In 2024, Argentina recorded a total of 9,735 dairy farms with 1,465,557 dairy cows. Approximately 82.8% of these farms were in three provinces: Santa Fe with 3,165 farms (34.7% of the national total); Córdoba with 2,566 farms (28.1%) and Buenos Aires with 1,830 farms (20%). The number of dairy cows in these provinces was 473,646, 457,516 and 404,285, respectively. The total annual milk production amounted to 10,590 million litres.
Dairy production systems in Argentina are predominantly pasture-based. The typical diet of lactating cows consists of approximately 45% pasture, 26% silage and 29% concentrate, primarily corn and soybean meal (Gastaldi et al., Reference Gastaldi, Litwin, Maekawa, Centeno, Engler, Cuatrin, Chimicz, Ferrer and Suero2015). In 2024, the average annual milk yield per cow was 7,138 l, with an average stocking rate of 1.4 cows per hectare (Datos claves de la lechería Argentina año, 2024).
Culling is defined as the removal of animals from the herd either through sale, death or slaughter (Doncel-Díaz et al., Reference Doncel-Díaz, Fariña, Caffarena, Giannitti and Riet-Correa2025). Culling has important economic and animal welfare implications. Dairy farm income is affected by the costs of raising or purchasing replacements. The replacement rate influences milk production, since incoming animals generally produce less milk than the cows they replace in the short term (Compton et al., Reference Compton, Heuer, Thomsen, Carpenter, Phyn and McDougall2017). Ideally, cows should remain in the production system at least until their fifth lactation, when they reach their full productive potential and offset the costs of rearing and maintenance (De Vries, Reference De Vries2020). In subsequent lactations, milk yield gradually declines (Vergara, Reference Vergara2019). Moreover, a high culling rate, particularly when due to mortality, may indicate deficiencies in animal welfare (de Vries et al., Reference de Vries, Bokkers, Dijkstra, Van Schaik and De Boer2011).
Recent surveys indicate that the average annual culling rate (ACR) of dairy cows in Argentina was 19.5%, with an average mortality rate (MR) of 6.6% (Roskopf et al., Reference Roskopf, Astesana, Molineri, Demateis Lera, Mascotti, Garro, Martinez and Frossasco2025a). Additionally, a study conducted on 126 farms from Argentina reported total culling rates (TCRs) ranging from 25.9 ± 8.1% in small grazing herds (<200 cows) to 41.1 ± 10.1% in large, intensive free-stall systems (501–1,000 cows) (Abdala and Molineri, Reference Abdala and Molineri2023).
Culling of dairy cows is an inevitable event, influenced by economic, social, health and management factors (Compton et al., Reference Compton, Heuer, Thomsen, Carpenter, Phyn and McDougall2017). Identifying and understanding the causes of culling is essential, as this knowledge serves as a scientific basis for designing herd management strategies that help improve production and health indicators and reduce unnecessary losses of productive animals (Thomsen and Houe, Reference Thomsen and Houe2023). The objective of this study was to describe the ACR and its main causes on dairy farms in the central region of Santa Fe, Argentina.
Materials and methods
A cross-sectional study was conducted between February and April 2025 on 77 dairy farms located in the central dairy region of Santa Fe, Argentina. The information analysed covered the period from January to December 2024. The sample size was calculated based on an estimated culling rate of 26% (Abdala and Molineri, Reference Abdala and Molineri2023), with a 95% confidence interval and an acceptable absolute error of less than 10%. Farms were randomly selected from a database that included all registered dairy operations within the study area. A formal invitation to participate in the study was sent to dairy farms, offering the benefit of receiving a written report with the study results and guaranteeing the confidentiality of the information provided. Of the total number of farms invited, 5% declined participation for various reasons. The high acceptance rate may be attributed to the institutional relevance and recognition of the research institute within this major dairy production region.
