How to Create Conditioned Taste Aversion for Grazing Ground Covers in Woody Crops with Small Ruminants

Conditioned taste aversion (CTA) is a learning behavior process where animals are trained to reject certain feed after gastrointestinal discomfort has been produced. Lithium chloride (LiCl) is the preferred agent used in livestock to induce CTA because it specifically stimulates the vomit center. In addition, LiCl is commercially available, and easy to prepare and administer using a drenching gun. Nevertheless, some factors have to be considered to obtain an effective long-lasting CTA, which allows small ruminants to graze during the cropping season. A key aspect is to use animals with no previous contact with the target plant (the plant chosen to be avoided; new feed). Due to their native neophobic feeding behavior, small ruminants can easily associate the negative feedback effects with the new feed, resulting in a strong and persistent CTA. The recommended doses are 200 and 225 mg LiCl/kg body weight (BW) for goats and sheep, respectively. To induce CTA, 100 g of the target plant should be individually offered for at least 30 min, and LiCl administered thereafter if the intake is greater than 10 g. Each time the animal eats the target plant without negative consequences, the CTA becomes weaker. Consequently, to minimize the risk of target plant consumption, it is essential to have sufficient palatable ground cover available. The presence of an alternative feed (of quality and quantity) prevents the accidental consumption of the target plant. A close monitoring of the flock is recommended to remove and re-dose any animal consuming more than 4 bites or 10 g of the target plant. At the beginning of each grazing season, check the CTA status of each animal before moving them to the crop

El aumento de la prolificidad en el ganado ovino: Efectos económicos en las explotaciones y fisiológico-nutritivos en corderas de raza Ripollesa

El presente trabajo presenta un estudio realizado en la Comunidad Autónoma de Cataluña (España) sobre las consecuencias económicas del aumento de la prolificidad en las explotaciones de una raza autóctona de aptitud cárnica (Ripollesa) y sus efectos sobre el perfil metabólico de las corderas de reposición. Se realizaron encuestas a 10 explotaciones representativas en dos provincias de dicha comunidad: Girona y Barcelona. Los datos obtenidos corresponden a una media del año 2010 y se analizaron y compararon estadísticamente mediante un análisis de varianza. Los resultados obtenidos muestran que las explotaciones ovinas estudiadas son de tipo familiar, con un tamaño medio de los rebaños de 554 ovejas y 20 machos, presentando una media de 353,5 ovejas manejadas por unidad de trabajo y año (UTA). En estas explotaciones, la prolificidad fue de 1,28 corderos/parto y la productividad 1,18 corderos vendidos/oveja y año. El margen neto medio obtenido fue de 10,7 €/oveja y año. Los ingresos totales medios fueron 146,8 €/oveja y año, en su mayor parte procedentes de la venta de los corderos (61,8%), le sigue las subvenciones (36,2%) y el resto de la venta del desvieje de ovejas y de la lana. Los costes totales medios fueron de 136,1 €/oveja y año. Los costes de alimentación fueron los de mayor importancia (43,2%) en los costes totales, seguidos de los costes de mano de obra (40,9%) y de las amortizaciones (6,1%). Las explotaciones con una prolificidad superior a la media (1,28 corderos/parto), fueron capaces de compensar el incremento actual de los costes, ganando más de 25,8 €/oveja y año. En el mismo sentido, un incremento de la prolificidad de 0,1 corderos/parto, se tradujo en una ganancia de 6,9 €. Se detectó una correlación elevada entre la productividad y el margen neto (R² = 0,5), aumentando en 4,3 €/oveja y año para cada 0,1 corderos producidos. Finalmente, el tamaño del rebaño resultó crítico en estas explotaciones, concluyéndose que es recomendable tener rebaños de más de 400 ovejas por explotación y una media de 300 ovejas manejadas por UTA

Pasturatge en oliverars: aplicació de l'aversió condicionada a l'olivera en cabres

