Browse or browsing: Investigating goat preferences for feeding posture, feeding height and feed type.

Goats naturally browse different forages in various postures; this differs from typical farm practice, thus there are opportunities to improve goat welfare by understanding what and how they like to eat. We investigated if feeding preference was related to posture, feeder height relative to the ground, and type of feed. Sixteen adult, Saanen cross females participated in two experiments comparing a floor-level feeder (grazing posture; farm standard), with an elevated feeder (browsing posture; Exp1) and a platform-level feeder (raised, grazing posture; Exp2), when two forages (leaves, grass) were offered. Measurements included feed intake (g of DM/feeder), feeder switching frequency, first feeder visited, latency to visit first feeder and exploration and non-feeding activity time. Effects of posture (Exp1), height (Exp2) and feed type were analyzed. Type of feed affected preference for feeding posture and height. All goats consumed leaves over grass (Exp1: POP: 188 ± 6.52 g, GRA: 20.3 ± 7.19 g; Exp2: POP: 191 ± 6.15 g, GRA: 0.231 ± 6.91 g; P < 0.001), and the feeder containing leaves was often visited first (Exp 1: GRA/POP: 94% of visits, P < 0.001, POP/GRA: 53%, P = 0.724; Exp 2: GRA/POP: 91%, P < 0.001; POP/GRA: 69%, P = 0.041). When goats received only leaves, they consumed more from the floor-level (162 ± 22.2 g) vs. elevated level (102 ± 21.9 g) feeder (P = 0.039). When goats received only grass, there was no posture or height preference; however, they changed feeders more frequently (at least 4x (Exp1) and 2x (Exp2) more than other combinations; P > 0.01). Feed intake was negatively affected by exploring time (Exp1 only: r = -0.541; P < 0.001) and performing non-feeding activities (Exp1: r = -0.698; P < 0.001; Exp2: r = -0.673; P < 0.001). We did not identify a preference for elevated feeding posture; however, we suggest that our short test (compared to previous work) encouraged goats to make choices based on line-of-sight and also that the elevated feeder design (replicated from previous work) made leaf access harder. Nonetheless, we highlight that some goats actively used the elevated feeder; this coupled with the clear preference for leaves over grass, suggests that offering feed type and presentation diversity would allow individuals to express their natural feeding behavior more fully.

Effect of feeding level during the prepubertal phase on mammary gland development in female goat kids.

The experiment reported in this research communication aimed to determine the effects of post-weaning feeding level after early weaning on mammary parenchyma development in Alpine goats. Thirty Alpine female goat kids were weaned early (at around 9.8 kg and 32 d of age) and fed different levels of concentrate: Control (C, 730 g DM/d, n = 10), Low (L, 365 g DM/d, n = 10) or High (H, 1090 g DM/d, n = 10) until 235 d of age with ad libitum hay and water. Half of the goat kids were slaughtered before puberty (at around 208 d of age) and half at midgestation (at around 308 d of age and 70 d of gestation) for mammary parenchyma sampling. A histological analysis, Western blot and DNA quantification were performed. Blood samples were taken before puberty and at midgestation to determine plasma levels of IGF-I and prolactin. The mammary gland weights before puberty and at midgestation were positively and significantly associated with concentrate level. However, the organization of the mammary parenchyma and protein expression and quantity of DNA in the parenchyma were similar among the three groups. Before puberty, prolactin and IGF-I concentrations were significantly increased by the feeding level. In conclusion, feeding level after early weaning did not impact mammary parenchyma structure although it modified the weight of the mammary gland. The establishment of the mammary gland was not impacted by rearing management before puberty. Hence, increasing the feeding level during the rearing period could be an interesting way to increase the body development of goats without impairing mammary development whilst having a positive impact on reproductive parameters such as litter weight.

Early weaning and high feeding level in post-weaning period did not impact milk production in Alpine dairy goats.