At each farm, a survey was conducted with the person responsible for herd management. During the survey, information was collected on general farm characteristics, including the total number of cows, number of lactating cows, number of dry cows, and the primiparous-to-multiparous ratio, as well as the type of production system (confined or pasture-based) and the calving interval in days (CI). Production and health records provided by the farmers were obtained from dairy herd management systems, from which individual data on culled cows were recorded and evaluated. Reasons for culling were classified according to the proposal for the National Animal Health Monitoring System (2002) into the following categories: udder problems (mastitis, conformation), reproductive problems (infertility, abortions), lameness (hoof disorders, trauma to limbs other than the hoof), other diseases, low production, age, behaviour and phenotype.
The ACR was defined as the proportion of cows removed from the herd by sale only. The ACR was calculated as follows:
\begin{equation*}ACR = \frac{{{\text{Number of cows sold in }}2024}}{{{\text{Average total number of cows in }}2024{\text{ }}}} \times 100\end{equation*}The MR was calculated as follows:
\begin{equation*}MR = \frac{{Number{\text{ }}of{\text{ }}cows{\text{ }}dead{\text{ }}in{\text{ }}2024}}{{Average{\text{ }}total{\text{ }}number{\text{ }}of{\text{ }}cows{\text{ }}in{\text{ }}2024}} \times 100\end{equation*}TCR was defined as the proportion of cows removed from the herd for any reason (sales + deaths). The average TCR was calculated as follows:
\begin{align*}& TCR \\
&= \frac{{Number{\text{ }}of{\text{ }}cows{\text{ }}sold{\text{ }}in{\text{ }}2024 + Number{\text{ }}of{\text{ }}cows{\text{ }}dead{\text{ }}in{\text{ }}2024}}{{Average{\text{ }}total{\text{ }}number{\text{ }}of{\text{ }}cows{\text{ }}in{\text{ }}2024}} \\
&\quad \times 100\end{align*}Finally, cow longevity (CL) was calculated as follows:
\begin{equation*}{{Cl = }}\frac{{{\text{100}}}}{{{{TCR}}}}{\text{ \times }}\frac{{{\text{365}}}}{{{{CI}}}}.\end{equation*}A descriptive statistical analysis was conducted to identify the frequencies and distributions of the variables TCR, ACR, MR and CL. Results were expressed as absolute and relative frequencies. The outcome variables were: the ACR (expressed as the number of cows sold in 2024 out of the average total number of cows in the herd), the MR (expressed as the number of cows dead in 2024 out of the average total number of cows in the herd) and the TCR (expressed as the number of cows sold, culled and dead in 2024 out of the average total number of cows in the herd). The effect of production system types (pasture-based and confined systems) on the outcome variable was evaluated using a generalized linear model with a binomial distribution and logarithmic link function. All statistical analyses were performed using the Infostat software (National University of Córdoba, Córdoba, Argentina).
Results
Characteristics of the surveyed dairy farms
A total of 77 dairy farms located in the central dairy region of Santa Fe Province were surveyed. The main characteristics of the different dairy production systems are presented in Table 1. Confined production systems (drylot) were used by 28.6% of dairy farms, while 71.4% operated under pasture-based systems with supplementation.
Descriptive characteristics of dairy farms from Santa Fe region (Argentina) according to production system
Table 1 Long description
Comparison of pasture-based and confined dairy farms by number of farms, herd totals, breed composition, herd-size distribution, and daily milk yield per cow. Pasture-based systems include 55 farms (71.4 percent) and confined systems include 22 farms (28.6 percent). Total cows are similar across systems, with 11,245 in pasture-based and 10,356 in confined. Confined herds have a higher proportion of Holstein cows (8,957, or 86.5 percent) and fewer Holstein crossbreds (1,399, or 13.5 percent) than pasture-based herds (7,551 Holsteins, 67.2 percent; 3,694 crossbreds, 32.9 percent). Herd sizes differ: pasture-based farms are mostly 100 to 199 cows (52.7 percent) and 200 to 499 cows (34.5 percent), while confined farms are mainly 200 to 499 cows (68.2 percent) with more very large herds of 500 or more cows (18.2 percent). Average daily milk yield per cow is higher in confined systems at 26.5 liters, compared with 19.2 liters in pasture-based systems; the values in parentheses indicate the reported range for each system. Percentages for breed and herd-size categories describe composition within each production system and may not sum exactly due to rounding.
