Possible subclinical hepatopathy after copper supplementation in farmed red deer

Parenteral Cu Supplementation of Late-Gestating and Lactating Iberian Red Deer Hinds Fed a Balanced Diet Reduces Somatic Cell Count and Modifies Mineral Profile of Milk

Simple Summary

The benefits of Cu supplementation have been reported for male deer and cows. In deer, supplementation with this mineral is frequent in males even in animals receiving balanced diets. The benefits of Cu supplementation for antler cortical thickness in adult deer and for deer meat characteristics have also been demonstrated. Since Cu supplementation of cows has positive effects to achieve optimal offspring growth, it could be interesting to assess such effects for hinds since this mineral is transported across the placenta and has an important role in animal growth. Our results in lactating hinds showed that Cu supplementation decreased the number of somatic cells, improving the health quality of the milk and indicating a lower risk of mastitis. It also increased Ca and K content of milk, although not that of Cu. This is the first study demonstrating that Cu supplementation during late-gestation and lactation in hinds fed a balanced diet could be a good strategy to reduce somatic cell count (improving the health quality of milk) and modify the mineral profile of milk increasing its Ca content.

Abstract

This study describes the effects that Cu supplementation of late-gestating and lactating females (hinds) of Iberian red deer fed a balanced diet have on milk production, composition, and somatic cell count (SCC). Experimental hinds (n = 9) were subcutaneously injected every 42 days with Cu (0.83 mg Cu/kg body weight) from day 202 of gestation until the end of lactation (week 18). Control hinds (n = 8) were injected with a physiological saline solution with the same volume and at the same frequency as the experimental group. Copper supplementation decreased the SCC from 1.64 to 1.36 log 10/mL (p = 0.003) and modified the milk mineral profile. In particular, milk from hinds supplemented with Cu had more Ca (p = 0.02), Mg (p = 0.06), and K (p = 0.03) than milk from control hinds. However, Cu supplementation did not influence the Cu content of milk. Therefore, it can be concluded that Cu supplementation of hinds fed a balanced diet from late-gestation to the end of lactation could be a good strategy to reduce SCC and modify the mineral profile of milk increasing its Ca content.

Evolution of blood serum mineral composition during antler growth and rut as consequence of Cu supplementation in captive red deer and its effects in mature antler composition

In the present study we assessed the effects of Cu supplementation and antler growth stage on mineral composition of serum and hard antler in red deer fed a balanced diet. Correlations between minerals were analysed for serum, for antlers, and between serum versus mature antler. Blood samples were drawn at Days –36, 54, 132 and 197 of the start of antler growth (SAG). Hard antlers were cut at Day 165 from SAG. The Cu supplemented group (n = 9) was injected with 0.83 mg Cu/kg of bodyweight, whereas the control group (n = 9) was injected with a physiological saline solution, both every 42 days between Days –36 (Cu supplied after blood sampling) and 132 from SAG. Supplementation with Cu increased (P < 0.05) the contents of P and Cu in serum but did not affect the antler mineral profile. Serum contents of Mg, Na, S, B and Cu increased during the antler growth, whereas contents of K, Al and Fe decreased in the same period (P < 0.001). At Day 54 from SAG in Cu group, serum P content correlated negatively with antler Ca content whereas Zn of serum and antler correlated positively (P < 0.05). The maximum number of correlations between the mineral profile of serum and hard antler was achieved at Day 132 from SAG (3.3, 4.7 and 12.9% for Days –36, 54 and 132, respectively). In conclusion, the analysis of specific minerals in serum could be used to detect in advance some mineral deficiencies in the antler.

Nutrition of antler growth in deer

Stags are susceptible to the effects of nutrition at several stages during their lives and during the antler cycle. Nutrition during the in utero, post-natal (suckling) and yearling stages influences the size of spike antlers, and, generally, there is a close relationship between bodyweight and antler weight in stags aged up to 5 years. While antler size is not greatly affected by nutrition during the growth of immature (velvet) antler, it is influenced by body size and condition at casting, i.e. at the beginning of new antler growth. Antler growth appears to have a high priority for nutrients, especially energy, protein and calcium. Antler growth in adult stags is little affected by diet protein concentrations over 7%, but supplements of protected protein or methionine may improve antler growth. Substantial amounts of calcium and phosphorus are sequestered in antlers as they become mineralised, and calcium is withdrawn from the skeleton in support of this. Feeding programs to obtain good antler growth involve recognising the periods when juvenile stags are susceptible to under-nutrition, and providing sufficient nutrients to re-establish adequate body condition in adult stags between the end of the rut and antler casting.