Cada dia l'agricultura incorpora noves pràctiques més respectuoses amb el medi ambient intentant aprofitar millor els recursos naturals i preservar-los de cara al futur. En el cas de l'oliverar, l'erosió que pateix el sòl, a causa de les pràctiques tradicionals de conreu, ha propiciat la implantació de cobertes vegetals que es controlen mitjançant l'ús de maquinària, o bé amb herbicides. L'inconvenient que comporten aquestes pràctiques i la inquietud per pràctiques més sostenibles han afavorit l'estudi de l'ús de bestiar per pasturar els camps d'oliveres. L'inconvenient és que les fulles de les oliveres són un aliment molt atractiu per a cabres i ovelles i poden malmetre l'arbre. Amb la finalitat que les cabres rebutgin menjar fulles d'olivera, es planteja la possibilitat de modificar el seu comportament alimentari, utilitzant diferents dosis de clorur de liti (LiCl), 175 mg LiCl/kg PV i 200 mg LiCl/kg PV. Els resultats obtinguts en cabres murcianogranadines mostren la possibilitat de generar aversió a les fulles d'olivera, que es va mantenir durant catorze mesos. L'aversió va ser més efectiva en el cas de les cabres que van rebre la dosi de 200 mg LiCl/kg PV.Each day brings new and more environmentally friendly practices to farming, trying to make better use of natural resources and to preserve them for the future. In the case of olive groves, the soil erosion to which this crop is exposed because of traditional farming systems is offset by the introduction of groundcover which is controlled by the use of machinery or herbicides. The drawback involved by these practices and concerns about more sustainable systems has encouraged the study of the use of grazing animals in olive groves. However, olive leaves are very attractive to goats and sheep, which could damage the trees. In order to make goats reject olive leaves, the aim of this study was to modify their feeding behaviour using lithium chloride (LiCl) in various doses (175 mg LiCl/kg BW and 200 mg LiCl/kg BW). The results obtained with Murciano-Granadina goats show that it is possible to generate a conditioned taste aversion to olive leaves, which was maintained for 14 months. Aversion was more effective in goats which received the 200 mg LiCl/kg BW dose.Cada día la agricultura incorpora nuevas prácticas más respetuosas con el medio ambiente intentando aprovechar mejor los recursos naturales y preservarlos de cara al futuro. En el caso del olivar, la erosión que sufre el terreno, debido a las prácticas tradicionales de cultivo, ha propiciado la implantación de cubiertas vegetales que se controlan mediante el uso de maquinaria, o bien con herbicidas. El inconveniente que conllevan estas prácticas y la inquietud por prácticas más sostenibles han favorecido el estudio del uso de animales para el pastoreo en los campos de olivos. El inconveniente es que las hojas de los olivos son un alimento muy atractivo para las cabras y ovejas y pueden dañar el árbol. Con la finalidad de que las cabras rechacen consumir hojas de olivo, se plantea la posibilidad de modificar su comportamiento alimentario, utilizando diferentes dosis de cloruro de litio (LiCl), 175 mg LiCl/kg PV y 200 mg LiCl/kg PV. Los resultados obtenidos en cabras murciano-granadinas muestran la posibilidad de generar aversión a las hojas de olivo, que se mantuvo durante catorce meses. La aversión fue más efectiva en el caso de las cabras que recibieron la dosis de 200 mg LiCl/kg PV

Responses to melatonin of 2 breeds of dairy ewes in early lactation under autumn photoperiod conditions

