) Technologies on Mature Cows

This study determined the potential of computer vision systems, namely the whole-side carcass camera (HCC) compared to the rib-eye camera (CCC) and dual energy X-ray absorptiometry (DXA) technology to predict primal and carcass composition of cull cows. The predictability (R2) of the HCC was similar to the CCC for total fat, but higher for lean (24.0%) and bone (61.6%). Subcutaneous fat (SQ), body cavity fat, and retail cut yield (RCY) estimations showed a difference of 6.2% between both CVS. The total lean meat yield (LMY) estimate was 22.4% better for CCC than for HCC. The combination of HCC and CCC resulted in a similar prediction of total fat, SQ, and intermuscular fat, and improved predictions of total lean and bone compared to HCC/CCC. Furthermore, a 25.3% improvement was observed for LMY and RCY estimations. DXA predictions showed improvements in R2 values of 26.0% and 25.6% compared to the HCC alone or the HCC + CCC combined, respectively. These results suggest the feasibility of using HCC for predicting primal and carcass composition. This is an important finding for slaughter systems, such as those used for mature cattle in North America that do not routinely knife rib carcasses, which prevents the use of CCC.

114 What Is the Impact of Dairy Influence Cattle on the Traditional Beef Industry Structure?

Abstract The U.S. cow inventory includes approximately 31 million beef cows and 9 million dairy cows, so flow of cattle from dairies into beef production influences the traditional beef industry structure. Dairy-influenced cattle have historically entered the beef supply chain as cull cows and calf-fed Holstein steers. Culled dairy cows account for approximately half of the cows harvested in the United States annually. Fed steers and heifers of dairy influence are estimated to account for 15% of annual steer and heifer slaughter. Advancements in data availability, genomics, and reproductive technologies have enabled more precise selection of dairy replacement heifers and more pregnancies to be allocated to a terminal sire. Recently, the use of beef semen to breed dairy cows that are not desirable for producing replacement heifers has become more widespread. Beef-on-dairy calves are often moved to calf ranches shortly after birth where they are weaned and grown before transitioning to traditional grow yards or feedlots. In comparison to traditional range beef production, calves of dairy origin are weaned at a younger age, have more restricted mobility early in life, and are fed a delivered ration for a greater number of days. While carcasses of dairy-originated fed cattle excel in subcutaneous leanness and marbling, calves originating from dairies typically experience greater morbidity, poorer feed conversion, and poorer dressed yields compared to native fed cattle. Future opportunities to optimize beef production from the dairy herd include refining sire selection to consistently produce high quality calves, reducing variation in calfhood management, and identifying optimal nutrition and growth technology programs for calves from dairies.

Associations between the breeding values of Holstein-Friesian bulls and longevity and culling reasons of their daughters

Taking into account functional traits in the breeding practice should lead to a longer productive life of cows. However, despite the increased contribution of these traits in bull selection indices, their daughters are frequently culled as early as the 2nd or 3rd lactation. The problem is whether and to what extent the genetic potential of animals is realized in the production practice. Therefore, the purpose of this study was to determine the associations between the breeding value (BV) of bulls and their daughters for cow longevity and culling reasons in the Holstein-Friesian cattle population in Poland. Data for 532 062 cows culled in 2012, 2015, and 2018 were analyzed. A majority of 5 045 cow sires originated from Poland, Germany, France, the Netherlands, and the United States. The highest variation in the contribution of culling reasons was for the cows culled at the age of 2–4 years. The contribution of the culling reasons, analyzed in relation to the cow culling age, remained similar and the only exception was culling because of old age, for which a significant increase was observed only for the culling age of at least 9 years (13.8%), which was reached by only 7.3% of the cows. The sires were characterized by generally high BV for conformation and reproductive traits. However, they had, at most, the average genetic potential for functional longevity. There were a number of beneficial associations found between the BV of bulls and the distribution of culling reasons in their daughters. For example, it concerns relations between the somatic cell score in milk and culling due to udder diseases and low milk yield, between the interval from calving to first insemination and low milk yield, between the protein yield and old age, or between the BV for certain conformation traits (size, udder) and cow culling due to age. In these cases, as the BV increased for a given trait, the contribution of the corresponding cow culling reason tended to decrease. Our study showed that it seems reasonable to consider Holstein-Friesian cows aged at least 9 years at culling to be long-living animals. This is primarily evidenced by the rapid increase in the culling due to old age in relation to younger cows. Nowadays the above age limit can be suggested as a criterion of longevity for Holstein-Friesian cows but the criterion should be updated to the relation genotype-environment-economy that tends to change over time.

