Positive correlation between the body weight of anestrous goats and their response to the male effect with sexually active bucks

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.

The use of photoperiod-treated bucks to induce a "male effect" does not compensate for the negative effects of nutritional restriction of the females in Mediterranean goats

This work examined the effect of acute nutritional restriction or supplementation one week before male introduction on the reproductive performances of the "male effect" when using photostimulated or control males in goats. On 22 March, 84 anoestrous does were placed with photostimulated bucks or with bucks which had received no treatments. One week before male introduction, the females were provided with different nutritional regimes: Supplemented, restricted or control females. The non-esterified fatty acids (NEFAs) and Insulin Growth Factor-1 (IGF-1) concentrations were measured in the same samples. Fecundity, fertility, prolificacy and productivity were also determined. No interaction between both sources of variation was observed in any of the reproductive variables studied. Treatment of the bucks increased the percentage of females expressing behavioural oestrous associated with ovulation (71% vs 90% for Natural and Photo groups, respectively, P < 0.05). The Supplemented females showed higher ovulation rate than Restricted females (1.77 ± 0.13 vs 1.05 ± 0.05, P < 0.001), fecundity (71% vs 43%, P < 0.05); fertility (76% vs 29%, P < 0.05) and productivity (1.00 ± 0.15 vs 0.29 ± 0.11 kids per female, P < 0.01). In the Supplemented females, the higher reproductive results could be due to the lower NEFAs and higher IGF-1 concentrations at ovulation and at the time of oestrus compared to the Restricted females. Thus, the present experiment results demonstrate that nutrition is an important factor in the response to the "male effect" at Mediterranean latitudes, and its negative effect cannot be counterbalanced by using photostimulated bucks.

Melatonin Treatment in Rams and Their Replacement with Novel Treated Rams Advance First Lambing and Increase Fertility in Sarda Ewe Lambs

Simple Summary

The goals of this study were to advance first mating in ewe lambs and to shorten the period ranging from weaning to first lambing. Sarda ewe lambs (n = 400) were separated into four groups of 100 and exposed for a 50-day breeding period to fertile, adult rams as follows: (1) RMR (Rams–Melatonin–Replacement) group: exposed to melatonin-treated rams which were replaced every 10 days; (2) RM (Rams–Melatonin) group: exposed to melatonin-treated rams which were not replaced; (3) RCR (Rams–Controls–Replacement) group: exposed to untreated rams which were replaced every 10 days; and (4) RC (Rams–Controls) group: exposed to untreated rams which were not replaced. In each group, lambing dates, fertility rate, litter size, and distance in days from ram introduction to lambing (DRIL) were recorded. The RMR group showed the highest fertility rate, whilst shorter DRIL and higher number of ewes that lambed in a shorter time frame were recorded both in RM and RMR groups, compared to controls. The findings highlighted that melatonin treatment in rams and their replacement allowed advancing first mating, increasing fertility rate, and improving lambing concentration.

Abstract

This study aims to find reliable strategies for advancing first mating and shortening the period from weaning to first lambing in ewe lambs. Sarda ewe lambs (n = 400) were selected from two farms and allocated into four separated groups of 100, all of which were exposed to fertile, adult rams over the course of a 50-day breeding period. The first treatment group (RMR) was exposed to four melatonin-treated rams which were replaced every ten days, whilst the second treatment group (RM) was exposed to four melatonin-treated rams which were not replaced. Alternatively, the first control group (RCR) was exposed to four untreated rams which were replaced every ten days, whilst the second control group (RC) was exposed to four untreated rams which were not replaced. In each group, lambing dates, fertility rate, litter size, and distance in days from ram introduction to lambing (DRIL) were recorded. The highest fertility rate was recorded in the RMR group (p ≤ 0.05). Shorter DRIL (p ≤ 0.01) and higher lambing concentrations were recorded in the RM and RMR groups as compared to the controls. The findings indicate that melatonin treatment of rams and their replacement at 10-day intervals results in earlier onset of first mating, increased fertility rate in ewe lambs, and a higher number of ewes that lambs in a shorter time frame.

