@conference {40217,
	title = {Ethics and animal production},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {50},
	year = {1990},
	month = {Jan},
	pages = {211-214},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {Research has shown some dairy cows show temporary falls in   plasma calcium concentration during the first six weeks of lactation.   By monitoring plasma calcium concentrations in 58 dairy cows in 4 herds   for 42 days postpartum it was found that 33\% showed at least one episode   of a fall in plasma calcium concentration to <1.9 mmol/l. The mean   plasma calcium concentration of these cows during this period was 2.15   mmol/l compared to 2.60 mmol/l for those cows which maintained plasma   calcium concentrations above 2.10 mmol/l for six weeks and 2.35 mmol/l   for another group which maintained plasma calcium concentration above   1.9 mmol/l but not always above 2.1 mmol/l. These mean calcium   concentrations differed significantly (P<0.001) among the three groups   and between sampling days after calving. There was no significant   association between herd and distribution of cows in each group and age   of cow was not significantly correlated with plasma calcium   concentration on days 7, 9, 19, 29 and 42 after calving or with the   overall mean concentrations. Sub-clinical hypocalcaemia may commonly   occur in early lactation and have significant effects on production and   reproduction in dairy cows.    },
	issn = {1176-5283},
	author = {Campbell AV}
}