Estimación de pérdidas económicas causadas por Trypanosoma vivax en un rodeo lechero de Argentina

En Argentina T. vivax fue descrito por primera vez en 2006 afectando ganado de carne de la Provincia de Formosa. Durante el verano/otoño de 2016/2017 se observaron los primeros brotes en la zona central de la Provincia de Santa Fe, afectando algunos rodeos lecheros. Se describe el impacto que este hemoparásito produjo en un establecimiento lechero con 220 vacas totales, donde los síntomas principales fueron abortos (n=17), diarrea, mala condición corporal, baja o nula producción de leche y muerte de vacas (7,5%). Las pérdidas totalizaron 58.802 USD considerando los abortos, muertes de vacas, venta de animales improductivos y gastos por tratamiento específico. Por tratarse de una enfermedad desconocida para la zona, la demora en realizar el diagnóstico exacerbó las pérdidas. El tratamiento de la totalidad de los bovinos adultos con diminazene detuvo el brote, siendo económicamente justificable su aplicación.

Effects of management decisions on genetic evaluation of simulated calving records using random regression

The objective of this study was to evaluate the effects of various data structures on the genetic evaluation for the binary phenotype of reproductive success. The data were simulated based on an existing pedigree and an underlying fertility phenotype with a heritability of 0.10. A data set of complete observations was generated for all cows. This data set was then modified mimicking the culling of cows when they first failed to reproduce, cows having a missing observation at either their second or fifth opportunity to reproduce as if they had been selected as donors for embryo transfer, and censoring records following the sixth opportunity to reproduce as in a cull-for-age strategy. The data were analyzed using a third-order polynomial random regression model. The EBV of interest for each animal was the sum of the age-specific EBV over the first 10 observations (reproductive success at ages 2-11). Thus, the EBV might be interpreted as the genetic expectation of number of calves produced when a female is given 10 opportunities to calve. Culling open cows resulted in the EBV for 3-yr-old cows being reduced from 8.27 ± 0.03 when open cows were retained to 7.60 ± 0.02 when they were culled. The magnitude of this effect decreased as cows grew older when they first failed to reproduce and were subsequently culled. Cows that did not fail over the 11 yr of simulated data had an EBV of 9.43 ± 0.01 and 9.35 ± 0.01 based on analyses of the complete data and the data in which cows that failed to reproduce were culled, respectively. Cows that had a missing observation for their second record had a significantly reduced EBV, but the corresponding effect at the fifth record was negligible. The current study illustrates that culling and management decisions, and particularly those that affect the beginning of the trajectory of sustained reproductive success, can influence both the magnitude and accuracy of resulting EBV.

The state of dairy cattle breeding in the Kurgan region

The purpose of the work was to analyze the state of dairy cattle breeding in the Kurgan region. In the region measures are systematically taken to improve the efficiency of the organization of selection and breeding work, improve reproduction traits, introduce advanced feeding methods, and organize artificial insemination of farm animals. Breeding work with dairy cattle in the region is aimed at creating animals that combine the adaptive properties and valuable features of Black-and-White cattle of the Trans-Urals with high productivity and suitability for intensive technology. It has been established that the average milk yield for 305 days of lactation for the controlled livestock in the region in 2019 was 6558 kg of milk. This was less than in the previous year by 0,73 % or 48 kg. According to the results of 2019 the average milk yield of cows in stud farms was 8098 kg, which was by 6,6 % less than in 2018. Pedigree breeding units worked more successfully where the average milk yield of cows increased by 1,54 % and amounted to 6777 kg. The productivity of cows in stud farms was by 19,5 % higher than in pedigree breeding units. Average age of cow culling in all categories of farms in the region in 2019 amounted to 3,4 calving, which was at the level of previous years. This indicator was slightly higher for pedigree breeding units in 2019, it was 3,9 calving. The main reason for the culling of animals is gynecological diseases for this reason 22,56 % of the cows in the farms in the region were culled, and in pedigree breeding units 30,34 % of cows. Recently, the main focus in the Kurgan region is on obtaining animals with a high proportion of genes for Holstein breed.