A total of 72 dairy ewes of 2 breeds (MN, Manchega, 72.4 ± 1.9 kg of body weight, n = 36; LC, Lacaune, 77.7 ± 2.3 kg of body weight; n = 36) were used to evaluate the lactational effects of melatonin implants in early lactation and under the short-day photoperiod conditions of autumn (experiment was centered on the winter solstice). Ewes lambed in autumn and were penned indoors in 12 balanced groups of 6 ewes by breed, body weight, age, and number of lambs, and randomly assigned to a 2 × 2 × 3 factorial design (treatment × breed × replicate). Ewes suckled their lambs for 28 d. Treatments were (1) melatonin (MEL), which received 1 subcutaneous implant of melatonin (18 mg/ewe) in the ear base at 35 ± 1 d (1 wk after lamb weaning), and (2) control, which did not receive any treatment. Ewes were fed ad libitum a total mixed ration (forage:concentrate, 60:40) and machine milked twice daily. Daily milk yield was automatically recorded from d 29 to 105 of lactation and sampled every 2 wk for composition. Jugular blood was sampled for plasma hormone analyses at 30, 50, 80, 110, and 124 d of lactation. Body reserves were assessed every 2 wk. Feed intake was measured by pen during 3 separated periods after the start of the treatments (wk 2 to 3, wk 6 to 7, and wk 10 to 11). Feed intake, and milk yield and composition varied by breed, but no MEL effects were detected on dry matter intake, milk yield, milk composition, or fat and protein standardized milk in either breed. As a result of the unique composition of the implants and the variable body weights of the ewes, the MEL treatment dose (on average, 0.24 mg/kg of body weight) was 6.8% greater in the MN (lighter) than in the LC (heavier) ewes. Plasmatic melatonin markedly increased in the MEL-treated ewes (on average, 111%), but despite the amount of MEL used, the MN responded greatly compared with the LC ewes (150 vs. 63%, respectively). No differences in basal plasmatic melatonin were detected between breeds (6.4 ± 1.1 pg/mL, on average), indicating the greater responsiveness to the implants of the lighter MN ewes. Plasmatic prolactin tended to decrease in the MEL-treated ewes (−35%, on average), but the effect was significant only in the MN ewes (−54%), in agreement with their greater response to MEL. No effects of MEL treatment were detected on plasmatic IGF-I in either breed. Moreover, body reserves did not vary by effect of MEL treatment or breed throughout the experiment. In conclusion, the use of exogenous melatonin as MEL implants, together with the endogenous melatonin naturally produced under short-day photoperiod conditions, had no effects on the early-lactation performances of dairy sheep, despite their breed and level of production

Effect of Soybean Oil Supplementation on Milk Production, Digestibility, and Metabolism in Dairy Goats under Thermoneutral and Heat Stress Conditions

In a previous work, we observed that heat-stressed goats suffer reductions in milk yield and its contents of fat and protein. Supplementation with soybean oil (SBO) may be a useful strategy to enhance milk quality. In total, eight multiparous Murciano-Granadina dairy goats (42.8 ± 1.3 kg body weight; 99 ± 1 days of lactation) were used in a replicated 4 × 4 Latin square design with four periods; 21 d each (14 d adaptation, 5 d for measurements and 2 d transition between periods). Goats were allocated to one of four treatments in a 2 × 2 factorial arrangement. Factors were no oil (CON) or 4% of soybean oil (SBO), and controlled thermal neutral (TN; 15 to 20 °C) or heat stress (HS; 12 h/d at 37 °C and 12 h/d at 30 °C) conditions. This resulted in four treatment combinations: TN-CON, TN-SBO, HS-CON, and HS-SBO. Compared to TN, HS goats experienced lower (p < 0.05) feed intake, body weight, N retention, milk yield, and milk protein and lactose contents. However, goats in HS conditions had greater (p < 0.05) digestibility coefficients (+5.1, +5.2, +4.6, +7.0, and +8.9 points for dry matter, organic matter, crude protein, neutral detergent fiber, and acid detergent fiber, respectively) than TN goats. The response to SBO had the same magnitude in TN and HS conditions. Supplementation with SBO had no effects on feed intake, milk yield, or milk protein content. However, SBO supplementation increased (p < 0.05) blood non-esterified fatty acids by 50%, milk fat by 29%, and conjugated linoleic acid by 360%. In conclusion, feeding 4% SBO to dairy goats was a useful strategy to increase milk fat and conjugated linoleic acid without any negative effects on intake, milk yield, or milk protein content. These beneficial effects were obtained regardless goats were in TN or HS conditions

Milk Production and Energetic Metabolism of Heat-Stressed Dairy Goats Supplemented with Propylene Glycol