Confined dairy production systems of the drylot type in Argentina are characterized by the permanent housing of cows in open-air pens, generally without direct access to pasture. These pens have compacted dirt floors, often improved through slopes and drainage systems to minimize mud formation. In addition, they are equipped with basic welfare infrastructure, including artificial shade, water troughs and linear feed bunks, where total mixed rations (TMR) are provided as the basis of the diet.
Pasture-based dairy production systems in Argentina are characterized by the predominant use of pastures as the basis of feeding, complemented with varying levels of energy and protein supplementation. Cows access pastures daily under rotational grazing management, supported by infrastructure such as paddock subdivisions, water points and laneways. Supplementation is mainly provided in the milking parlour or at external feed bunks and may include concentrates, silages and, in some cases, partial mixed rations.
The number of animals per farm included in the study, stratified by production system, is presented in Table 1. Most of the included dairy farms used only Holstein cows and the average daily milk yield per cow was 24 l (range: 13–37 l) (Table 1).
Dairy cow culling
Pasture-based systems had a lower overall TCR compared to confined systems (P < 0.001). The average total ACR in pasture-based systems was 22.3% (range: 10–34%), whereas in confined systems it was 31% (range: 22–54%). Cows in confined systems had an odds ratio (OR) of 1.9 (95% CI: 1.8–2.1) of being culled from the herd compared to cows in pasture-based systems.
Pasture-based systems also had a lower ACR compared to confined systems (P < 0.001). The ACR of cows culled in pasture-based systems was 15.6% (range: 2–30%), while in confined systems it was 23.6% (range: 14–43%). Cows in confined systems had almost two times higher odds of being culled from the herd, compared to cows in pasture-based systems (OR = 1.9; 95% CI: 1.9–2.1).
Confined systems exhibited a higher MR compared to pasture-based systems (P < 0.001). The MR in pasture-based systems was 6.7% (range: 2–20%), while in confined systems it was 7.4% (range: 4–17 %). Cows in confined systems had almost 1.3 times higher odds of dying on-farm compared to cows in pasture-based systems (OR = 1.29; 95% CI: 1.16–1.4).
No significant differences in culling were observed among breeds (P > 0.05).
Causes of culling and mortality
The main causes of culling in confined systems were reproductive disorders (31.9%), udder problems (22.5%) and hoof disorders (14.9%). The main causes of culling in pasture-based systems were reproductive disorders (33.8%), udder problems (20.5%) and infectious diseases (13.5%). The main causes of culling in different production systems are shown in Table 2.
Causes of culling and mortality in dairy cows according to production systema
Table 2 Long description
Percent distributions with confidence intervals compare reasons for culling and for mortality in pasture-based versus confined dairy systems, with p-values and odds ratios for system differences. For culling, reproductive problems were the top reason in both systems, about 34 percent in pasture-based and 32 percent in confined. Pasture-based systems had higher culling for infectious diseases (about 14 percent versus 5 percent) and for cow age (about 6 percent versus 2 percent). Confined systems had higher culling for hoof disorders (about 15 percent versus 9 percent) and for unreported causes (about 12 percent versus 6 percent). For mortality, confined systems were higher for traumatic deaths (about 28 percent versus 17 percent), mastitis (about 13 percent versus 5 percent), and several other categories including digestive disorders, poisoning, and heat. Pasture-based systems were higher for infectious-disease mortality (about 21 percent versus 7 percent) and slightly higher for unreported mortality causes (about 20 percent versus 18 percent). Most comparisons show statistically significant differences, while cow-age mortality and “other causes” mortality do not show clear differences based on the reported p-values.
a Odds of culling or mortality: pasture-based vs. confined systems.
The main cause of culling for both systems was reproductive problems (P < 0.001). Cows in pasture-based systems had 1.7 times higher odds of being culled for this cause than cows in confined systems (OR = 1.7; 95% CI: 1.5–1.9; Table 2).