EFFICIENCY OF APPLICATION OF THE PREPARATION ON THE BASIS OF IODINE FOR MASTITIS IN COWS

The article presents the results of establishing the effectiveness of the use of an experimental preparation based on iodine for various forms of cow mastitis in a farm for the production of commercial milk. Inflammation of the mammary gland is the most common condition in productive herds of cows. Subclinical mastitis, which does not manifest with typical clinical signs for this pathology, is a particular health hazard, but qualitative changes in milk are determined by laboratory tests. Also huge economic losses on farms are recorded during the diagnosis of clinical forms of mastitis in the livestock, which often lead to premature culling of cows, a decrease in the quantity and quality of milk received from them. A set of measures for the diagnosis, treatment and prevention of mastitis also requires constant expenditure of funds. The work was carried out during 2020 in a farm that specializes in the production of commercial milk. The experimental drug under study contains iodine as the main active ingredient, which has a pronounced bactericidal and bacteriostatic effect against a wide range of microorganisms - causative agents of mastitis. It also has a general stimulating effect on the immune system of the udder. As synergistic components, the experimental drug contains compounds with pronounced analgesic, decongestant and astringent effects at the site of the development of the pathological process. At the first stage of the research, the influence of the experimental drug on the qualitative characteristics of milk was determined.
 The number of somatic cells was determined in milk after application of the experimental agent after 24, 48, 72 hours and 7 days. At the second stage of the research, we compared the effectiveness of various methods for diagnosing subclinical mastitis in cows during the dry period.
 When we analyzed the data obtained on the effect of the investigated experimental drug based on iodine on the number of somatic cells in the milk of cows with subclinical and clinical (catarrhal and purulent-catarrhal) forms of mastitis, we established a positive dynamics of their gradual decrease. This indicator reached the maximum level of decrease on the seventh day after application of the drug, both in subclinical and in clinical forms (catarrhal and purulent-catarrhal) mastitis, which amounted to 298.6 ± 11.6; 308.6 ± 14.4 and 328.6 ± 34.4 th./ml. The introduction of a drug with a similar compositional composition for the main active ingredients, it was not possible to achieve a similar effect on the dynamics of the reduction of somatic cells.

Are Marbling and the Prediction of Beef Eating Quality Affected by Different Grading Sites?

For the European abattoirs, the preferred carcass grading site is at the fifth rib, and cutting at the tenth rib as in Australia could lead to a lower economic value of the carcass. Therefore, the objective of this study was to compare the grading scores of marbling and the meat and fat color on Musculus longissimus thoracis et lumborum (LTL) at the fifth and the tenth thoracic vertebrae. The consequences on the prediction of beef eating quality using the Meat Standards Australia (MSA) grading scheme were also evaluated for cull cows, which produce the majority of beef consumed in France. Carcasses from 208 French cattle, mainly Limousine cows, were graded according to the Australian Beef Carcase Chiller Assessment System (ABCAS) used for the implementation of the MSA system. The results indicate that there was no significant difference in the marbling score, between the fifth and the tenth ribs and hence in the MSA index and in the Global Quality [meat quality (MQ4)] scores calculated from marbling values from either the fifth rib or the tenth rib. However, the meat color at the tenth rib was significantly darker than that at the fifth rib (p < 0.01), and the fat color at the tenth rib was significantly yellower than that at the fifth rib (p < 0.001). The results of this study suggest that the grading of marbling can be conducted on M. LTL at the fifth thoracic vertebrae for routine use of the MSA system in France and, more generally, in Europe. However, further investigation and adjustment would be needed for other critical MSA scores (such as rib fat thickness) while respecting the European carcass quartering practices.

