A Circular Economy Approach to Integrate Divergent Ruminant Production Systems: Using Dairy Cow Feed Leftovers to Enhance the Out-of-Season Reproductive Performance in Goats

Based on a circular economy approach, we evaluated the possible effect of targeted supplementation with leftover feed from dairy cows (i.e., intensive system) on the reproductive performance of crossbred/rangeland goats (i.e., extensive system) in arid Northern Mexico. During the deep-anestrous season (i.e., March-April, 25° North), multiparous goats (n = 38) with a similar body weight (BW) and body condition score (BCS) were randomly assigned to two groups: (1) supplemented group (SG; n = 19; BCS: 1.76 ± 0.07; BW: 43.7 ± 1.8 kg), receiving 400 g goat d-1 of dairy-cow-feed leftovers prior to grazing; and (2) non-supplemented group (NS; n = 19; BCS: 1.76 ± 0.06; BW: 44.3 ± 2.5 kg). Both groups were directed to the rangeland for a period of ≈8 h. While the experimental period lasted 36 d, the experimental breeding considered 11 d (d0-d10). The anovulatory status of goats was ultrasonographically confirmed on days -20, -10, and -1 prior to male-female interaction. Previously, bucks were separated for 3 weeks from the experimental females and received exogenous testosterone every third day (i.e., 50 mg i.m.) prior to mating. With respect to the response variables, namely BW, BCS, blood glucose levels (BGLs), estrus induction (GIE, %), latency to estrus (LTE, h), estrus duration (ED, h), and luteal tissue volume (LTV, mm), no differences (p > 0.05) occurred between experimental groups. However, the response variables, namely goats ovulating (GO, %; 78.9 vs. 47.3), total number of corpuses luteum (TNCL, n; 27 vs. 13), ovulation rate (OR, n; 1.42 vs. 0.73), multiple ovulation (MO, %; 73.3 vs. 55.5), and pregnancy rate on d 36 (PRd36, %, 68.4 vs. 36.8), favored (p < 0.05) the SG over the NS goats. Our results demonstrate that connecting the circularity of two divergent ruminant production systems (i.e., cow-intensive and goat-extensive) by using dairy cows' feed leftovers as a targeted supplementation strategy in anestrous goats under a marginal-rangeland production system enhanced out-of-season reproductive outcomes (i.e., ovulation rate and pregnancy rate), thus benefiting marginal goat producers and their families.

Targeted Glutamate Supply Boosts Insulin Concentrations, Ovarian Activity, and Ovulation Rate in Yearling Goats during the Anestrous Season

The neuroendocrine regulation of the seasonal reproductive axis requires the integration of internal and external signals to ensure synchronized physiological and behavioral responses. Seasonal reproductive changes contribute to intermittent production, which poses challenges for optimizing goat product yields. Consequently, a significant objective in seasonal reproduction research is to attain continuous reproduction and enhance profitability in goat farming. Glutamate plays a crucial role as a modulator in several reproductive and metabolic processes. Hence, the aim of this study was to evaluate the potential impact of exogenous glutamate administration on serum insulin concentration and ovarian function during the out-of-season period in yearling goats. During the anestrous season, animals were randomly located in individual pens to form two experimental groups: (1) glutamate (n = 10, live weight (LW) = 29.1 ± 1.02 kg, body condition score (BCS) = 3.4 ± 0.2 units) and (2) control (n = 10; LW = 29.2 ± 1.07 kg, BCS = 3.5 ± 0.2), with no differences (p < 0.05) regarding LW and BCS. Then, goats were estrus-synchronized, and blood sampling was carried out for insulin quantification. Ovaries were ultrasonographically scanned to assess ovulation rate (OR), number of antral follicles (AFs), and total ovarian activity (TOA = OR + AF). The research outcomes support our working hypothesis. Certainly, our study confirms that those yearling goats treated with exogenous glutamate displayed the largest (p < 0.05) insulin concentrations across time as well as an augmented (p < 0.05) out-of-season ovarian activity.

PSX-7 Induction of sexual behavior of Dorper rams treated with GnRH in northern Mexico

We evaluated whether the GnRH application induces the sexual behavior of Dorper rams in northern Mexico (26º N). Rams (n = 12) were divided into 2 homogenous groups (n = 6 each) in body weight (80.0 ± 2.8 kg) and a body condition of (3.3 ± 0.2 units, scale of 1–5). One group (GnRH) received 100 Μ g of GnRH i.m., every 3 d x 1 week, while the other (CONT) received 0.5 ml of physiological saline solution every 3 d x 1 week. At the end of the treatments, rams were subjected to a sexual behavior test by exposing each male to one estrus female during both appetitive (ASB, anogenital sniffing, approaching, kicking, vocalizations) and consummatory (CSB: unsheathing, mount attempt, full mount, mount with unsheathing and mount with ejaculation) sexual behaviors where registered. The CSA and CSC behavior frequencies were compared by a χ 2 test (SYSTAT 12). Both ASB and CSB behaviors favored (P &lt; 0.05) to the GnRH rams; ASB 77% vs 23% and CSB 76% vs 23%. A demonstration of GnRH in Dorper rams in northern Mexico (26 ° N) induced sexual behavior; this should be of interest to enhance the out-of-season reproductive outcomes in the sheep industry.

PSX-20 Effect of nutritional supplementation upon colostrum quality in goats under rangeland conditions in Northern México

The aim of this study was to evaluate the effect of pre-partum nutritional supplementation upon colostrum quality in goats managed under extensive grazing conditions (November and December) in northern Mexico (26ºN). Multiparous-pregnant crossbred native goats (n = 43; 130 days of gestation) were randomly divided into 2 groups homogenized by body weight (BW, kg) and body condition score (BCS, units; scale:1 emaciated to 5: obese): GS (nutritionally supplemented group; n = 22 and GC (control group; n = 21). Nutritional Supplementation consisted of chicken manure (40%), wheat bran (27%), sorghum seed (27%), molasses (4%), and salt (2%); totaling 500 g; 18% CP, 2.7 Mcal/kg DM, offered from 22 d pre-partum to 7 d post-partum. Colostrum was collected during the first 24 h postpartum and preserved at 5 °C until analyzed. Response variables were BW, BCS, and fat and lactose percentages. While data were analyzed by ANOVA, mean differences were analyzed with a Student-t test (SYSTAT 10). Results are shown in table 1. To conclude, pre-partum nutritional supplementation only enhanced BCS at parturition and the lactose content, with no effect upon fat percentage in goats managed under semiarid-subtropical rangeland conditions in Northern Mexico (26 ° NL).

Collapse