The main causes of mortality were traumatic (27.9%) in confined systems and infectious diseases (20.7%) in pasture-based systems (P < 0.001; Table 2). Cows in confined systems had three times higher odds of death due to trauma than cows in pasture-based systems (OR = 3; 95% CI: 2.3–4). Cows in pasture-based systems had 1.7 times higher odds of death due to infectious disease than cows in confined systems (OR = 1.7; 95% CI: 1.2–2.5; Table 2).
Cow longevity
The overall average calving interval for all farms was 441.6 days (range: 380–450 days). No significant differences were found in the calving interval between the different production systems (P = 0.964). In pasture-based systems, the average calving interval was 441.9 days (range: 380–549), while in confined systems it was 440.6 days (range: 397–503).
On the other hand, pasture-based systems had greater CL compared to confined systems (P < 0.001). The average longevity of cows in pasture-based systems was 4.3 lactations (range: 2–9), whereas in confined systems it was 2.9 lactations (range: 1.4–4).
Discussion
Studying the causes of culling in dairy cows in Argentina is complex due to the lack of standardized classification criteria and nomenclature, as well as the scarcity of individual animal health records on farms. On the other hand, data entry is often performed retrospectively, sometimes during periods that differ from those in which the events actually occurred. In this context, the present study aimed to establish methodological bases for future local prospective studies with greater specificity in identifying the causes of culling. However, the results should be interpreted considering the potential biases inherent to observational interview-based studies, particularly selection bias associated with voluntary farm participation, which could affect the estimation of culling and MRs.
In this study, pasture-based dairy systems predominated (70%) over confined systems (30%), reflecting the traditional structure of Argentine dairy production, in which grazing constitutes the nutritional base, complemented by varying levels of supplementation (Lazzarini et al., Reference Lazzarini, Llonch and Baudracco2024). However, this proportion differs from national estimates, which indicate that approximately 90% of dairy farms operate under pasture-based systems and 10% under confined systems (Lazzarini et al., Reference Lazzarini, Llonch and Baudracco2024). This discrepancy may be attributed to regional differences, as factors such as climate, pasture availability, farm size and the degree of production intensification influence the adoption of either production system. Confined systems also exhibited higher average daily milk yield per cow, likely associated with a greater level of management of intensification and the use of higher energy-density diets (White et al., Reference White, Benson, Washburn and Green2002).
In this study, culling and MRs differed from those reported by other authors from Argentina. Abdala and Molineri (Reference Abdala and Molineri2023) reported a higher TCR (25.9%), a similar culling rate, and a higher MR (9.1%) than those observed in our study (22.3%, 15.6% and 6.7%, respectively). These differences may be partly explained by the data source, as the study by Abdala and Molineri (Reference Abdala and Molineri2023) relied on records from farm management software companies, thereby restricting the analysis to farms with formal recording systems and potentially higher levels of intensification and production control. A non-randomized study carried out on 12 dairy farms in Uruguay reported similar values for total culling (22.6%) (Doncel-Díaz et al., Reference Doncel-Díaz, Fariña, Caffarena, Giannitti and Riet-Correa2025). However, it documented higher culling (18.1%) and lower mortality (4.5%) (Doncel-Díaz et al., Reference Doncel-Díaz, Fariña, Caffarena, Giannitti and Riet-Correa2025). These differences may be attributable to more effective diagnostic services, identification of odds factors and the implementation of appropriate control and prophylactic measures (Doncel-Díaz et al., Reference Doncel-Díaz, Fariña, Caffarena, Giannitti and Riet-Correa2025).
Approximately 53% of culling in the region was attributed to reproductive disorders and mammary health problems, with no marked differences between production systems. This value is lower than those reported in Uruguay and Canada, where these causes accounted for 61% and 58% of total culling, respectively (De Souza et al., Reference De Souza, Pinto, da Cruz, de Oliveira, Pedrosa, Oliveira, Miglior, Schenkel and Brito2023; Doncel-Díaz et al., Reference Doncel-Díaz, Fariña, Caffarena, Giannitti and Riet-Correa2025). However, the value observed in our study is higher than those reported in predominantly pasture-based dairy systems, such as New Zealand (45.4%) and Australia (30.6%) (Kerslake et al., Reference Kerslake, Amer, O'neill, Wong, Roche and Phyn2018; Wondatir Workie et al., Reference Wondatir Workie, Gibson and van der Werf2021), as well as in mainly confined systems, such as the United States (24%) (Lozada-Soto et al., Reference Lozada-Soto, Gaddis, Tiezzi, Jiang, Ma, Toghiani, VanRaden and Maltecca2024) and Denmark (41%) (Thomsen and Houe, Reference Thomsen and Houe2023). In contrast, studies conducted in Iran reported intermediate values, with approximately 40% of culling associated with these causes.