Prediction of genetic merit for live weight and body condition score in dairy cows using routinely available linear type and carcass data

Accurate estimates of genetic merit for both live weight and body condition score (BCS) could be useful additions to both national- and herd-breeding programs. Although recording live weight and BCS is not technologically arduous, data available for use in routine genetic evaluations are generally lacking. The objective of the present study was to explore the usefulness of routinely recorded data, namely linear type traits (which also included BCS but only assessed visually) and carcass traits in the pursuit of genetic evaluations for both live weight and BCS in dairy cows. The data consisted of on-farm records of live weight and BCS (assessed using both visual and tactile cues) from 33,242 dairy cows in 201 commercial Irish herds. These data were complemented with information on 6 body-related linear type traits (i.e., stature, angularity, chest width, body depth, BCS, and rump width) and 3 cull cow carcass measures (i.e., carcass weight, conformation, and fat cover) on a selection of these animals plus close relatives. (Co)variance components were estimated using animal linear mixed models. The genetic correlation between the type traits stature, angularity, body depth, chest width, rump width, and visually-assessed BCS with live weight was 0.68, -0.28, 0.43, 0.64, 0.61, and 0.44, respectively. The genetic correlation between angularity and BCS measured on farm (based on both visual and tactile appraisal) was -0.79; the genetic and phenotypic correlation between BCS assessed visually as part of the linear assessment with BCS assessed by producers using both tactile and visual cues was 0.90 and 0.27, respectively. The genetic (phenotypic) correlation between cull cow carcass weight and live weight was 0.81 (0.21), and the genetic (phenotypic) correlation between cull cow carcass fat cover and BCS assessed on live cows was 0.44 (0.12). Estimated breeding values (EBV) for live weight and BCS in a validation population of cows were generated using a multitrait evaluation with observations for just the type traits, just the carcass traits, and both the type traits and carcass traits; the EBV were compared with the respective live weight and BCS phenotypic observations. The regression of phenotypic live weight on its EBV from the multitrait evaluations was 1.00 (i.e., the expectation) when the EBV was generated using just linear type trait data, but less than 1 (0.83) when using just carcass data. However, the regression changed across parities and stages of lactation. The partial correlation (after adjusting for contemporary group, parity by stage of lactation, heterosis, and recombination loss) between phenotypic live weight and EBV for live weight estimated using the 3 different scenarios (i.e., type only, carcass only, type plus carcass) ranged from 0.38 to 0.43. Although the prediction of phenotypic BCS from its respective EBV was relatively good when using just the linear type trait data (regression coefficient of 0.83 with a partial correlation of 0.22), the predictive ability of BCS EBV based on just carcass data was poor and should not be used. Overall, linear type trait data are a useful source of information to predict live weight and BCS with minimal additional predictive value from also including carcass data. Nonetheless, in the absence of linear type trait data, information on carcass traits can be useful in predicting genetic merit for mature cow live weight. Prediction of cow BCS from cow carcass data is not recommended.

Is meat from cull cows tougher?

Meat from cull cows is traditionally sold in Australia for mincemeat, but this study examined whether there is potential to add value by identifying meat of higher quality from older cattle. Dentition and ossification score were recorded for 173 Angus cattle of known age, ranging from 26 months to 12.6 years. Longissimus and semitendinosus muscles were sampled to assess the effect of chronological age on shear force and connective tissue. Age explained variation in shear force of the semitendinosus better than in the longissimus muscle, but had little effect on shear force values per se. At 2 days postmortem, 18% of the longissimus muscles were classified as tender reaching 65% as ageing extended to 14 days. Soluble collagen was a better predictor of age than total collagen. This study shows that the current practice of routinely selling meat from culled cows as mincemeat overlooks a valuable opportunity to grade and sell a significant proportion at higher price as prime cuts.

Intramuscular collagen characteristics and expression of related genes in skeletal muscle of cull cows receiving a high-energy diet

We aimed to investigate differences in the synthesis and metabolism of intramuscular collagen in the Longissimus thoracis (LT) muscle between heifers and cull-cows fed high-energy diet. Ten cull-cows, (74.9 ± 3.2 months age, weighing 536 ± 14.55 kg) and ten heifers (18.4 ± 3.2 months age, weighting 310.5 ± 14.5 kg) were fed with high-energy diets for 150 days. The total collagen content did not differ between treatments. Greater collagen solubility was observed in heifers than cull-cows, although no differences in lysyl oxidase activity were observed between treatments. No differences were observed for mRNA expression of CO1A1, MMP2, MMP9 and TIMP2 between treatments. However, cull-cows presented greater mRNA expression of COL3A1, TIMP1 and TIMP3 than heifers. Our data give no indication that feeding a high-energy diet to cull-cows decreases the concentration of intramuscular collagen in the LT muscle or increases its solubility in respect to the collagen solubility in LT muscles from heifers on the same diet.

