Allocation of feed based on individual dairy cow live weight changes

Responses of dairy cows to weekly individualized feeding strategies for dairy cows regarding their metabolic status

In dairy farms, cows are commonly fed a mixture of forages and concentrates ad libitum. To improve the energetic status and productivity of dairy cows, individualized feeding strategies have been proposed. One of this strategy is providing supplemental concentrates to adjust the forage-to-concentrate ratio based on factors like individual milk yield or calculated energy balance. This strategy can affect milk production and cow health, though consistent rules for adjustment are lacking. The objectives of this study were to evaluate the effects of an individualized feeding strategy, adjusted weekly based on the body weight gain of dairy cows, on production performance; and to determine if the metabolic status of the cows could be predicted early in lactation to take it into account into the decisions rules of the strategy. A total of 40 multiparous Holstein cows were involved in a 4-mo trial. The cows entered the experiment individually after calving and were initially fed a standard ration with a fixed 3 kg of extra concentrate per day for the first 8 d (on average). The cows were then paired based on calving date, parity (2 or 3), and body weight gain over the initial week. One cow from each pair was assigned to the Standard Feeding (SF) strategy, which continued receiving the fixed ration, while the other was assigned to the Precision Feeding (PF) strategy, which received a variable amount of extra concentrate adjusted weekly based on body weight gain. Measurements included weekly body weight, daily milk yield, and daily intakes of concentrates and forages. Blood samples were collected to measure metabolites (glucose, BHB, NEFA) for metabolic profiling. The results showed no significant differences in overall body weight gain, milk yield, or intakes (concentrates and/or forages). Two metabolic clusters were identified based on blood metabolites (glucose, BHB, NEFA), predicting cows' metabolic status with 90% accuracy. The balanced cluster had higher milk production, feed intake, and lost more body weight than the imbalanced cluster. Alternative variables like body weight gain and total feed intake can be used to predict metabolic clusters, achieving up to 70% accuracy. To conclude, cows fed this precision feeding strategy had similar performances than those fed the standard feeding strategy. Long-term effect of this strategy should be studied. Metabolic profiling predicted cows' metabolic status suggesting its potential for enhancing individualized feeding decisions.

Comparison of imputation methods for missing production data of dairy cattle

Nowadays, vast amounts of data representing feed intake, growth, and environmental impact of individual animals are being recorded in on-farm settings. Despite their apparent use, data collected in real-world applications often have missing values in one or several variables, due to reasons including human error, machine error, or sampling frequency misalignment across multiple variables. Since incomplete datasets are less valuable for downstream data analysis, it is important to address the missing value problem properly. One option may be to reduce the dataset to a subset that contains only complete data, but considerable data may be lost via this process. The current study aimed to compare imputation methods for the estimation of missing values in a raw dataset of dairy cattle including 454 553 records collected from 629 cows between 2009 and 2020. The dataset was subjected to a cleaning process that reduced its size to 437 075 observations corresponding to 512 cows. Missing values were present in four variables: concentrate DM intake (CDMI, missing percentage = 2.30%), forage DM intake (FDMI, 8.05%), milk yield (MY, 15.12%), and BW (64.33%). After removing all missing values, the resulting dataset (n = 129 353) was randomly sampled five times to create five independent subsets that exhibit the same missing data percentages as the cleaned dataset. Four univariate and nine multivariate imputation methods (eight machine learning methods and the MissForest method) were applied and evaluated on the five repeats, and average imputation performance was reported for each repeat. The results showed that Random Forest was overall the best imputation method for this type of data and had a lower mean squared prediction error and higher concordance correlation coefficient than the other imputation methods for all imputed variables. Random Forest performed particularly well for imputing CDMI, MY, and BW, compared to imputing FDMI.

ASAS-NANP SYMPOSIUM: MATHEMATICAL MODELING IN ANIMAL NUTRITION: Opportunities and Challenges of Confined and Extensive Precision Livestock Production