In this study, reproductive problems accounted for 33.9% of culling in pasture-based systems and 31.9% in confined systems. These values are comparable to those reported in Spain, where reproductive causes represent approximately 30% (Armengol and Fraile, Reference Armengol and Fraile2018) of culling in dairy herds. However, they are higher than those reported in the United States and Canada, where reproductive problems generally account for 20–25% of total dairy cow culling (Moreira et al., Reference Moreira, Passafaro, Schaefer and Rosa2021). The United Kingdom reported a culling rate of 37% due to reproductive problems (Taylor et al., Reference Taylor, Channa, Hanks and Taylor2024). Overall, these results confirm that reproductive failures are among the main determinants of culling in dairy systems, regardless of the production system.
Several studies have reported that infectious agents, including Neospora caninum, bovine viral diarrhoea virus, infectious bovine rhinotracheitis virus and Brucella spp., are important causes of abortion and impaired fertility, with effects extending beyond the abortive event, compromising subsequent pregnancies, and reducing conception rates (Asmare et al., Reference Asmare, Regassa, Robertson, Martin and Skjerve2013; Softic et al., Reference Softic, Asmare, Granquist, Godfroid, Fejzic and Skjerve2018). In addition, inadequate nutritional management during the transition period may induce postpartum energy deficits that, together with other predisposing factors, increase the odds of endometritis and reproductive failure (Roche, Reference Roche2006). The lack of reproductive protocols adapted to the production system may also contribute to increased infertility.
The specific characteristics of production systems in our region, such as a high dog population, frequent use of natural service, the introduction of animals from multiple herds to maintain stock, nutritional deficiencies associated with inadequate technical advice or adverse climatic conditions, may have favoured culling due to reproductive causes. Finally, the possibility of reporting errors due to limited diagnostic confirmation and the lack of a systematic investigation of the underlying causes of culling cannot be ruled out (Yanga and Jaja, Reference Yanga and Jaja2022)
Udder problems accounted for 20.5–22.5% of total culling in our study, depending on the production system. These values are comparable to those reported in Estonia and Brazil, where udder disorders explain approximately 20–23% of culling in dairy herds (Rilanto et al., Reference Rilanto, Reimus, Orro, Emanuelson, Viltrop and Mõtus2020; Almeida et al., Reference Almeida, Paula, Marquetti, Poczynek, Silva, Navarro, Valloto, Horst and Pedrosa2025). In contrast, studies conducted in the United States, Canada, and Spain report lower proportions (McCluskey, Reference McCluskey2002; Armengol and Fraile, Reference Armengol and Fraile2018; CDIC, 2020), generally ranging between 10% and 15%. In contrast, Uruguay has reported higher values, close to 30% of total culling attributed to udder problems (Doncel-Díaz et al., Reference Doncel-Díaz, Fariña, Caffarena, Giannitti and Riet-Correa2025). Mastitis constitutes the main component of this category and has a significant impact on milk yield and milk quality, resulting in substantial economic losses associated with reduced productivity and increased treatment and management costs. In severe cases, mastitis can lead to premature culling or even death of affected cows (Seegers et al., Reference Seegers, Fourichon and Beaudeau2003). In addition, unfavourable udder conformation, including low udder height and reduced rear udder width, has been associated with an increased likelihood of culling, as these traits can hinder milking practices and increase the odds of injuries and intramammary infections (Bretschneider et al., Reference Bretschneider, Arias and Cuatrin2015). In Argentina, the available information on mastitis prevalence and its contribution to culling is limited. In a study conducted in Argentina, Roskopf et al. (Reference Roskopf, Frossasco, Molineri, Demateis Llera, Garro and Martinez2025b) determined that for 47.5% of producers, mastitis represents a major problem. This lack of data, together with the heterogeneous implementation of mastitis control programmes, deficiencies in hygiene practices, pathogen-contaminated environments, and the inappropriate use of antibiotics, may help explain the relatively higher culling rates due to udder problems observed compared with other countries.
