Page 63 - Revista Anual - Nº19

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BIBLIOGRÁFICA

considering the indicators’ reliability while developing
AUTORES PORTUGUESES welfare assessment protocols.
Vieira, A. et al; Animal. 2018 Jan 8:1-8

Mammary gland and milk fatty acid composition of
Inter-observer reliability of animal-based welfare in- two dairy goat breeds under feed-restriction.
dicators included in the Animal Welfare Indicators Goat dairy products are an important source of animal
welfare assessment protocol for dairy goats. protein in the tropics. During the dry season, pasture
This study was conducted within the context of the scarcity leads animals to lose up to 40% of their body
Animal Welfare Indicators (AWIN) project and the un- weight, a condition known as Seasonal Weight Loss
derlying scientific motivation for the development of the (SWL) that is one of the major constraints in ruminant
study was the scarcity of data regarding inter-observer production. Breeds with high tolerance to SWL are rele-
reliability (IOR) of welfare indicators, particularly given vant to understand the physiological responses to pas-
the importance of reliability as a further step for de- ture scarcity so they could be used in programs for ani-
veloping on-farm welfare assessment protocols. The mal breeding. In the Canary Islands there are two dairy
objective of this study is therefore to evaluate IOR of goat breeds with different levels of tolerance to SWL: the
animal-based indicators (at group and individual-level) Palmera, susceptible to SWL; and the Majorera, tolerant
of the AWIN welfare assessment protocol (prototype) to SWL. Fat is one of the milk components most affec-
for dairy goats. In the design of the study, two pairs of ted by environmental and physiological conditions. This
observers, one in Portugal and another in Italy, visited study hypothesises that feed-restriction affects Majorera
10 farms each and applied the AWIN prototype proto- and Palmera breeds differently, leading to different fatty
col. Farms in both countries were visited between Ja- acid profiles in the mammary gland and milk. An interac-
nuary and March 2014, and all the observers received tion between breed and feed-restriction was observed
the same training before the farm visits were initiated. in the mammary gland. Feed-restriction was associated
Data collected during farm visits, and analysed in this with an increase in oleic acid and a decrease in palmitic
study, include group-level and individual-level obser- acid percentage in the Palmera breed whereas no diffe-
vations. The results of our study allow us to conclude rences were observed in the Majorera breed. Palmitic
that most of the group-level indicators presented the and oleic acids together constituted around 60% of the
highest IOR level (‘substantial’, 0.85 to 0.99) in both total fatty acids identified, which suggests that Palmera
field studies, pointing to a usable set of animal-based breed is more susceptible to SWL. In milk, feed-restric-
welfare indicators that were therefore included in the tion affected both breeds similarly. Regarding the inte-
first level of the final AWIN welfare assessment pro- raction of the breed with the treatment, we also obser-
tocol for dairy goats. Inter-observer reliability of in- ved similar responses in both breeds, but this influence
dividual-level indicators was lower, but the majority affects only around 2% of the total fatty acids. In gene-
of them still reached ‘fair to good’ (0.41 to 0.75) and ral, Majorera breed is more tolerant to feed-restriction.
‘excellent’ (0.76 to 1) levels. In the paper we explo- Palma, M. et al; J Dairy Res. 2017 Aug;84(3):264-271
re reasons for the differences found in IOR between
the group and individual-level indicators, including how Application of a Dot Blot Hybridization Platform to
the number of individual-level indicators to be asses- Assess Streptococcus uberis Population Structure
sed on each animal and the restraining method may in Dairy Herds.
have affected the results. Furthermore, we discuss the Streptococcus uberis is considered one of the most
differences found in the IOR of individual-level indica- important pathogens associated with bovine mastitis.
tors in both countries: the Portuguese pair of obser- While traditionally acknowledged as an environmental
vers reached a higher level of IOR, when compared pathogen, S. uberis has been shown to adopt a con-
with the Italian observers. We argue how the reasons tagious epidemiological pattern in several dairy herds.
behind these differences may stem from the restraining Since different control strategies are employed depen-
method applied, or the different background and expe- ding on the mode of transmission, in-depth studies of S.
rience of the observers. Finally, the discussion of the uberis populations are essential to determine the best
results emphasizes the importance of considering that practices to control this pathogen. In this work, we opti-
reliability is not an absolute attribute of an indicator, but mized and validated a dot blot platform, combined with
derives from an interaction between the indicators, the automatic image analysis, to rapidly assess the popula-
observers and the situation in which the assessment is tion structure of infective S. uberis, and evaluated its ef-
taking place. This highlights the importance of further ficiency when compared to multilocus sequence analy-