Modern animal scientists, industry, and managers have never faced a more complex world. Precision livestock technologies have altered management in confined operations to meet production, environmental, and consumer goals. Applications of precision technologies have been limited in extensive systems such as rangelands due to lack of infrastructure, electrical power, communication, and durability. However, advancements in technology have helped to overcome many of these challenges. Investment in precision technologies is growing within the livestock sector, requiring the need to assess opportunities and challenges associated with implementation to enhance livestock production systems. In this review, precision livestock farming and digital livestock farming are explained in the context of a logical and iterative five-step process to successfully integrate precision livestock measurement and management tools, emphasizing the need for precision system models (PSMs). This five-step process acts as a guide to realize anticipated benefits from precision technologies and avoid unintended consequences. Consequently, the synthesis of precision livestock and modeling examples and key case studies help highlight past challenges and current opportunities within confined and extensive systems. Successfully developing PSM requires appropriate model(s) selection that aligns with desired management goals and precision technology capabilities. Therefore, it is imperative to consider the entire system to ensure that precision technology integration achieves desired goals while remaining economically and managerially sustainable. Achieving long-term success using precision technology requires the next generation of animal scientists to obtain additional skills to keep up with the rapid pace of technology innovation. Building workforce capacity and synergistic relationships between research, industry, and managers will be critical. As the process of precision technology adoption continues in more challenging and harsh, extensive systems, it is likely that confined operations will benefit from required advances in precision technology and PSMs, ultimately strengthening the benefits from precision technology to achieve short- and long-term goals.

Meal patterns of weaned dairy calves are affected by previous dietary experience and associated with competition surrounding individual feed bins

The objective of this study was to evaluate how meal patterns of recently weaned and group-housed dairy calves are subject to effects of previous dietary experience and associated with competition for feed. During the preweaning period, Holstein heifer and bull calves were provided diets differing in provision and presentation of forage as follows: (1) pelleted starter only (n = 12), (2) starter and chopped coastal bermudagrass provided in separate buckets (n = 13), (3) starter and chopped coastal bermudagrass mixed together in the same bucket (n = 15), or (4) starter, chopped coastal bermudagrass, and liquid molasses mixed together in 1 bucket (n = 13). At 58 ± 2 (mean ± standard deviation) days of age, following weaning, calves were mingled between treatments and moved into group housing in weekly age-based cohorts (7 ± 2 calves/group; 8 groups total), and all were provided the mixed diet (without molasses). Within group pens, calves were fed individually using the Calan Broadbent feeding system (American Calan Inc.). Calves were monitored for 1 wk following introduction to the group pen. Feed intake was measured daily. Behavioral data, describing feeding times and competition for feed, were recorded continuously for 48 h beginning after a 5-d adaptation to the group pen. Calves previously provided starter only had longer, less frequent meals than calves previously provided forage in any form, and they tended to consume less feed compared with those previously provided starter and hay separately, with calves previously provided mixed diets having intermediate intakes. We observed occurrences of displacements at bins, which were followed by replacements and feed stealing on some occasions, where 34% of calves consumed feed from a bin assigned to another calf on at least 1 occurrence, and 64% of calves were stolen from at least once. Competition at feed bins was not affected by previous dietary treatments, but was associated with meal patterns. Actor displacement rate was negatively associated with meal frequency and duration, but calves that were displaced more often were those that spent more time feeding. These results suggested a possible carryover effect of previous exposure to forage on postweaning meal patterns following a dietary change. Further, we found that competitive behavior varied considerably between individuals, occurring frequently despite feeding calves using individually-assigned feeding bins, and was associated with meal characteristics. These results highlighted the importance of considering both previous dietary experience and social factors when evaluating feeding behavior.

Individual dairy cow management: achievements, obstacles and prospects

This review deals with the prospects and achievements of individual dairy cow management (IDCM) and the obstacles and difficulties encountered in attempts to successfully apply IDCM into routine dairy management. All aspects of dairy farm management, health, reproduction, nutrition and welfare are discussed in relation to IDCM. In addition, new IDCM R&D goals in these management fields are suggested, with practical steps to achieve them. The development of management technologies is spurred by the availability of off-the-shelf sensors and expanded recording capacity, data storage, and computing capabilities, as well as by demands for sustainable dairy production and improved animal wellbeing at a time of increasing herd size and milk production per cow. Management technologies are sought that would enable the full expression of genetic and physiological potential of each cow in the herd, to achieve the dairy operation's economic goals whilst optimizing the animal's wellbeing. Results and conclusions from the literature, as well as practical experience supported by published and unpublished data are analyzed and discussed. The object of these efforts is to identify knowledge and management routine gaps in the practical dairy operation, in order to point out directions and improvements for successful implementation of IDCM in the dairy cows' health, reproduction, nutrition and wellbeing.