Heat-stressed dairy animals increase their reliance on glucose. This elevated glucose demand is partially met by increasing the conversion of glucogenic amino acids (AA) in the liver. Propylene glycol (PG) is a glucogenic precursor and was not tested in dairy goats under thermoneutral (TN) and heat stress (HS) conditions simultaneously. We hypothesize that if HS-goats are fed with PG, they would get more glucose and consequently spare more glucogenic AA for milk protein synthesis rather than gluconeogenesis. Eight multiparous dairy goats (40.8 ± 1.1 kg body weight; 84 ± 1 days in milk) were used in a replicated 4 × 4 Latin square design of 4 periods; 21 d each (14 d adaptation, 5 d for measurements, and 2 d of transition). Goats were allocated to one of 4 treatments in a 2 × 2 factorial arrangement. Factors were control (CO) without PG or 5% of PG, and thermoneutral (TN; 15 to 20 °C) or heat stress (HS; 12 h/d at 37 °C and 12 h/d at 30 °C) conditions. Feed intake, rectal temperature, respiratory rate, milk yield, milk composition, and blood metabolites were measured. Compared to TN, HS goats had lower (p < 0.01) feed intake (-34%), fat-corrected milk (-15%), and milk fat (-15%). Heat-stressed goats also tended (p < 0.10) to produce milk with lower protein (-11%) and lactose (-4%) contents. Propylene glycol increased blood glucose (+7%; p < 0.05), blood insulin (+37%; p < 0.10), and body weight gain (+68%; p < 0.05), but decreased feed intake (-9%; p < 0.10) and milk fat content (-23%; p < 0.01). Furthermore, blood non-esterified fatty acids (-49%) and β-hydroxybutyrate (-32%) decreased (p < 0.05) by PG. In conclusion, supplementation of heat-stressed dairy goats with propylene glycol caused milk fat depression syndrome, but reduced body weight loss that is typically observed under HS conditions. Supplementation with lower doses of PG would avoid the reduced feed intake and milk fat depression, but this should be tested

Effects of Cold Exposure on Some Physiological, Productive, and Metabolic Variables in Lactating Dairy Goats

Low winter temperatures in some regions have a negative impact on animal performance, behavior, and welfare. The objective of this study was to evaluate some physiological, metabolic, and lactational responses of dairy goats exposed to cold temperatures for 3 weeks. Eight Murciano-Granadina dairy goats (41.8 kg body weight, 70 days in milk, and 2.13 kg/day milk) were used from mid-January to mid-March. Goats were divided into 2 balanced groups and used in a crossover design with 2 treatments in 2 periods (21 days each, 14 days adaptation and 7 days for measurements). After the first period, goats were switched to the opposite treatment. The treatments included 2 different controlled climatic conditions with different temperature-humidity index (THI) values. The treatments were: thermoneutral conditions (TN; 15 to 20 °C, 45% humidity, THI = 58 to 65), and cold temperature (CT; −3 to 6 °C, 63% humidity, THI = 33 to 46). Goats were fed ad libitum a total mixed ration (70% forage and 30% concentrate) and water was freely available. Goats were milked at 0800 and 1700 h. Dry matter intake, water consumption, rectal temperature, and respiratory rate were recorded daily (days 15 to 21). Body weight was recorded at the start and end of each period. Milk samples for composition were collected on 2 consecutive days (days 20 and 21). Insulin, glucose, non-esterified fatty acids (NEFA), ß-hydroxybutyrate (BHB), cholesterol, and triglycerides were measured in blood on d 21. Compared to TN goats, CT goats had similar feed intake, but lower water consumption (−22 ± 3%), respiratory rate (−5 ± 0.8 breaths/min), and rectal temperature (−0.71 ± 0.26 °C). Milk yield decreased by 13 ± 3% in CT goats, but their milk contained more fat (+13 ± 4%) and protein (+14 ± 5%), and consequently the energy-corrected milk did not vary between TN and CT goats. The CT goats lost 0.64 kg of body weight, whereas TN goats gained 2.54 kg in 21 days. Blood insulin and cholesterol levels were not affected by CT. However, values of blood glucose, NEFA, hematocrit, and hemoglobin increased or tended to increase by CT, whereas BHB and triglycerides decreased. Overall, CT goats produced less but concentrated milk compared to TN goats. Despite similar feed intake and blood insulin levels CT goats had increased blood glucose and NEFA levels. The tendency of increased blood NEFA indicates that CT goats mobilized body fat reserves to cover the extra energy needed for heat production under cold conditions

