Prenatal heat stress effects on gestation and postnatal behavior in kid goats

Abstract

Consequences of heat stress during pregnancy can affect the normal development of the offspring. In the present experiment, 30 Murciano-Granadina dairy goats (41.8 ± 5.7 kg) were exposed to 2 thermal environments varying in temperature-humidity index (THI) from 12 days before mating to 45 days of gestation. The environmental conditions were: gestation thermal-neutral (GTN; THI = 71 ± 3); and gestation heat stress (GHS; THI = 85 ± 3). At 27 ± 4 days old, GTN-born female kids (n = 16) and GHS-born ones (n = 10) were subjected to 2 tests: arena test (AT) and novel object test (NOT), the latter was repeated at 3 months of age. Additionally, 8 months after birth, a subset of growing goats (n = 8) coming from GTN and GHS (16.8 ± 3.4 kg BW) were exposed consecutively to 2 environmental conditions: a basal thermal-neutral period (THI = 72 ± 3) for 7 days, and a heat-stress period (THI = 87 ± 2) for 21 days. In both periods, feeding behavior, resting behavior, other active behaviors (exploring, grooming), thermally-associated behaviors and posture were recorded. The gestation length was shortened by 3 days in GHS goats. In the AT, GHS kids showed a lower number of sniffs (P < 0.01) compared to GTN. In the NOT, GHS kids also tended to show a lower number of sniffs (P = 0.09). During heat exposure, GTN and GHS growing goats spent more time resting as well as exhibited more heat-stress related behaviors such as panting and drinking (P < 0.001); however, no differences were observed between both groups. In conclusion, heat stress during the first third of pregnancy shortened gestation length and influenced the exploratory behavior of the kids in the early life without impact on the behavior during the adulthood when exposed to heat stress.