The experiment reported in this Research Communication aimed to determine the combined effects of early weaning and post-weaning feeding level on growth, reproductive parameters and milk yield in Alpine goats. Sixty-four Alpine goat kids were weaned abruptly at either 12·2 (±1·40) kg (40 d of age, E) or 17·7 (±2·30) kg (60 d of age, No). After weaning, E and No goats were subjected to 2 feeding strategies (n = 16): ad libitum concentrate until 130 d of age and then 620 g DM/d/goat until 200 d of age (EC and NoC) or ad libitum concentrate until 200 d of age (EAL and NoAL). Goats were weighed twice a month until 200 d of age. Pregnancy rate and litter size were recorded. Daily milk yield was measured by milk meter during the first lactation. Up to 60 d of age, average daily gain (ADG) of E kids was significantly lower than No kids. From 60 to 130 d of age, ADG of the four treatments were not different. After 130 d of age, EC and NoC kids had lower ADG than EAL and NoAL kids. Pregnancy rates of EAL and NoAL goats were lower than those of EC and NoC. Milk yield was not modified by weaning weight or feeding management. Milk quality was not affected by any treatment. To conclude, the age at weaning as well as the feeding level after weaning did not negatively impact growth and milk yield. We hypothesise that the establishment of the lactation function is not impacted by rearing management. Hence, decreasing the age at weaning could be an interesting way to reduce the cost of the rearing period in goat kids.

Long-term consequences of feed restriction during late pregnancy in goats on feeding behavior and emotional reactivity of female offspring.

Feed restriction during pregnancy can have detrimental effects on offspring development both during the juvenile period and during adult life. Long-term effects of maternal feed restriction during the last third of pregnancy on growth, metabolism and behavior of female kids, with a focus on feeding behavior and emotional reactivity, were studied in goats. Female kids born to control (CONT, n=17) or born to feed restricted goats (REST, n=15) were artificially reared and monitored from birth to 24 months of age. Maternal feeding restriction globally reduced live weight (P<0.001) and body condition score (P=0.02) of REST compared to CONT offspring. Females from the REST group had a higher daily feed intake (P=0.05) and tended to eat more rapidly (P=0.09) than females from the CONT group at 12 months of age. One year later, REST goats still ate more than CONT goats (P=0.05). Glucose metabolism did not appear to be modified as no differences were observed in glucose or insulin responses to an intravenous glucose tolerance test. No differences in time budget were found at 12 months of age. However, the HPA axis response to an ACTH injection was greater in REST than in CONT goats: higher peak cortisol concentration (P=0.02) and a greater area under the curve were found (P=0.01) at 14 months of age. In conclusion, maternal feed restriction during late pregnancy modified both feeding behavior and the stress physiology of female offspring for up to 2 years of age. However, the changes observed were small.

Effect of a supplement rich in linolenic acid added to the diet of post partum dairy cows on ovarian follicle growth, and milk and plasma fatty acid compositions.

The objective of this study was to determine the effect of a linseed supplement on follicle growth, progesterone concentrations and milk and plasma fatty acids in dairy cows post partum. Sixteen Holstein cows were given a basal total mixed diet plus one of two supplements: control (C; extruded soybeans; n = 8) or linseed (L; extruded linseeds; n = 8). One month after calving oestrous cycles were synchronised (PRID). Follicle growth and milk progesterone concentrations were measured every 2 d over the induced oestrous cycle. Milk production characteristics were unaffected by treatment. The L cows lost significantly more BCS than the C cows (P < 0.01). Plasma insulin, glucose and urea were unaffected by the treatment. Plasma NEFA tended to be affected by the treatment (L > C, P = 0.08). The proportions of 18:3n-3 in milk and plasma were increased by L compared to C (P < 0.001 and P < 0.01, respectively). There was an effect of dietary supplement on the numbers of small follicles (L < C, P < 0.05). Milk progesterone was unaffected by treatment. In conclusion, the increased supply of 18:3n-3 to the cows had only a modest effect on follicle populations and corpus luteum activity was unchanged.