Controlled trial of the effect of negative dietary cation-anion difference prepartum diets on milk production, reproductive performance, and culling of dairy cows

Our objective was to assess the effects of feeding negative dietary cation-anion difference (DCAD) prepartum diets on milk production, reproductive performance, and culling. Cows from 4 commercial farms in Ontario, Canada were enrolled in a pen-level controlled trial from November 2017 to April 2019. Close-up pens (1 per farm) with cows 3 wk before calving were randomly assigned to a negative DCAD (TRT; -108 mEq/kg of dry matter; target urine pH 6.0-6.5) or a control diet (CON; +105 mEq/kg of dry matter with a placebo supplement). Each pen was fed TRT or CON for 3 mo (1 period), and then switched to the other treatment for the next period (4 periods per farm). Data from 15 experimental units (8 pen treatments in TRT and 7 in CON), with a total of 1,086 observational units (cows), were included. The effect of treatment on milk yield at the first 3 milk recording tests of lactation was assessed with linear regression models accounting for repeated measures. The risk of pregnancy at first artificial insemination and culling by 30, 60, and 305 d in milk (DIM) were analyzed with logistic regression models, and effects on time to first AI, pregnancy, and culling were assessed with Cox proportional hazards models. All models included treatment, parity, and their interactions, accounting for pen-level randomization and clustering of animals within farm with random effects, giving 10 degrees of freedom for treatment effects. Multiparous cows fed TRT produced more milk at the first (42.0 vs. 38.8 ± 1.2 kg/d) and second (44.2 vs. 41.7 ± 1.3 kg/d) milk tests. However, multiparous cows fed TRT tended to have 0.2 percentage units less milk fat content at these tests. Although multiparous cows fed TRT tended to have greater energy-corrected milk at the first test (least squares means ± standard error: TRT = 46.1 ± 0.9 vs. CON = 43.8 ± 1 kg/d), there were no differences observed in energy-corrected milk at the second or third tests. In primiparous cows, there was no effect of treatment on milk production. Multiparous cows fed TRT had greater pregnancy to first insemination (TRT = 42 ± 3 vs. CON = 32 ± 4%) and tended to have shorter time to pregnancy [hazard ratio (HR) = 1.20; 95% CI: 0.96-1.49]. In primiparous cows fed TRT, time to pregnancy was increased (HR = 0.76; 95% CI: 0.59-0.99). Culling by 30 DIM tended to be less in TRT (3.3 ± 1.1%) than CON (5.5 ± 1.8%). No effect of treatment on culling by 305 DIM was detected in primiparous cows, but in multiparous cows, the TRT diets decreased the odds of culling (21.3 ± 1.9 vs. 31.7 ± 2.8%) and daily risk of culling to 305 DIM (HR = 0.64; 95% CI: 0.46 to 0.89). Under commercial herd conditions, prepartum negative DCAD diets improved milk production and reproductive performance, and reduced culling risk in multiparous cows. In primiparous cows, TRT diets had no effect on milk yield or culling, but increased the time to pregnancy. Our results suggest that negative DCAD diets should be targeted to multiparous cows.

The Use of Artificial Neural Networks and a General Discriminant Analysis for Predicting Culling Reasons in Holstein-Friesian Cows Based on First-Lactation Performance Records.

Simple SummaryRoutinely collected data on the performance of dairy cows are a valuable source of information on the beginning, course, and completion of their productive life. As a result, when using sufficiently accurate methods, one can analyze and optimize the milk production process at a herd level from the breeding and economic point-of-view. In this context, it is important to have a possibility to early predict culling reasons for cows, since, in the case of finding an effective method, it would be possible to modify breeding actions and farm management practices without anticipating the end of the animals’ productive lives. Therefore, the aim of the present study was to verify whether artificial neural networks and a general discriminant analysis may be an effective tool for predicting the culling reasons in cows based on routinely collected first-lactation data. It turned out that they were most effective in predicting culling due to old age and reproductive problems. It is significant because infertility is one of the conditions that are the most difficult to eliminate in dairy herds.The aim of the present study was to verify whether artificial neural networks (ANN) may be an effective tool for predicting the culling reasons in cows based on routinely collected first-lactation records. Data on Holstein-Friesian cows culled in Poland between 2017 and 2018 were used in the present study. A general discriminant analysis (GDA) was applied as a reference method for ANN. Considering all predictive performance measures, ANN were the most effective in predicting the culling of cows due to old age (99.76–99.88% of correctly classified cases). In addition, a very high correct classification rate (99.24–99.98%) was obtained for culling the animals due to reproductive problems. It is significant because infertility is one of the conditions that are the most difficult to eliminate in dairy herds. The correct classification rate for individual culling reasons obtained with GDA (0.00–97.63%) was, in general, lower than that for multilayer perceptrons (MLP). The obtained results indicated that, in order to effectively predict the previously mentioned culling reasons, the following first-lactation parameters should be used: calving age, calving difficulty, and the characteristics of the lactation curve based on Wood’s model parameters.

