Effect of pre-weaning concentrate supplementation on peripheral distribution of leukocytes, functional activity of neutrophils, acute phase protein and behavioural responses of abruptly weaned and housed beef calves

Abstract

Background: The effect of pre-weaning concentrate supplementation on peripheral distribution of leukocytes, functional activity of neutrophils, acute phase protein response, metabolic and behavioural response, and performance of abruptly weaned and housed beef calves was investigated. Calves were grazed with their dams until the end of the grazing season when they were weaned and housed (day (d) 0) in a concrete slatted floor shed, and offered grass silage ad libitum plus supplementary concentrates. Twenty-six days prior to weaning and housing, 20 singled suckled, pure-bred Simmental male (non-castrated), (n = 10, m) and female (n = 10, f) calves were assigned to one of two treatments (i) concentrate supplement (CS: n = 10 (5 m and 5 f), mean age (s.d.) 201 (12.8) d, mean weight (s.d.) 258 (20.2) kg) or (ii) no concentrate supplement (controls) (NCS: n = 10, (5 m and 5 f), mean age (s.d.) 201 (13.4) d, mean weight (s.d.) 257 (19.6) kg) pre-weaning.

Results: There was a treatment × sampling time interaction (P < 0.05) for percentage CD4+ and WC1+ (γδ T cells) lymphocytes and concentration of plasma globulin. On d 2, percentage CD4+ lymphocytes decreased (P < 0.001) in both treatments. Subsequently on d 7, percentage of CD4+ lymphocytes increased (P < 0.01) in CS compared with d 0, whereas percentage of CD4+ lymphocytes in NCS did not differ (P > 0.05) from d 0. On d 2, WC1+ lymphocytes decreased (P < 0.05) in both treatments but the decrease was greater (P <0.05) in NCS than CS. Subsequently, percentages did not differ (P > 0.05) from pre-weaning baseline. On d 2, the increase in concentration of globulin was greater (P < 0.05) in CS compared with NCS, and subsequently there was no difference between treatments. Pre-weaning ADG was 1.07 (s.e.m.) (0.26) kg and 0.99 (s.e.m.) (0.26) kg for CS and NCS, respectively. Post-weaning, CS calves spent more time lying compared with NCS calves.

Conclusions: Calves supplemented with concentrate prior to weaning had a lesser reduction in WC1+ lymphocytes, increased percentage CD4+ lymphocytes and concentration of total protein, and spent more time lying post-weaning, compared with non-supplemented calves.

Figure 1

Experimental design and sample collection schedule for beef calves that were supplemented with concentrates for 26 d prior to abrupt weaning (d 0) and subsequently offered grass silage plus concentrates at housing. * denotes additional blood collection time-points for haematological analysis and rectal body temperature recordings. Concentrate supplemented (CS) calves were offered concentrates for 26 d prior to weaning, whereas non supplemented (NCS) calves were not offered concentrates during the pre-weaning period (d -26 to d 0). On d 0, all calves were abruptly weaned, housed and offered grass silage ad libitium plus concentrates.

Figure 2

Effect of concentrate supplementation for 26 d pre-weaning on percentage CD4⁺ lymphocytes in abruptly weaned and housed beef calves. CS = concentrate supplement prior to abrupt weaning (n = 10), NCS = no concentrate supplement prior to abrupt weaning (n = 10). ^{a, b, c}Between days, least squares means without a common superscript differ (P <0.05). ^{x, y}Within a day, least squares means without a common superscript differ (P <0.01).

Figure 3

Effect of concentrate supplementation for 26 d pre-weaning on percentage (a) WC1⁺ and (b) MHC Class II⁺ lymphocytes in abruptly weaned and housed beef calves. CS = concentrate supplement prior to abrupt weaning (n = 10). NCS = no concentrate supplement prior to abrupt weaning (n = 10). ^{a, b,}Between days, least squares means without a common superscript differ (P <0.001). ^{x, y}Within a day, least squares means without a common superscript differ (P <0.001). There was a significant treatment × sampling time interaction for percentage WC1⁺ lymphocytes.