Metabolic and behavior responses of lactating goats under heat stress

Altres ajuts: acords transformatius de la UABHeat stress (HS) negatively affects animal performance, but little is known about energetic metabolism and behavior changes in dairy goats under HS conditions. Eight multiparous Murciano-Granadina dairy goats (43.3 ± 1.6 kg BW; 2 ± 0.04 L milk/d; 81 ± 3 days of lactation) were kept in metabolism cages and randomly assigned to two treatments varying in the temperature humidity index (THI). The design was crossover (two 28-d periods) and treatments were: 1) thermal neutral (TN; 15-20C, 40-45% humidity, THI = 59-65), and 2) heat stress (HS 12 h/d at 37◦C and 40%, and 12 h/d at 30◦C and 40%, THI = 86 and 77, respectively). Jugular silicon catheters were fitted, and glucose tolerance test (0.25 g/kg BW), insulin tolerance test (4.6 μg/kg BW) and epinephrine challenge (2 μg/kg BW) were conducted. Before and after each metabolite administration, blood samples were collected for the analysis of insulin, glucose, and nonesterified fatty acids (NEFA). Also, behavior variables (position changes, duration of remaining standing, as well as eating and drinking bouts and duration) were observed at day 3 of each period by video cameras. Heat stress reduced (P < 0.01) feed intake (< 29%), milk yield (< 10%), milk fat (-12%), milk protein (-14%), and milk casein (-13%). Goats in both groups had similar blood NEFA after insulin administration, but NEFA values were greater (P < 0.05) in TN than HS goats after epinephrine infusion. The HS goats secreted lower (P < 0.05) amounts of insulin than TN goats in response to the glucose tolerance test. Additionally, TN and HS goats had similar number of eating bouts, but the duration of each bout was shorter in HS than in TN. Also, HS had greater number of drinking bouts with no differences in drinking bout durations between groups. In conclusion, body lipid tissue of HS goats became more resistant to lipolysis, making them unable to mobilize body fat reserves despite the negative energy balance. In addition, the reduction in feed intake by HS was because of the shorter time of eating bouts, whereas the greater water consumption was related to the increase in drinking bouts

Lactational responses of heat-stressed dairy goats to dietary L-carnitine supplementation

Heat stress causes significant losses in milk production, and nutritional strategies are needed to alleviate its effects. Endogenous carnitine synthesis is also reduced by heat stress (HS). Carnitine plays a central role in fatty acid oxidation and buffers the toxic effects of acyl groups. We hypothesized that carnitine supplementation would make up for any carnitine deficiencies during HS and improve lipid metabolism. The objective was to evaluate rumen-protected L-carnitine (CAR) supplementation in dairy goats under thermo-neutral (TN) or HS conditions. Four Murciano-Granadina dairy goats were used in a four × four Latin square design. Goats were allocated to one of four treatments in a two × two factorial arrangement. Factors were 1) diet: control (CON) or supplementation with CAR (1 g/d); and 2) ambient conditions: TN (15 to 20 °C) or HS (0900 to 2100 h at 35 °C, 2100 to 0900 h at 28 °C). Blood free-, acetyl-, and total-carnitine concentrations increased almost three times by supplementation. Despite this efficient absorption, CAR had no effect on feed intake, milk production or blood metabolites in TN or HS conditions. Heat stress increased rectal temperature and respiratory rate. Additionally, HS goats experienced 26% loss in feed intake, but they tended to eat longer particle sizes. Compared to TN, heat-stressed goats lost more subcutaneous fat (difference in fat thickness measured before and after each period = −0.72 vs. +0.64 mm). In conclusion, supplemented L-carnitine was efficiently absorbed, but it had no lactational effects on performance of goats under thermo-neutral or heat stress conditions