Dairy cows fed a low energy diet before dry-off show signs of hunger despite ad libitum access

Drying-off is one important management step in commercial dairy farms and consists of ceasing milk production artificially at a specific point in time, generally 2 months before the next calving. Drying-off typically comprises dietary changes as well as gradual or abrupt changes in daily milking frequency, which may challenge the welfare of high-yielding cows. This study investigated the isolated and combined effects of different feed energy densities (normal lactation diet versus energy-reduced diet, both offered ad libitum) and daily milking frequencies (twice versus once) on the feeding motivation of dairy cows on two separate days prior to dry-off (i.e. the day of last milking) using a push-gate feeder. During both days, cows on the energy-reduced diet pushed more than five times more weight to earn the final feed reward and were nearly ten times faster to feed on the first reward than cows on the normal lactation diet. Illustrating the importance of developing more animal welfare-friendly dry-off management, these results illustrate that cows show signs of hunger prior to dry-off when provided a diet with reduced energy density, although offered for ad libitum intake.

Review: extended lactation in dairy cattle

This paper reviews the effects of extended lactation (EXT) as a strategy in dairy cattle on milk production and persistency, reproduction, milk quality, lifetime performance of the cow and finally the economic effects on herd and farm levels as well as the impact on emission of greenhouse gas at product level. Primiparous cows are able to produce equal or more milk per feeding day during EXT compared with a standard 305-d lactation, whereas results for multiparous cows are inconsistent. Cows managed for EXT can achieve a higher lifetime production while delivering milk with unchanged or improved quality properties. Delaying insemination enhances mounting behaviour and allows insemination after the cow's energy balance has become positive. However, in most cases EXT has no effect or a non-significant positive effect on reproduction. The EXT strategy sets off a cascade of effects at herd and farm level. Thus, the EXT strategy leads to fewer calvings and thereby expected fewer diseases, fewer replacement heifers and fewer dry days per cow per year. The optimal lifetime scenario for milk production was modelled to be an EXT of 16 months for first parity cows followed by an EXT of 10 months for later lactations. Modelling studies of herd dynamics indicate a positive effect of EXT on lifetime efficiency (milk per dry matter intake), mainly originating from benefits of EXT on daily milk yield in primiparous cows and the reduced number of replacement heifers. Consequently, EXT also leads to reduced total meat production at herd level. For the farmer, EXT can give the same economic return as a traditional lactation period. At farm level, EXT can contribute to a reduction in the environmental impact of dairy production, mainly as a consequence of the reduced production of beef. A wider dissemination of the EXT concept will be supported by methods to predict which cows may be most suitable for EXT, and clarification of how milking frequency and feeding strategy through the lactation can be organised to support milk yield and an appropriate body condition at the next calving.

Is rumination time an indicator of methane production in dairy cows?

As long as large-scale recording of expensive-to-measure and labor-consuming traits, such as dry matter intake (DMI) and CH₄ production (CH₄P), continues to be challenging in practical conditions, alternative traits that are already routinely recorded in dairy herds should be investigated. An ideal indicator trait must, in addition to expressing genetic variation, have a strong correlation with the trait of interest. Our aim was to estimate individual level and phenotypic correlations between rumination time (RT), CH₄P, and DMI to determine if RT could be used as an indicator trait for CH₄P and DMI. Data from 343 Danish Holstein cows were collected at the Danish Cattle Research Centre for a period of approximately 3 yr. The data set consisted of 14,890 records for DMI, 15,835 for RT, and 6,693 for CH₄P. Data were divided in primiparous cows only (PC) and all cows (MC), and then divided in lactation stage (early, mid, late, and whole lactation) to analyze the changes over lactation. Linear mixed models, including an animal effect but no pedigree, were used to estimate the correlations among traits. Phenotypic and individual level correlations between RT and both CH₄P and DMI were close to zero, regardless of lactation stage and data set (PC or MC). However, CH₄P and DMI were highly correlated, both across lactation stages and data sets. In conclusion, RT is unsuitable to be used as an indicator trait for either CH₄P or DMI. Our study failed to validate RT as a useful indicator trait for both CH₄P and DMI, but more studies with novel phenotypes can offer different approaches to select and incorporate important yet difficult to record traits into breeding goals and selection indexes.

Effect of substituting soybean meal and canola cake with dried distillers grains with solubles at 2 dietary crude protein levels on feed intake, milk production, and milk quality in dairy cows