A conceptual model of the human-animal relationships dynamics during newborn handling on cow-calf operation farms

Neonate calves are usually handled a day after birth for navel care and identification. During this procedure the newly calved cows usually become agitated and, in some cases, exhibit aggressive behavior toward humans, increasing the risk of accidents for both, humans and animals. In order to understand the dynamic relationships between cow, calf, and cowhand's behavior expressed in this particular situation, a conceptual model was built by using the system dynamics methodology. Three dynamic hypotheses were formulated regarding the cause-effect relationship between: i) livestock-handling quality and maternal aggressiveness; ii) livestock-handling quality and newborn calf reactivity, and; iii) newborn calf reactivity and maternal aggressiveness. The first two hypotheses indicated that the improvement (increase) in handling quality will cause an effect in the opposite direction, decreasing cow's aggressiveness and calf's reactivity towards the cowhands. The third hypothesis indicated that the greater the calf's reactivity, the greater will be the cow's aggressiveness, interconnecting cow-calf behaviors. Moreover, the cow, calf, and cowhand subsystems are also comprised of other variables such as human and animal welfare and the occurrence of labor accidents. The combination of these three subsystems constituted a complex general dynamic model highlighting the connection among all agents involved in newborn handling procedure. Despite the complexity it is possible to identify components that promote, simultaneously, human and animal welfare when carrying out newborn calves handling procedures, offering opportunities to develop and adopt system management strategies. In this way, to reduce the risks of labor accidents and the impoverishment of overall welfare it is necessary to focus on three different factors, as follow: i) human behavior, ii) animal behavior, and iii) handling facilities. Thus, it is recommended to implement human capacity-building courses, the culling of aggressive cows and the use of appropriate facilities for the handling of newborn calves.

Immunization with a novel recombinant protein (YidR) reduced the risk of clinical mastitis caused by Klebsiella spp. and decreased milk losses and culling risk after Escherichia coli infections

The primary objective of this study was to evaluate the protective efficacy of a novel recombinant subunit vaccine containing the protein YidR (rYidR) against clinical mastitis (CM) caused by Klebsiella spp. and Escherichia coli. Given that E. coli infection is known to cause metritis, we also evaluated the effect of rYidR vaccination on the incidence of metritis and conception at the first artificial insemination. Retained placenta and abortion incidence, milk production and composition, and serological responses to specific antigens were also evaluated. In total, 3,107 cows were blocked by parity and randomly allocated into 1 of 3 treatment groups: experimental recombinant subunit vaccine containing the YidR protein (rYidR); commercial vaccine composed of Klebsiella pneumoniae siderophore receptors and porin protein (Kleb-SRP; KlebVax, Epitopix, Willmar, MN); and sterile water adjuvanted with aluminum hydroxide (20%; placebo). Vaccinations were performed at the dry-off for cows, and at 223 ± 3 d of pregnancy for pre-fresh heifers. A second administration was given at 21 ± 3 d after the first injection. Vaccination with rYidR significantly reduced the incidence of CM caused by Klebsiella spp. (3.2%) when compared with the placebo (5.1%) group. No difference was observed on risk of Klebsiella CM between Kleb-SRP (5.9%) and placebo groups. Cows in the rYidR group that experienced E. coli CM had a lower risk of death or culling (12.5%) compared with the Kleb-SRP (27.6%) and placebo groups (27.8%). Furthermore, among cows that developed E. coli CM, rYidR-immunized cows produced more milk than did cows in the placebo and Kleb-SRP groups. Regardless of CM occurrence, rYidR-immunized cows tended to have higher milk production up to the eighth month of lactation than cows in the other groups. No significant effect of treatment was observed on the overall incidence of abortion and metritis; however, the risk of retained placenta tended to be lower for the rYidR group (4.7%) compared with the placebo group (6.7%). In addition, primiparous cows in the rYidR group had the highest conception risk at the first artificial insemination (48.3%) compared with the placebo (39.5%) group, and no significant difference was observed when the Kleb-SRP (40.1%) group was compared with the placebo group. Generally, higher antibody serum titers (IgM and IgG) were observed for the immunized groups compared with the placebo. In conclusion, the rYidR vaccine reduced the risk of CM caused by Klebsiella spp. and the mortality or culling of cows with E. coli infections. Other benefits of the novel vaccine include maintenance of milk production after CM caused by E. coli, and higher conception risk at the first service in primiparous cows compared with cows in the placebo and Kleb-SRP groups.

