Influence of peripartum on the erythrogram of Holstein dairy cows.

The peripartum period comprises the last three weeks of gestation to three weeks after calving. During this period, many adaptations occur in preparation for calving and the onset of lactation. These are of endocrine, metabolic and immunological nature and include increases in circulating concentrations of oestrogen, non-esterified fatty acids and beta-hydroxybutyrate, and reduced serum concentrations of progesterone, calcium, glucose, insulin and insulin-like growth factor 1. During this phase, there is an increase in the demand for nutrients to support colostrum and milk manufacturing, and foetal growth, all of which intensify a negative energy balance, and it becomes necessary to mobilise body fat to meet this deficit. Owing to these adaptations, the peripartum period is a challenging phase for the health of the cow. It is also the most critical period of a dairy cow’s production cycle, as it determines the success or failure of the future productive and reproductive performance. Due to the changes that occur during the peripartum and the associated increase in the incidence of metabolic disease during this phase, it is essential to monitor the health of the herd by various means, including through blood tests, and to perform interventions if necessary. In this context, evaluation of the blood profile is useful, especially in terms of detecting the presence of anaemia of various aetiologies. Thus, in order to avoid erroneous diagnoses, knowledge of the effect of any physiological changes on the blood profile could be useful when interpreting results. Moreover, with the exception of haematocrit, the blood profile of Holstein dairy cows during peripartum has not been described previously in detail. Thus, the aim of the study of the authors cited below was to do that.

Blood samples were collected from a total of 48 cows on days 18, 12, 8, 5 and 2 before calving, at calving, and on days 1, 7, 14, 21, 30, 45 and 60 after calving. Analyses of red blood cell (RBC) count, haemoglobin concentration, haematocrit, mean corpuscular volume, mean corpuscular haemoglobin, mean corpuscular haemoglobin concentration and RBC distribution width were performed. Body condition score (BCS) and milk yield were also monitored.     

The results show that the highest value of red blood cells was 6.10 × 1012 per litre at calving and the lowest value was 5.03 × 1012 per litre 21 days after calving. For haemoglobin and haematocrit the highest values were 10.48 g per decilitre and 33.5% at calving, respectively and the lowest values were 8.28 g per decilitre and 26.1% on day 30 after calving, respectively. In the case of BCS, the highest and the lowest values were 3.50 points and 2.73 points on days 18 before calving and 45 after parturition, respectively and for milk yield the lowest and the highest values were 21.5 Litre and 27.0 Litre on days 7 and 45 after calving, respectively, which was significantly different. Of the total number of cows, 41.7% had RBC, haemoglobin and haematocrit values below the reference intervals during at least one collection point during the after calving period.

The data of the study showed that some cows suffered reduction in selected blood profiles after calving. Therefore, in future research the focus should be on elucidating the relationship between inflammatory processes and the blood profile of dairy cows during the peripartum period to facilitate interpretation of laboratory results.

Reference:

Paiano, R.B., Birgel D.B. & Birgel Junior, E.H., 2020. Influence of peripartum on the erythrogram of Holstein dairy cows. Journal of the South African Veterinary Association 91(0), a1975. https://doi.org/ 10.4102/ jsava.v91i0.1975