Are dairy cows with a more reactive temperament less efficient in energetic metabolism and do they produce more enteric methane?

It remains unknown whether dairy cows with more reactive temperament produce more enteric methane (CH4) and are less bioenergetically efficient than the calmer ones. The objectives of this study were (a) to evaluate the relationship between cattle temperament assessed by traditionally used tests with energetic metabolism and enteric CH4 emissions by crossbred dairy cows; (b) to assess how cows' restlessness in respiration chambers affects energetic metabolism and enteric CH4 emissions. Temperament indicators were evaluated for 28 primiparous F1 Holstein-Gyr cows tested singly in the handling corral (entrance time, crush score, flight speed, and flight distance) and during milking (steps, kicks, defecation, rumination, and kick the milking cluster off). Cows' behaviors within respiration chambers were also recorded for each individual kept singly. Digestibility and calorimetry trials were performed to obtain energy partitioning and CH4 measures. Cows with more reactive temperament in milking (the ones that kicked the milking cluster off more frequently) spent 25.24% less net energy on lactation (P = 0.04) and emitted 36.77% more enteric CH4/kg of milk (P = 0.03). Furthermore, cows that showed a higher frequency of rumination at milking parlor allocated 57.93% more net energy for milk production (P < 0.01), spent 50.00% more metabolizable energy for milk production (P < 0.01) and 37.10% less CH4/kg of milk (P = 0.04). Regarding the handling temperament, most reactive cows according to flight speed, lost 29.16% less energy as urine (P = 0.05) and tended to have 14.30% more enteric CH4 production (P = 0.08), as well as cows with a lower entrance time (most reactive) that also lost 13.29% more energy as enteric CH4 (P = 0.04). Temperament and restless behavior of Holstein-Gyr cows were related to metabolic efficiency and enteric CH4 emissions. Cows' reactivity and rumination in the milking parlor, in addition to flight speed and entrance time in the squeeze chute during handling in the corral, could be useful measures to predict animals more prone to metabolic inefficiency, which could negatively affect the sustainability of dairy systems.

Reduced space in outdoor feedlot impacts beef cattle welfare.

There is a trend to reduce the space allowance per animal in cattle feedlot, despite its potential negative impact on animal welfare. Aiming to evaluate the effects of space allowance per animal in outdoor feedlots on beef cattle welfare, a total of 1350 Nellore bulls (450 pure and 900 crossbred) were confined for 12 weeks using three space allowances: 6 (SA6), 12 (SA12) and 24 (SA24) m2/animal (n = 450 per treatment). Bulls were housed in three pens per treatment (n = 150 per pen). The first 6 weeks in the feedlot were defined as 'dry' and the last as 'rainy' period, according to the accumulated precipitation. Animal-based (body cleanliness, health indicators and maintenance behaviour) and environmental-based indicators (mud depth and air dust concentration) were assessed weekly during the feedlot period. Most of the health indicators (nasal and ocular discharge, hoof and locomotion alterations, diarrhoea, bloated rumen and breathing difficulty) were assessed in a subset of 15 animals randomly selected from each pen. Coughs and sneezes were counted in each pen. Maintenance behaviours (number of animals lying and attending the feed bunk) were recorded with scan sampling and instantaneous recording at 20-min intervals. Postmortem assessments were carried out in all animals by recording the frequencies of macroscopic signs of bronchitis, pulmonary emphysema, nephritis and urinary cyst and by measuring the weight and cortical and medullar areas of adrenal glands (n = 30 per pen). Compared with SA12 and SA24, SA6 showed a greater number of sneezes per minute during the dry period and a greater percentage of animals with locomotion alterations during the rainy period. Coughing, diarrhoea and nasal discharge affected a larger number of animals in the SA6 relative to the other two groups. During the rainy period, there was a lower percentage of animals with nasal and ocular discharge, and a greater percentage of animals with abnormal hoof and lying. A lower percentage of animals in SA6 and SA12 (but not SA24) attended the feed bunk during the rainy relative to the dry period. A mud depth score of 0 (no mud) was most frequent in SA24 pens, followed by SA12 and then SA6. Adrenal gland weight and cortical area were lower in SA24 animals compared with those in SA6 and SA12. The results show that decreasing the space allowance for beef cattle in outdoor feedlots degrades the feedlot environment and impoverishes animal welfare.

Genetic parameter estimates for prenatal and postnatal mortality in Nellore cattle.