Reproductive performance in goats and causes of perinatal mortality: a review

Goat meat production is an expanding industry in Australia. However, there is limited data quantifying the levels of reproductive performance, particularly under extensively grazed rangeland conditions, which would inform interventions to improve performance. This review aimed to quantify the levels of reproduction, time and causes of reproductive wastage in goats. It considers the levels of fertility, fecundity, embryonic loss, fetal loss and post-natal survival reported under Australian conditions, and comparisons are made with international reports. Key management factors that may contribute to reproductive performance include breed, seasonality, nutritional conditions, and weather conditions at kidding. While goats are potentially prolific breeders, in Australia, the variation in weaning rate (kids/doe joined) among properties is large (51–165%), although the causes of this variation are not well defined. Generally, conception and kidding rates are high, although fetal loss associated with undernutrition is more likely in goats than sheep. As with sheep, perinatal losses are generally the largest source of wastage, with an average 20% kid mortality, but this level is influenced by litter size and appears to be higher under extensive rangeland systems. The causes of perinatal kid loss under Australian conditions are similar to those in sheep, with starvation–mismothering–exposure and dystocia or stillbirth the key causes. Studies are needed to accurately quantify the level and causes of reproductive wastage in commercial herds, including a range of management situations, to enable effective interventions to be developed.

Body condition and stage of seasonal anestrus interact to determine the ovulatory response after male biostimulation in anovulatory Criollo × Nubian goats

The effect of goat nutritional condition on the response to biostimulation with sexually active males during different stages of anestrus was determined. Fifty-eight Criollo × Nubian females on high and low body mass index (BMI) diets were used. Each BMI group was divided into two for biostimulation with sexually active males during May (mid-anestrus) or July (transition period). Ovulatory responses to biostimulation were characterized from serum progesterone, as well as the delay for response (first and second ovulations followed by a normal length luteal phase, O-WNLP). The percentage of goats showing one O-WNLP was greater in the high BMI group than in the low BMI group and greater during the transition period than in the mid-anestrus. However, the interaction between factors revealed that the difference between BMI groups was only significant in the transition period and the difference between stages was only significant in goats with high BMI. Occurrence of a second O-WNLP tended to be greater in the high BMI group than in the low BMI group. Response delay was shorter in the transition period than in mid-anestrus. In conclusion, female nutritional status interacting with the stage of anestrus determined the ovulatory response to male biostimulation in crossbred Criollo goats.

Effects of different supplemental soya bean oil levels on the performance of prepubertal Saanen goats: Oestrogen and progesterone release

The aim of this study was to investigate the effects of different levels of soya bean oil in the total diet on the growth rate, metabolic changes, and oestrogen and progesterone release in Saanen goats. After dietary adaptation, 21 prepubertal goats (weight of 29.12 ± 0.91 kg, 230 days old) were randomly distributed among three diets of D2: inclusion of 2% soya bean oil in the total diet; D3: basal diet - inclusion of 3% soya bean oil in the total diet; and D4: inclusion of 4% soya bean oil in the total diet. The basal diet (D3) was formulated to promote a daily gain of 0.140 kg. The goats were weighed, and their blood samples were collected weekly. Glucose, cholesterol, triglycerides, total protein, urea, non-esterified fatty acids, beta-hydroxybutyrate, oestrogen and progesterone in the plasma were measured. Prepubertal goats that were fed D4 exhibited a significantly lower dry matter intake, urea and cholesterol levels compared with the goats that were fed D2 and D3. Indeed, goats that were fed D4 displayed a significantly lower final weight than goats that were fed D2 and D3. In contrast, the inclusion of soya bean oil in the diet increased the progesterone and oestrogen concentrations, and goats that were fed D4 released a significantly higher concentration of progesterone than those that were fed D2 and D3. Furthermore, the percentage of goats with a progesterone level greater than 1 ng/ml (functional Corpus luteum) was significantly higher among the goats that were fed D3 and D4 than among those that were fed D2. In this study, although the inclusion of 4% soya bean oil in the diet decreased dry matter intake and growth rate, it increased progesterone concentration and the percentage of goats with a functional Corpus luteum, suggesting that the inclusion of soya bean oil accelerated puberty in prepubertal goats.

