Social dominance in prepubertal dairy heifers allocated in continuous competitive dyads: Effects on body growth, metabolic status, and reproductive development

Abstract

The objective of this study was to compare the body weight (BW) and size, metabolic status, and reproductive development of dominant and subordinate prepubertal dairy heifers allocated in competitive dyads. Sixteen Holstein and Jersey × Holstein prepubertal heifers (means ± SEM; 250.8 ± 9.8 d; 208.5 ± 13.9 kg of BW) were assigned to 8 homogeneous dyads according to breed, age, and BW. Dyads were housed in pens separated 1 m from each other during 120 d, receiving a total mixed ration on a 5% restriction of their potential dry matter intake, and had access to the same feeder (60 cm) throughout the experiment. Dominant and subordinate heifers were defined based on the winning agonistic interactions in each dyad. Body development was recorded every 20 d in all heifers, and blood samples were collected on the same days to determine endocrine and metabolic status. The maximum follicle diameter, number of follicles >6 mm, and the presence of corpus luteum were observed weekly by ultrasound. Heifer BW (269.3 vs. 265.3 ± 1.5 kg) and average daily gains (0.858 vs. 0.770 ± 0.02 kg/d) were greater in dominant than subordinate heifers. On d 30, 37, and 53, dominant heifers had more follicles than subordinate heifers, and maximum follicle diameter was greater in dominant than in subordinate heifers (10.0 vs. 9.0 ± 0.3 mm). Dominant heifers achieved puberty earlier than subordinate heifers (313.9 ± 4.9 vs. 329.6 ± 5.7 d) with similar BW (279.4 ± 2.6 vs. 277.4 ± 5.8 kg). Glucose concentrations were greater in dominant than subordinate heifers (89.2 vs. 86.8 ± 1.2 mg/dL), but cholesterol concentrations were greater in subordinate than dominant heifers (86.1 vs. 90.2 ± 2.6 mg/dL). We concluded that, under continuous competitive situations, dominant heifers were more precocious than subordinate ones, achieving an earlier puberty. Dominant heifers had greater body growth and glucose concentrations than subordinate heifers, which may be responsible, at least in part, for the differences on reproductive development between heifers of different social status.

Carryover effects of pre- and postweaning planes of nutrition on reproductive tract development and estrous cycle characteristics in Holstein heifers

“…licular growth can be hypothesized. For instance, Fiol et al (2017) compared prepubertal Holstein heifers according to their social behavior and reported that relative to subordinate heifers, dominant heifers achieved a greater BW, had greater circulating glucose, greater number of follicles, greater maximum follicle diameter, and achieved puberty earlier, likely because they had more frequent access to feed due to their dominant demeanor. Furthermore, decreased circulating insulin and IGF-1, induced by reducing the dietary energy contents in the postweaning diet (Armstrong et al, 2001) or by feed restriction (Lents et al, 2013), were negatively associated with the dominant follicle size in cycling heifers (Armstrong et al, 2001;Lents et al, 2013).…”

A 100-Year Review: Stress physiology including heat stress

“…However, these effects appear to be acute and are not likely to robustly affect production. Social dominance has also been shown to affect feeding behavior, growth rate, metabolic status, and age at onset of puberty (Fiol et al, 2017).…”

Does Size Matters? Relationships among Social Dominance and Some Morphometric Traits upon Out-of-Season Reproductive Outcomes in Anestrus Dairy Goats Treated with P4 + eCG

“…Since no differences in LW at puberty occurred between HSR vs. LSR females, such an increased glucose level may explain the amplified productive and reproductive outcomes shown by the HSR-group [36]. Based on these findings [8,36], such an increased glucose level favoring the HSR-females may have been positively related to increases in LW, augmenting in turn both metabolic status and reproductive function in a GnRH-LH dependent fashion, a possible scenario occurring in the HSR-goats of this study. In this respect, although diverse neural and hormonal cues are involved as drivers of the hypothalamic-pituitary-gonadal axis, the common and undisputable initiator involved the activation of GnRH neurons [15].…”