Effects of dairy cow temperament on milk yield: a systematic review and meta-analysis.

The temperament of dairy cows interferes in milk yield and quality, but there is a lack of consensus throughout the literature. Thus, systematic review (SR) and meta-analysis (MA) methodologies were used to assess the effects of dairy cow temperament on milk yield. Our literature search included four electronic databases (CABI Abstracts, Web of Science, PubMed, and Scopus) and bibliographies of the publications included on MA. As inclusion criteria, we considered publications about the temperament of lactating cows and its effect on daily milk yield and total milk yield (whole lactation). A random effect-MA was carried out separately for daily milk yield and total milk yield related to each class of cows' temperament, 'low' (low reactivity, calm animals), 'intermediate' (intermediate reactivity), and 'high' (high reactivity, reactive animals). A total of eight publications reporting 75 trials were included in the analyses for daily milk yield, and three publications reporting nine trials for total milk yield. For daily and total milk yield the heterogeneity between publications was high (I2 = 99.9%). Cows of European breeds with intermediate temperament produced less milk daily than the calm (P = 0.020) and reactive ones (P < 0.001). In the case of primiparous cows, those with intermediate temperament produced less milk daily (P < 0.001) than the reactive ones, while for multiparous, the intermediate produced less than calm (P = 0.032) and reactive cows (P < 0.001). Regarding the stage of lactation, cows evaluated throughout lactation with a calm temperament tended (P = 0.081) to produce more milk than the intermediate ones, but less than the reactive ones (P < 0.001). For total milk yield, reactive cows tended to produce more than the calm (P = 0.082) and intermediate (P = 0.001) ones. Among European and primiparous cows, reactive cows produced more than the intermediate (P = 0.001). According to our results, we cannot confirm what we expected, that calmer cows would be the most productive for both daily and total yield.

Individual differences in the behavior of dairy cows can affect their productive performance. In an attempt to summarize the scientific information available, we conducted a systematic review and meta-analysis to identify the effects of dairy cows' temperament on milk yield. We hypothesize that calmer cows would produce more milk. We found nine publications with quantitative data available to be included in a meta-analysis. Eight additional publications that addressed the topic of interest but did not present data enough to be included in the meta-analysis (i.e., evaluated the relationships between temperament and milk yield using correlations or regressions) were used to perform a qualitative synthesis. The results of our meta-analysis indicated that the reactive cows were more productive than the calm or intermediate ones, contradicting our initial hypothesis. According to the results of the qualitative synthesis, most of the publications reported a negative association between reactive temperament and milk yield, indicating that calmer cows would produce more milk. We concluded that there are divergences in the information available about the temperament and production of dairy cows. We highlight the need for greater methodological and analytical standardization to allow a broader quantitative synthesis of the temperament effects on milk yield.

The effects of heat stress on milk production and the grazing behavior of dairy Holstein cows milked by an automatic milking system.

The objective of the present study was to evaluate the productive performance and grazing behavior of 25 primiparous and 44 multiparous Holstein cows in a pasture-based automatic milking system (AMS) while experiencing heat stress (defined as a temperature-humidity index [THI] ≥ 68). Productive traits were analyzed according to the THI from days 0, -1, -2, and -3 in relation to the milking day, and grazing behaviors (expressed as the percentage of daily observation time) were related to the average THI only on the day of observation. Milk yield was not associated with the THI on day 0, but a significant linear relationship was found with the THI on the three previous days, decreasing approximately 0.18 kg (primiparous) and 0.40 kg (multiparous) per THI unit increment. In contrast, for multiparous cows only, the milking frequency was positively associated with the THI on the day of evaluation but not on the previous days, increasing 0.01 milking/THI unit increments. Additionally, for each unit of THI increment, cows spent 0.14% more time standing, whereas they exhibited a decrease in grazing, lying, and ruminating behaviors time by 0.30%, 0.04%, and 0.70%, respectively, for both parities. In conclusion, milk loss was related to heat stress conditions from the previous days, but not milking frequency, which increased with the THI of the same milking day. Lower grazing, lying, and ruminating activities and greater standing behavior were observed due to heat stress.

In higher temperature conditions, dairy cows under pasture-based automatic milking systems may experience heat stress, affecting their health and productive performance. In the present study, the relationships between heat stress, measured by the temperature­humidity index (THI), productive traits, and grazing behaviors were evaluated. Cows exhibited an increase in milking frequency and their time standing, decreasing the time grazing, lying, and ruminating as the THI increased on the same day. Additionally, cows had decreased milk production when the THI increased in the previous days. Understanding how cows adjust their grazing behavior to handle changes in the environment allows for the development of management strategies designed to improve animal welfare.

Metabolic profile and productivity of dairy Holstein cows milked by a pasture-based automatic milking system during early lactation: Effects of cow temperament and parity.

This study aimed to evaluate the influence of temperament and parity on milk production and metabolic responses of Holstein cows in a pasture-based automatic milking system. Thirty-five primiparous and 58 multiparous cows were classified as 'calm', 'intermediate' or 'reactive' in each of the temperament tests conducted: milking reactivity (MR), race time (RT), flight speed, and flight distance. The milk yield and milk composition, as well as the blood biochemistry, were measured during the first 10 weeks of lactation. Primiparous cows produced less milk than multiparous cows (24.0 ± 0.8 vs. 34.2 ± 0.6 L/d, respectively, P Ë‚ 0.0001), while the serum beta-hydroxybutyrate concentration differences according to parity were not detected. Multiparous cows that were classified as 'reactive' on MR and RT tests produced 3 kg/d more milk and had greater concentrations of milk components than 'calm' cows (P ≤ 0.05). There was no such relation in primiparous cows. Also, cows scored 'reactive' on RT showed greater milking frequency (2.50 ± 0.05 vs. 2.35 ± 0.04 milking/d; P = 0.01) and blood beta-hydroxybutyrate concentrations (1.28 ± 0.09 vs. 0.92 ± 0.10 mmol/L; P = 0.04) than RT 'calm' cows. In conclusion, the cows' temperament was associated with milk production and metabolism, which depended on parity and the temperament tests used. Although productive performance was different between parities, lipomobilization was not.

Temperament in Captivity, Environmental Enrichment, Flight Ability, and Response to Humans in an Endangered Parrot Species.

Temperament assessment is useful in reintroduction programs. Reactivity to humans and flight ability are also important behavioral aspects for captive parrots candidates to reintroduction. The study aimed: a) to evaluate if behavioral responses to environmental enrichment differ as a function of temperament in captive Vinaceous-breasted Amazon parrots (Amazona vinacea) and b) to evaluate if the behavioral responses to environmental enrichment are related to flight ability and animal's reaction to human when offered food. A temperament assessment was performed and behavioral evaluations of parrots (n = 13) using an ethogram were carried out, in two phases: unenriched and enriched. Flight skill and food reward tests were also performed. Two temperament dimensions were described ("vigilance" and "risk-taking"). Parrots categorized as "vigilant" spent less time feeding on the feeder and interacting with environment. Animals with compromised flight ability spent more time preening, had lower frequency of vocalizations, tended to have fewer negative social interactions, and interacted less with the enrichment than individuals with better flight ability. Flight performance and temperament of captive parrots should be considered while planning and executing environmental enrichment techniques.