The pattern of LH secretion and the ovarian response to the ‘ram effect’ in the anoestrous ewe is influenced by body condition but not by short-term nutritional supplementation

In sheep, the ‘ram effect’ induces out-of-season fertility and good nutrition increases prolificacy. This experiment determined if fatness or short-term nutritional supplementation modified the response to the ‘ram effect’. A group of 48 Île-de-France ewes were fed diets that produced groups with body-condition scores (BCS) of >3.0 and <2.0. Within each BCS group animals were supplemented daily with 500 g of lupins from Day –5 to Day 0 (ram introduction) resulting in four groups: low BCS, supplemented (n = 7) and non-supplemented (n = 8) and high BCS, supplemented (n = 12) and non-supplemented (n = 11). The blood concentrations of glucose and insulin and the LH response to gonadotrophin-releasing hormone (GnRH) were determined. After the ‘ram effect’ the pattern of LH pulsatility, the LH surge and ovarian responses were analysed. Low BCS ewes had lower glucose and insulin (P < 0.001) and supplementation increased both (P ≤ 0.001). The increase in LH induced by GnRH was reduced in low BCS ewes (P = 0.015) but it was not affected by supplementation. Similarly, LH pulsatility was reduced in low BCS ewes (P < 0.05). The LH surge and ovarian cyclicity were not affected but the follow-up cycle was delayed (P = 0.034) and progesterone was reduced (P = 0.029) in low BCS ewes. There was an effect of BCS on ovulation rate (P < 0.05). These results show that the BCS can modify the response to the ‘ram effect’ and that supplementation has little effect on this response.

Progesterona plasmática de ovelhas submetidas ao efeito-macho e mantidas sob diferentes condições nutricionais

Dosou-se a concentração plasmática de progesterona (P4) em ovelhas Santa Inês (SI), Suffolk (SU) e Romney Marsh (RM) em anestro sazonal e submetidas ao efeito-macho, as quais receberam ou não suplementação alimentar. Machos vasectomizados foram introduzidos no grupo de fêmeas após um período prévio de isolamento de 60 dias, e amostras de sangue foram colhidas antes e após a introdução dos machos. Houve efeito (P<0,01) de período, raça, interação período x raça e interação suplementação x período x raça sobre a concentração de P4. Nas ovelhas SI ocorreu aumento (P<0,01) da concentração de P4 após a introdução do macho, indicando que houve aumento na atividade cíclica reprodutiva desse grupo. A suplementação, neste caso, potencializou este aumento. Nas ovelhas SU e RM não ocorreram modificações na concentração de P4 (P>0,01) após a introdução dos machos, nem houve efeito de suplementação. O efeito-macho foi eficaz em induzir a atividade reprodutiva durante o anestro sazonal em ovelhas SI, mas não em ovelhas SU e RM, e a associação dessa prática com a suplementação alimentar é recomendada para ovelhas da raça nativa SI.

In vitro maturation and fertilization of prepubertal and pubertal black Bengal goat oocytes

Oocytes retrieval, in vitro maturation (IVM) and fertilization (IVF) efficiency are inevitable steps towards in vitro production of embryos. In the present study, these parameters were investigated in the ovaries of prepubertal (n = 31) and pubertal (n = 61) black Bengal goats obtained from a slaughterhouse. Nuclear maturation was evaluated upon aspiration and following IVM in TCM-199 (Earle's salt with L-glutamine and sodium bicarbonate) for 27 h at 39℃ under 5% CO₂ in humidified air. The oocytes retrieval and efficiency (mean ± SD) per prepubertal and pubertal goats were 5.2 ± 0.6 and 6.8 ± 0.6, and 77.3 ± 0.1% and 80.5 ± 0.6%, respectively. Anaphase I - telophase I stages differed significantly (7.3 ± 0.8 vs. 2.6 ± 0.2, p < 0.05) between the two groups of goats. After IVM, the percentages of metaphase II were significantly higher (66.3 vs. 60.3, p < 0.05) in pubertal goats than in their prepubertal counterparts. The percentages of normal in vitro fertilization (IVF) in Fert-Tyrode's albumin lactate pyruvate of pubertal goat oocytes did not differ between Percoll and swim-up sperm separation methods (36.7 ± 0.9% vs. 32.7 ± 1.3%, p > 0.05). Furthermore, sperm capacitation by heparin alone or in combination with ionomycin did not lead to a significant increase in the normal fertilization rate (34.8 ± 1.7 vs. 32.2 ± 1.5%, respectively) in the oocytes of pubertal goats. In conclusion, the ovaries of pubertal black Bengal goats obtained from the slaughterhouse could be used for in vitro embryo production. However, further optimization of the IVM and IVF techniques are necessary for satisfactory in vitro embryo production.