The aim of this study was to estimate genetic parameters for prenatal (PRE) and postnatal (POS) mortality in Nellore cattle. A total of 13 141 (PRE) and 17 818 (POS) records from Nellore females were used. PRE and POS were recorded using binary scale scores: a score of '1' was given to calves that were born alive (PRE) and those that were alive at weaning (POS), and a score of '0' was given to calves that were not alive at or around birth (PRE), as well as to those weighed at birth but not at weaning (POS). The relationship matrix included 698 sires, 107 paternal grandsires and 69 maternal grandsires. Data were analysed using Bayesian inference and a sire-maternal grandsire threshold model, including contemporary groups as random effects, and the classes of dam age at the beginning of mating season (for PRE), and dam age at calving and birthweight (linear covariable) (for POS), as fixed effects. For both traits, the covariance between direct and maternal effects (rD,M ) was estimated (rD,M ≠ 0) or fixed at zero (rD,M  = 0). PRE and POS rates were 3.00 and 4.04%, respectively. Estimates of direct and maternal heritability were 0.07 and 0.17, respectively, for PRE, and 0.02 and 0.07, respectively, for POS, assuming rD,M  = 0. For rD,M  ≠ 0, these estimates were 0.07 and 0.12, respectively, for PRE, and 0.03 and 0.07, respectively, for POS. The correlation estimates between direct and maternal effects were -0.71 (PRE) and -0.33 (POS). PRE and POS show low genetic variability, indicating that these traits probably suffer major environmental influences. Additionally, our study shows that the maternal genetic component affects preweaning calf mortality twice as much (or more) as the direct genetic component. A large number of offspring per sire is necessary in progeny tests to genetically decrease calf mortality.

A note comparing the welfare of Zebu cattle following three stunning-slaughter methods.

The objective of this study was to assess welfare of cattle during bleeding after slaughter with or without stunning. A total of 434 bulls were distributed across three slaughter treatments: penetrating captive bolt stunning followed by chest sticking (PCB, N=279), non-penetrating captive bolt stunning followed by halal slaughter (NPCB, N=67) and shechita without previous stunning (SHE, N=88). Four measures of possible consciousness and return to sensibility were recorded 20 and 60 s after bleeding as welfare indicators. They were the frequencies of responses to nostril stimulation and tongue pinch, spontaneous eye blinking, and rhythmic breathing. All responses were absent in stunned cattle at both 20 and 60 s, and in SHE cattle 7, 4, 10, and 100% of the animals presented these responses, respectively. Repeat shots were required for 46% NPCB and 2% PCB (P<0.05). The application of religious slaughter without previous stunning may result in greater risk of cattle suffering, pain and distress at slaughter.

Genetic associations between temperament and performance traits in Nellore beef cattle.

The aim of this study was to estimate genetic associations between temperament and performance traits. Temperament was evaluated in yearling male and female Nellore cattle, using four traits: temperament score (TS), for assessing animals' reactions in a corral pen (n = 25,691); movement score (MOV), for animals' movements recorded inside the crush; crush score (CS), for animal's general reactivity inside the crush; and flight speed (FS), for the speed (in m/s) at which the animals exited the crush (n = 11,697, for the last three methods); for all the temperament traits, lower scores indicate animals with calmer temperament. Performance traits were visual scores for conformation (C), finishing precocity (P) and muscling (M) evaluated at yearlings, and average daily gain (ADG) was estimated from weaning to yearling. Bayesian inference using Gibbs sampling was applied to estimate (co)variance components and genetic and phenotypic parameters. Heritability estimates for the temperament traits ranged from 0.07 (CS) to 0.28 (FS). Genetic correlations of the temperament traits with ADG and C, P and M were negative and ranged from -0.02 to -0.31. Phenotypic correlations were negative and consistently lower than the genetic, ranging from -0.08 to -0.02. It was concluded that the temperament traits assessed had favourable genetic correlation estimates with the performance traits studied. However, indirect responses in temperament when selecting for higher ADG and visual scoring system of C, P and M, will be low.

Genetic variability for temperament indicators of Nellore cattle.

The aim of this study was to estimate genetic parameters of 4 temperament indicator traits for Nellore cattle and evaluate the possibility of using such traits as selection criteria in breeding programs. Temperament was assessed for 23,420 male and female animals at 550 d of age, which were born between 2002 and 2009. A temperament score (TS) was used, which is based on a scale from 1 to 5 and considers the reaction of animals after exiting the crush. Moreover, 9,150 individuals born in 2008 and 2009 were measured for these characteristics: movement score (MOV), where animals were scored from 1 to 5 according to their movement inside the crush; crush score (CS), which assigns scores from 1 to 4 for the general reactivity inside the crush; and flight speed (FS), which is a recording of the speed (m/s) at which animals exit the crush after being weighed. The weaning weight (WW) was included in the multitrait analysis to reduce the effect of the selection performed at weaning. Bayesian inference using Gibbs sampling was applied to estimate (co)variance components and breeding values of the animals. The model included random direct additive genetic and residual effects, fixed effects of contemporary groups, age of the dam (classes), and age of the animal as covariate (linear and quadratic effects for WW and TS, and only linear effects for the other traits). A linear model was applied to WW and FS, whereas a threshold model was used for TS, CS, and MOV. Heritability estimates for FS, TS, CS, and MOV were 0.35, 0.15, 0.19, and 0.18, respectively. The genetic correlation estimates of FS with TS (0.85), CS (0.85), and MOV (0.76) were high, although the phenotypic correlations were low (between 0.18 and 0.25). For CS and MOV, the genetic and phenotypic correlation estimates were high (0.99 and 0.71, respectively). We concluded that all of the temperament indicator traits addressed in this study presented enough genetic variability to respond to selection; however, the use of FS would result in a faster genetic gain. With regard to the practical applicability in breeding programs, the use of FS is also favorable because it produces data on a continuous scale, allows for recording of the data electronically, and requires low investment.