Culling due to hoof disorders was significantly more frequent in confined systems than in pasture-based systems, with a lower relative odd observed in the latter. These findings are consistent with studies conducted in the United States, Canada, Denmark and the United Kingdom, where hoof disorders account for approximately 10–20% of culling in dairy herds (Cook et al., Reference Cook, Nordlund and Oetzel2004; Randall et al., Reference Randall, Green, Chagunda, Mason, Archer, Green and Huxley2015; Solano et al., Reference Solano, Barkema, Mason, Pajor, LeBlanc and Orsel2016; Thomsen and Houe, Reference Thomsen and Houe2023). In contrast, countries with predominantly pasture-based production systems, such as New Zealand and Ireland, report proportions of culling attributable to hoof disorders below 10% (Mason et al., Reference Mason, Müller, Huxley and Laven2023; Conneely and Ryan, Reference Conneely and Ryan2024). The higher culling rate observed in confined dairy farms in this study may be attributed to inherent characteristics of this production system, including greater exposure to wet and high stocking density, reduced exercise due to shorter walking distances compared with pasture-based systems and nutritional imbalances that predispose cows to hoof lesions. Conversely, pasture-based systems are characterized by greater physical activity and surfaces with lower moisture or mud accumulation, conditions that favour hoof health and reduce the incidence of these disorders.
Mortality due to traumatic causes was significantly higher in confined systems compared with pasture-based systems (27.9% vs. 16.9%), with lower relative odds observed in the latter. These results are consistent with those reported in countries where confined production systems predominate, such as the United States and Canada, where traumatic causes account for approximately 20–30% of total mortality in dairy herds (Miller et al., Reference Miller, Kuhn, Norman and Wright2008; McConnel et al., Reference McConnel, Garry, Lombard, Kidd, Hill and Gould2009). In confined dairy systems in Denmark and the Spain, traumatic causes account for between 15% and 25% of total mortality in dairy cows (Thomsen et al., Reference Thomsen, Kjeldsen, Sørensen and Houe2004; Armengol and Fraile, Reference Armengol and Fraile2018). In contrast, the values observed in the pasture-based systems of this study are comparable to those reported in countries with similar production systems, such as New Zealand and Ireland, which report lower proportions of mortality due to traumatic causes, generally below 15–20% (Ring et al., Reference Ring, McCarthy, Kelleher, L and Berry2018; Cuttance et al., Reference Cuttance, Mason, Hea, Bryan and Laven2024). Overall, these findings reinforce the evidence that confinement increases the odds of traumatic mortality in dairy cows. This may be attributed to the fact that confined systems often feature pens or alleys with slippery flooring, which increases the odds of falls and injuries (Valkova et al., Reference Valkova, Vecerek, Voslarova, Kaluza and Takacova2021). Additionally, confined systems typically exhibit higher rates of assisted calving, which further elevate the odds of injuries that can result in mortality or necessitate culling of affected cows.
The mortality due to metabolic diseases was significantly higher in pasture-based systems (10.9%) compared with confined systems (2.1%). These findings differ from those reported in the international literature, where in countries dominated by confined production systems, such as the United States, Canada and Italy, metabolic disorders account for approximately 8–21% of mortality in adult dairy cows (Dechow and Goodling, Reference Dechow and Goodling2008; McConnel et al., Reference McConnel, Garry, Lombard, Kidd, Hill and Gould2009; Fusi et al., Reference Fusi, Angelucci, Lorenzi, Bolzoni and Bertocchi2017). In contrast, in countries with predominantly pasture-based systems, such as New Zealand, mortality due to these causes is generally below 5% (Macdonald et al., Reference Macdonald, Penno, Lancaster, Bryant, Kidd and Roche2017; Mason et al., Reference Mason, Cuttance, Laven and Phyn2020). Given that metabolic disorders are mainly associated with intensive production systems and nutritional management during the transition period, the results observed in this study may be explained, in pasture-based systems, by a potential over-reporting of metabolic causes due to the lack of precise veterinary diagnosis, as well as by nutritional imbalances related to adverse climatic conditions and insufficient technical advice. Conversely, in confined systems, an underreporting of cases by producers or farm workers may have occurred, together with more controlled nutritional management associated with greater standardization and monitoring of feeding practices.