The effect of flushing and stimulus of estrogenized does on reproductive performance of anovulatory-range goats

This study was conducted to determine whether flushing or the stimulus of estrogenized goats is necessary to achieve a high reproductive response in anestrous goats on rangeland. Does were feed-supplemented on rangeland (flushed, n = 20). Other group was exposed to estrogenized does during the mating period (stimulated, n = 20). A third group was both supplemented and stimulated (stimulated-flushed, n = 20) and other group grazed on rangeland only (control, n = 18). More goats in the stimulated and stimulated-flushed groups showed estrus during the first 5 days of joining (45% and 60%, respectively) than the control and flushed groups (11% and 5%, respectively; P < 0.05). Flushing did not improve prolificacy and reduced (P < 0.05) kidding rates (40% and 35% for the flushed and stimulated-flushed groups, respectively) compared to 67% and 55% for the control and stimulated groups, respectively. This experiment demonstrates potential shortcomings of use of flushing in range goats with inadequate nutrition during gestation.

Observations on hand-mating behaviors, several physiological and hematological parameters in Turkish dairy goats

The aims of this study were to examine hand-mating behavior of doe and buck and relationships of courtship behavior and physiological and hematological traits according to gestation results. Duration from beginning of observation until mating (M-C), duration between two copulations (C-C) and courtship behavioral index value of each sex (CBIVD; courtship behavioral index value of doe, CBIVB; courtship behavioral index value of buck) and mounting behavior of buck, were observed. Experience of doe was affected of CBIVD and CBIVB (P=0.01 and P=0.01, respectively). Bucks mounted significantly higher times on experienced does than on inexperienced ones (P=0.00). On the other hand service number decreased with an increase in M-C (P=0.00). Elevated service number was observed with increased mounting frequency of buck (P=0.03). There were strong correlations between CBIVD and CBIVB (r=0.48, P=0.00). Pregnancy was not influenced by vaginal pH value. Does, which gave multiple births, had higher vaginal pH (P=0.05). Rectal temperature difference of doe had no influence on success of mating and birth type. On the other hand, birth type was affected by rectal temperature difference of buck. There was no significant difference of hematological parameters according to mating results. Hemoglobin, red blood cell count and mean corpuscular hemoglobin concentration values were higher in single births and mean cell volume value was lower in single births.

Effect of body condition score of does and use of bucks subjected to added artificial light on estrus response of Alpine goats

The effects of body condition score of does and exposure to sexually active bucks after exposure to long-day artificial photoperiod were examined in mature anovulatory French Alpine goat in Northern Mexico. In June, goats in good (2.3 +/- 0.2, scale 1 to 4; n = 10) or poor (1.6 +/- 0.3; n = 10) body condition were exposed during 15 day to sexually active bucks, which had been exposed to long photoperiod (16:8-h light-dark cycle, starting in December). A third group of goats in good body condition was exposed to bucks kept under the natural photoperiod of this region (26 degrees N). All goats in good body condition exposed to bucks treated with prolonged photoperiod exhibited estrus behavior, whereas only 50% of the does in poor body condition showed estrous behavior during the 15-day buck exposure. None of the does in good body condition showed estrus when exposed to bucks under natural photoperiod. These results revealed that a good body condition is required for maximum estrus response in anestrous Alpine goats and that exposure of bucks to long photoperiod in winter is essential for an adequate stimulus to reestablish estrus cycles in anovulatory Alpine does in Northern Mexico.