The Onset of Maternal Behavior in Sheep and Goats: Endocrine, Sensory, Neural, and Experiential Mechanisms

In sheep and goats, the onset of maternal behavior at parturition is characterized by a first phase called maternal responsiveness during which the mother is attracted to any newborn. In a second phase, called maternal selectivity, the mother establishes a selective bond with her young so that she only accepts it at suckling. After a description of the behavioral expression of both phases, this chapter reviews the physiological, sensory, and neural mechanisms involved. These two behavioral processes are synchronized with parturition by the vaginocervical stimulation induced by the expulsion of the newborn. Olfactory cues provided by the neonate are involved in maternal responsiveness and selectivity. Oxytocin supported by estrogens is the key factor for maternal responsiveness. The neural network involved in maternal responsiveness is mainly hypothalamic and is different from the circuitry involved in selectivity, which mainly concerns olfactory processing regions. Visual and auditory cues are necessary for offspring recognition at a distance. This multisensory recognition suggests that mothers form a mental image of their young. Maternal experience renders mothers more responsive to maternally relevant physiology and to young-related sensory inputs.

The Opuntia Effect Improves Dam-Kid Metabolic Markers, Augments Colostrum Quality and Enhances Kid-To-Dam Behavioral Interactions in Crossbred Goats and their Offspring under Semiarid-Rangeland Conditions

The possible effect of protein-enriched Opuntia cladode supplementation during the pre- and post-partum stages (-25 days to +15 days; day 0 = kidding) upon dam-kid metabolic status, colostrum-milk quality, and some behavioral kid-to-dam interaction in goats managed under rangeland extensive conditions was evaluated. Multiparous crossbred goats (n = 30), homogeneous regarding live weight (LW; 55.9 ± 1.03 kg) and body condition score (BCS; 2.5 ± 0.2 units), were randomly assigned to (1) protein-enriched Opuntia (PEO; n = 10; 29.8% crude protein (CP), 2.2 Mcal ME kg-1), (2) non-enriched Opuntia (NEO; n = 10; 6.4% CP, 2.1 Mcal ME kg-1), and (3) control (CON; n = 10, non-supplemented). The PEO and NEO goats were individually supplemented with Opuntia cladodes (250 g day-1; 09:00-10:00 a.m.; 25 days pre- and 15 days post-partum); then, all groups grazed in a marginal rangeland (10:00 a.m. to 06:00 p.m.). LW, BCS, and blood samples to quantify serum glucose (GLU) levels were collected weekly from day -25 up to day +15 in both dams (pre- and post-partum) and kids (post-partum). At 4h and 8h post-partum, kid-to-dam behavioral tests were performed; approaches (APRO, units), animal-to-animal contact (ACONT, s), latency-to-contact (LCONT, s), and high (HPB) and low (LPB) bleats were registered. The response variables LW (58.2 ± 3.5 kg), GLU from does (66.4 ± 3.3 mg/dL), colostrum fat (12.3 ± 1.15%), non-fatty solids (20.9 ± 2.1%), density (64.4 ± 7.0%), and protein (8.1 ± 0.8%), as well as milk density (31.2 ± 1.7%) and protein (3.9 ± 0.3%), favored the PEO group. Moreover, the dam-to-kid 4 h LPB (34.5 ± 4.6 frequency), as well as kid-to-dam 8 h LCONT-own (100 ± 35.5 s) and LPB (25.2 ± 6.9 frequency) also favored the PEO group. To conclude, peripartum supplementation with protein-enriched Opuntia cladodes emerged as a key alternative to enhance the dam-kid metabolic status, to improve colostrum quality and some milk components (density and protein), as well as to expand the kid-to-dam bond in goat production systems under marginal extensive conditions.

Short communication: reproductive response to concentrate supplementation of mixed-breed goats on rangeland

The effect of concentrate supplementation to crossbred goats on rangeland during the dry period on their reproductive performance was investigated. Goats were assigned into two groups: a concentrate supplemented (S; n = 91) group and an unsupplemented (UNS; n = 118) group. S goats received 350 g/day of concentrate per head, 30 days prior to breeding (flushing in winter) and 30 days during the last trimester of pregnancy. UNS goats presented a lower (P < 0.01) liveweight at the onset of the breeding period than did the S group (38.2 ± 3.7 vs. 44.4 ± 3.6 kg). Average daily gains during pregnancy were higher (P < 0.01) in the S group than UNS goats (15.5 ± 1.2 vs. - 0.5 ± 5.1 g/d). S goats had a higher (P < 0.01) kidding rate (87.1%) than the UNS goats (54.7%). Litter size for UNS and S goats was 1.39 and 2.00, respectively (P < 0.01). Serum triiodothyronine, tetraiodothyronine, and cortisol concentration at the end of the flushing period were not affected by concentrate supplementation. Serum glucose (88.7 ± 3.8 vs. 95.7 ± 5.3 mg/dL), total protein (6.9 ± 1.1 vs. 8.2 ± 1.2 mg/dL), and blood urea nitrogen (17.1 vs. 21.0 ± 4.3 mg/dL) concentrations were lower for UNS goats as compared with S goats. In conclusion, concentrate supplementation in crossbred goats on rangeland markedly improved body mass changes during gestation and the reproductive performance, which implies that malnutrition is a major barrier affecting fertility of goats and liveweight of kids in this rangeland.