The mortality due to mastitis in dairy cows in Argentina was also different between systems, with an observed rate of 5.2% in pasture-based compared with 12.6% in confined systems. Our results are consistent with previous studies, highlighting the importance of mastitis as a cause of mortality in dairy cows. In a study conducted in Finland, mastitis was reported as the leading cause of mortality based on necropsy findings, accounting for approximately 26% of cases (Hagner et al., Reference Hagner, Nordgren, Aaltonen, Sarjokari, Rautala, Sironen, Sakura and Rajala-Schultz2023). In countries with predominantly intensive production systems, such as the United States and Canada, direct mortality due to mastitis is generally lower, as severe cases represent a relatively small proportion of the total and benefit from timely diagnosis and treatment (McConnel et al., Reference McConnel, Lombard, Wagner and Garry2008). Similarly, in pasture-based systems, such as those in New Zealand, mortality attributed to mastitis is also low (Compton et al., Reference Compton, Heuer, Thomsen, Carpenter, Phyn and McDougall2017). The differences observed among countries may be explained by variations in early detection, herd health management, access to veterinary treatments and environmental conditions that influence the occurrence of severe mastitis.
A total of 20.3% and 17.2% of the deaths recorded in pasture-based and confined systems, respectively, lacked a reported cause. Necropsy is a fundamental tool for determining the immediate cause of death (Thomsen and Houe, Reference Thomsen and Houe2006; McConnel et al., Reference McConnel, Garry, Lombard, Kidd, Hill and Gould2009); however, in the present study, these animals were not subjected to post-mortem examination, which limited the accurate diagnostics of mortality causes. This limitation may be attributed to operational factors, such as veterinarian availability or willingness at the time of the event, delays in reporting deaths by farm personnel, or accessibility constraints for performing the procedure. Accurate determination of the cause of death is essential for the implementation of targeted management and health strategies aimed at preventing similar events and reducing involuntary herd losses.
In our study, pasture-based systems exhibited greater longevity compared to confined systems. These results are consistent with findings from Argentina, where Masía et al. (Reference Masía, Molina, Vissio, Balzarini, De la Sota and Piccardi2022) reported longevity of four lactations for cows in pasture-based systems versus three lactations in confined systems. Similarly, Berry et al. (Reference Berry, Wall and Pryce2011) reported that cows in pasture-based herds in Ireland had longevity of 4.2–4.5 lactations. In contrast, De Vries (Reference De Vries2017) noted that cows in confined systems in the United States had longevity of 2.5–3 lactations.
Confined systems tend to maximize individual production, which is often achieved at the expense of longevity and overall system sustainability. Maintaining a low culling rate contributes to greater long-term productive and economic efficiency, as it allows the recovery of rearing costs and extends the productive lifespan of each cow (Dallago et al., Reference Dallago, Wade, Cue, McClure, Lacroix, Pellerin and Vasseur2021).
Conclusions
The findings of this study provide a characterization of dairy farms in the central region of Santa Fe province across production systems. Confined systems generally exhibited higher average milk yields per cow, whereas pasture-based systems showed lower overall culling and MRs and greater CL. The main causes of culling and mortality – including reproductive problems, udder and hoof disorders, infectious diseases and low milk production – were common to both systems, underscoring the universal importance of effective herd health monitoring, reproductive management and disease prevention.
Acknowledgements
The authors wish to express their sincere gratitude to the dairy workers and producers of Santa Fe Province for their generosity, collaboration, and willingness to share their time and knowledge. Their support and hospitality during farm visits were essential to the success of this study.