Association of blood calcium concentration in the first 3 days after parturition and energy balance metabolites at day 3 in milk with disease and production outcomes in multiparous Jersey cows

Research exploring specific associations of markers of negative energy balance and Ca in postpartum Jersey cows with lactation performance is lacking. Our objectives were to evaluate the associations of total Ca concentration (tCa) measured at 1 through 3 d in milk (DIM) and free fatty acids (FFA), β-hydroxybutyrate (BHB), and glucose measured at 3 DIM with (1) the risk of multiparous Jersey cows being diagnosed with early-lactation diseases and culling, (2) milk production in the first 9 wk of lactation, and (3) the risk of pregnancy in the first 150 DIM. A cohort study was performed in 1 dairy herd in Texas. Multivariable Poisson regression models were built to evaluate the association of the analytes of interest with the risks of early-lactation diseases and culling in the first 60 DIM (i.e., binary outcomes). Linear mixed models were used to evaluate the association of the analytes of interest with milk production within the first 9 wk of lactation, and a Cox proportional hazard model was built to assess the risk of pregnancy within 150 DIM. A total of 380 cows were used in the final analyses. Total Ca measured at 1 through 3 DIM was not associated with the risk of metritis. Cows with increased FFA and BHB had an increased risk of being diagnosed with metritis and clinical mastitis, respectively. Increased concentrations of glucose and FFA and decreased tCa at 3 DIM were associated with an increased risk of culling. Reduced tCa concentrations at 1 DIM (≤1.84 mmol/L) and 2 DIM (≤2.04 mmol/L) were associated with increased milk production across the first 9 wk of lactation compared with tCa concentrations above those thresholds. Total Ca was not associated with milk production when assessed at 3 DIM, whereas increased FFA (≥0.37 mmol/L) and decreased glucose (≤2.96 mmol/L) at 3 DIM were associated with increased milk production. None of the metabolites measured were associated with the risk of pregnancy in the first 150 DIM. Our results demonstrate that tCa concentration assessed in the first 3 DIM show temporary associations with milk production and culling in multiparous Jersey cows. Although increased concentration of FFA assessed at 3 DIM was associated with greater milk yield, it was a detrimental factor for the risk of metritis. This study attempted to better elucidate the relationship of tCa, FFA, BHB, and glucose assessed in early postpartum with health and performance of Jersey cows. Based on this study, assessments performed at 3 DIM using tCa concentration ≤1.99 mmol/L for increased risk of early-lactation culling and FFA ≥0.43 mmol/L for increased risk of metritis could be used as starting points. More studies evaluating the dynamics of energy balance markers and tCa in postpartum Jersey cows using a greater number of herds are needed to better inform dairy consultants on critical levels for exacerbated postpartum negative energy balance and subclinical hypocalcemia for the Jersey breed.

Cattle Feeding Benchmark Data: Fall &amp; Winter 2018 Spring &amp; Summer 2019

<font face="Times New Roman, serif"><span style="font-size: 13.3333px;">A summary of closeouts collected by the Iowa State University Feedlot Monitor software from the fall of 2018 through the summer of 2019 is provided on feedlot heifers, steers, mixed pens, white fat cull cows, dairy beef and preconditioning cattle when numbers on these groups were adequate.</span></font>