A survey of management practices that influence calf welfare and an estimation of the annual calf mortality risk in pastured dairy herds in Uruguay

Abstract

Despite the importance of dairy farming in Uruguay, little information on dairy systems in this country is available in the scientific literature, and management practices that influence calf welfare at the herd level have not been explored. The aims of this study were to (1) describe the prepartum and calf-rearing systems, as well as the management practices that may influence calf welfare in pastured dairy herds in Uruguay, (2) estimate the annual calf mortality risk from birth to weaning, and (3) identify the primary clinical disease syndromes shown by the calves before death. A survey comprising a farm visit and a questionnaire was conducted on 225 randomly selected dairies with >30 milking cows, in 3 strata (31-99, 100-299, and ≥300 milking cows) of 6 Uruguayan departments where dairies are concentrated. Retrospective information from July 2013 to June 2014 was collected. A descriptive analysis was performed and results were inferred into the national dairy cattle population. Several management practices that could contribute to poor calf welfare were identified in a large proportion of farms. The annual calf mortality risk (calves that died between birth and weaning/calves born death or alive × 100, n = 149 farms) was 15.2%. Age at weaning averaged 75 d. Farmers reported that the most common clinical syndromes were diarrhea and respiratory disease in 85.2% and 47.5% of the farms, respectively. There was no continuous veterinary advice in 61.3% of the farms, 20.0% lacked data records, 38.5% had poor drainage in the prepartum area with waterlogging after rainfall, 52.1% monitored the prepartum area ≤2 times per day during the calving season, 65.1% did not perform navel antisepsis on newborns, 62.3% separated the calves from their dams at >24 h postpartum, 95.2% did not have a colostrum management program, 72.4% did not rotate the calf-rearing areas, 59.0% did not disinfect the calf feeders, 85.7% did not have staff dedicated exclusively to calf rearing, and 39.8% did not separate sick from healthy calves. The average volume of milk or milk replacer offered per calf was 4.5 L/day. Several of the identified management practices that affect calf welfare in the prepartum and calf-rearing periods could explain the high mortality risk. An effort should be made to conduct extension work focusing on the dissemination of good management practices to improve calf welfare and reduce calf mortality in Uruguayan dairy farms.

Causes of neonatal calf diarrhea and mortality in pasture-based dairy herds in Uruguay: a farm-matched case-control study

“…Although vaccination to prevent NCD is recommended in all dairy farms, it is most meaningful in those where colostrum management practices are adequate. Unfortunately, inadequate colostrum management practices are widespread among dairy farms in Uruguay [4], which may partially explain the high percentage of calves with low STP concentrations found in our study. Regarding the lack of statistical association between STP and preweaning death, it should be noted that among 31 calves with STP values < 5.6 g/dl, 14 had missing data on preweaning death.…”

“…This growth was due to increased stocking rates, individual milk production and the milking cow:dry cow ratio [2], indicating a production intensification process. However, the national dairy stock did not grow significantly over the past decade [2], which has partly been attributed to a relatively high (15.2%) nationwide annual dairy calf mortality risk from birth to weaning [4]. Despite this, little information is available in the scientific literature on the causes of dairy calf diseases and death in this country.…”

“…Despite this, little information is available in the scientific literature on the causes of dairy calf diseases and death in this country. Neonatal calf diarrhea (NCD) is the leading cause of dairy calf morbidity and mortality within the first month of life [4,5]. Affected calves suffer from dehydration, electrolyte imbalances, and metabolic acidosis, which, if left untreated, can lead to death [6].…”

Lethal and semi-lethal mutations in Holstein calves in Uruguay

“…Three hundred eighty-three Holstein calves (1-to 30-day-old) from 27 farms located in the main dairy region of uruguay were sampled in 2016 as part of a larger epidemiological study on neonatal diarrhea in dairy calves (SCHILd et al, 2020). Blood samples from diarrheic and non-diarrheic calves were collected from the jugular vein into Vacutainer ® tubes (4 ml) with Lithium Heparin 75 uSP units, transported to the laboratory, and stored at 4 °C until genomic dNA extraction.…”

“…Holstein-based milk production in uruguay is one of the most important sectors of the country's economy, with dairy farms distributed throughout the country, mainly in the southeastern region. In recent decades, the national dairy stock has decreased mainly due to a drastic fall in pregnancy rate (20-30%), increased calving-conception interval (from 131 to 175 days between 1997 and 2011) (MeIKLe et al, 2013), and high birth-to-weaning calf mortality, averaging 18% (SCHILd et al, 2020). Another contributing factor could be the predominance of North American Holstein-Friesian genetics in the national herd (90%), a breed in which most recessive mutations affecting reproductive efficiency and health traits have been discovered in recent years.…”