Dried distillers grain with solubles (DDGS) is an alternative source of feed protein for dairy cows. Previous studies found that DDGS, based on grains other than corn, can substitute for soybean meal and canola cake as a dietary protein source without reducing milk production or quality. As societal concerns exist, and in many areas strict regulation, regarding nitrogen excretion from dairy cows, the dairy industry has focused on reducing dietary protein level and nitrogen excretion. In the present study, we investigated the use of DDGS as a protein source, at a marginally low dietary crude protein (CP) levels, in a grass-clover and corn silage-based ration. The experiment involved 24 Holstein cows and 2 protein sources (DDGS or soybean-canola mixture) fed at 2 levels of CP (14 or 16%) in a 4 × 4 Latin square design. The aim of this study was to evaluate the effect of both protein source and protein level on feed intake, milk yield, and milk quality. The results indicated that feed intake, milk yield, and protein in milk increased when the protein level in the ration was 16% CP compared with 14%. We found no effect of substituting the soybean-canola mixture with DDGS. Moreover, no sensory problems were observed when comparing fresh milk with stored milk, and milk taste was unaffected by DDGS. Milk from cows fed DDGS had a slightly higher content of linoleic acid and conjugated linoleic acid (CLA 9-11), and lower content of C11 to C17 fatty acids than cows fed diets with the soybean-canola mixture. Cows fed the diets with 16% CP produced milk with higher oleic acids and lower palmitic acid content than cows fed 14% CP diets. To conclude, DDGS can substitute for a soybean-canola mixture without affecting feed intake, milk yield and quality, or sensory quality. Under the conditions of this experiment, feeding 16% CP compared with 14% CP in the ration can increase feed intake and milk production.

Lameness Affects Cow Feeding But Not Rumination Behavior as Characterized from Sensor Data

Using automatic sensor data, this is the first study to characterize individual cow feeding and rumination behavior simultaneously as affected by lameness. A group of mixed-parity, lactating Holstein cows were loose-housed with free access to 24 cubicles and 12 automatic feed stations. Cows were milked three times/day. Fresh feed was delivered once daily. During 24 days with effectively 22 days of data, 13,908 feed station visits and 7,697 rumination events obtained from neck-mounted accelerometers on 16 cows were analyzed. During the same period, cows were locomotion scored on four occasions and categorized as lame (n = 9) or not lame (n = 7) throughout the study. Rumination time, number of rumination events, feeding time, feeding frequency, feeding rate, feed intake, and milk yield were calculated per day, and coefficients of variation were used to estimate variation between and within cows. Based on daily sums, using each characteristic as response, the effects of lameness and stage of lactation were tested in a mixed model. With rumination time as response, each of the four feeding characteristics, milk yield, and lameness were tested in a second mixed model. On a visit basis, effects of feeding duration, lameness, and milk yield on feed intake were tested in a third mixed model. Overall, intra-individual variation was <15% and inter-individual variation was up to 50%. Lameness introduced more inter-individual variation in feeding characteristics (26–50%) compared to non-lame cows (17–29%). Lameness decreased daily feeding time and daily feeding frequency, but increased daily feeding rate. Interestingly, lameness did not affect daily rumination behaviors, fresh matter intake, or milk yield. On a visit basis, a high feeding rate was associated with a higher feed intake, a relationship that was exacerbated in the lame cows. In conclusion, cows can be characterized in particular by their feeding behavior, and lame cows differ from their non-lame pen-mates in terms of fewer feed station visits, faster eating, less time spent feeding, and more variable feeding behavior. Further, daily rumination time was slightly negatively associated with feeding rate, a relationship which calls for more research to quantify rumination efficiency relative to feeding rate.

Milk fatty acid composition and production performance of Danish Holstein and Danish Jersey cows fed different amounts of linseed and rapeseed

Fat supplements are used in diets for dairy cows to increase energy intake and milk production and the fatty acid composition of the feed affects milk fatty acid composition. A total of 74 Danish Holstein and 41 Danish Jersey cows were divided into 4 groups and the cows within each group were fed a mixed ration supplemented with 0, 3.5, 6.8, or 10.2% of dry matter of a linseed:rapeseed (1:3) mixture during lactation wk 6 to 30. Milk yield, fat, and lactose contents were not affected by treatments for Danish Holsteins, whereas these parameters increased when increased amounts of oilseeds were fed to Danish Jerseys. For both breeds, milk protein content decreased when increased amounts of oilseeds were fed. The milk fatty acid composition showed higher concentrations of saturated fatty acids and lower concentrations of unsaturated fatty acids in milk fat from Danish Jerseys compared with Danish Holsteins. Increased amounts of oilseeds in feed increased milk fat concentration of all C18 fatty acids except C18:2 n-6, whereas the content of C6 to C14, C11 to C17, and in particular, C16, decreased. This effect was more pronounced for Danish Holsteins than for Danish Jerseys. The apparent recovery of C18:2 n-6 and C18:3 n-3 decreased when increased amounts of oilseeds were fed; however, this was most likely due to increased amounts of fatty acid from feed used for other energy demands than milk production. It was concluded that up to 6.8% of oilseed supplementation can be fed without production problems and, in many cases, with positive production responses, including an improved milk fatty acid profile.