The presence of black vultures at the calving sites and its effects on cows' and calves' behaviour immediately following parturition.

Black vultures (Coragyps atratus) are often present near calving sites, and under this situation they may play a positive role by removing animal carcasses and afterbirth or a negative role by attacking neonate calves or disturbing cow-calf behaviours following parturition. Cow-calf behaviour was recorded over a 4-year study period from a total of 300 births involving 200 Nellore, 54 Guzerat, 20 Gyr and 26 Caracu cows. The calving site in relation to the location of the herd, considering cow-calf pairs within, close or distant to the herd, the presence of vultures and the behaviour of cows and calves were recorded instantaneously, at 5-min interval. On average, vultures were present at 80% of the calving sites. The frequency of vultures present at calving sites was dependent on the years for the Nellore herd, increasing from 1998 to 2003. When vultures were present, the time that the cow was in contact with its calf decreased, and the percentage of time that the cow was standing still increased. Vultures were observed pecking cows and their neonates during 34.1% of all recordings. However, in only two cases pecking injuries were actually observed on calves that were noted to be very weak. The preliminary results suggest that although black vultures cannot be characterized as a predator of neonate calves, they sometimes attack neonate calves and their presence near the calving sites alter the behaviours of cows and calves.

Genetic associations between flight speed and growth traits in Nellore cattle.

The aim of the present study was to estimate genetic parameters for flight speed and its association with growth traits in Nellore beef cattle. The flight speed (FS) of 7,402 yearling animals was measured, using a device composed of a pair of photoelectric cells. Time interval data (s) were converted to speed (m/s) and faster animals were regarded as more reactive. The growth traits analyzed were weaning weight (WW), ADG from weaning to yearling age, and yearling scrotal circumference (SC). The (co)variance components were estimated using REML in a multitrait analysis applying an animal model. The model included random direct additive genetic and residual effects, fixed effects of contemporary groups, age of dam (classes), and age of animal as covariable. For WW, the model also included maternal genetic and permanent environmental random effects. The direct heritability estimate for FS was 0.26 ± 0.05 and direct heritability estimates for WW, SC, and ADG were 0.30 ± 0.01, 0.48 ± 0.02, and 0.19 ± 0.01, respectively. Estimates of the genetic correlation between FS and the growth traits were -0.12 ± 0.07 (WW), -0.13 ± 0.08 (ADG), and -0.11 ± 0.07 (SC). Although the values were low, these correlations showed that animals with better temperaments (slower FS) tended to present better performance. It is possible to infer that longterm selection for weight and scrotal circumference can promote a positive genetic response in the temperament of animals. Nevertheless, to obtain faster genetic progress in temperament, it would be necessary to perform direct selection for such trait. Flight speed is an easily measured indicator of temperament and can be included as a selection criterion in breeding programs for Nellore cattle.

The relationship between dairy cow hygiene and somatic cell count in milk.

Corporal hygiene is an important indicator of welfare for dairy cows and is dependent on facilities, climate conditions, and the behavior of the animals. The objectives of this study were to describe how the hygiene conditions of dairy cows vary over time and to assess whether a relationship exists between hygiene and somatic cell count (SCC) in milk. Monthly hygiene evaluations were conducted on lactating cows in 2 dairy farms for 9 consecutive months, totaling 3,554 evaluations from 545 animals. Hygiene was measured using a 4-point scoring system (very clean, clean, dirty, and very dirty) for 4 areas of the animal's body (leg, flank, abdomen, and udder) and combining these scores to generate a composite cleanliness score. A total of 2,218 milk samples was analyzed from 404 cows to determine SCC and somatic cell linear scores (SCLS). Individual variation was observed in the hygiene of cows throughout the year, with the highest proportion of clean cows being observed in August and the lowest in January. In spite of this seasonal variation, approximately half (55.62%) of the cows displayed consistent cleanliness scores, with 45.86% of them remaining consistently clean (very clean or clean) and 9.76% remaining dirty (very dirty or dirty) over the course of the study. The very clean cows had the lowest SCLS, followed by the clean, dirty, and very dirty cows (no statistically significant differences were found between the latter 2 groups). The most critical months for cow hygiene were those with the greatest rainfall, when a reduction in the welfare of cows and higher SCC values were observed. The evaluation and control of dairy cow hygiene are useful in defining management strategies to reduce problems with milk and improve the welfare of the animals.