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Physiological, lactational, and blood metabolite profile of dairy goats exposed to low ambient temperatures.

A. A. K. Salama




Physiological, lactational, and blood metabolite profile of dairy goats exposed to low ambient temperatures.
W. Coloma-Garcia1,2, N. Mehaba1, X. Such1, G. Caja1, A. A. K. Salama*1. 1Research Group in Ruminants (G2R), Universitat Autonoma de Barcelona Barcelona, Spain, 2Facultad de Medicina Veterinaria, Universidad Agraria del Ecuador Guayaquil, Ecuador.

Low winter temperatures in some regions combined with increasingly frequent extreme cold waves have a negative impact on animal performance, behavior, and welfare. The objective of this study was to evaluate the physiological, metabolic, and lactational responses of dairy goats to low ambient temperatures during 3 weeks. Eight Murciano-Granadina dairy goats in mid-lactation were divided into 2 balanced groups and randomly assigned to 2 treatments: thermoneutral (TN; 15 to 20�C) and low temperature (LT; −3 to 6�C). The experimental design was a crossover with 2 treatments in 2 periods (21 d each). Goats received a total mixed ration (70% forage and 30% concentrate) and water ad libitum and were machine-milked twice daily (8 and 17 h). Feed intake, water consumption, rectal temperature, and respiration rate were recorded daily. Milk samples for composition were collected weekly. Insulin, glucose, nonesterified fatty acids (NEFA), β-hydroxybutyrate (BHBA), cholesterol, and triglycerides were measured in blood. Body weight was recorded at the start and end of each period. Compared with TN goats, LT goats had similar feed intake and milk yield, but lower (P < 0.05) water consumption (−23%), respiratory rate (−6 breaths/min) and rectal temperature (−0.32�C). Furthermore, milk of LT goats had greater (P < 0.05) contents of fat (+12%), protein (+11%), and lactose (+4%). The LT goats lost −0.45 kg BW, whereas TN goats gained 2.2 kg (SE of the difference = 0.77; P < 0.05). Insulin and cholesterol blood levels were not affected by LT. However, values of blood glucose, NEFA, hematocrit and hemoglobin were increased (P < 0.05) by LT, whereas BHBA and triglycerides decreased (P < 0.05). In conclusion, Murciano-Granadina dairy goats during lactation were sensitive to cold temperatures. The LT goats maintained feed intake and milk production, but produced milk with greater fat and protein contents. The LT goats mobilized body fat reserves to cover the extra energy needed for heat production under cold conditions.

Keywords: cold temperature, milk production, metabolism.