The effect of housing condition on the performance of two types of activity meters to detect estrus in dairy cows.

When the daily routine of a cow is disturbed, it may have a detrimental effect on the performance of activity meters to detect estrus. It is possible that during the pasture period, the daily routine of cows is disturbed, adversely affecting the performance of activity meters to detect estrus which does not happen when the cows are housed indoors. The objective of this study was to investigate whether housing conditions (pasture or indoor) affected the performance of activity meters to detect estrus in dairy cows. In this research, two types of activity meters were used, an activity meter attached to the leg and one mounted on the neck. Cows of two different herds were equipped with the Smarttag Leg and the Smarttag Neck (Nedap livestock management, Groenlo, the Netherlands). The study began during the pasture period (September) and ended during the indoor period (January). The pasture period ended at the beginning of November. So, about two months of pasture period and two months of indoor period were studied. Milk samples were collected twice a week during the morning milking and true estrus was determined by milk progesterone concentrations. In total, the dataset consisted of 95 true estrous periods and 1992 true non-estrous days of 56 cows for the pasture period and 138 true estrous periods and 3164 true non-estrous days of 65 cows for the indoor period. Overall, no differences in sensitivity, positive predictive value (PPV) and specificity were found between the pasture and indoor period for both types of sensors. There was also no difference in the performance between leg and neck activity meters. Sensitivity was between 76 and 82%, PPV was between 87 and 92% and specificity was between 99 and 100%. In conclusion, the sensitivity, PPV and specificity did not differ between the pasture and indoor period. This means that, in our study, the performance of both types of activity meters to detect estrus is not affected by housing conditions.

Individual behavioural characteristics in pigs--influences of group composition but no differences in cortisol responses.

To determine the effect of group composition on backtest (Bt) responses and to determine the predictive value of the Bt for the physiological stress response to weaning and mixing, 814 pigs were backtested at 3, 10 and 17 days of age. Twenty-nine percent of all pigs were cross-fostered at 3 days according to Bt responses and groups were formed of animals with high responses (HR) only, low responses (LR) only or mixed groups of animals with high, intermediate and low responses (MISC). Original litters (OR, no cross-fostering) were used as controls. Cortisol responses were measured in saliva after weaning at 4 weeks of age and after moving and mixing at 9 weeks of age. In HR groups, mean Bt responses decreased after cross-fostering while in LR groups, mean Bt scores increased. In both groups, Bt responses of individual animals before and after cross-fostering were not correlated. In MISC and OR groups, all Bt scores were correlated. Weaning and mixing caused a significant rise in cortisol in all animals while moving or weighing did not. No relations were found between Bt scores and cortisol levels. We conclude that Bt behaviour can change according to the social environment between 3 and 10 days. This could be intentional, to form a varied group, or it might be caused by a change in the hypothalamic-pituitary-adrenal (HPA) function due to social stress. At an older age, this ability is lost and common farm practises such as regrouping, weaning and mixing of piglets at ages >10 days might have a negative effect on the piglets.

A note on the influence of starting position, time of testing and test order on the backtest in pigs.

The backtest determines the coping behaviour of a piglet in a standardised stress situation, which might be a measure for the coping style of that animal. Backtest results are related to other parameters such as immune responses and production. In this study, the backtest was standardised and it was studied if time of testing or the order in which animals were tested influenced backtest results. One hundred and eight-four piglets from 18 sows were tested at 3, 10 and 17 days of age. Before testing, the sow was disturbed to ensure that all piglets were awake. This standardisation of the starting position before testing did not improve the correlations between backtest results in the successive tests. No relations were found between backtest results and time of testing or test order.

[Individual behavioral characteristics of pigs and their impact on production]. / Individuele gedragskarakteristieken van varkens en de relatie met productieresultaten.

Two studies were carried out with pigs to determine the relationship between back test results and production parameters and between back test results and other factors. In the first study, 823 piglets were tested with the back test at 10 and 17 days of age. Production parameters such as average daily weight gain and lean meat percentage were determined. In the second study, the back test was performed on 566 piglets at 3, 10, and 17 days of age. The number of escape attempts in the back test (back test score) of the mother was known for 364 piglets. Parameters concerning the health of the sow and piglets were recorded, as well as the sow's reaction to piglet removal for testing. The relationships between production parameters and back test scores of the animals were calculated, as well as the influence of birth weight, sex (all males were castrated), parents, and health parameters on back test scores. Back test scores were fairly consistent over successive tests for each piglet. Males had higher back test scores than females, and piglets from sows with low back test scores also had low scores. Finally, a higher back test score was correlated with a higher lean meat percentage and a better carcass grading at slaughter; no relation with daily weight gain was found. It is concluded that there are individual differences in the way pigs cope with a stressful situation, as measured with the back test, and that this coping behaviour is consistent. A positive correlation exists between back test scores at a young age and lean meat percentage at slaughter. The response to stress, and hence back test scores, is assumed to be inheritable.

Quantifying risk factors of coccidiosis in broilers using on-farm data based on a veterinary practice.

A study was done to find and quantify risk factors for coccidiosis. The study population consisted of 4774 broiler flocks kept on 177 farms. Flocks were considered a case when at least one bird in the flock showed microscopic presence of oocysts in intestinal scrapings in a grow-out cycle. Other flocks were defined as controls. This was done for three types of Eimeria: Eimeria acervulina, Eimeria tenella and Eimeria maxima. Logistic regression was used to assess variables that influence the occurrence of Eimeria species. There were 49 variables, based on animal, flock or farm level. There was an enhanced risk of coccidiosis due to environmental and management factors that increase the risk of introducing contamination or that are related to hygienic measures. These include lack of use of overalls by visitors, a farmyard which is difficult to clean, bad hygienic status, personnel who might also be working on other farms, presence of other animals on the farm, and feeding and drinking systems which are more difficult to clean. Also, the presence of other diseases on the farm and Eimeria species found in the previous flock increased the risk of coccidiosis.